Inhibition of penicillin-binding protein 3 of <i>Escherichia coli</i> K-12. Effects upon growth, viability and outer membrane barrier function

Curtis, Nigel A. C.; Eisenstadt, Rosemary L.; Turner, Kath A.; White, Anthony J.

doi:10.1093/jac/16.3.287

Cited by 25 publications

(31 citation statements)

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“…Prc cleaves the periplasmic C termini of PBP3 (10) and lipoprotein NlpI (63). Aztreonam specifically inhibits the transpeptidase activity of PBP3, disrupting septal murein synthesis and elongating cells (41,42,64). Cleavage of PBP3 by Prc is not essential for bacterial growth and morphogenesis at low salinity (Fig.…”

Section: Resultsmentioning

confidence: 99%

Salinity-Dependent Impacts of ProQ, Prc, and Spr Deficiencies on Escherichia coli Cell Structure

et al. 2014

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ProQ is a cytoplasmic protein with RNA chaperone activities that reside in FinO-and Hfq-like domains. Lesions at proQ decrease the level of the osmoregulatory glycine betaine transporter ProP. Lesions at proQ eliminated ProQ and Prc, the periplasmic protease encoded by the downstream gene prc. They dramatically slowed the growth of Escherichia coli populations and altered the morphologies of E. coli cells in high-salinity medium. ProQ and Prc deficiencies were associated with different phenotypes. ProQ-deficient bacteria were elongated unless glycine betaine was provided. High-salinity cultures of Prcdeficient bacteria included spherical cells with an enlarged periplasm and an eccentric nucleoid. The nucleoid-containing compartment was bounded by the cytoplasmic membrane and peptidoglycan. This phenotype was not evident in bacteria cultivated at low or moderate salinity, nor was it associated with murein lipoprotein (Lpp) deficiency, and it differed from those elicited by the MreB inhibitor A-22 or the FtsI inhibitor aztreonam at low or high salinity. It was suppressed by deletion of spr, which encodes one of three murein hydrolases that are redundantly essential for enlargement of the murein sacculus. Prc deficiency may alter bacterial morphology by impairing control of Spr activity at high salinity. ProQ and Prc deficiencies lowered the ProP activity of bacteria cultivated at moderate salinity by approximately 70% and 30%, respectively, but did not affect other osmoregulatory functions. The effects of ProQ and Prc deficiencies on ProP activity are indirect, reflecting their roles in the maintenance of cell structure.O smotic stress perturbs cell structure, composition, and function (1). Despite retaining their rod-like shape, Escherichia coli cells cultivated in high-salinity minimal medium maintain lower hydration, turgor pressure, and growth rate than those cultivated at a lower salinity that is optimal for growth (2). The elastic murein sacculus is believed to buffer effects of osmotically induced water fluxes on cell structure (3). E. coli can attenuate osmotically induced dehydration by accumulating small, uncharged, or zwitterionic organic solutes called osmolytes (1, 4, 5). For example, transporter ProP mediates the accumulation of diverse solutes, including proline and glycine betaine, thereby restoring cellular hydration and stimulating bacterial growth in high-salinity media (6, 7).ProQ is a cytoplasmic protein that binds RNA, facilitating RNA duplexing and strand exchange (8). Previous work showed that proQ lesions decreased ProP levels and attenuated ProP activity (the proQ transport phenotype). These effects occurred when bacteria expressed proP from the chromosome or a plasmid-based P BAD promoter during growth in low-to moderate-salinity media and were reversed by plasmid-based proQ expression (8, 9). Here, we show that proQ lesions dramatically slow the growth of E. coli populations in high-salinity medium and alter the morphologies of E. coli cells (the proQ growth and morphological phenotypes...

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Section: Resultsmentioning

confidence: 99%

Salinity-Dependent Impacts of ProQ, Prc, and Spr Deficiencies on Escherichia coli Cell Structure

et al. 2014

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“…The numerous HMW PBPs belonging to class A that are present in leptospires may compensate for the loss of PBP1a production. Like in E. coli (13), the L. interrogans PBP3 mutant forms filamentous cells, suggesting its involvement in cell division. However, unlike E. coli, FtsI does not appear to be essential in Leptospira (52).…”

Section: Discussionmentioning

confidence: 99%

Deciphering Morphological Determinants of the Helix-Shaped Leptospira

et al. 2011

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Leptospira spp. are thin, highly motile, slow-growing spirochetes that can be distinguished from other bacteria on the basis of their unique helical shape. Defining the mechanisms by which these bacteria generate and maintain this atypical morphology should greatly enhance our understanding of the fundamental physiology of these pathogens. In this study, we showed that peptidoglycan sacculi from Leptospira spp. retain the helical shape of intact cells. Interestingly, the distribution of muropeptides was different from that in the Escherichia coli model, indicating that specific enzymes might be active on the peptidoglycan macromolecule. We could alter the shape of Leptospira biflexa with the broad-spectrum ␤-lactam antibiotic penicillin G and with amdinocillin and aztreonam, which are ␤-lactams that preferentially target penicillin-binding protein 2 (PBP2) and PBP3, respectively, in some species. Although genetic manipulations of Leptospira spp. are scarce, we were able to obtain mutants with alterations in genes encoding PBPs, including PBP3. Loss of this protein resulted in cell elongation. We also generated an L. biflexa strain that conditionally expresses MreB. Loss of the MreB function was correlated with morphological abnormalities such as a localized increased diameter and heterogeneous length. A prolonged depletion of MreB resulted in cell lysis, suggesting that this protein is essential. These findings indicate that important aspects of leptospiral cell morphology are determined by the cytoskeleton and the murein layer, thus providing a starting point for a better understanding of the morphogenesis in these atypical bacteria.

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“…In Escherichia coli, rapid cell lysis by beta-lactam drugs requires inactivation of PBP lb (19) or both PBPs la and lb (18, 24). Inactivation of PBP 2 by target-specific betalactams results in the formation of spherical cells, whereas beta-lactam binding to PBP 3 causes inhibition of septation and the appearance of filamentous cells (3,(16)(17)(18). Haemophilus influenzae PBPs have been studied less extensively.…”

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“…Evidence now exists that PBP functions can be multiple and may vary depending on growth conditions and physiological status (1,2,11,14). In addition, to investigate beta-lactam and PBP relationships, studies with deletion (16, 24) or temperature-sensitive (3,5,(17)(18)(19) mutants with altered PBPs are necessary since betalactams often act on many targets.To understand beta-lactam susceptibility and resistance in the genus Haemophilus and, in particular, in H. influenzae strains, it is important to obtain a better knowledge of their target proteins. Here we report the temperature activation and the temperature sensitivities ofH.…”

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confidence: 99%

Haemophilus influenzae penicillin-binding proteins 1a and 3 possess distinct and opposite temperature-modulated penicillin-binding activities

Malouin

Bryan

1988

Antimicrob Agents Chemother

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Upon investigation of penicillin-binding proteins (PBPs) The enzymatic functions of high-molecular-weight penicillin-binding proteins (PBPs) are essential in cell wall peptidoglycan synthesis (20, 23). Beta-lactam antibiotics must bind to those specific targets to exert their inhibitory effects. In Escherichia coli, rapid cell lysis by beta-lactam drugs requires inactivation of PBP lb (19) or both PBPs la and lb (18, 24). Inactivation of PBP 2 by target-specific betalactams results in the formation of spherical cells, whereas beta-lactam binding to PBP 3 causes inhibition of septation and the appearance of filamentous cells (3,(16)(17)(18). Haemophilus influenzae PBPs have been studied less extensively. PBP 3 inactivation by target-specific beta-lactams results in cell filamentation as in E. coli, indicating a similarity in structure and function (13).Description of beta-lactam and PBP interactions have often been simplified in the past. Evidence now exists that PBP functions can be multiple and may vary depending on growth conditions and physiological status (1,2,11,14). In addition, to investigate beta-lactam and PBP relationships, studies with deletion (16, 24) or temperature-sensitive (3,5,(17)(18)(19) mutants with altered PBPs are necessary since betalactams often act on many targets.To understand beta-lactam susceptibility and resistance in the genus Haemophilus and, in particular, in H. influenzae strains, it is important to obtain a better knowledge of their target proteins. Here we report the temperature activation and the temperature sensitivities ofH. influenzae PBPs 1 and 3, respectively, and how these properties should prove useful for studying PBP function in this species and, possi-

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Inhibition of penicillin-binding protein 3 of Escherichia coli K-12. Effects upon growth, viability and outer membrane barrier function

Cited by 25 publications

References 0 publications

Salinity-Dependent Impacts of ProQ, Prc, and Spr Deficiencies on Escherichia coli Cell Structure

Salinity-Dependent Impacts of ProQ, Prc, and Spr Deficiencies on Escherichia coli Cell Structure

Deciphering Morphological Determinants of the Helix-Shaped Leptospira

Haemophilus influenzae penicillin-binding proteins 1a and 3 possess distinct and opposite temperature-modulated penicillin-binding activities

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