Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for subject:(G3C9). Showing records 1 – 2 of 2 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


The Ohio State University

1. Peachman, Scott Frederick. A Computational Study of Organophosphorus Nerve Agent Binding to Recombinant Human Paraoxonase 1 G3C9 Mutants with Engineered Stereospecificity.

Degree: MS, Chemistry, 2009, The Ohio State University

HuPON1 (Human Paraoxonase 1) has been targeted as a potential ‘bioscavenger’ enzyme to hydrolyze organophosphorus (OP) nerve agent compounds. With little structural data and an unknown active site mechanism, a collaborative project involving the Weizmann Institute, the USAMRICD (United States Army Medical Research Institute of Chemical Defense), NIH, and other universities was developed with the goal of engineering HuPON1 for catalytic and broad substrate hydrolysis of OP nerve agents. Along with directed evolution and mutagenesis techniques, computational modeling has proved effective in finding important active site residues for binding. Directed evolution studies by the Weizmann Institute of Science developed highly expressible rePON1 variant G3C9, and later stereospecific coumarin-OP mutants 2B4, 3B3, and 8C8. Computational models of these variants were relaxed through molecular dynamics, and used in docking studies with coumarin-OPs, V-agents, and G-agents. The ability to turn over the more toxic (-) isomer of nerve agents exclusively has been sought in recent directed evolution and mutagenesis studies. In order to rationalize the method of producing (-) isomer stereospecificity, mutants of negligible specificity (G3C9), (+) isomer specificity (2B4/3B3), and (-) isomer specificity (8C8), were computationally studied and compared by molecular dynamics results and docking conformations. Unique binding modes were seen amongst the models for the same coumarin-OP ligands, which may be due to spatial changes in the active sites. A movement of the catalytic calcium was observed in each mutant, with an attempted rationalization by the way active site mutations affect the calcium coordination environment. The combination of calcium movement and spatial changes in active sites has been considered important in rationalizing stereospecificity. The G3C9 variant displayed two predominant binding modes for low energy coumarin-OP and V-agent compounds. No consistent theme was observed between (R) and (S) isomer binding conformations. Kinetic data from G3C9 single mutants with coumarin-OP substrates was obtained to rationalize docking results. The 3B3 and 2B4 mutants display a lowered calcium environment likely due to alternative conformations of active site mutations L240S and T332A. Stereospecificity for (+) isomer coumarin-OPs was investigated through binding pose MM-PB/SA energy and orientation relative to a proposed hydrolysis mechanism involving His285, Asp269, and a water nucleophile. The VR / VX ratio for V-agents in the 2B4/3B3 variants was explored through binding energy. The recently evolved 8C8 variant was compared to related variants 2H4 and 4E9 to investigate calcium movement and coordination environment in stereospecific mutants for toxic (-) isomer coumarin-OP hydrolysis. A distinct calcium environment was seen, with calcium residue coordination reflective of that seen in related crystal structures by the Weizmann Institute. Coumarin-OPs in 8C8 were shown to not mimic their associated G-agents in… Advisors/Committee Members: Hadad, Christopher (Advisor).

Subjects/Keywords: Chemistry; G3C9; PON1

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Peachman, S. F. (2009). A Computational Study of Organophosphorus Nerve Agent Binding to Recombinant Human Paraoxonase 1 G3C9 Mutants with Engineered Stereospecificity. (Masters Thesis). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1253606667

Chicago Manual of Style (16th Edition):

Peachman, Scott Frederick. “A Computational Study of Organophosphorus Nerve Agent Binding to Recombinant Human Paraoxonase 1 G3C9 Mutants with Engineered Stereospecificity.” 2009. Masters Thesis, The Ohio State University. Accessed August 15, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253606667.

MLA Handbook (7th Edition):

Peachman, Scott Frederick. “A Computational Study of Organophosphorus Nerve Agent Binding to Recombinant Human Paraoxonase 1 G3C9 Mutants with Engineered Stereospecificity.” 2009. Web. 15 Aug 2020.

Vancouver:

Peachman SF. A Computational Study of Organophosphorus Nerve Agent Binding to Recombinant Human Paraoxonase 1 G3C9 Mutants with Engineered Stereospecificity. [Internet] [Masters thesis]. The Ohio State University; 2009. [cited 2020 Aug 15]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1253606667.

Council of Science Editors:

Peachman SF. A Computational Study of Organophosphorus Nerve Agent Binding to Recombinant Human Paraoxonase 1 G3C9 Mutants with Engineered Stereospecificity. [Masters Thesis]. The Ohio State University; 2009. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1253606667


The Ohio State University

2. Baldauff, Rachel Michelle. Interaction of Recombinant Paraoxonase-1 with Reconstituted High-Density Lipoproteins.

Degree: MS, Chemistry, 2011, The Ohio State University

Overwhelming evidence suggests that low levels of high-density lipoproteins (HDL) increase one’s odds of developing coronary artery disease (CAD). This phenomenon could be due in part to the hydrolase activity of the enzyme human serum paraoxonase-1 (huPON1) that is found bound to the HDL in the circulatory system. Many studies have indicated lowered atherogenic effects due to raised huPON1/HDL levels. In order to fully understand these correlations, more insight into how the interaction of huPON1 and HDL may be delivering its beneficial properties is needed. In the current study, the interactions between reconstituted HDL (rHDL) particles and fluorophore-labeled variants of PON1 (G3C9-ybbR and five other variants) were probed via fluorescence anisotropy, effects on arylesterase and paraoxonase activities, and changes in arylesterase activity upon binding to rHDL. While the mutations to the hydrophobic signal sequence (L12A and L12K) did not appear to have significant effects on the arylesterase or paraoxonase activities, the mutations on the active site lid (W194A and W194K) caused increases in both activities. While the fluorescence anisotropy measurements were unable to reveal anything about the binding affinity, the arylesterase stimulation due to rHDL binding did. Advisors/Committee Members: Gustafson, Terry (Advisor), Magliery, Thomas (Advisor).

Subjects/Keywords: Biochemistry; rePON1; rHDL; G3C9

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Baldauff, R. M. (2011). Interaction of Recombinant Paraoxonase-1 with Reconstituted High-Density Lipoproteins. (Masters Thesis). The Ohio State University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=osu1321986125

Chicago Manual of Style (16th Edition):

Baldauff, Rachel Michelle. “Interaction of Recombinant Paraoxonase-1 with Reconstituted High-Density Lipoproteins.” 2011. Masters Thesis, The Ohio State University. Accessed August 15, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1321986125.

MLA Handbook (7th Edition):

Baldauff, Rachel Michelle. “Interaction of Recombinant Paraoxonase-1 with Reconstituted High-Density Lipoproteins.” 2011. Web. 15 Aug 2020.

Vancouver:

Baldauff RM. Interaction of Recombinant Paraoxonase-1 with Reconstituted High-Density Lipoproteins. [Internet] [Masters thesis]. The Ohio State University; 2011. [cited 2020 Aug 15]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1321986125.

Council of Science Editors:

Baldauff RM. Interaction of Recombinant Paraoxonase-1 with Reconstituted High-Density Lipoproteins. [Masters Thesis]. The Ohio State University; 2011. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=osu1321986125

.