title: Role of penicillin-binding protein 1b in competitive stationary-phase survival of Escherichia coli.
abstract: The penicillin-binding proteins (PBPs) catalyze the synthesis and modification of bacterial cell wall peptidoglycan. Although the biochemical activities of these proteins have been determined in Escherichia coli, the physiological roles of many PBPs remain enigmatic. Previous studies have cast doubt on the individual importance of the majority of PBPs during log phase growth. We show here that PBP1b is vital for competitive survival of E. coli during extended stationary phase, but the other nine PBPs studied are dispensable. Loss of PBP1b leads to the stationary phase-specific competition defective phenotype and causes cells to become more sensitive to osmotic stress. Additionally, we present evidence that this protein, as well as AmpC, may assist in cellular resistance to beta-lactam antibiotics.
authors.affiliation: Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90078-2910, USA.
authors.forename: Evan D
authors.initials: ED
authors.lastname: Pepper
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Farrell
authors.forename: Steven E
authors.initials: SE
authors.lastname: Finkel
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology; D017077:Culture Media, Conditioned; D004926:Escherichia coli / Q000254:growth & development / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000502:physiology*; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability; D009154:Mutation; D009994:Osmolar Concentration; D046915:Penicillin-Binding Proteins / Q000235:genetics / Q000502:physiology*; D046928:Peptidoglycan Glycosyltransferase / Q000235:genetics / Q000502:physiology*; D010641:Phenotype; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase / Q000235:genetics / Q000502:physiology*; D018440:beta-Lactam Resistance / Q000502:physiology; D001618:beta-Lactamases / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D017077:Culture Media, Conditioned; D029968:Escherichia coli Proteins; D046915:Penicillin-Binding Proteins; D046928:Peptidoglycan Glycosyltransferase; C478681:penicillin-binding protein 1B, E coli; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase; C048795:AmpC beta-lactamases; D001618:beta-Lactamases