Abstract Penicillin-binding proteins (PBPs) are enzymes responsible for the polymerization of the glycan strand and the cross-linking between glycan chains as well as the target proteins for β-lactam antibiotics. Mutational alterations in PBPs can confer resistance either by reducing binding of the antibiotic to the active site or by evolving a β-lactamase activity that degrades the antibiotic. How To Transfer File Using Putty Serial Monitor. As no systematic studies have been performed to examine the potential of all PBPs present in one bacterial species to evolve increased resistance against β-lactam antibiotics, we explored the ability of fifteen different defined or putative PBPs in Salmonella enterica to acquire increased resistance against penicillin G. We could after mutagenesis and selection in presence of penicillin G isolate mutants with amino-acid substitutions in the PBPs, FtsI, DacB and DacC (corresponding to PBP3, PBP4 and PBP6) with increased resistance against β-lactam antibiotics. Our results suggest that: (i) most evolved PBPs became ‘generalists” with increased resistance against several different classes of β-lactam antibiotics, (ii) synergistic interactions between mutations conferring antibiotic resistance are common and (iii) the mechanism of resistance of these mutants could be to make the active site more accessible for water allowing hydrolysis or less binding to β-lactam antibiotics. Citation: Sun S, Selmer M, Andersson DI (2014) Resistance to β-Lactam Antibiotics Conferred by Point Mutations in Penicillin-Binding Proteins PBP3, PBP4 and PBP6 in Salmonella enterica. PLoS ONE 9(5): e97202. Drivers Subsonic Controller Mods.
Editor: Axel Cloeckaert, Institut National de la Recherche Agronomique, France Received: March 16, 2014; Accepted: April 16, 2014; Published: May 8, 2014 Copyright: © 2014 Sun et al. This is an open-access article distributed under the terms of the, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction.
All data are included within the manuscript. Funding: This work was supported by grants from the Swedish Research Council to DIA (grant 2012–3482) and MS (grant 2013–5930). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. Introduction The bacterial peptidoglycan, a three-dimensional, net-like mesh, is the major constituent of the cell wall. Penicillin-binding proteins (PBPs) are a family of enzymes that are responsible for the polymerization of the glycan strand and the cross-linking between glycan chains. These proteins are referred as PBPs due to their ability to bind to β-lactam antibiotics, and based on their molecular weights, PBPs can be classified into two groups: low molecular weight PBPs and high molecular weight PBPs, each of which is subdivided into three classes based on amino-acid sequence similarities.
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