Studies of the Class A High-Molecular Weight Penicillin-Binding Proteins in Bacillus subtilis

McPherson, Derrell C.

Studies of the Class A High-Molecular Weight Penicillin-Binding Proteins in Bacillus subtilis

dc.contributor.author	McPherson, Derrell C.	en
dc.contributor.committeechair	Popham, David L.	en
dc.contributor.committeemember	Walker, Richard A.	en
dc.contributor.committeemember	Stevens, Ann M.	en
dc.contributor.committeemember	Larson, Timothy J.	en
dc.contributor.committeemember	Falkinham, Joseph O. III	en
dc.contributor.department	Biology	en
dc.date.accessioned	2014-03-14T20:10:26Z	en
dc.date.adate	2003-04-25	en
dc.date.available	2014-03-14T20:10:26Z	en
dc.date.issued	2003-04-16	en
dc.date.rdate	2004-04-25	en
dc.date.sdate	2003-04-22	en
dc.description.abstract	The survival of all organisms depends on their ability to perform certain enzymatic activities and the ability to construct certain structures. In prokaryotes, enzymes are required for the final reactions of peptidoglycan (PG) synthesis, the structural element of the bacterial cell wall. These proteins, known as penicillin-binding proteins (PBPs), are identified through the presence of conserved motifs within their functional domains. The Class A high-molecular weight PBPs are bifunctional, performing the penicillin-sensitive transpeptidase activity and the glycosyl transferase (GT) activity required for the polymerization of the glycan strands. The Class A PBPs in Bacillus subtilis are PBP1, PBP4, PBP2c, and PBP2d (YwheE) and they are encoded by ponA, pbpD, pbpF, and pbpG (ywhE), respectively. These proteins appear to be somewhat functionally redundant because removal of one or more does not cause any noticeable change in phenotype. However, the loss of PBP1 has previously been demonstrated in B. subtilis to cause a decreased growth rate and changes in morphology of vegetative cells, both of which are increased upon the additional loss of PBP4. Furthermore, the loss of sporulation-expressed Class A PBPs, PBP2c and 2d, causes a 10,000-fold decrease in the production of heat resistant spores. This double mutant is shown to have changes in the structural parameters of cortex PG that appear minor when compared to other strains, but are coupled with a large defect on the deposition of cortex PG, apparently from the synthesis of an abnormal germ cell wall. The Class A PBPs are believed to be the only proteins capable of performing the GT activity and it is therefore believed that cell viability requires the presence of at least one functional Class A PBP. This requirement has been demonstrated in other organisms, but a B. subtilis strain lacking all Class A PBPs is viable. The phenotypical changes seen in the PBP1 mutant are exacerbated in this strain. The GT activity remaining in this strain is sensitive to the antibiotic moenomycin in vitro whereas it appears resistant in vivo. Identification of the protein(s) performing this novel GT activity will rely on the demonstration of the GT activity in vitro.	en
dc.description.degree	Ph. D.	en
dc.identifier.other	etd-04222003-140931	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-04222003-140931/	en
dc.identifier.uri	http://hdl.handle.net/10919/27119	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	McPhersonAbstract.pdf	en
dc.relation.haspart	McPhersonETD.pdf	en
dc.relation.haspart	McPhersonBiblio.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	peptidoglycan	en
dc.subject	sporulation	en
dc.subject	germ cell wall	en
dc.subject	glycosyl transferase	en
dc.subject	Bacillus subtilis	en
dc.subject	penicillin-binding proteins	en
dc.title	Studies of the Class A High-Molecular Weight Penicillin-Binding Proteins in Bacillus subtilis	en
dc.type	Dissertation	en
thesis.degree.discipline	Biology	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	doctoral	en
thesis.degree.name	Ph. D.	en