subject:(non heme iron dependent enzyme)

Penn State University

1. Wang, Chen. Mechanistic Studies On Three Organophosphonate-processing Enzymes, Hppe, Hepd And Mpns.

Degree: 2014, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/23396

► Naturally occurring phosphonates and phosphinates have bioactivities (e.g., herbicidal, antibiotic) that are useful in agriculture and medicine. Phosphonate and phosphinate compounds can potently inhibit enzymes… (more)

▼ Naturally occurring phosphonates and phosphinates have bioactivities (e.g., herbicidal, antibiotic) that are useful in agriculture and medicine. Phosphonate and phosphinate compounds can potently inhibit enzymes in various metabolic pathways by functioning as stable mimics of phosphate esters and carboxylic acids. Biosynthetic pathways to phosphonate and phosphinate compounds have proven to be treasure troves for the discovery of unusual enzymatic reactions. The investigation of these conserved pathways has revealed three unprecedented biochemical steps catalyzed by the non-heme-iron(II) enzymes, HppE [(S)-2-hydroxypropyl-1-phosphonate epoxidase], HEPD (2-hydroxyethylphosphonate dioxygenase) and MPnS (methylphosphonate synthase). The work described herein focused on understanding both the mechanisms of the individual reactions and the structural/functional features of each enzyme important in specifying its reaction and pathway. The iron-dependent epoxidase, HppE, converts (S)-2-hydroxypropyl-1-phosphonate (S-HPP) to the antibiotic, fosfomycin [(1R, 2S)-epoxypropylphosphonate], in an unusual 1,3-dehydrogenation of a secondary alcohol to an epoxide. HppE had been classified as an oxidase, with proposed mechanisms differing primarily in the identity of the O2-derived iron complex that abstracts hydrogen (H•) from C1 of S-HPP to initiate epoxide ring closure. In my work, we showed that the preferred co-substrate is actually H2O2 and that HppE therefore almost certainly employs an iron(IV)-oxo complex as the H• abstractor. Reaction with H2O2 is accelerated by bound substrate and produces fosfomycin catalytically with a stoichiometry of unity. The ability of catalase to suppress the HppE activity previously attributed to its direct utilization of O2 showed that reduction of O2 and utilization of the resultant H2O2 were actually operant. The mechanism of the conversion of 2-hydroxyethylphosphonate to hydroxymethylphosphonate (2-HEP) catalyzed by iron-dependent enzyme, HEPD during the biosynthesis of the commercial herbicide, phosphinothricin, had been enigmatic. By using rapid-kinetic and spectroscopic methods, we detected an iron(IV)-oxo (ferryl) intermediate in the HEPD reaction. Kinetic analysis suggested that the intermediate is kinetically competent to be on the productive pathway. The accumulation of this intermediate only with substrate having deuterium in the abstracted pro-S position of C2 of 2-HEP implied that the ferryl intermediate abstracts this hydrogen, but the increased accumulation of the ferryl complex in 2H2O solvent implied that the hydrogen becomes solvent-exchangeable before the ferryl abstracts it. To account for these unanticipated results, a mechanism involving initial abstraction of the pro-S hydrogen by an Fe(III)-superoxo precursor to the ferryl complex, transfer of a hydroxyl group containing the originally abstracted hydrogen to C2 concomitant with formation of the ferryl complex, and an unprecedented abstraction of H• from the newly installed C2 OH group by the ferryl complex was proposed.… Advisors/Committee Members: Carsten Krebs, Dissertation Advisor/Co-Advisor, Joseph M Bollinger Jr., Committee Chair/Co-Chair, Squire J Booker, Committee Member, Michael Thomas Green, Committee Member, James Homer Tumlinson Iii, Committee Member.

Subjects/Keywords: Organophosphonate; mechanism; HppE; HEPD; MPnS; non-heme-iron dependent enzyme

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APA (6^th Edition):

Wang, C. (2014). Mechanistic Studies On Three Organophosphonate-processing Enzymes, Hppe, Hepd And Mpns. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/23396

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Wang, Chen. “Mechanistic Studies On Three Organophosphonate-processing Enzymes, Hppe, Hepd And Mpns.” 2014. Thesis, Penn State University. Accessed January 18, 2021. https://submit-etda.libraries.psu.edu/catalog/23396.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Wang, Chen. “Mechanistic Studies On Three Organophosphonate-processing Enzymes, Hppe, Hepd And Mpns.” 2014. Web. 18 Jan 2021.

Vancouver:

Wang C. Mechanistic Studies On Three Organophosphonate-processing Enzymes, Hppe, Hepd And Mpns. [Internet] [Thesis]. Penn State University; 2014. [cited 2021 Jan 18]. Available from: https://submit-etda.libraries.psu.edu/catalog/23396.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Wang C. Mechanistic Studies On Three Organophosphonate-processing Enzymes, Hppe, Hepd And Mpns. [Thesis]. Penn State University; 2014. Available from: https://submit-etda.libraries.psu.edu/catalog/23396

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Illinois – Urbana-Champaign

2. Peck, Spencer. Mechanistic investigations of enzymes in phosphonate metabolism.

Degree: PhD, 0335, 2015, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/73062

► Synthetic and naturally-occurring phosphonates have found widespread use in both agriculture and medicine. A program at the Institute for Genomic Biology at the University of… (more)

Subjects/Keywords: Phosphonate biosynthesis; enzymology; non-heme iron-dependent enzyme; 2-Hydroxyethylphosphonate dioxygenase (HEPD); methylphosphonate synthase (MPnS)

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APA (6^th Edition):

Peck, S. (2015). Mechanistic investigations of enzymes in phosphonate metabolism. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/73062

Chicago Manual of Style (16^th Edition):

Peck, Spencer. “Mechanistic investigations of enzymes in phosphonate metabolism.” 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 18, 2021. http://hdl.handle.net/2142/73062.

MLA Handbook (7^th Edition):

Peck, Spencer. “Mechanistic investigations of enzymes in phosphonate metabolism.” 2015. Web. 18 Jan 2021.

Vancouver:

Peck S. Mechanistic investigations of enzymes in phosphonate metabolism. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2142/73062.

Council of Science Editors:

Peck S. Mechanistic investigations of enzymes in phosphonate metabolism. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/73062

University of Otago

3. Siakkou, Eleni. Kinetics of Cysteine Dioxygenase .

Degree: 2011, University of Otago

URL: http://hdl.handle.net/10523/1932

► Cysteine dioxygenase (CDO) is a non-heme mono-iron enzyme, which catalyses the first step of cysteine metabolism in various species. It is known that malfunction of… (more)

▼ Cysteine dioxygenase (CDO) is a non-heme mono-iron enzyme, which catalyses the first step of cysteine metabolism in various species. It is known that malfunction of this enzyme has implications for health in mammals but despite extensive research over the past four decades, no consensus with respect to the kinetics and mechanism of CDO has been reached. An important factor is the presence of a naturally occurring post-translational modification between Cys93 and Tyr157 in the mammalian form of the enzyme, which enhances activity and requires the presence of cysteine and oxygen for its formation. Another factor is the reactivity of the substrate cysteine, which can be oxidised to various products in the absence of CDO and form disulfide adducts with free cysteine residues within the enzyme. These adducts are thought to have detrimental effects on CDO activity, and this is of particular importance when assessing CDO activity in vitro, where supraphysiological levels of cysteine substrate are present. The aim of this work was to develop a method for CDO activity assays, which provided both analytical and structural data for the subsequent assessment of CDO kinetics and establishment of a kinetic profile. Analytical data had to encompass information about both enzymatic and non-enzymatic oxidation of cysteine. The methods used to obtain this information were high performance liquid chromatography in combination with evaporative light scattering detection. Structural information assessing the presence of the activity-enhancing crosslink was obtained using denaturing gel electrophoresis. The great advantage of the method developed here was that analytical and structural information was obtained from the same sample and thus allowed direct correlation between these aspects. The method was used to assess activity of recombinant CDO from rat and a bacterium. Rat CDO was expressed as wild-type and a mutant (C164S), which lacked a cysteine residue at the active site entrance and could therefore not form a disulfide at this position with exogenous cysteine. Both types of rat CDO possessed the crosslink and were approximately 15-fold more active than bacterial CDO, which lacked this post-translational modification. Dependent on pH and the fraction of crosslinked enzyme present in an assay, rat CDO also had the ability to further increase activity through crosslink formation. This resulted in sigmoidal product formation curves during crosslink formation and indicated that crosslink formation possibly proceeded via an intermediate, which further increased enzyme activity. Advisors/Committee Members: Jameson, Guy N. L (advisor).

Subjects/Keywords: cysteine dioxygenase; enzyme activity assay; enzyme kinetics; non-heme iron enzyme

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APA (6^th Edition):

Siakkou, E. (2011). Kinetics of Cysteine Dioxygenase . (Doctoral Dissertation). University of Otago. Retrieved from http://hdl.handle.net/10523/1932

Chicago Manual of Style (16^th Edition):

Siakkou, Eleni. “Kinetics of Cysteine Dioxygenase .” 2011. Doctoral Dissertation, University of Otago. Accessed January 18, 2021. http://hdl.handle.net/10523/1932.

MLA Handbook (7^th Edition):

Siakkou, Eleni. “Kinetics of Cysteine Dioxygenase .” 2011. Web. 18 Jan 2021.

Vancouver:

Siakkou E. Kinetics of Cysteine Dioxygenase . [Internet] [Doctoral dissertation]. University of Otago; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10523/1932.

Council of Science Editors:

Siakkou E. Kinetics of Cysteine Dioxygenase . [Doctoral Dissertation]. University of Otago; 2011. Available from: http://hdl.handle.net/10523/1932

University of Michigan

4. Doyon, Tyler. Development and Characterization of Non-heme Iron Biocatalysts for Complex Molecule Synthesis.

Degree: PhD, Chemical Biology, 2020, University of Michigan

URL: http://hdl.handle.net/2027.42/163195

► Nature has evolved myriad biocatalytic tools for selective synthesis. The three-dimensional architecture of an enzyme active site enables the direct construction of new bonds with… (more)

▼ Nature has evolved myriad biocatalytic tools for selective synthesis. The three-dimensional architecture of an enzyme active site enables the direct construction of new bonds with exquisite site-, chemo-, and stereo-selectivity. Seeking to take advantage of these characteristics, researchers have leveraged biocatalysts for the rapid synthesis of natural products and complex molecules, developing sustainable methods to address long-standing challenges in synthetic chemistry. In recent years, this approach has been expanded to combine chemo- and biocatalytic methods in a single vessel, enabling transformations of increasing complexity to occur in a streamlined process. This thesis describes the development of novel, one-pot chemoenzymatic methods for the synthesis of complex molecules and natural products. Specifically, this work leveraged non-heme iron (NHI) alpha-ketoglutarate-dependent enzymes to access reactive ortho-quinone methide (o-QM) and radical intermediates for the construction of chroman and tropolone natural products. These studies provide a platform for the development of NHI enzymes as scalable and selective catalysts for the synthesis of complex molecules. The described research involved the development NHI enzymes CitB and ClaD to perform selective benzylic C–H hydroxylation of ortho-phenolic compounds. This biocatalytic method offered numerous advantages over small molecule oxidants, which often exhibit poor site- and chemo-selectivity for benzylic hydroxylation reactions. In comparison, CitB and ClaD provided strict control over the site of oxidation, avoiding the need for blocking or protecting groups to achieve selective catalysis. The substrate scope of this transformation was evaluated for these biocatalysts and a scalable reaction platform was developed for this transformation, demonstrating the ability of NHI enzymes to serve as sustainable and selective catalysts for benzylic C–H hydroxylation. The products of this selective oxidation were fully characterized and were shown to serve as reactive precursors for the formation of o-QMs in a one-pot process. Compared to traditional synthetic approaches to one-pot o-QM generation, a biocatalytic route offers the advantage of selective oxidation, leading to controlled generation of the reactive o-QM intermediate. These intermediates were elaborated in one-pot, modular chemoenzymatic fashion through 1,4-addition and [4+2] cycloaddition reactions demonstrating the synthetic utility of this approach for synthesizing complex scaffolds. Overall, this biocatalytic reaction platform offered an improved selectivity profile over traditional oxidative approaches to o-QM synthesis, enabling facile one-pot benzylic oxidation and functionalization in a scalable reaction format. A second focus of this work involved the chemoenzymatic synthesis of 7-membered aromatic compounds known as tropolones. Efficient synthetic access to this structurally-diverse class of metabolites represents a significant challenge to the development of novel tropolone pharmaceuticals.… Advisors/Committee Members: Narayan, Alison Rae Hardin (committee member), Lehnert, Nicolai (committee member), Mapp, Anna K (committee member), Sherman, David H (committee member).

Subjects/Keywords: biocatalysis; chemoenzymatic; natural product synthesis; non-heme iron enzyme; Chemistry; Science

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Doyon, T. (2020). Development and Characterization of Non-heme Iron Biocatalysts for Complex Molecule Synthesis. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/163195

Chicago Manual of Style (16^th Edition):

Doyon, Tyler. “Development and Characterization of Non-heme Iron Biocatalysts for Complex Molecule Synthesis.” 2020. Doctoral Dissertation, University of Michigan. Accessed January 18, 2021. http://hdl.handle.net/2027.42/163195.

MLA Handbook (7^th Edition):

Doyon, Tyler. “Development and Characterization of Non-heme Iron Biocatalysts for Complex Molecule Synthesis.” 2020. Web. 18 Jan 2021.

Vancouver:

Doyon T. Development and Characterization of Non-heme Iron Biocatalysts for Complex Molecule Synthesis. [Internet] [Doctoral dissertation]. University of Michigan; 2020. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2027.42/163195.

Council of Science Editors:

Doyon T. Development and Characterization of Non-heme Iron Biocatalysts for Complex Molecule Synthesis. [Doctoral Dissertation]. University of Michigan; 2020. Available from: http://hdl.handle.net/2027.42/163195

5. Widger, Leland Robert. MONONUCLEAR NONHEME IRON(II) MODEL COMPLEXES WITH MIXED N/S DONOR SETS: PRIMARY AND SECONDARY COORDINATION SPHERE EFFECTS.

Degree: 2014, Johns Hopkins University

URL: http://jhir.library.jhu.edu/handle/1774.2/36924

► Oxygen defines the aerobic environment in which much of life on earth exists. Nature has necessarily evolved a number of metalloenzyme-catalyzed reactions that utilize, as… (more)

▼ Oxygen defines the aerobic environment in which much of life on earth exists. Nature has necessarily evolved a number of metalloenzyme-catalyzed reactions that utilize, as well as protect against, molecular oxygen (O2) and its derivatives. Dioxygen is a particularly interesting molecule; it is found in nature mostly as a triplet diradical, rendering an otherwise powerful oxidizing agent relatively inert toward organic matter since reactions are spin-forbidden under standard conditions. However when activated by an appropriate catalyst (usually a transition metal), triplet oxygen can become extremely reactive in the form of singlet oxygen or one of a series of species that are collectively called “reactive oxygen species” (ROS). These ROS (superoxide, hydrogen peroxide, hydroxyl radical, organic peroxides and peroxynitrite) are responsible for performing some of the most important and recognizable reactions in biochemistry. In the Goldberg research group, we are particularly interested in unraveling the mysteries of what some refer to as the “oxygen economy,” the many reactions which ultimately make up a global cycle between H2O and O2. One general class of enzymes that contribute to this cycle are the nonheme iron oxygenases, enzymes that active O2 to oxidize a substrate utilizing a non-porphyrinoid iron center. The nonheme iron oxygenases encompass a massive variety of individual centers, each with its own unique ligand set and subsequent function. We are particularly interested in understanding the role of sulfur, which is present in some of these enzymes, and my interests have focused on building synthetic model systems inspired by two specific nonheme iron metalloenzymes that contain iron- sulfur centers: cysteine dioxygenase (CDO) and superoxide reductase (SOR). By making structural models of these systems we hope to build our understanding of the specific ii ligand environment around the iron centers, and how they impart the observed reactivity and selectivity at the metal center. One interesting property of metalloenzymes is their ability to incorporate redox cofactors or non-innocent ligands that have been implicated as critical aspects of various enzymatic reactivity. Chapter 2 discusses a study where an additional reducing equivalent was incorporated into a CDO model complex, known to undergo biomimetic S- oxygenation. The known iron(II) complex [FeII(LN3S)(OTf)] was used as starting material to prepare the new biomimetic (N4S(thiolate)) iron(II) complexes [FeII(LN3S)(py)](OTf) and [FeII(LN3S)(DMAP)](OTf), where LN3S is a tetradentate bis(imino)pyridine (BIP) derivative with a covalently tethered phenylthiolate donor. These complexes were characterized by X-ray crystallography, UV-vis, 1H NMR, and Mössbauer spectroscopy, as well as electrochemistry. A nickel(II) analogue, [NiII(LN3S)](BF4), was also synthesized and characterized by structural and spectroscopic methods. Cyclic voltammetric studies showed all of these complexes undergo a single reduction process with E1/2 between -0.9 to -1.2 V versus… Advisors/Committee Members: Goldberg, David P (advisor).

Subjects/Keywords: Non-heme; Iron; Oxygen;

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APA (6^th Edition):

Widger, L. R. (2014). MONONUCLEAR NONHEME IRON(II) MODEL COMPLEXES WITH MIXED N/S DONOR SETS: PRIMARY AND SECONDARY COORDINATION SPHERE EFFECTS. (Thesis). Johns Hopkins University. Retrieved from http://jhir.library.jhu.edu/handle/1774.2/36924

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Widger, Leland Robert. “MONONUCLEAR NONHEME IRON(II) MODEL COMPLEXES WITH MIXED N/S DONOR SETS: PRIMARY AND SECONDARY COORDINATION SPHERE EFFECTS.” 2014. Thesis, Johns Hopkins University. Accessed January 18, 2021. http://jhir.library.jhu.edu/handle/1774.2/36924.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Widger, Leland Robert. “MONONUCLEAR NONHEME IRON(II) MODEL COMPLEXES WITH MIXED N/S DONOR SETS: PRIMARY AND SECONDARY COORDINATION SPHERE EFFECTS.” 2014. Web. 18 Jan 2021.

Vancouver:

Widger LR. MONONUCLEAR NONHEME IRON(II) MODEL COMPLEXES WITH MIXED N/S DONOR SETS: PRIMARY AND SECONDARY COORDINATION SPHERE EFFECTS. [Internet] [Thesis]. Johns Hopkins University; 2014. [cited 2021 Jan 18]. Available from: http://jhir.library.jhu.edu/handle/1774.2/36924.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Widger LR. MONONUCLEAR NONHEME IRON(II) MODEL COMPLEXES WITH MIXED N/S DONOR SETS: PRIMARY AND SECONDARY COORDINATION SPHERE EFFECTS. [Thesis]. Johns Hopkins University; 2014. Available from: http://jhir.library.jhu.edu/handle/1774.2/36924

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Otago

6. Souness, Richard James. Binding of Sulfur Ligands to Cysteine Dioxygenase: A Crystallographic, Spectroscopic and Computational Study .

Degree: 2013, University of Otago

URL: http://hdl.handle.net/10523/3737

► Cysteine dioxygenase (CDO) is a non-heme mono-iron enzyme that catalyses the oxidation of cysteine to cysteine sulfinic acid (CSA) by the addition of the two… (more)

▼ Cysteine dioxygenase (CDO) is a non-heme mono-iron enzyme that catalyses the oxidation of cysteine to cysteine sulfinic acid (CSA) by the addition of the two oxygen atoms from dioxygen to the thiol group of cysteine. In many species, this is the first step of the catabolism of cysteine to its constituent parts. Elevated levels of cysteine in the body have been found to be associated with many disease states. Many well studied non-heme mono-iron enzymes contain the iron bound to two histidines and a carboxylate containing residue. However, as the iron in CDO is bound to three histidine residues, information about the mechanism of other non-heme mono-iron enzymes cannot be easily extrapolated to CDO. The aim of this work was to structurally and electronically characterise CDO in the resting state and with the addition of the substrate (cysteine), two catalytically inactive cysteine analogues (homocysteine and 3-mercaptopropionic acid (3MPA)) and the product (CSA). These states were characterised using X-ray crystallography, Mössbauer spectroscopy and density functional theory calculations. The resting state of CDO contained an octahedral iron(II) with three labile water ligands. Cysteine bound bidentate to the iron(II) via the thiol and the amino group, while homocysteine bound to the ferrous iron by the sulfur and possibly by the amino group as well. Homocysteine was not a substrate of CDO as its increased size blocked the oxygen binding site to iron, preventing the reaction from occurring. 3MPA by itself did not interact strongly with the iron of CDO, however, a persulfide derivative of 3MPA bound directly to the iron of CDO. Information about CSA binding is consistent with CSA bound in a tridentate manner by the two oxygen atoms of the sulfinic acid group and the amine nitrogen. In all states, the iron remained as high spin iron(II). It was concluded that cysteine required the correct length and both the amine and carboxylate to bind to CDO and be catalytically active and that the mechanism occurred via oxygen activation with the iron playing a redox active role. Advisors/Committee Members: Jameson, Guy N. L (advisor).

Subjects/Keywords: Cysteine dioxygenase; Mössbauer spectroscopy; Macromolecular X-ray crystallography; Density functional theory calculations; non-heme mono-iron enzyme

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Souness, R. J. (2013). Binding of Sulfur Ligands to Cysteine Dioxygenase: A Crystallographic, Spectroscopic and Computational Study . (Doctoral Dissertation). University of Otago. Retrieved from http://hdl.handle.net/10523/3737

Chicago Manual of Style (16^th Edition):

Souness, Richard James. “Binding of Sulfur Ligands to Cysteine Dioxygenase: A Crystallographic, Spectroscopic and Computational Study .” 2013. Doctoral Dissertation, University of Otago. Accessed January 18, 2021. http://hdl.handle.net/10523/3737.

MLA Handbook (7^th Edition):

Souness, Richard James. “Binding of Sulfur Ligands to Cysteine Dioxygenase: A Crystallographic, Spectroscopic and Computational Study .” 2013. Web. 18 Jan 2021.

Vancouver:

Souness RJ. Binding of Sulfur Ligands to Cysteine Dioxygenase: A Crystallographic, Spectroscopic and Computational Study . [Internet] [Doctoral dissertation]. University of Otago; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10523/3737.

Council of Science Editors:

Souness RJ. Binding of Sulfur Ligands to Cysteine Dioxygenase: A Crystallographic, Spectroscopic and Computational Study . [Doctoral Dissertation]. University of Otago; 2013. Available from: http://hdl.handle.net/10523/3737

University of Michigan

7. Waugh, Matthew William. Molecules to Burn: A Mechanistic Characterization of Cyanobacterial Aldehyde Deformylating Oxygenase.

Degree: PhD, Chemical Biology, 2015, University of Michigan

URL: http://hdl.handle.net/2027.42/113585

► The development of hydrocarbon based biofuels that can replace fossil fuels is essential to address the challenge of energy sustainability. However, there are few known… (more)

▼ The development of hydrocarbon based biofuels that can replace fossil fuels is essential to address the challenge of energy sustainability. However, there are few known biosynthetic pathways to produce these molecules and, generally, they are not well understood. The focus of this dissertation is to explore one of the very few biosynthetic routes to produce entirely unfunctionalized hydrocarbons through investigation of the highly unusual reaction catalyzed by cyanobacterial aldehyde deformylating oxygenase (cADO). To investigate the proton transfer step, solvent isotope effect (SIE) studies were undertaken. No appreciable difference in rate in D2O or H2O was observed, implying that proton transfer is not a kinetically significant step. However, when the ratio of protium to deuterium in the product alkane was measured as a function of the mole fraction of D2O, a D2OSIEobs of 2.19 ± 0.02 was observed. We interpret this SIE as most likely arising from a reactant state equilibrium isotope effect on a proton donor with an inverse fractionation factor, for which Φ = 0.45, consistent with an iron-bound water molecule being the proton donor to the alkane. Substrate analogs and binding channel mutations were used to investigate substrate binding or product release acting as a non-chemical rate limiting step. The kinetics of the mutants were investigated using octadecanal and, although no increase apparent rate was observed, two mutants displayed shifts in KM. These results suggest the hydrophobic pocket may be important in determining the binding affinity of long chain substrates. Protein film voltammetry experiments were used to explore the electrochemistry of cADO. The midpoint reduction potential was determined to be -73 ± 10 mV (vs SHE). Catalytic cyclic voltammetry with heptanal indicated a lower limit on alkane turnover of kobs > 0.63 per s, significantly faster than the rate of ~1 per min observed in solution. Interestingly, an alternative reaction was observed with enzyme and O2 indicating a futile cycle leading to H2O2 formation. These observations indicate that inefficient interactions with the reducing system or a partitioning effect between alkane and H2O2 turnover may be responsible for the sluggish activity of cADO. Advisors/Committee Members: Marsh, E Neil G. (committee member), Palfey, Bruce Allan (committee member), Lin, Nina (committee member), Ragsdale, Stephen W. (committee member).

Subjects/Keywords: Biofuels; Non-Heme Iron Oxygenase; Aldehyde Decarbonylase; Protein Film Voltammetry; Solvent Isotope Effects; Enzyme Kinetics; Biological Chemistry; Science

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Waugh, M. W. (2015). Molecules to Burn: A Mechanistic Characterization of Cyanobacterial Aldehyde Deformylating Oxygenase. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/113585

Chicago Manual of Style (16^th Edition):

Waugh, Matthew William. “Molecules to Burn: A Mechanistic Characterization of Cyanobacterial Aldehyde Deformylating Oxygenase.” 2015. Doctoral Dissertation, University of Michigan. Accessed January 18, 2021. http://hdl.handle.net/2027.42/113585.

MLA Handbook (7^th Edition):

Waugh, Matthew William. “Molecules to Burn: A Mechanistic Characterization of Cyanobacterial Aldehyde Deformylating Oxygenase.” 2015. Web. 18 Jan 2021.

Vancouver:

Waugh MW. Molecules to Burn: A Mechanistic Characterization of Cyanobacterial Aldehyde Deformylating Oxygenase. [Internet] [Doctoral dissertation]. University of Michigan; 2015. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2027.42/113585.

Council of Science Editors:

Waugh MW. Molecules to Burn: A Mechanistic Characterization of Cyanobacterial Aldehyde Deformylating Oxygenase. [Doctoral Dissertation]. University of Michigan; 2015. Available from: http://hdl.handle.net/2027.42/113585

University of Illinois – Urbana-Champaign

8. Bigi, Marinus. I. Biomimetic oxidations using non-heme iron catalysis. II. Palladium- and hypervalent iodine-catalyzed tandem wacker-dehydrogenation of terminal olefins.

Degree: PhD, 0335, 2013, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/44446

► ABSTRACT I. BIOMIMETIC OXIDATIONS USING NON-HEME IRON CATALYSIS Nature’s oxidation catalysts promote a remarkable variety of highly selective oxidation reactions of alkanes, olefins, and arenes.… (more)

▼ ABSTRACT I. BIOMIMETIC OXIDATIONS USING NON-HEME IRON CATALYSIS Nature’s oxidation catalysts promote a remarkable variety of highly selective oxidation reactions of alkanes, olefins, and arenes. Inspired by this diversity of reactivity, the chemical community has long sought to replicate enzymatic reactivity within the synthetic laboratory, both for the purposes of better understanding enzymatic reaction mechanisms and to advance the frontier of chemical synthesis. In the first part of this thesis, a series of projects exploring novel oxidation reactivity and mechanism, as well as several unique synthetic applications, will be described. First, a comprehensive study of the use of carboxylic acids as directing groups for non-heme iron catalyzed C—H hydroxylation will be described. Examination of substrates for C—H hydroxylation that featured unfavorable electronic, steric, or stereoelectronic effects demonstrated that carboxylic acids were capable of overcoming these substrate biases during hydroxylation. The developed methodology was utilized to install the C2 oxidation on a taxane derivative, demonstrating the first example of such an oxidation using a small molecule catalyst or reagent. Second, the unexpected discovery of ‘double oxidation’ products resulting from non-heme iron catalyzed C—H hydroxylation of carboxylic acid-containing substrates will be described. The mechanism accounting for their formation was studied in detail and suggested operation of mixed desaturase/oxygenase reactivity, only previously observed within natural systems. These studies suggested that, in analogy to nature, a short-lived substrate-derived carbon-centered radical either underoges hydroxyl rebound to provide for C—H hydroxylation or further oxidation to an olefin intermediate en route to ‘double oxidation’. Third, oxidation of the characteristic furan ring of a cafestol derivative using a non-heme iron catalyst allowed the rapid synthesis of tricalysiolide B, a natural product isolated in 2006 from Japanese tree bark. This result suggested that non-heme iron oxygenases were responsible for metabolizing cafestol to tricalysiolide B within tricalysia dubia, and demonstrated how non-heme iron catalysis can be used to rapidly test biosynthetic proposals. II. PALLADIUM AND HYPERVALENT IODINE-CATALYZED TANDEM WACKER- DEHYDROGENATION OF TERMINAL OLEFINS Catalytic C—H functionalization reactions promise to increase synthetic efficiency by enabling the direct installation of useful functionality onto traditionally unreactive hydrocarbon frameworks. The White group has pioneered a toolbox of synthetically useful palladium-catalyzed allylic C—H functionalization reactions of terminal olefins, including C—O, C—N, and C—C bond forming reactions. This section will describe the discovery and development of a palladium/hypervalent iodine-catalyzed tandem Wacker-dehydrogenation reaction, allowing direct access to linear α,β-unsaturated ketones from readily available terminal olefins. Advisors/Committee Members: White, Maria C. (advisor), White, Maria C. (Committee Chair), Katzenellenbogen, John A. (committee member), Nuzzo, Ralph G. (committee member), Hull, Kami L. (committee member).

Subjects/Keywords: Non-heme; Iron Catalysis; oxidation; catalysis; biomimetic

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APA (6^th Edition):

Bigi, M. (2013). I. Biomimetic oxidations using non-heme iron catalysis. II. Palladium- and hypervalent iodine-catalyzed tandem wacker-dehydrogenation of terminal olefins. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/44446

Chicago Manual of Style (16^th Edition):

Bigi, Marinus. “I. Biomimetic oxidations using non-heme iron catalysis. II. Palladium- and hypervalent iodine-catalyzed tandem wacker-dehydrogenation of terminal olefins.” 2013. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 18, 2021. http://hdl.handle.net/2142/44446.

MLA Handbook (7^th Edition):

Bigi, Marinus. “I. Biomimetic oxidations using non-heme iron catalysis. II. Palladium- and hypervalent iodine-catalyzed tandem wacker-dehydrogenation of terminal olefins.” 2013. Web. 18 Jan 2021.

Vancouver:

Bigi M. I. Biomimetic oxidations using non-heme iron catalysis. II. Palladium- and hypervalent iodine-catalyzed tandem wacker-dehydrogenation of terminal olefins. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2142/44446.

Council of Science Editors:

Bigi M. I. Biomimetic oxidations using non-heme iron catalysis. II. Palladium- and hypervalent iodine-catalyzed tandem wacker-dehydrogenation of terminal olefins. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/44446

University of Georgia

9. Sanders, Brian Clark. Synthesis and properties of non-heme iron-NOx complexes for the generation of nitroxyl donors and nitrite reduction catalysts.

Degree: 2016, University of Georgia

URL: http://hdl.handle.net/10724/33789

► The biological interplay between Fe and NyOx is significant to both human physiology and the remediation of global pollution. The interconversion of NyOx species is… (more)

▼ The biological interplay between Fe and NyOx is significant to both human physiology and the remediation of global pollution. The interconversion of NyOx species is primarily mediated by metalloenzymes, in which Fe plays a critical role. Due to their critical role in biology and the environment, the study of Fe-NyOx interactions is of fundamental interest in coordination chemistry. Additionally, thiol-containing biomolecules have direct interaction with Fe-NyOx. For example, Fe(III)-NO2 complexes react with thiols to NO or HNO and the corresponding sulfenic acids. Given the complex interplay between NyOx, Fe, and thiols, there is a need to rationalize this intricate chemistry through model complexes. Our approach involves the design and synthesis of modular non-heme complexes in which donor strength, flexibility, and secondary-sphere interactions are readily tuned. This methodology has facilitated the isolation and characterization of the first non-heme {FeNO}8 and Fe(II)(NO2)2 complexes, and allowed for the first study of their reactivity with Fe(III)-porphyrins, Fe(III)-myoglobin, thiols, and protons. From these reactivity studies we have demonstrated nitroxyl-transfer to metMb to give MbNO, thus outlining the proof-of-principle for the rational design of metal-based HNO donors. Moreover, we have demonstrated that reactions of non-heme {FeNO}7/8 complexes with thiols ultimately leads to various dinitrosyl iron complexes (DNICs) in an oxidation state dependent manner. These results suggest a possible route to DNIC formation from non-heme {FeNO}7/8 complexes in biology. Lastly, the development of non-heme NO2- reduction catalysts is discussed. In the presence of H+/thiols the selective and catalytic conversion of NO2- to NO(g) is observed. However, in the presence of only thiols, a net three-electron reduction of Fe(II)(NO2)2 to the Fe(I)(NO)2 DNIC is observed, and suggests a possible role for Fe-NO2 and thiols in the formation of biological DNICs. Described in this dissertation is the synthesis, characterization, and reactivity of a series of non-heme Fe-NOx complexes, which provides the basis for the development of non-heme NO2 reduction catalysts and Fe-based HNO donor molecules for the purpose of cardiovascular therapies and environmental remediation.

Subjects/Keywords: Nitroxyl; Nitrite; Nitric Oxide; Non-heme; Iron

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APA (6^th Edition):

Sanders, B. C. (2016). Synthesis and properties of non-heme iron-NOx complexes for the generation of nitroxyl donors and nitrite reduction catalysts. (Thesis). University of Georgia. Retrieved from http://hdl.handle.net/10724/33789

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sanders, Brian Clark. “Synthesis and properties of non-heme iron-NOx complexes for the generation of nitroxyl donors and nitrite reduction catalysts.” 2016. Thesis, University of Georgia. Accessed January 18, 2021. http://hdl.handle.net/10724/33789.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sanders, Brian Clark. “Synthesis and properties of non-heme iron-NOx complexes for the generation of nitroxyl donors and nitrite reduction catalysts.” 2016. Web. 18 Jan 2021.

Vancouver:

Sanders BC. Synthesis and properties of non-heme iron-NOx complexes for the generation of nitroxyl donors and nitrite reduction catalysts. [Internet] [Thesis]. University of Georgia; 2016. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10724/33789.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sanders BC. Synthesis and properties of non-heme iron-NOx complexes for the generation of nitroxyl donors and nitrite reduction catalysts. [Thesis]. University of Georgia; 2016. Available from: http://hdl.handle.net/10724/33789

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Texas – Austin

10. -5387-6362. The mechanism study of fumitremorgin B dioxygenase and engineered human cystathionine gamma lyase.

Degree: PhD, Biochemistry, 2018, University of Texas – Austin

URL: http://hdl.handle.net/2152/68396

► Peroxy-containing compounds represent a large class of natural products with many demonstrated beneficial effects to human health. Yet, very little is known about how endoperoxide… (more)

▼ Peroxy-containing compounds represent a large class of natural products with many demonstrated beneficial effects to human health. Yet, very little is known about how endoperoxide functionality is incorporated into the natural products. In the first section of this dissertation, we have done the biochemical and structural research on the protein Fumitremorgin B dioxygenase, which is the first non-heme iron enzyme catalyzing an endoperoxide formation reaction. This work discloses mechanistic understanding to explain this unprecedented transformation. Distinct from all currently known α-ketoglurarate-dependent mononuclear non-heme iron enzymes, FtmOx1 incorporates molecular oxygen into the product without O-O bond scission, suggesting a novel mechanism. Indeed, the structural data reveal a surprising and unique arrangement of α-ketoglutarate (α-KG). Once the co-factor α-KG binds to the iron center, the remaining site for oxygen binding and activation is completely shielded from substrate access. This is in dramatic contrast to currently characterized α-ketoglurarate-dependent mononuclear non-heme iron enzymes, in which the oxygen binding site directly faces the substrate to be oxidized. From the crystal structure, we identify a tyrosine residue (Y224) as the residue shielding the mononuclear iron center from substrate access. The following biochemical study has shown that upon Y224A and Y224F mutation, the reaction is shifted from endoperoxide formation to a traditional α-ketoglurarate-dependent mononuclear non-heme iron enzyme catalyzed oxidative hydroxylation reaction. Further EPR study and pre-steady state analysis suggested an organic radical formed during catalysis. Those structural and biochemical data allow us to formulate a mechanistic model to account for this unprecedented endoperoxide formation reaction in which Y224 will form a tyrosyl radical and acting as a bridge to connect between the iron center and the substrate. Cancer cells exhibit different metabolism compared to normal tissue, this has been shown to be a successful target in clinical. It has been found that some types of cancer are dependent on particular amino acids since they are not able to synthesize these amino acids themselves. Thus the strategy of starving tumor cell from its specific essential amino acid has great potential in anti-tumor therapeutic development. To consume the essential amino acid L-Methionine, human cystathionine-γ-lyase has been engineered to utilize methionine as substrate. One of the variants (hCGL-NLV) derived from this strategy showed altered specificity from cystathionine to methionine with improved half life compared with bacterial methionine gamma lyase. To understand the structural rationale to direct further bioengineering design, we obtained the crystal structures of this variant CGL-NLV in both an active and inactive conformations. The comparison between the two forms of hCGL-NLV highlighted a salt bridge between active site essential arginine residue (R62) and co-factor PLP that is attenuated upon high salt… Advisors/Committee Members: Zhang, Yan Jessie (advisor), Georgiou, George (committee member), Hackert, Marvin L. (committee member), Iverson, Brent L. (committee member), Whitman, Chris P. (committee member).

Subjects/Keywords: Endoperoxide formation; Tyrosyl radical; Non-heme iron protein; Novel α-ketoglutarate binding orientation; CGS-like protein; Engineered enzyme; Salt dependence; Substrate selectivity shift

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APA (6^th Edition):

-5387-6362. (2018). The mechanism study of fumitremorgin B dioxygenase and engineered human cystathionine gamma lyase. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/68396

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Chicago Manual of Style (16^th Edition):

-5387-6362. “The mechanism study of fumitremorgin B dioxygenase and engineered human cystathionine gamma lyase.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed January 18, 2021. http://hdl.handle.net/2152/68396.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

MLA Handbook (7^th Edition):

-5387-6362. “The mechanism study of fumitremorgin B dioxygenase and engineered human cystathionine gamma lyase.” 2018. Web. 18 Jan 2021.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Vancouver:

-5387-6362. The mechanism study of fumitremorgin B dioxygenase and engineered human cystathionine gamma lyase. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2152/68396.

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Council of Science Editors:

-5387-6362. The mechanism study of fumitremorgin B dioxygenase and engineered human cystathionine gamma lyase. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/68396

Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete

Boston University

11. Gregor, Lauren Christine. Mechanistic studies of functional mononuclear and binuclear non-heme iron enzyme model complexes using variable temperature stopped-flow UV/vis spectroscopy.

Degree: PhD, Chemistry, 2014, Boston University

URL: http://hdl.handle.net/2144/15102

► Variable-temperature stopped-flow (VT-SF) electronic spectroscopy (-85 to -50°C) was utilized to study the reactivity properties of a family of synthetic mononuclear and binuclear non-heme iron… (more)

▼ Variable-temperature stopped-flow (VT-SF) electronic spectroscopy (-85 to -50°C) was utilized to study the reactivity properties of a family of synthetic mononuclear and binuclear non-heme iron enzyme active site analogs. This technique was used to investigate the mechanisms of interactions of two diiron complexes, the diferrous [FeII2(H2Hbamb)2(NMI)2] and the mixed valent [FeII,FeIII(H2Hbamb)2]+, with either oxygen-atom donor (OAD) molecules or the mechanistic probe peroxide, 2-methyl-1-phenylprop-2-yl hydroperoxide (MPPH), and substrates containing weak C-H and O-H bonds. Single turnover studies with 9,10-dihydroanthracene (9,10-DHA) and the deuterated analog, d4-9,10-DHA allowed for the determination of kinetic isotope effects (KIE) which show an inverse KIE and evidence of a disproportionation mechanism. Previous investigations showed the rate of catalytic oxidation of cyclohexane to cyclohexanol by [FeII2(H2Hbamb)2(NMI)2] and MPPH decreased over time. Current VT-SF data show evidence of product inhibition by means of a pre-equilibrium process that inhibits the reaction of the oxidant with the [FeII,FeII] complex. Also examined is the ability of the [FeII,FeIII(H2Hbamb)2]+ complex to catalytically oxidize phenols to phenoxyl radicals via a putative [FeIV=O] species. The reactivity properties of substituted phenols that vary in their oxidation potentials and bond dissociation energies (BDE) was investigated by VT-SF electronic spectroscopic studies to gain insight into the mechanism of oxidation by the [FeII,FeIII] complex. Mechanistic studies were also performed utilizing a mononuclear non-heme iron complex [FeII(N2O1)(CH3OH)Cl2], which can bind alpha-keto acids (e.g. alpha-ketoglutarate, benzoylformate) in a bidentate fashion. Reactivity studies utilizing O2 shows coupled decarboxylation of the alpha-keto acid with catalytic oxidation of the methanol solvent formaldehyde (285 turnovers). In non-reactive solvents, the [FeII(N2O1)(alpha-KG)] adduct complex is capable of catalytically oxidizing a variety of substrates such as 9,10-dihydroanthracene, 2,4-di-tert-butyl phenol, cyclohexene, and cyclooctane at 25°C utilizing O2 as the oxidant. Investigations to the binding of alpha-keto acids to the mononuclear iron complex in the absence of O2 by VT-SF as well as binding studies with NO are discussed. Finally, VT-SF studies were performed to probe the reaction of O2 with [FeII(N2O1)(alpha-KG)(CH3OH)] and the proposed mechanism is discussed. The relevance of these data to non-heme iron enzymes like soluble Methane Monooxygenase, Ribonucleotide Reductase, and Taurine Dioxygenase is discussed.

Subjects/Keywords: Chemistry; Inorganic; Kinetics; Mechanism; Non-heme iron; Stopped-flow; Syntheitc

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APA (6^th Edition):

Gregor, L. C. (2014). Mechanistic studies of functional mononuclear and binuclear non-heme iron enzyme model complexes using variable temperature stopped-flow UV/vis spectroscopy. (Doctoral Dissertation). Boston University. Retrieved from http://hdl.handle.net/2144/15102

Chicago Manual of Style (16^th Edition):

Gregor, Lauren Christine. “Mechanistic studies of functional mononuclear and binuclear non-heme iron enzyme model complexes using variable temperature stopped-flow UV/vis spectroscopy.” 2014. Doctoral Dissertation, Boston University. Accessed January 18, 2021. http://hdl.handle.net/2144/15102.

MLA Handbook (7^th Edition):

Gregor, Lauren Christine. “Mechanistic studies of functional mononuclear and binuclear non-heme iron enzyme model complexes using variable temperature stopped-flow UV/vis spectroscopy.” 2014. Web. 18 Jan 2021.

Vancouver:

Gregor LC. Mechanistic studies of functional mononuclear and binuclear non-heme iron enzyme model complexes using variable temperature stopped-flow UV/vis spectroscopy. [Internet] [Doctoral dissertation]. Boston University; 2014. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2144/15102.

Council of Science Editors:

Gregor LC. Mechanistic studies of functional mononuclear and binuclear non-heme iron enzyme model complexes using variable temperature stopped-flow UV/vis spectroscopy. [Doctoral Dissertation]. Boston University; 2014. Available from: http://hdl.handle.net/2144/15102

Boston University

12. McNally, Joshua. Synthetic and density functional theory studies of dioxygen activating non-heme iron model complexes.

Degree: PhD, Chemistry, 2014, Boston University

URL: http://hdl.handle.net/2144/15130

► A long standing global scientific challenge has been the activation of O2 at a single metal center, and use of the subsequent metal-based oxidant for… (more)

▼ A long standing global scientific challenge has been the activation of O2 at a single metal center, and use of the subsequent metal-based oxidant for a variety of difficult chemical transformations. Towards this end, computational and synthetic methods have been utilized in an approach to develop model compounds capable of this type of chemistry, and to better understand the electronic and mechanistic properties of the observed catalytic reactivity. We have developed a first generation catalyst that has been shown to be fully functional in utilizing α-keto acids for the catalytic activation of O2 and oxidation of organic substrates in a highly conserved manner. This reactivity takes place at room temperature and standard pressure, and resembles the type of chemistry performed by mononuclear non-heme enzymes, which inspired the design of the catalyst. However, these solution-phase reactions do not benefit from the controlled environment provided by a protein active site, and solution studies and DFT simulations demonstrate an isomeric family of reactive species that ultimately deactivate via a dimerization pathway. A second generation catalyst, which incorporates ligand aromatic functionality, has been developed. This complex has been shown to catalytically oxide methanol to formaldehyde in the presence of α-ketoglutarate using O2. The aromatic group provides a synthetic platform, allowing a variety of substituents geared toward increasing complex solubility and the tuning of the redox properties of the metal center. Additionally, the ligand has been functionalized to allow for the immobilization of the catalyst using an azido-functionalized solid support, by means of 'click' chemistry. A procedure for the immobilization of the catalyst has been developed that sets the stage for the preparation of a material that will diminish dimerization and inactivation. Additional insights into potential reaction pathways of the first generation catalyst have been obtained from DFT studies. These simulations have provided energetic comparisons of proposed intermediates and set the stage for future computational and spectroscopic studies. This synergistic approach will not only allow for detailed electronic and mechanistic descriptions of the intimate mechanism, but will be used in the development of next generation catalysts that that can be tuned for desired reactivity properties.

Subjects/Keywords: Chemistry; Density functional theory; Dioxygen activation; Non-heme iron

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APA (6^th Edition):

McNally, J. (2014). Synthetic and density functional theory studies of dioxygen activating non-heme iron model complexes. (Doctoral Dissertation). Boston University. Retrieved from http://hdl.handle.net/2144/15130

Chicago Manual of Style (16^th Edition):

McNally, Joshua. “Synthetic and density functional theory studies of dioxygen activating non-heme iron model complexes.” 2014. Doctoral Dissertation, Boston University. Accessed January 18, 2021. http://hdl.handle.net/2144/15130.

MLA Handbook (7^th Edition):

McNally, Joshua. “Synthetic and density functional theory studies of dioxygen activating non-heme iron model complexes.” 2014. Web. 18 Jan 2021.

Vancouver:

McNally J. Synthetic and density functional theory studies of dioxygen activating non-heme iron model complexes. [Internet] [Doctoral dissertation]. Boston University; 2014. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2144/15130.

Council of Science Editors:

McNally J. Synthetic and density functional theory studies of dioxygen activating non-heme iron model complexes. [Doctoral Dissertation]. Boston University; 2014. Available from: http://hdl.handle.net/2144/15130

University of Georgia

13. Cheatum, Wren Hilliard. Synthetic analogs of the non-heme iron center in superoxide reductase.

Degree: 2014, University of Georgia

URL: http://hdl.handle.net/10724/25764

► Reactive oxygen species, such as superoxide, are associated with many diseases including cancer, diabetes, and atherosclerosis. In order to protect against the presence of reactive… (more)

Subjects/Keywords: Superoxide; Superoxide reductase; Non-heme iron; Bioinorganic chemistry; synthetic analog

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APA (6^th Edition):

Cheatum, W. H. (2014). Synthetic analogs of the non-heme iron center in superoxide reductase. (Thesis). University of Georgia. Retrieved from http://hdl.handle.net/10724/25764

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Cheatum, Wren Hilliard. “Synthetic analogs of the non-heme iron center in superoxide reductase.” 2014. Thesis, University of Georgia. Accessed January 18, 2021. http://hdl.handle.net/10724/25764.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Cheatum, Wren Hilliard. “Synthetic analogs of the non-heme iron center in superoxide reductase.” 2014. Web. 18 Jan 2021.

Vancouver:

Cheatum WH. Synthetic analogs of the non-heme iron center in superoxide reductase. [Internet] [Thesis]. University of Georgia; 2014. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10724/25764.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Cheatum WH. Synthetic analogs of the non-heme iron center in superoxide reductase. [Thesis]. University of Georgia; 2014. Available from: http://hdl.handle.net/10724/25764

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

14. Gokhale, Aditya S. The Effect of Cooking on Formation of Bioavailable Species of Iron from Chicken Breast Muscle.

Degree: MS, Food Science, 2011, University of Massachusetts

URL: https://scholarworks.umass.edu/theses/681

► Chicken breast muscle was cooked to an internal temperature of 165^oF by four methods: boiling, baking, sautéing and deep-frying. All cooking methods led to… (more)

Subjects/Keywords: chicken muscle; cooking; non-heme iron; bioavailability; dialyzability; Food Science

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APA (6^th Edition):

Gokhale, A. S. (2011). The Effect of Cooking on Formation of Bioavailable Species of Iron from Chicken Breast Muscle. (Masters Thesis). University of Massachusetts. Retrieved from https://scholarworks.umass.edu/theses/681

Chicago Manual of Style (16^th Edition):

Gokhale, Aditya S. “The Effect of Cooking on Formation of Bioavailable Species of Iron from Chicken Breast Muscle.” 2011. Masters Thesis, University of Massachusetts. Accessed January 18, 2021. https://scholarworks.umass.edu/theses/681.

MLA Handbook (7^th Edition):

Gokhale, Aditya S. “The Effect of Cooking on Formation of Bioavailable Species of Iron from Chicken Breast Muscle.” 2011. Web. 18 Jan 2021.

Vancouver:

Gokhale AS. The Effect of Cooking on Formation of Bioavailable Species of Iron from Chicken Breast Muscle. [Internet] [Masters thesis]. University of Massachusetts; 2011. [cited 2021 Jan 18]. Available from: https://scholarworks.umass.edu/theses/681.

Council of Science Editors:

Gokhale AS. The Effect of Cooking on Formation of Bioavailable Species of Iron from Chicken Breast Muscle. [Masters Thesis]. University of Massachusetts; 2011. Available from: https://scholarworks.umass.edu/theses/681

University of Notre Dame

15. Beatrice Blanc. Relationship between active site structure and chemistry in dioxygen producing chlorite dismutases</h1>.

Degree: Chemistry and Biochemistry, 2012, University of Notre Dame

URL: https://curate.nd.edu/show/3j333199s86

► This thesis focuses on understanding the relationship between the active site structure and function in the heme-containing enzyme chlorite dismutase from Dechloromonas aromatica (DaCld).… (more)

▼ This thesis focuses on understanding the relationship between the active site structure and function in the heme-containing enzyme chlorite dismutase from Dechloromonas aromatica (DaCld). DaCld decomposes chlorite (ClO2-) into chloride (Cl-) and oxygen (O2) via an efficient reaction that is nearly diffusion controlled. Due to the existence of advanced structure-activity models for heme peroxidases and the similarity of the behavior of peroxide and chlorite as substrates, we initiated our structure-function studies in 2008 by analogy to these enzymes. In 2009, the crystal structures of DaCld and a second Cld were solved for the first time, allowing us to consider the influence of structural elements directly. We investigated the role of an arginine residue (Arg183) in the pocket above the heme plane in catalysis using diverse biochemistry, molecular biology and spectroscopy techniques (notably stopped-flow, resonance Raman, UV/Visible). We mutated this residue, which has an alkylguanidinium side chain, to lysine (primary amine), glutamine (alkylamide), and alanine (methyl), and studied both the native (wild type, WT) and modified forms. We had found earlier that the rate of catalysis and several spectroscopic properties of the WT protein are pH-dependent. We proposed that this was either due to acid/base chemistry at Arg183 (analogous to an active-site His in peroxidase), or to the mobility of its side chain due to pH-dependent hydrogen bond formation/cleavage. The latter model was most consistent with the available data; particularly resonance Raman (rR) data for the ferrous carbonyl form of WT and mutant proteins. By reacting the protein with peracids, we were able to characterize Compound I (oxoferryl porphyrin radical) which decays to a Compound ES-like species where the porphyrin radical migrates to a nearby tryptophan residue. We mutated three conserved tryptophan residues in DaCld’s active site in order to attempt to block off radical migration and stabilize Compound I. The ability of DaCld to produce such a great amount of oxygen can be used for other needs, for example in the prevention of tissue necrosis. DaCld offers the possibility of production of O2 in situ in a regulated fashion and without generation of toxic byproducts. Advisors/Committee Members: W. Robert Scheidt, Committee Member, Jennifer L. Dubois, Committee Member, Masaru K. Kuno, Committee Member, Kenneth W. Henderson, Committee Member.

Subjects/Keywords: Heme enzyme; Oxygen

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APA (6^th Edition):

Blanc, B. (2012). Relationship between active site structure and chemistry in dioxygen producing chlorite dismutases</h1>. (Thesis). University of Notre Dame. Retrieved from https://curate.nd.edu/show/3j333199s86

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Blanc, Beatrice. “Relationship between active site structure and chemistry in dioxygen producing chlorite dismutases</h1>.” 2012. Thesis, University of Notre Dame. Accessed January 18, 2021. https://curate.nd.edu/show/3j333199s86.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Blanc, Beatrice. “Relationship between active site structure and chemistry in dioxygen producing chlorite dismutases</h1>.” 2012. Web. 18 Jan 2021.

Vancouver:

Blanc B. Relationship between active site structure and chemistry in dioxygen producing chlorite dismutases</h1>. [Internet] [Thesis]. University of Notre Dame; 2012. [cited 2021 Jan 18]. Available from: https://curate.nd.edu/show/3j333199s86.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Blanc B. Relationship between active site structure and chemistry in dioxygen producing chlorite dismutases</h1>. [Thesis]. University of Notre Dame; 2012. Available from: https://curate.nd.edu/show/3j333199s86

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Swedish University of Agricultural Sciences

16. Friemann, Rosmarie. Structure-function studies of iron-sulfur enzyme systems.

Degree: 2005, Swedish University of Agricultural Sciences

URL: http://pub.epsilon.slu.se/739/

► Iron-sulfur clusters are among the most ancient of metallocofactors and serve a variety of biological functions in proteins, including electron transport, catalytic, and structural roles.… (more)

▼ Iron-sulfur clusters are among the most ancient of metallocofactors and serve a variety of biological functions in proteins, including electron transport, catalytic, and structural roles. Two kinds of multicomponent enzyme systems have been investigated by X-ray crystallography, the ferredoxin/thioredoxin system and bacterial Rieske non-heme iron dioxygenase (RDO) systems. The ferredoxin/thioredoxin system is a light sensitive system controlling the activities of key enzymes involved in the assimilatory (photosynthetic) and dissimilatory pathways in chloroplasts and photosynthetic bacteria. The system consists of a ferredoxin, ferredoxin:thioredoxin reductase (FTR), and two thioredoxins, Trx-m and Trx-f. In light, photosystem I reduces ferredoxin that reduces Trx-m and Trx-f. This two-electron reduction is catalyzed by FTR that contains a [4Fe-4S] center and a proximal disulfide bridge. When the first electron is delivered by the ferredoxin, an intermediate is formed where one thiol of the proximal disulfide attacks the disulfide bridge of thioredoxin. This results in a transient protein-protein complex held together by a mixed disulfide between FTR and Trx-m. This complex is stabilized by using a C40S mutant Trx-m and its structure have been determined. RDOs consists of a flavoprotein reductase and often a ferredoxin that transfer electrons from NAD(P)H to the terminal dioxygenase. The terminal dioxygenase catalyze the enantioselective addition of dioxygen in the initial degradation of aromatic compounds, producing cis-dihydrodiols. The structures of three dioxygenases, nitrobenzene dioxygenase (NBDO), 2-nitrotoluene (2NTDO) and toluene dioxygenase (TDO), as well as the two electron transfer proteins of the TDO system, toluene dioxygenase reductase (TDOR) and toluene dioxygenase ferredoxin (TDOF), have been determined. The dioxygenase structures are all alpha3beta3 heterohexamers similar to other RDOs. The catalytic a subunit contains a Rieske iron-sulfur cluster and a mononuclear iron at the active site. 2NTDO and NBDO are both able to degrade nitroaromatic compounds. Their structures and structures of NBDO in complex with two nitroarene substrates reveal the structural basis for the dihydroxylation of nitroarene compounds. The electron transfer pathway from NADH via TDOR and the TDOF to the TDO is described in relation to the obtained structures of the TDO system.

Subjects/Keywords: iron; sulphur; enzymes; enzyme activity; analytical methods; molecular biology; Iron-sulfur protein; Rieske non-heme iron dioxygenase; ferredoxin thioredoxin:reductase; thioredoxin; nitroarene; X-ray crystallography

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APA (6^th Edition):

Friemann, R. (2005). Structure-function studies of iron-sulfur enzyme systems. (Doctoral Dissertation). Swedish University of Agricultural Sciences. Retrieved from http://pub.epsilon.slu.se/739/

Chicago Manual of Style (16^th Edition):

Friemann, Rosmarie. “Structure-function studies of iron-sulfur enzyme systems.” 2005. Doctoral Dissertation, Swedish University of Agricultural Sciences. Accessed January 18, 2021. http://pub.epsilon.slu.se/739/.

MLA Handbook (7^th Edition):

Friemann, Rosmarie. “Structure-function studies of iron-sulfur enzyme systems.” 2005. Web. 18 Jan 2021.

Vancouver:

Friemann R. Structure-function studies of iron-sulfur enzyme systems. [Internet] [Doctoral dissertation]. Swedish University of Agricultural Sciences; 2005. [cited 2021 Jan 18]. Available from: http://pub.epsilon.slu.se/739/.

Council of Science Editors:

Friemann R. Structure-function studies of iron-sulfur enzyme systems. [Doctoral Dissertation]. Swedish University of Agricultural Sciences; 2005. Available from: http://pub.epsilon.slu.se/739/

University of Illinois – Urbana-Champaign

17. Snapper, Gregory. Non-heme iron C-H oxidation: tolerance of nitrogen-containing motifs with application to amino-acid and peptide oxidation.

Degree: MS, 0335, 2013, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/45655

► Direct oxidation of C-H bonds using non-heme iron catalysis has proven to be a highly useful transformation since its development in recent years. The ability… (more)

▼ Direct oxidation of C-H bonds using non-heme iron catalysis has proven to be a highly useful transformation since its development in recent years. The ability to directly install oxygen into a hydrocarbon framework negates the need for pre-oxidized materials, and allows for quick and efficient access to more diverse and complex molecules; in some cases, access to motifs that would not otherwise be accessible is possible. Furthermore, ligation at the iron center with a tetra-dentate amine complex containing two adjacent, equatorial active sites on the metal has allowed for synthetically useful levels of reactivity, with the added benefit of predictable selectivity and even directing group effects. In addition, the PDP ligand framework has been shown amenable to various steric and electronic modifications, allowing for tuning of reactivity and selectivity. Key limitations are still prevalent in the methodology, however, including lack of an enantioselective variant, and little/no tolerance of certain common functional groups including amines and most aromatic rings. This work describes development of novel substrate protection methods to address the functional group tolerance of nitrogen-containing substrates, with further application to oxidation of amino-acids and small peptides. Due to inherent catalyst reactivity and reaction conditions, highly complex molecules with a variety of functional groups remain challenging for C-H oxidation, a process that is highly desired in academic and industrial settings alike. The inherent ligation capabilities of nitrogen to iron (exemplified by the tetra-amine PDP ligand) obviate the difficulty in tolerating a substrate containing any variety of amine motifs. Novel protection strategies using various electron-withdrawing group on nitrogen were developed which prevent this ligation, and allow for productive oxidation at distal sites on the molecule. Due to the abundance of various classes of amines, different protective group strategies were developed, depending on which type of amine was present. Application of these protective schemes was then applied to amino-acid and peptide settings. An added benefit of an ester moiety adjacent to the amine allowed for simple nitrosulfonyl protection, whereby oxidation of aliphatic side chain residues was possible. In other cases, certain residues were found to be oxidatively stable. In dipeptide settings, selectivity trends were studied between various residues, and it was also found that residue position (N- vs. C- terminus) greatly affected reactivity trends. Overall this process has been shown to greatly surpass current state of the art methods for amino-acid and peptide oxidation/diversification, and increases the synthetic potential for development of pharmaceuticals of this variety. Advisors/Committee Members: White, M. Christina (advisor).

Subjects/Keywords: C-H Oxidation; Non-Heme Iron; Peptide Oxidation; Alkaloid C-H Oxidation

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APA (6^th Edition):

Snapper, G. (2013). Non-heme iron C-H oxidation: tolerance of nitrogen-containing motifs with application to amino-acid and peptide oxidation. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/45655

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Snapper, Gregory. “Non-heme iron C-H oxidation: tolerance of nitrogen-containing motifs with application to amino-acid and peptide oxidation.” 2013. Thesis, University of Illinois – Urbana-Champaign. Accessed January 18, 2021. http://hdl.handle.net/2142/45655.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Snapper, Gregory. “Non-heme iron C-H oxidation: tolerance of nitrogen-containing motifs with application to amino-acid and peptide oxidation.” 2013. Web. 18 Jan 2021.

Vancouver:

Snapper G. Non-heme iron C-H oxidation: tolerance of nitrogen-containing motifs with application to amino-acid and peptide oxidation. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2013. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2142/45655.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Snapper G. Non-heme iron C-H oxidation: tolerance of nitrogen-containing motifs with application to amino-acid and peptide oxidation. [Thesis]. University of Illinois – Urbana-Champaign; 2013. Available from: http://hdl.handle.net/2142/45655

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Minnesota

18. Knoot, Cory. Mechanistic and structural studies of the non-heme iron oxygenase enzymes protocatechuate 3,4-dioxygenase, CmlA, and CmlI.

Degree: PhD, Biochemistry, Molecular Bio, and Biophysics, 2015, University of Minnesota

URL: http://hdl.handle.net/11299/177150

► Oxygenase enzymes catalyze a remarkable variety of challenging biological transformations using molecular dioxygen (O2) as a cosubstrate. Oxygenases make possible the direct reaction of ground-state… (more)

▼ Oxygenase enzymes catalyze a remarkable variety of challenging biological transformations using molecular dioxygen (O2) as a cosubstrate. Oxygenases make possible the direct reaction of ground-state triplet O2 with organic singlet substrates, a transformation that is spin-forbidden by quantum mechanics. The set of chemical processes by which enzymes overcome this forbidden reaction are collectively termed ‘O2 activation.’ The result of oxygenase reactions is incorporation of one or both atoms of O from O2 into the organic substrate. Because of the critical role of oxygenases in many fundamental biological processes, an understanding of the catalytic and regulatory mechanisms that underlie O2 activation is required for the development of new medical, industrial, ecological and agricultural technologies. Non-heme iron oxygenases use mononuclear iron or diiron cofactors that are not coordinated in a porphyrin scaffold. This dissertation focuses on structural and mechanistic studies of three non-heme iron enzymes. The first, protocatechuate 3,4-dioxygenase (3,4-PCD), is an archetypal aromatic ring-cleaving oxygenase from soil bacteria that uses the oxidized form (Fe3+) of the iron cofactor to react with O2. It is a member of one of only two enzyme families that use Fe3+ to activate O2. CmlA is a diiron cluster-containing oxygenase that is involved in the non-ribosomal peptide synthetase-mediated biosynthesis of the antibiotic chloramphenicol. It catalyzes the first step in this pathway: the β-hydroxylation of an amino acid precursor of the antibiotic. The third enzyme, CmlI, also uses a diiron cluster cofactor and catalyzes the final step in chloramphenicol biosynthesis by converting the arylamine group of the chloramphenicol precursor to its arylnitro analog. Herein, we report the determination of the X-ray crystal structures of the two most critical oxygenated intermediates in the 3,4-PCD catalytic cycle and characterize the reaction of the enzyme with diagnostic substrates. This work confirms mechanistic proposals that have existed since the 1960s and lays the groundwork for future studies. In the last two chapters of the dissertation, we report the X-ray crystal structures of CmlA and CmlI and compare their structures to other diiron cluster-utilizing enzymes. We also discuss the insights gained into their catalytic and regulatory mechanisms.

Subjects/Keywords: Antibiotic biosynthesis; Non-heme iron; O2 activation; Oxygenase; Reactive intermediates; X-ray crystallography

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Knoot, C. (2015). Mechanistic and structural studies of the non-heme iron oxygenase enzymes protocatechuate 3,4-dioxygenase, CmlA, and CmlI. (Doctoral Dissertation). University of Minnesota. Retrieved from http://hdl.handle.net/11299/177150

Chicago Manual of Style (16^th Edition):

Knoot, Cory. “Mechanistic and structural studies of the non-heme iron oxygenase enzymes protocatechuate 3,4-dioxygenase, CmlA, and CmlI.” 2015. Doctoral Dissertation, University of Minnesota. Accessed January 18, 2021. http://hdl.handle.net/11299/177150.

MLA Handbook (7^th Edition):

Knoot, Cory. “Mechanistic and structural studies of the non-heme iron oxygenase enzymes protocatechuate 3,4-dioxygenase, CmlA, and CmlI.” 2015. Web. 18 Jan 2021.

Vancouver:

Knoot C. Mechanistic and structural studies of the non-heme iron oxygenase enzymes protocatechuate 3,4-dioxygenase, CmlA, and CmlI. [Internet] [Doctoral dissertation]. University of Minnesota; 2015. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/11299/177150.

Council of Science Editors:

Knoot C. Mechanistic and structural studies of the non-heme iron oxygenase enzymes protocatechuate 3,4-dioxygenase, CmlA, and CmlI. [Doctoral Dissertation]. University of Minnesota; 2015. Available from: http://hdl.handle.net/11299/177150

19. Baum, Amanda Elizabeth. Synthesis and Characterization of Biologically Relevant Fe(II) Complexes Containing Redox-Active (Hydro)quinone Ligands.

Degree: 2016, Marquette University

URL: https://epublications.marquette.edu/dissertations_mu/647

► Redox-active p-(hydro)quinones work in concert with transition-metal centers to facilitate electron transfers in numerous biological contexts. While p-(hydro)quinones are known to interact with both heme… (more)

▼ Redox-active p-(hydro)quinones work in concert with transition-metal centers to facilitate electron transfers in numerous biological contexts. While p-(hydro)quinones are known to interact with both heme and nonheme iron cofactors, the nonheme systems are particularly relevant to photosynthetic and bioremediation processes. In photosynthesis, two p-quinones facilitate an electron transfer away from the photoexcited P680 cofactor via a non-heme Fe(II) center. Based on EPR results, this interaction results in formation of transient Fe(II)/p-semiquinone (pSQ) species. In addition, a superoxo-iron(II)-pSQ species has been proposed as an intermediate of the oxidative cleavage mechanism of hydroquinone dioxygenases (HQDOs), which play a central role in the catabolism of aromatic pollutants. Despite the prevalence of iron-(hydro)quinone interactions observed in nature, there is a dearth of reported synthetic analogs. We therefore aimed to synthesize five-coordinate monoiron(II) complexes featuring a variety of substituted p-quinone ligand or p-hydroquinone ligands. These complexes contain a tris(3,5-diphenylpyrazolyl)borate (Ph2Tp) or tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine (Ph2TIP) supporting ligand to mimic the different types of facial triads found in nonheme iron dioxygenases. The corresponding Fe(II)-pSQ intermediates were generated via two methods: (i) chemical reduction of the mononuclear Fe(II)-p-quinone complexes, and (ii) proton-coupled electron transfer from an iron-hydroquinonate precursor. The presence of a pSQ radical coupled to a high-spin Fe(II) center was confirmed by spectroscopic (UV-vis, EPR, resonance Raman) and computational (DFT) methods. Recent O2 reactivity studies have examined the ability of these complexes to serve as functional HQDO models. Additionally, we synthesized a diiron(II) species that, upon treatment with a chemical oxidant, yields a stable complex in which two Fe(II) centers are bridged by a p-semiquinone radical. The unique S=7/2 electronic structure of this complex was studies extensively by spectroscopic and computational methods and represents the first complex to feature Fe(II) centers bound to a semiquinonate radical. Further studies were focused on the development of additional dimetal(II) species bridged by varying hydroquinonate ligands to explore their potential of generating novel species that display a high degree of electronic coupling upon one-electron oxidation. Advisors/Committee Members: Fiedler, Adam T., Gardinier, James R., Kincaid, James R..

Subjects/Keywords: Biomimetic; Hydroquinones; Non-heme Iron Dioxygenases; Quinones; Redox-active ligands; Inorganic Chemistry

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APA (6^th Edition):

Baum, A. E. (2016). Synthesis and Characterization of Biologically Relevant Fe(II) Complexes Containing Redox-Active (Hydro)quinone Ligands. (Thesis). Marquette University. Retrieved from https://epublications.marquette.edu/dissertations_mu/647

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Baum, Amanda Elizabeth. “Synthesis and Characterization of Biologically Relevant Fe(II) Complexes Containing Redox-Active (Hydro)quinone Ligands.” 2016. Thesis, Marquette University. Accessed January 18, 2021. https://epublications.marquette.edu/dissertations_mu/647.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Baum, Amanda Elizabeth. “Synthesis and Characterization of Biologically Relevant Fe(II) Complexes Containing Redox-Active (Hydro)quinone Ligands.” 2016. Web. 18 Jan 2021.

Vancouver:

Baum AE. Synthesis and Characterization of Biologically Relevant Fe(II) Complexes Containing Redox-Active (Hydro)quinone Ligands. [Internet] [Thesis]. Marquette University; 2016. [cited 2021 Jan 18]. Available from: https://epublications.marquette.edu/dissertations_mu/647.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Baum AE. Synthesis and Characterization of Biologically Relevant Fe(II) Complexes Containing Redox-Active (Hydro)quinone Ligands. [Thesis]. Marquette University; 2016. Available from: https://epublications.marquette.edu/dissertations_mu/647

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of New Mexico

20. Campbell, Heather. Comparison of monotherapy with angiotensin-converting enzyme inhibitors or angtiotensin receptor blockers in improving health outcomes among veteran patients with type 2 diabetes.

Degree: College of Pharmacy, 2011, University of New Mexico

URL: http://hdl.handle.net/1928/12866

► Diabetes is a world-wide epidemic; 90-95% of diabetes cases are type 2 in nature. Albuminuria and hypertension are risk factors of diabetes complications, specifically nephropathy… (more)

▼ Diabetes is a world-wide epidemic; 90-95% of diabetes cases are type 2 in nature. Albuminuria and hypertension are risk factors of diabetes complications, specifically nephropathy and cardiovascular disease. Angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) are recommended as monotherapy to reduce albuminuria and hypertension. Because of this, we sought to compare patients with type 2 diabetes (P2DM) who received neither therapy to those who received either monotherapy for end-stage renal disease (ESRD), cardio- and cerebro- vascular disease, and all-cause mortality. Additionally, because there are very limited data on comparisons between ACEI and ARB therapies, none of which compare occurrence of incident cardio- or cerebro- vascular disease or mortality, these monotherapies were compared. Moreover, because diabetes incidence is expected to increase, healthcare utilization was also analyzed. This longitudinal study followed P2DM maximally for five years. Comparisons between patients receiving neither therapy and either monotherapy were performed with multivariate logistic or negative binomial regression, while comparisons between ACEI and ARB patients were performed with propensity score weighted logistic or negative binomial regression. Compared to neither therapy, ACEI patients were associated with lower odds of ESRD, higher odds of incident cardio- or cerebro- vascular disease events, lower odds of mortality, and higher incidence rates of healthcare utilization. Treatment selection existed between ACEI and ARB monotherapies in P2DM, necessitating propensity score analysis (PSA). Fortunately, the PSA balanced between group characteristics and had substantial overlap in propensity scores between groups, allowing for precise estimates of causal interpretation. No differences were found between ACEI and ARB monotherapies for all endpoints studied. Since only associations can be found between comparisons of ACEI and ARB patients with neither patients and because ACEIs or ARBs are recommended in guidelines, significance is focused on comparisons between ACEI and ARB patients. This is the second study lasting more than a year comparing outcomes of ACEI and ARB monotherapies for nephropathy and the first study comparing ACEI and ARB monotherapies for other endpoints. This study confirms that ACEIs and ARBs have no significant difference in effects for two years mean follow-up. Until this study, similar effects have only been assumed. Advisors/Committee Members: Khan, Nasreen, Raisch, Dennis W., Borrego, Matthew E., Murata, Glen H., Sather, Mike R..

Subjects/Keywords: Non-insulin-dependent diabetes – Chemotherapy; Angiotensin converting enzyme – Inhibitors; Angiotensin II – Antagonists.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Campbell, H. (2011). Comparison of monotherapy with angiotensin-converting enzyme inhibitors or angtiotensin receptor blockers in improving health outcomes among veteran patients with type 2 diabetes. (Doctoral Dissertation). University of New Mexico. Retrieved from http://hdl.handle.net/1928/12866

Chicago Manual of Style (16^th Edition):

Campbell, Heather. “Comparison of monotherapy with angiotensin-converting enzyme inhibitors or angtiotensin receptor blockers in improving health outcomes among veteran patients with type 2 diabetes.” 2011. Doctoral Dissertation, University of New Mexico. Accessed January 18, 2021. http://hdl.handle.net/1928/12866.

MLA Handbook (7^th Edition):

Campbell, Heather. “Comparison of monotherapy with angiotensin-converting enzyme inhibitors or angtiotensin receptor blockers in improving health outcomes among veteran patients with type 2 diabetes.” 2011. Web. 18 Jan 2021.

Vancouver:

Campbell H. Comparison of monotherapy with angiotensin-converting enzyme inhibitors or angtiotensin receptor blockers in improving health outcomes among veteran patients with type 2 diabetes. [Internet] [Doctoral dissertation]. University of New Mexico; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1928/12866.

Council of Science Editors:

Campbell H. Comparison of monotherapy with angiotensin-converting enzyme inhibitors or angtiotensin receptor blockers in improving health outcomes among veteran patients with type 2 diabetes. [Doctoral Dissertation]. University of New Mexico; 2011. Available from: http://hdl.handle.net/1928/12866

University of Georgia

21. Silaghi-Dumitrescu, Radu. Non-heme iron proteins from anaerobic bacteria involved in nitrosative stress protection.

Degree: 2014, University of Georgia

URL: http://hdl.handle.net/10724/22230

► Acetogenic bacteria grow anaerobically and use CO 2 and an electron donor such as H 2 to produce acetate. Some acetogens, such as Moorella thermoacetica… (more)

Subjects/Keywords: FprA; nitric oxide reductase; oxidase; nitrosative stress; oxidative stress; non-heme iron; nitrosyl; crystal structure; flavoprotein; diiron, mechanism

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APA (6^th Edition):

Silaghi-Dumitrescu, R. (2014). Non-heme iron proteins from anaerobic bacteria involved in nitrosative stress protection. (Thesis). University of Georgia. Retrieved from http://hdl.handle.net/10724/22230

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Silaghi-Dumitrescu, Radu. “Non-heme iron proteins from anaerobic bacteria involved in nitrosative stress protection.” 2014. Thesis, University of Georgia. Accessed January 18, 2021. http://hdl.handle.net/10724/22230.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Silaghi-Dumitrescu, Radu. “Non-heme iron proteins from anaerobic bacteria involved in nitrosative stress protection.” 2014. Web. 18 Jan 2021.

Vancouver:

Silaghi-Dumitrescu R. Non-heme iron proteins from anaerobic bacteria involved in nitrosative stress protection. [Internet] [Thesis]. University of Georgia; 2014. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10724/22230.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Silaghi-Dumitrescu R. Non-heme iron proteins from anaerobic bacteria involved in nitrosative stress protection. [Thesis]. University of Georgia; 2014. Available from: http://hdl.handle.net/10724/22230

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

22. Fournier, Eugénie. Structure et dynamique fonctionnelle de l'ACC oxydase étudiées par marquage de spin suivi par la spectroscopie RPE : Exploring functional dynamics of ACC oxidase by site-directed spin labeling coupled to EPR spectroscopy.

Degree: Docteur es, Sciences chimiques, 2018, Aix Marseille Université

URL: http://www.theses.fr/2018AIXM0583

►

L’ACC Oxydase est une enzyme à Fe(II) non-hémique impliquée dans la biosynthèse de l’éthylène chez les plantes. Notre compréhension du mécanisme ainsi le rôle des… (more)

▼

L’ACC Oxydase est une enzyme à Fe(II) non-hémique impliquée dans la biosynthèse de l’éthylène chez les plantes. Notre compréhension du mécanisme ainsi le rôle des différents cofacteurs nécessite l’obtention des données structurales. Une structure cristallographique a été publiée montrant la partie C-terminale (C-term) éloignée du site actif. Ce n’est pas la conformation active car la partie C-term est essentielle à l’activité. Un modèle structural a été construit dans lequel la partie C-term est tournée vers le site actif. Différentes conformations semblent donc possibles. Le marquage de spin couplé à la spectroscopie RPE est une technique puissante pour sonder la dynamique structurale des protéines. Elle implique la liaison de nitroxydes sur des cystéines. Il est possible d’analyser la mobilité des sondes pour obtenir des informations sur leur environnement local. Par l’utilisation de techniques de RPE avancées, des mesures de distances entre deux sondes sont possibles. Des mutants portant une ou deux cystéines ont été conçus. La dynamique des mutants marqués a été étudiée in vitro par RPE. Par RPE impulsionnelle, des distances ont été mesurées pour l’ACCO en présence de différentes combinaisons de cofacteurs. Les distances expérimentales ont été comparées à celles prédites à partir des structures cristallographiques et du modèle structural et aussi à celles obtenues par des calculs de dynamique moléculaire. Pour cibler d’autres positions sur l’ACCO, l’introduction d’un acide aminé non naturel a été réalisée avec succès permettant d’obtenir de premières données structurales. Des données structurales préliminaires par RPE in cell sont également présentées

ACC Oxidase is a nonheme iron(II) containing enzyme involved in the biosynthesis of ethylene in plants. ACCO reaction mechanism and the role of the various cofactors are not well understood and structural and dynamic data are still required. A crystallographic structure has been reported showing the C-terminal part (C-term) away from the active site. This is not the active conformation as it has been shown that the C-term is essential. Later, a structural model has been proposed in which the C-term is folded towards the active site. Different conformations can be hypothesized. A technique well suited to monitor protein dynamics is site-directed spin labeling followed by EPR spectroscopy. It relies on the insertion of a nitroxide derivative on cysteines. Using this approach, it is possible to analyze the mobility of the label in order to obtain information on its local environment. Moreover using advanced EPR techniques, it is possible to acquire interspin distances between two incorporated probes. Mutants bearing one or two cysteines at desirable positions were designed. The dynamics of labeled mutants were studied in vitro using continuous wave EPR. By pulsed EPR, distances were recorded for ACCO in presence of different combinations of cofactors. The experimental distances were compared to the predicted ones obtained from the crystallographic and model…

Advisors/Committee Members: Simaan, Ariane Jalila (thesis director), Belle, Valérie (thesis director).

Subjects/Keywords: Enzyme à fer non-hémique; Nitroxyde; Spectroscopie RPE; ACC Oxydase; Nonheme iron enzyme; Nitroxide; EPR spectroscopy; ACC Oxidase

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APA (6^th Edition):

Fournier, E. (2018). Structure et dynamique fonctionnelle de l'ACC oxydase étudiées par marquage de spin suivi par la spectroscopie RPE : Exploring functional dynamics of ACC oxidase by site-directed spin labeling coupled to EPR spectroscopy. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2018AIXM0583

Chicago Manual of Style (16^th Edition):

Fournier, Eugénie. “Structure et dynamique fonctionnelle de l'ACC oxydase étudiées par marquage de spin suivi par la spectroscopie RPE : Exploring functional dynamics of ACC oxidase by site-directed spin labeling coupled to EPR spectroscopy.” 2018. Doctoral Dissertation, Aix Marseille Université. Accessed January 18, 2021. http://www.theses.fr/2018AIXM0583.

MLA Handbook (7^th Edition):

Fournier, Eugénie. “Structure et dynamique fonctionnelle de l'ACC oxydase étudiées par marquage de spin suivi par la spectroscopie RPE : Exploring functional dynamics of ACC oxidase by site-directed spin labeling coupled to EPR spectroscopy.” 2018. Web. 18 Jan 2021.

Vancouver:

Fournier E. Structure et dynamique fonctionnelle de l'ACC oxydase étudiées par marquage de spin suivi par la spectroscopie RPE : Exploring functional dynamics of ACC oxidase by site-directed spin labeling coupled to EPR spectroscopy. [Internet] [Doctoral dissertation]. Aix Marseille Université 2018. [cited 2021 Jan 18]. Available from: http://www.theses.fr/2018AIXM0583.

Council of Science Editors:

Fournier E. Structure et dynamique fonctionnelle de l'ACC oxydase étudiées par marquage de spin suivi par la spectroscopie RPE : Exploring functional dynamics of ACC oxidase by site-directed spin labeling coupled to EPR spectroscopy. [Doctoral Dissertation]. Aix Marseille Université 2018. Available from: http://www.theses.fr/2018AIXM0583

University of Illinois – Urbana-Champaign

23. Miner, Kyle D. Rational design of functional heme copper oxidases in myoglobin.

Degree: PhD, 0318, 2012, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/29570

► Proteins are involved in nearly every process that occurs in living systems, either as a main participant in the process or preforming a supporting role.… (more)

▼ Proteins are involved in nearly every process that occurs in living systems, either as a main participant in the process or preforming a supporting role. It is estimated that approximately half of proteins in living systems are associated with a metal in some fashion. With such a high percentage of proteins interacting with metals, it may not be a surprise that most cellular pathways that have at least one metalloprotein performing one or more steps. Many, if not all, of the most important and complex processes that occur in living systems are performed by a metalloprotein. These processes include photosynthesis, cellular respiration, and nucleic acid repair. The metals in these proteins expand the potential chemistry beyond what can be done with only the 20 naturally occurring amino acids. However, nature uses relatively few metal complexes, such as heme cofactors or iron sulfur clusters or metal ions, considering the number of functions that metalloproteins perform. Also, nature uses a surprisingly small number of protein domains and folds compared the number of possible folds. In metalloproteins, both the metal and protein environment surrounding it play an important role in determining the chemistry that is performed. The protein adjusts the properties of the metal, such as the redox potential or the number of open coordination sites. Many metal ions found in metalloproteins are less reactive outside of a protein environment. Despite many years of study, we are only beginning to understand the functioning of large complex metalloproteins, such as heme copper oxidases (HCOs) in respiration or the oxygen evolving complex in photosystems. Large complex proteins pose two problems with respect to studying function. Large complexes are relatively difficult to isolate in a biologically relevant form and the multiple metal sites can either interfere with spectroscopic analysis or require the use of relatively sophisticated methodology. As an alternative to studying these complex proteins, we have chosen instead to redesign an existing well-studied heme protein, myoglobin, to mimic the bimetallic, heme-CuB site of HCOs. This is the site where molecular oxygen is converted to water as part of cellular respiration. The conversion of oxygen to water is highly difficult as there are many highly reactive intermediates that must stabilized so that the reaction can result in water formation. Such a redesign can be thought of as going from the “bottom up” with respect to the desired function. In the process of building up such a model, we are producing minimalistic versions in order to see what the function of each of the structural features is and how it affects chemistry. This thesis describes the improvement of an existing myoglobin based model system of HCOs, named CuBMb, where an non-native copper site was previously engineered into myoglobin by adding two histidine residues. Along with the native histidine, the resulting site resembles the CuB site found in HCOs. This model protein is purified without metal in the CuB… Advisors/Committee Members: Lu, Yi (advisor), Lu, Yi (Committee Chair), Cronan, John E. (committee member), Gennis, Robert B. (committee member), Rienstra, Chad M. (committee member).

Subjects/Keywords: Protein Design; Heme Copper Oxidases; Enzyme modeling

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APA (6^th Edition):

Miner, K. D. (2012). Rational design of functional heme copper oxidases in myoglobin. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/29570

Chicago Manual of Style (16^th Edition):

Miner, Kyle D. “Rational design of functional heme copper oxidases in myoglobin.” 2012. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 18, 2021. http://hdl.handle.net/2142/29570.

MLA Handbook (7^th Edition):

Miner, Kyle D. “Rational design of functional heme copper oxidases in myoglobin.” 2012. Web. 18 Jan 2021.

Vancouver:

Miner KD. Rational design of functional heme copper oxidases in myoglobin. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2012. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/2142/29570.

Council of Science Editors:

Miner KD. Rational design of functional heme copper oxidases in myoglobin. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2012. Available from: http://hdl.handle.net/2142/29570

Macquarie University

24. Smith, Jason R. Indoleamine 2,3-dioxygenase 1: mapping the active site and discovery of novel inhibitors.

Degree: 2012, Macquarie University

URL: http://hdl.handle.net/1959.14/1138188

►

"A thesis submitted in the partial fulfillment of the requirements for the award of the degree of Master of Philosophy."

1. Introduction – 2. Selection… (more)

▼

"A thesis submitted in the partial fulfillment of the requirements for the award of the degree of Master of Philosophy."

1. Introduction – 2. Selection and synthesis of photoaffinity labels – 3. Photoaffinity labelling of rhIDO-1 by azidotryptophans – 4. IDO-1 and small molecule inhibitors – 5. Experiments to further understand the interactions of selected scaffolds with rhIDO-1 – 6. In silico screening of new IDO-1 inhibitors – 7. Conclusions and future directions.

Indoleamine 2,3‐dioxygenase‐1 (IDO‐1) is a heme‐containing enzyme that catalyses the initial step in the major pathway of L‐tryptophan catabolism; the kynurenine pathway. A large body of evidence has been accumulating for its immunosuppressive and tumoural escape roles and its applicability as a therapeutic target. Of particular interest is the possibility that IDO‐1 inhibition may arrest, and sometimes revert, tumour growth. To date only two molecules have achieved phase 1 clinical testing, therefore, there exists a continuing need for the development of new IDO‐1 inhibitors as therapeutic leads. This project seeks to combine experimental and computational approaches to firstly, understand the process of ligand binding to IDO‐1, and secondly, screen for new and unique inhibitors of IDO‐1. Progress has been made towards mapping the ligand binding interactions of IDO‐1 through photoaffinity labelling. This involved synthesis of substrate analogues capable of forming covalent linkages to the enzyme in a controlled manner. Analysis of these experiments through mass spectrometric techniques was then used to identify sites of attachment. Parallel to this, high throughput in silico screening (utilising multiple pharmacophores and an innovative ‘What‐If’ docking technique) was performed, and identified four novel inhibitors with a unique esterimidamide structural element. These models suggest that these molecules show great promise for development of potent and specific IDO‐1 inhibitors.

1 online resource (x, 203 pages) illustrations

Advisors/Committee Members: Macquarie University. Department of Chemistry and Biomolecular Sciences.

Subjects/Keywords: Heme oxygenase; Enzyme inhibitors; Indoleamine 2,3-dioxygenase-1; heme oxygenase; enzyme inhabitors

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APA (6^th Edition):

Smith, J. R. (2012). Indoleamine 2,3-dioxygenase 1: mapping the active site and discovery of novel inhibitors. (Masters Thesis). Macquarie University. Retrieved from http://hdl.handle.net/1959.14/1138188

Chicago Manual of Style (16^th Edition):

Smith, Jason R. “Indoleamine 2,3-dioxygenase 1: mapping the active site and discovery of novel inhibitors.” 2012. Masters Thesis, Macquarie University. Accessed January 18, 2021. http://hdl.handle.net/1959.14/1138188.

MLA Handbook (7^th Edition):

Smith, Jason R. “Indoleamine 2,3-dioxygenase 1: mapping the active site and discovery of novel inhibitors.” 2012. Web. 18 Jan 2021.

Vancouver:

Smith JR. Indoleamine 2,3-dioxygenase 1: mapping the active site and discovery of novel inhibitors. [Internet] [Masters thesis]. Macquarie University; 2012. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1959.14/1138188.

Council of Science Editors:

Smith JR. Indoleamine 2,3-dioxygenase 1: mapping the active site and discovery of novel inhibitors. [Masters Thesis]. Macquarie University; 2012. Available from: http://hdl.handle.net/1959.14/1138188

Utah State University

25. Allen, Karin. A Novel Role for Non-Heme Iron in Myoglobin Oxidation: An Examination of the Antioxidant Effects of Iron Chelating Compounds in Meat and Myoglobin Model Systems.

Degree: PhD, Nutrition, Dietetics, and Food Sciences, 2009, Utah State University

URL: https://digitalcommons.usu.edu/etd/374

► Myoglobin (Mb) oxidation, and the subsequent browning, is the primary basis for consumer rejection of fresh retail beef. Considerable effort has been directed by… (more)

▼ Myoglobin (Mb) oxidation, and the subsequent browning, is the primary basis for consumer rejection of fresh retail beef. Considerable effort has been directed by the industry towards the development of techniques that can enhance color stability. However, the underlying mechanism of Mb oxidation has been studied extensively, but is still not entirely understood. It is known that chelation of iron and copper delays Mb oxidation and browning, but a clear role for these metals has not been established in any current Mb oxidation mechanism. The objective of the current study was to examine the possibility that iron plays a more direct role in Mb oxidation, and that metal chelators such as milk mineral (MM) and sodium tripolyphosphate can inhibit this action. MM, a colloidal calcium phosphate of large molecular weight and undetermined structure, was demonstrated to be a high-affinity iron chelator. Non-heme iron was found to stimulate Mb oxidation even in the absence of lipid, showing for the first time that the role of ferrous iron was not limited to promoting lipid oxidation, but instead has a yet-to-be determined role as a pro-oxidant factor in Mb oxidation. Ferrous iron was found to promote Mb oxidation under standard atmospheric conditions, while in high oxygen systems this effect was not seen. Addition of catalase did not affect Mb oxidation. However, in iron-containing systems, catalase significantly slowed Mb oxidation, while MM addition completely reversed the stimulatory effect of added iron. Type I radical-quenching antioxidants were found to rapidly reduce ferric iron to the ferrous form. This strong reducing ability accounted for the pro-oxidant effects of rosmarinic acid and eugenol in the lipid-free Mb model system. In raw ground beef, Type I antioxidants were highly effective at preventing Mb oxidation in the presence of lipid. Of the Type II chelators examined, only MM was able to delay Mb oxidation as well as the Type I antioxidants, possibly because it is not as susceptible to enzymatic hydrolysis. Advisors/Committee Members: Daren P Cornforth, Marie K. Walsh, Jeffrey R. Broadbent, ;.

Subjects/Keywords: iron chelation; meat color; myoglobin oxidation; non-heme iron; Agricultural and Resource Economics

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APA (6^th Edition):

Allen, K. (2009). A Novel Role for Non-Heme Iron in Myoglobin Oxidation: An Examination of the Antioxidant Effects of Iron Chelating Compounds in Meat and Myoglobin Model Systems. (Doctoral Dissertation). Utah State University. Retrieved from https://digitalcommons.usu.edu/etd/374

Chicago Manual of Style (16^th Edition):

Allen, Karin. “A Novel Role for Non-Heme Iron in Myoglobin Oxidation: An Examination of the Antioxidant Effects of Iron Chelating Compounds in Meat and Myoglobin Model Systems.” 2009. Doctoral Dissertation, Utah State University. Accessed January 18, 2021. https://digitalcommons.usu.edu/etd/374.

MLA Handbook (7^th Edition):

Allen, Karin. “A Novel Role for Non-Heme Iron in Myoglobin Oxidation: An Examination of the Antioxidant Effects of Iron Chelating Compounds in Meat and Myoglobin Model Systems.” 2009. Web. 18 Jan 2021.

Vancouver:

Allen K. A Novel Role for Non-Heme Iron in Myoglobin Oxidation: An Examination of the Antioxidant Effects of Iron Chelating Compounds in Meat and Myoglobin Model Systems. [Internet] [Doctoral dissertation]. Utah State University; 2009. [cited 2021 Jan 18]. Available from: https://digitalcommons.usu.edu/etd/374.

Council of Science Editors:

Allen K. A Novel Role for Non-Heme Iron in Myoglobin Oxidation: An Examination of the Antioxidant Effects of Iron Chelating Compounds in Meat and Myoglobin Model Systems. [Doctoral Dissertation]. Utah State University; 2009. Available from: https://digitalcommons.usu.edu/etd/374

Vanderbilt University

26. Pishchany, Glib. Human hemoglobin as an iron source of Staphylococcus aureus.

Degree: PhD, Microbiology and Immunology, 2011, Vanderbilt University

URL: http://hdl.handle.net/1803/12452

► MICROBIOLOGY AND IMMUNOLOGY HUMAN HEMOGLOBIN AS AN IRON SOURCE OF STAPHYLOCOCCUS AUREUS GLIB PISHCHANY Dissertation under the direction of Professor Eric P. Skaar Staphylococcus aureus… (more)

Subjects/Keywords: Staphylococcus aureus; iron; heme; hemoglobin; Isd; infection

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APA (6^th Edition):

Pishchany, G. (2011). Human hemoglobin as an iron source of Staphylococcus aureus. (Doctoral Dissertation). Vanderbilt University. Retrieved from http://hdl.handle.net/1803/12452

Chicago Manual of Style (16^th Edition):

Pishchany, Glib. “Human hemoglobin as an iron source of Staphylococcus aureus.” 2011. Doctoral Dissertation, Vanderbilt University. Accessed January 18, 2021. http://hdl.handle.net/1803/12452.

MLA Handbook (7^th Edition):

Pishchany, Glib. “Human hemoglobin as an iron source of Staphylococcus aureus.” 2011. Web. 18 Jan 2021.

Vancouver:

Pishchany G. Human hemoglobin as an iron source of Staphylococcus aureus. [Internet] [Doctoral dissertation]. Vanderbilt University; 2011. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/1803/12452.

Council of Science Editors:

Pishchany G. Human hemoglobin as an iron source of Staphylococcus aureus. [Doctoral Dissertation]. Vanderbilt University; 2011. Available from: http://hdl.handle.net/1803/12452

Princeton University

27. Boaz, Nicholas Charles. The Development and Study of Practical C-H Functionalization Reactions Using Mechanistic Tools .

Degree: PhD, 2015, Princeton University

URL: http://arks.princeton.edu/ark:/88435/dsp01ks65hf52g

► The unactivated C-H bonds of hydrocarbons are some of the most common chemical functionalities in organic molecules. Despite their ubiquity, they are some of the… (more)

▼ The unactivated C-H bonds of hydrocarbons are some of the most common chemical functionalities in organic molecules. Despite their ubiquity, they are some of the most difficult functional groups to manipulate because of their kinetic inertness, stemming from the strong non-polar C-H bond. The focus of this work is the development and mechanistic study of processes that break strong C-H bonds in a selective manner. Sulfonated oxoFeIV porphyrins (models of the compound II state of CYP) are shown to be basic with measureable pKa values. This measured pKa represents a novel two-proton electromeric equilibrium between oxoFeIV porphyrin and the corresponding (OH2)2FeIII porphyrin cation radicals. The nature of this equilibrium, in combination with the empirical observation of both substrate and solvent-derived deuterium kinetic isotope effects, indicates a new mode of C-H bond scission. The solvent-proton-assisted, proton-coupled electron transfer proposed leads to a net increase in the thermodynamic driving force of C-H cleavage when compared to a single proton model. An extension of this work shows that sulfonated iron porphyrins were shown to have oxidation behavior, which was highly dependant upon both the electronics of the porphyrin ring and the novel two-proton pKa. The mechanism of a reaction system that utilizes combinations of high-valent iodine oxides and catalytic amounts of chloride to selectively oxidize methane was determined to function via a radical pathway. Mechanistic studies suggest a catalytic cycle where alkyl radicals generated by hydrogen atom abstraction from chlorine atoms are able to react with iodine generated in situ. The transiently formed alkyl iodide then undergoes solvolysis to yield the product ester. This process of radical based C-H ester formation is extended to substrates containing benzylic C-H bonds by replacing the catalyst with the well-studied N-oxyl catalyst N-hydroxyphthalimide (NHPI). This NHPI-iodate system was shown to be effective in the functionalization of primary and secondary benzylic C-H bonds in moderate to good yield. Advisors/Committee Members: Groves, John T (advisor).

Subjects/Keywords: C-H Activation; Heme; Iodine; Iron; Methane

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APA (6^th Edition):

Boaz, N. C. (2015). The Development and Study of Practical C-H Functionalization Reactions Using Mechanistic Tools . (Doctoral Dissertation). Princeton University. Retrieved from http://arks.princeton.edu/ark:/88435/dsp01ks65hf52g

Chicago Manual of Style (16^th Edition):

Boaz, Nicholas Charles. “The Development and Study of Practical C-H Functionalization Reactions Using Mechanistic Tools .” 2015. Doctoral Dissertation, Princeton University. Accessed January 18, 2021. http://arks.princeton.edu/ark:/88435/dsp01ks65hf52g.

MLA Handbook (7^th Edition):

Boaz, Nicholas Charles. “The Development and Study of Practical C-H Functionalization Reactions Using Mechanistic Tools .” 2015. Web. 18 Jan 2021.

Vancouver:

Boaz NC. The Development and Study of Practical C-H Functionalization Reactions Using Mechanistic Tools . [Internet] [Doctoral dissertation]. Princeton University; 2015. [cited 2021 Jan 18]. Available from: http://arks.princeton.edu/ark:/88435/dsp01ks65hf52g.

Council of Science Editors:

Boaz NC. The Development and Study of Practical C-H Functionalization Reactions Using Mechanistic Tools . [Doctoral Dissertation]. Princeton University; 2015. Available from: http://arks.princeton.edu/ark:/88435/dsp01ks65hf52g

University of Western Ontario

28. Tiedemann, Michael T. Heme Binding and Transfer in the Isd Heme Scavenging Pathway of Staphylococcus aureus.

Degree: 2012, University of Western Ontario

URL: https://ir.lib.uwo.ca/etd/545

► The antibiotic resistant bacterium Staphylococcus aureus is a significant problem in hospitals and communities worldwide. Survival of the bacterium in the host is reliant on… (more)

Subjects/Keywords: Staphylcoccus aureus; iron-regulated surface determinant; heme transfer pathway; heme binding proteins; heme transfer kinetics; heme analogs; Other Chemistry

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APA (6^th Edition):

Tiedemann, M. T. (2012). Heme Binding and Transfer in the Isd Heme Scavenging Pathway of Staphylococcus aureus. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/545

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Tiedemann, Michael T. “Heme Binding and Transfer in the Isd Heme Scavenging Pathway of Staphylococcus aureus.” 2012. Thesis, University of Western Ontario. Accessed January 18, 2021. https://ir.lib.uwo.ca/etd/545.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Tiedemann, Michael T. “Heme Binding and Transfer in the Isd Heme Scavenging Pathway of Staphylococcus aureus.” 2012. Web. 18 Jan 2021.

Vancouver:

Tiedemann MT. Heme Binding and Transfer in the Isd Heme Scavenging Pathway of Staphylococcus aureus. [Internet] [Thesis]. University of Western Ontario; 2012. [cited 2021 Jan 18]. Available from: https://ir.lib.uwo.ca/etd/545.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Tiedemann MT. Heme Binding and Transfer in the Isd Heme Scavenging Pathway of Staphylococcus aureus. [Thesis]. University of Western Ontario; 2012. Available from: https://ir.lib.uwo.ca/etd/545

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Missouri – Columbia

29. Punthasee, Puminan. The development of the first generation of exo-affinity labeling agents, inactivators of protein tyrosine phosphatase 1B.

Degree: 2014, University of Missouri – Columbia

URL: https://doi.org/10.32469/10355/44428

► Type II Diabetes (T2DB) is one of the worldwide problems characterized by ineffective insulin signal transduction as a result of insulin resistance and impaired glucose… (more)

Subjects/Keywords: Author supplied: exo-affinity labeling agent, time-dependent inactivation, enzyme inactivator, protein tyrosine phosphatase 1B, dephosphorylation; Non-insulin-dependent diabetes – Treatment; Protein-tyrosine phosphatase – Inhibitors

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APA (6^th Edition):

Punthasee, P. (2014). The development of the first generation of exo-affinity labeling agents, inactivators of protein tyrosine phosphatase 1B. (Thesis). University of Missouri – Columbia. Retrieved from https://doi.org/10.32469/10355/44428

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Punthasee, Puminan. “The development of the first generation of exo-affinity labeling agents, inactivators of protein tyrosine phosphatase 1B.” 2014. Thesis, University of Missouri – Columbia. Accessed January 18, 2021. https://doi.org/10.32469/10355/44428.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Punthasee, Puminan. “The development of the first generation of exo-affinity labeling agents, inactivators of protein tyrosine phosphatase 1B.” 2014. Web. 18 Jan 2021.

Vancouver:

Punthasee P. The development of the first generation of exo-affinity labeling agents, inactivators of protein tyrosine phosphatase 1B. [Internet] [Thesis]. University of Missouri – Columbia; 2014. [cited 2021 Jan 18]. Available from: https://doi.org/10.32469/10355/44428.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Punthasee P. The development of the first generation of exo-affinity labeling agents, inactivators of protein tyrosine phosphatase 1B. [Thesis]. University of Missouri – Columbia; 2014. Available from: https://doi.org/10.32469/10355/44428

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Ottawa

30. Robinson, Bryce. The Oxidation of Fe (II), Fe (II) Mineral, and Rapid Denitrification under Cyanobacterial Interfacial Competition by Novel NDFe(II)OB, Pseudogulbenkiania ferrooxidans sp. MAI-1 .

Degree: 2019, University of Ottawa

URL: http://hdl.handle.net/10393/39468

► Nitrogen is an essential constituent and building unit of all living organisms, and the primary limiting nutrient on our planet such that its cycle widely… (more)

▼ Nitrogen is an essential constituent and building unit of all living organisms, and the primary limiting nutrient on our planet such that its cycle widely depends on the diverse nitrogen-transforming microorganisms, such as denitrifiers. Oxygen minimum zones or hypoxic aquatic ecosystems account for 30-50% of all nitrogen denitrification and under dynamic transformation imbalance, of measure dependent variable modularity, little is known about discrete shifts in denitrification competition by various microorganisms of divergent metabolism; or the Fe (II) – Fe (III) redox linking process. Novel nitrate dependent Fe (II) oxidizing bacteria as rapid denitrifier and iron oxidizer can significantly oxidize various iron minerals (magnetite and ferrous mono sulfide). Evidence of nitrate dependent Fe (II) oxidation by the bacterium P. ferrooxidans sp. MAI-1 could shed light as a novel competitor at microaerophilic (<2.0mg/L DO, -100 – +100 mV) interfacial competition with cyanobacteria Microcystis aeruginosa corollary to ecosystem eutrophication and concomitant microcystin production, with the goal of abating a toxic cyanobacterial bloom. Nitrate Dependent Iron Oxidizing Bacteria (NDFe(II)OB) showed rapid nitrate reduction (>25 mg/L NO2, day 7) and consequent bright-orange iron oxides. Saturation indices (day 1 and 8 SI = log (IAP/Ksp), showed non exclusive vivianite formation i.e., 3.80 and 0.44-0.55, respectively, with near complete oxidation by day 8, significantly abating logarithmic growth over a fourteen day period (p>0.01). N-N dichotomies are not purely exclusive, as terminal PO4 competition differed by ~0.1 mg/L after a 15 day period, with approximately one five hundred times more N-nitrogen loss compared to P-phosphorus loss difference. Early logarithmic cyanobacteria cell counts under the presence of the competitor decreased by >20% by day 18 of growth. This is consistent with the classical view that under primary metabolite exhaustion, interspecific competition should lead to competitive exclusion and not niche differentiation.

Subjects/Keywords: cyanobacteria; nitrate dependent iron oxidizer

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APA (6^th Edition):

Robinson, B. (2019). The Oxidation of Fe (II), Fe (II) Mineral, and Rapid Denitrification under Cyanobacterial Interfacial Competition by Novel NDFe(II)OB, Pseudogulbenkiania ferrooxidans sp. MAI-1 . (Thesis). University of Ottawa. Retrieved from http://hdl.handle.net/10393/39468

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Robinson, Bryce. “The Oxidation of Fe (II), Fe (II) Mineral, and Rapid Denitrification under Cyanobacterial Interfacial Competition by Novel NDFe(II)OB, Pseudogulbenkiania ferrooxidans sp. MAI-1 .” 2019. Thesis, University of Ottawa. Accessed January 18, 2021. http://hdl.handle.net/10393/39468.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Robinson, Bryce. “The Oxidation of Fe (II), Fe (II) Mineral, and Rapid Denitrification under Cyanobacterial Interfacial Competition by Novel NDFe(II)OB, Pseudogulbenkiania ferrooxidans sp. MAI-1 .” 2019. Web. 18 Jan 2021.

Vancouver:

Robinson B. The Oxidation of Fe (II), Fe (II) Mineral, and Rapid Denitrification under Cyanobacterial Interfacial Competition by Novel NDFe(II)OB, Pseudogulbenkiania ferrooxidans sp. MAI-1 . [Internet] [Thesis]. University of Ottawa; 2019. [cited 2021 Jan 18]. Available from: http://hdl.handle.net/10393/39468.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Robinson B. The Oxidation of Fe (II), Fe (II) Mineral, and Rapid Denitrification under Cyanobacterial Interfacial Competition by Novel NDFe(II)OB, Pseudogulbenkiania ferrooxidans sp. MAI-1 . [Thesis]. University of Ottawa; 2019. Available from: http://hdl.handle.net/10393/39468

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Open Access Theses and Dissertations