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PBP1A Directly Interacts with the Divisome Complex to Promote Septal Peptidoglycan Synthesis in Acinetobacter baumannii. J Bacteriol 2022; 204:e0023922. [PMID: 36317921 PMCID: PMC9765026 DOI: 10.1128/jb.00239-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The class A penicillin-binding proteins (aPBPs), PBP1A and PBP1B, are major peptidoglycan synthases that synthesize more than half of the peptidoglycan per generation in Escherichia coli. Whereas aPBPs have distinct roles in peptidoglycan biosynthesis during growth (i.e., elongation and division), they are semiredundant; disruption of either is rescued by the other to maintain envelope homeostasis and promote proper growth. Acinetobacter baumannii is a nosocomial pathogen that has a high propensity to overcome antimicrobial treatment. A. baumannii contains both PBP1A and PBP1B (encoded by mrcA and mrcB, respectively), but only mrcA deletion decreased fitness and contributed to colistin resistance through inactivation of lipooligosaccharide biosynthesis, indicating that PBP1B was not functionally redundant with the PBP1A activity. While previous studies suggested a distinct role for PBP1A in division, it was unknown whether its role in septal peptidoglycan biosynthesis was direct. Here, we show that A. baumannii PBP1A has a direct role in division through interactions with divisome components. PBP1A localizes to septal sites during growth, where it interacts with the transpeptidase PBP3, an essential division component that regulates daughter cell formation. PBP3 overexpression was sufficient to rescue the division defect in ΔmrcA A. baumannii; however, PBP1A overexpression was not sufficient to rescue the septal defect when PBP3 was inhibited, suggesting that their activity is not redundant. Overexpression of a major dd-carboxypeptidase, PBP5, also restored the canonical A. baumannii coccobacilli morphology in ΔmrcA cells. Together, these data support a direct role for PBP1A in A. baumannii division and highlights its role as a septal peptidoglycan synthase. IMPORTANCE Peptidoglycan biosynthesis is a validated target of β-lactam antibiotics, and it is critical that we understand essential processes in multidrug-resistant pathogens such as Acinetobacter baumannii. While model systems such as Escherichia coli have shown that PBP1A is associated with side wall peptidoglycan synthesis, we show herein that A. baumannii PBP1A directly interacts with the divisome component PBP3 to promote division, suggesting a unique role for the enzyme in this highly drug-resistant nosocomial pathogen. A. baumannii demonstrated unanticipated resistance and tolerance to envelope-targeting antibiotics, which may be driven by rewired peptidoglycan machinery and may underlie therapeutic failure during antibiotic treatment.
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Farias BOD, Bianco K, Nascimento APA, Gonçalves de Brito AS, Moreira TC, Clementino MM. Genomic Analysis of Multidrug-Resistant Enterococcus faecium Harboring vanA Gene from Wastewater Treatment Plants. Microb Drug Resist 2022; 28:444-452. [PMID: 35172112 DOI: 10.1089/mdr.2021.0254] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The emergence of vancomycin-resistant Enterococcus faecium (Efm) harboring vanA gene and multidrug-resistant determinants is a relevant public health concern. It is an opportunistic pathogen responsible for nosocomial infections widely distributed in the environment, including wastewater treatment plants (WWTPs). Our study addresses a genomic investigation of vanA-carrying Efm from WWTPs in Brazil. Samples from five WWTPs supplied with sewage from different sources were evaluated. Here we present whole-genome sequencing of eight vanA-Efm isolates performed on Illumina MiSeq platform. All these isolates presented multidrug-resistant profile, and five strains were from treated wastewater. Multiple antimicrobial resistance genes (ARGs) were found, such as aph(3')-IIIa, ant(6')-Ia, erm(B), and msrC, some of them being allocated in plasmids. The virulence profile was predominantly constituted by efaAfm and acm genes and all isolates, except for one, were predicted as human pathogens. Multilocus sequence typing analysis revealed a new allele and five different STs, three previously described (ST32, ST168, and ST253) and two novel ones (ST1893 and ST1894). Six strains belonged to CC17, often associated with hospital outbreaks. As far as our knowledge, no genomic studies of vanA-Efm recovered from WWTPs revealed isolates belonging to CC17 in Brazil. Therefore, our findings point to the environmental spread of Efm carrying multiple ARGs.
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Affiliation(s)
- Beatriz Oliveira de Farias
- Fundação Oswaldo Cruz, Instituto Nacional de Controle de Qualidade em Saúde-Avenida Brasil, Rio de Janeiro, Rio de Janeiro, Brasil
| | - Kayo Bianco
- Fundação Oswaldo Cruz, Instituto Nacional de Controle de Qualidade em Saúde-Avenida Brasil, Rio de Janeiro, Rio de Janeiro, Brasil
| | - Ana Paula Alves Nascimento
- Fundação Oswaldo Cruz, Instituto Nacional de Controle de Qualidade em Saúde-Avenida Brasil, Rio de Janeiro, Rio de Janeiro, Brasil
| | | | - Thais Costa Moreira
- Fundação Oswaldo Cruz, Instituto Nacional de Controle de Qualidade em Saúde-Avenida Brasil, Rio de Janeiro, Rio de Janeiro, Brasil
| | - Maysa Mandetta Clementino
- Fundação Oswaldo Cruz, Instituto Nacional de Controle de Qualidade em Saúde-Avenida Brasil, Rio de Janeiro, Rio de Janeiro, Brasil
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Maréchal M, Amoroso A, Morlot C, Vernet T, Coyette J, Joris B. Enterococcus hirae LcpA (Psr), a new peptidoglycan-binding protein localized at the division site. BMC Microbiol 2016; 16:239. [PMID: 27729019 PMCID: PMC5059904 DOI: 10.1186/s12866-016-0844-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2016] [Accepted: 09/21/2016] [Indexed: 12/26/2022] Open
Abstract
Background Proteins from the LytR-CpsA-Psr family are found in almost all Gram-positive bacteria. Although LCP proteins have been studied in other pathogens, their functions in enterococci remain uncharacterized. The Psr protein from Enterococcus hirae, here renamed LcpA, previously associated with the regulation of the expression of the low-affinity PBP5 and β-lactam resistance, has been characterized. Results LcpA protein of E. hirae ATCC 9790 has been produced and purified with and without its transmembrane helix. LcpA appears, through different methods, to be localized in the membrane, in agreement with in silico predictions. The interaction of LcpA with E. hirae cell wall indicates that LcpA binds enterococcal peptidoglycan, regardless of the presence of secondary cell wall polymers. Immunolocalization experiments showed that LcpA and PBP5 are localized at the division site of E. hirae. Conclusions LcpA belongs to the LytR-CpsA-Psr family. Its topology, localization and binding to peptidoglycan support, together with previous observations on defective mutants, that LcpA plays a role related to the cell wall metabolism, probably acting as a phosphotransferase catalyzing the attachment of cell wall polymers to the peptidoglycan. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0844-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maxime Maréchal
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium
| | - Ana Amoroso
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium
| | - Cécile Morlot
- University Grenoble Alpes, IBS, Grenoble, F-38044, France.,CNRS, IBS, Grenoble, F-38044, France.,CEA, IBS, Grenoble, F-38044, France
| | - Thierry Vernet
- University Grenoble Alpes, IBS, Grenoble, F-38044, France.,CNRS, IBS, Grenoble, F-38044, France.,CEA, IBS, Grenoble, F-38044, France
| | - Jacques Coyette
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium
| | - Bernard Joris
- Physiologie et génétique bactérienne, Centre d'Ingénierie des Protéines, Université de Liège, Institut de Chimie, Liège, B-4000, Belgium.
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Serine/threonine protein phosphatase-mediated control of the peptidoglycan cross-linking L,D-transpeptidase pathway in Enterococcus faecium. mBio 2014; 5:e01446-14. [PMID: 25006233 PMCID: PMC4161250 DOI: 10.1128/mbio.01446-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The last step of peptidoglycan polymerization involves two families of unrelated transpeptidases that are the essential targets of β-lactam antibiotics. d,d-transpeptidases of the penicillin-binding protein (PBP) family are active-site serine enzymes that use pentapeptide precursors and are the main or exclusive cross-linking enzymes in nearly all bacteria. However, peptidoglycan cross-linking is performed mainly by active-site cysteine l,d-transpeptidases that use tetrapeptides in Mycobacterium tuberculosis, Clostridium difficile, and β-lactam-resistant mutants of Enterococcus faecium. We have investigated reprogramming of the E. faecium peptidoglycan assembly pathway by a switch from pentapeptide to tetrapeptide precursors and bypass of PBPs by l,d-transpeptidase Ldtfm. Mutational alterations of two signal transduction systems were necessary and sufficient for activation of the l,d-transpeptidation pathway, which is essentially cryptic in wild-type strains. The first one is a classical two-component regulatory system, DdcRS, that controls the activity of Ldtfm at the substrate level. As previously described, loss of DdcS phosphatase activity leads to production of the d,d-carboxypeptidase DdcY and conversion of the pentapeptide into the tetrapeptide substrate of Ldtfm. Here we show that full bypass of PBPs by Ldtfm also requires increased Ser/Thr protein phosphorylation resulting from impaired activity of phosphoprotein phosphatase StpA. This enzyme negatively controlled the level of protein phosphorylation both by direct dephosphorylation of target proteins and by dephosphorylation of its cognate kinase Stk. In combination with production of DdcY, increased protein phosphorylation by this eukaryotic-enzyme-like Ser/Thr protein kinase was sufficient for activation of the l,d-transpeptidation pathway in the absence of mutational alteration of peptidoglycan synthesis enzymes. The mechanism of acquisition of high-level ampicillin resistance involving bypass of the penicillin-binding proteins (PBPs) by l,d-transpeptidase Ldtfm was incompletely understood, as production of tetrapeptide precursors following transcriptional activation of the ddc locus by the DdcRS two-component regulatory system was necessary but not sufficient for full activation of the l,d-transpeptidation pathway. Here, we identified the release of a negative control of Ser/Thr protein phosphorylation mediated by phosphatase StpA as the additional factor essential for ampicillin resistance. Thus, bypass of PBPs by Ldtfm requires the modification of signal transduction regulatory systems without any gain of function by mutational alteration of peptidoglycan biosynthetic enzymes. In contrast, previously characterized mechanisms of antibiotic resistance involve horizontal gene transfer and mutational alteration of drug targets. Activation of the l,d-transpeptidation pathway reported in this study is an unprecedented mechanism of emergence of a new metabolic pathway since it involved the recruitment of preexisting functions following modifications of regulatory circuits.
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Sauvage E, Derouaux A, Fraipont C, Joris M, Herman R, Rocaboy M, Schloesser M, Dumas J, Kerff F, Nguyen-Distèche M, Charlier P. Crystal structure of penicillin-binding protein 3 (PBP3) from Escherichia coli. PLoS One 2014; 9:e98042. [PMID: 24875494 PMCID: PMC4038516 DOI: 10.1371/journal.pone.0098042] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/28/2014] [Indexed: 11/24/2022] Open
Abstract
In Escherichia coli, penicillin-binding protein 3 (PBP3), also known as FtsI, is a central component of the divisome, catalyzing cross-linking of the cell wall peptidoglycan during cell division. PBP3 is mainly periplasmic, with a 23 residues cytoplasmic tail and a single transmembrane helix. We have solved the crystal structure of a soluble form of PBP3 (PBP357–577) at 2.5 Å revealing the two modules of high molecular weight class B PBPs, a carboxy terminal module exhibiting transpeptidase activity and an amino terminal module of unknown function. To gain additional insight, the PBP3 Val88-Ser165 subdomain (PBP388–165), for which the electron density is poorly defined in the PBP3 crystal, was produced and its structure solved by SAD phasing at 2.1 Å. The structure shows a three dimensional domain swapping with a β-strand of one molecule inserted between two strands of the paired molecule, suggesting a possible role in PBP357–577 dimerization.
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Affiliation(s)
- Eric Sauvage
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
- * E-mail:
| | - Adeline Derouaux
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Claudine Fraipont
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Marine Joris
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Raphaël Herman
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Mathieu Rocaboy
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Marie Schloesser
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Jacques Dumas
- Sanofi R&D, protein production, 13 quai Jules Guesde, 94403 Vitry sur Seine, France
| | - Frédéric Kerff
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Martine Nguyen-Distèche
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
| | - Paulette Charlier
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5a et Institut de Chimie B6a, Sart Tilman, Liège, Belgium
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Sauvage E, Kerff F, Terrak M, Ayala JA, Charlier P. The penicillin-binding proteins: structure and role in peptidoglycan biosynthesis. FEMS Microbiol Rev 2008; 32:234-58. [PMID: 18266856 DOI: 10.1111/j.1574-6976.2008.00105.x] [Citation(s) in RCA: 882] [Impact Index Per Article: 55.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Eric Sauvage
- Centre d'Ingénierie des Protéines, Institut de Physique B5a et Institut de Chimie B6a, University of Liège, Sart Tilman, Belgium.
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