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

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1. Cameron, Elizabeth Ann. The Structure and Function of the Starch Utilization System in Bacteroides thetaiotaomicron.

Degree: PhD, Microbiology & Immunology, 2014, University of Michigan

Degradation of polysaccharides is an important function performed by the human gut microbiota. Bacterial carbohydrate metabolism in the gut not only provides the host with a significant portion of their daily nutrients, but is also a major factor shaping the composition of the microbial community. The Bacteroidetes, one of the two dominant bacterial taxa in the human gut, degrade a large number of carbohydrates via expression of unique multi-protein complexes, each targeting a different glycan. The first such system described was the starch utilization system (Sus) in Bacteroides thetaiotaomicron (Bt), an eight protein system required for the bacterium to metabolize starch. Homologous “Sus-like” systems are found in the majority of gut Bacteroidetes with some species devoting up to 20% of their genome to encoding them. The Bt Sus is a model for glycan acquisition by the Bacteroidetes, and the work presented here addresses several important questions regarding the structure and function of individual Sus proteins as well as how these components function together to efficiently acquire and degrade the abundant dietary glycan starch. The crystal structures of two Sus outer-membrane proteins (OMPs), SusE and SusF, were solved revealing that they both contain multiple starch binding sites. In total the Sus OMPs (SusD,E,F and G) contain eight non-enzymatic starch binding sites that we demonstrate serve unique functions in starch catabolism. The SusD binding site is uniquely involved in initial sensing of available starch, leading to upregulation of the sus locus. Conversely, the SusE,F and G binding sites are important during starch catalysis, enhancing starch growth rate in a manner dependent on expression of the Bt polysaccharide capsule. We hypothesize these binding sites help overcome the barrier created by the bacterial capsule, which may obstruct access to starch. In vivo studies show that the Sus binding sites confer a fitness advantage to Bt on a starch-rich diet. Finally, we present the first single-molecule imaging studies performed with live Bt cells that provides evidence for a highly dynamic starch-induced Sus complex. These studies provide important insight into the mechanisms of carbohydrate metabolism by gut symbionts, a process that significantly affects human health. Advisors/Committee Members: Martens, Eric Charles (committee member), Saper, Mark A. (committee member), Swanson, Michele S. (committee member), Koropatkin, Nicole (committee member), Sandkvist, Maria B. (committee member).

Subjects/Keywords: Microbiota; Bacterial Carbohydrate Metabolism; Microbiology and Immunology; Health Sciences

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

APA (6th Edition):

Cameron, E. A. (2014). The Structure and Function of the Starch Utilization System in Bacteroides thetaiotaomicron. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/109005

Chicago Manual of Style (16th Edition):

Cameron, Elizabeth Ann. “The Structure and Function of the Starch Utilization System in Bacteroides thetaiotaomicron.” 2014. Doctoral Dissertation, University of Michigan. Accessed November 17, 2019. http://hdl.handle.net/2027.42/109005.

MLA Handbook (7th Edition):

Cameron, Elizabeth Ann. “The Structure and Function of the Starch Utilization System in Bacteroides thetaiotaomicron.” 2014. Web. 17 Nov 2019.

Vancouver:

Cameron EA. The Structure and Function of the Starch Utilization System in Bacteroides thetaiotaomicron. [Internet] [Doctoral dissertation]. University of Michigan; 2014. [cited 2019 Nov 17]. Available from: http://hdl.handle.net/2027.42/109005.

Council of Science Editors:

Cameron EA. The Structure and Function of the Starch Utilization System in Bacteroides thetaiotaomicron. [Doctoral Dissertation]. University of Michigan; 2014. Available from: http://hdl.handle.net/2027.42/109005

2. Dong, Shengli. Characterization of the oligosaccharides of B. anthracis exosporium.

Degree: PhD, 2010, University of Alabama – Birmingham

Fatal systemic anthrax is caused by exposure to spores of Bacillus anthracis. The outermost layer of the B. anthracis spore is called the exosporium. It consists of a paracrystalline basal layer and an external hair-like nap. The filaments of the hair-like nap are primarily composed of the glycoprotein BclA. Our previous studies showed that a 715-Da tetrasaccharide and a 324-Da disaccharide are attached to BclA through GalNAc. We named the novel nonreducing terminal sugar of the 715-Da tetrasaccharide anthrose. We subsequently proposed a plausible anthrose biosynthetic pathway and identified a gene cluster of four continuous genes that appeared to encode anthrose biosynthetic enzymes. These genes, bas3322 to bas3319, encode an enoyl-CoA hydratase, a glycosyltransferase, an aminotransferase, and an O-acyltransferase. We devised a novel microhydrazinolysis procedure that greatly facilitated our studies of the oligosaccharides. We knew that the oligosaccharides were linked to BclA through GalNAc residues and we attempted to identify the gene that encoded the enzyme for GalNAc biosynthesis. We subsequently identified the gene, bas5304. We found it encodes a bifunctional UDP-Glu/GlcNAc 4-epimerase, which converts UDP-GlcNAc to UDP-GalNAc. Surprisingly, a Δbas5304 mutant still made oligosaccharides. However, monosaccharide analysis of oligosaccharides of the mutant revealed that GalNAc had been replaced by GlcNAc. Thus, while GalNAc appears to be the preferred amino sugar for the linkage of oligosaccharides to the BclA protein backbone, in its absence, GlcNAc can serve as a substitute linker. We also examined BclA oligosaccharides of mutant spores in which individual genes in anthrose operon had been deleted. Deletion of the first gene of the operon, bas3322, resulted in the production of abnormal pentasaccharides containing anthrose analogs. Deletion of either gene bas3320 or gene bas3319 resulted in the disappearance of the pentasaccharide and the appearance of a new tetrasaccharide with a nonreducing terminal 3-O-methyl rhamnose. Deletion of gene bas3321 resulted in BclA being substituted only with the trisaccharide, evidence that the gene encodes a dTDP-β-L-rhamnose α-1,3-L-rhamnosyl-transferase. To further confirm their roles in anthrose biosynthesis, we cloned and expressed three of the genes of the anthrose operon and experimentally demonstrated that the proteins exhibited the predicted activities.

1 online resource (xiii, 142 p.) : ill., digital, PDF file.

Biochemistry and Molecular Genetics

Joint Health Sciences

exosporium glycoprotein oligosaccharides anthrose hydrazinolysis

UNRESTRICTED

Advisors/Committee Members: Pritchard, David G., Hollingshead, Susan K.<br>, Kearney, John F.<br>, Popov, Kirill M.<br>, Turnbough, Charles L..

Subjects/Keywords: Amino Sugars  – biosynthesis<; br>; Bacillus anthracis  – genetics<; br>; Bacillus anthracis  – metabolism<; br>; Bacterial Proteins  – metabolism<; br>; Carbohydrate Epimerases  – metabolism<; br>; Deoxyglucose  – analogs & derivatives<; br>; Glycoproteins<; br>; Oligosaccharides<; br>; Operon

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

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

APA (6th Edition):

Dong, S. (2010). Characterization of the oligosaccharides of B. anthracis exosporium. (Doctoral Dissertation). University of Alabama – Birmingham. Retrieved from http://contentdm.mhsl.uab.edu/u?/etd,1237

Chicago Manual of Style (16th Edition):

Dong, Shengli. “Characterization of the oligosaccharides of B. anthracis exosporium.” 2010. Doctoral Dissertation, University of Alabama – Birmingham. Accessed November 17, 2019. http://contentdm.mhsl.uab.edu/u?/etd,1237.

MLA Handbook (7th Edition):

Dong, Shengli. “Characterization of the oligosaccharides of B. anthracis exosporium.” 2010. Web. 17 Nov 2019.

Vancouver:

Dong S. Characterization of the oligosaccharides of B. anthracis exosporium. [Internet] [Doctoral dissertation]. University of Alabama – Birmingham; 2010. [cited 2019 Nov 17]. Available from: http://contentdm.mhsl.uab.edu/u?/etd,1237.

Council of Science Editors:

Dong S. Characterization of the oligosaccharides of B. anthracis exosporium. [Doctoral Dissertation]. University of Alabama – Birmingham; 2010. Available from: http://contentdm.mhsl.uab.edu/u?/etd,1237

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