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Voedts H, Anoyatis-Pelé C, Langella O, Rusconi F, Hugonnet JE, Arthur M. (p)ppGpp modifies RNAP function to confer β-lactam resistance in a peptidoglycan-independent manner. Nat Microbiol 2024; 9:647-656. [PMID: 38443580 DOI: 10.1038/s41564-024-01609-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 01/16/2024] [Indexed: 03/07/2024]
Abstract
(p)ppGpp is a nucleotide alarmone that controls bacterial response to nutrient deprivation. Since elevated (p)ppGpp levels confer mecillinam resistance and are essential for broad-spectrum β-lactam resistance as mediated by the β-lactam-insensitive transpeptidase YcbB (LdtD), we hypothesized that (p)ppGpp might affect cell wall peptidoglycan metabolism. Here we report that (p)ppGpp-dependent β-lactam resistance does not rely on any modification of peptidoglycan metabolism, as established by analysis of Escherichia coli peptidoglycan structure using high-resolution mass spectrometry. Amino acid substitutions in the β or β' RNA polymerase (RNAP) subunits, alone or in combination with the CRISPR interference-mediated downregulation of three of seven ribosomal RNA operons, were sufficient for resistance, although β-lactams have no known impact on the RNAP or ribosomes. This implies that modifications of RNAP and ribosome functions are critical to prevent downstream effects of the inactivation of peptidoglycan transpeptidases by β-lactams.
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Affiliation(s)
- Henri Voedts
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université Paris Cité, Paris, France
| | - Constantin Anoyatis-Pelé
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université Paris Cité, Paris, France
| | - Olivier Langella
- GQE-Le Moulon/PAPPSO, Université Paris-Saclay, INRAE, CNRS, AgroParisTech, IDEEV, Gif-sur-Yvette, France
| | - Filippo Rusconi
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université Paris Cité, Paris, France
- GQE-Le Moulon/PAPPSO, Université Paris-Saclay, INRAE, CNRS, AgroParisTech, IDEEV, Gif-sur-Yvette, France
| | - Jean-Emmanuel Hugonnet
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université Paris Cité, Paris, France.
| | - Michel Arthur
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université Paris Cité, Paris, France.
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Voedts H, Kennedy SP, Sezonov G, Arthur M, Hugonnet JE. Genome-wide identification of genes required for alternative peptidoglycan cross-linking in Escherichia coli revealed unexpected impacts of β-lactams. Nat Commun 2022; 13:7962. [PMID: 36575173 PMCID: PMC9794725 DOI: 10.1038/s41467-022-35528-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 12/06/2022] [Indexed: 12/28/2022] Open
Abstract
The D,D-transpeptidase activity of penicillin-binding proteins (PBPs) is the well-known primary target of β-lactam antibiotics that block peptidoglycan polymerization. β-lactam-induced bacterial killing involves complex downstream responses whose causes and consequences are difficult to resolve. Here, we use the functional replacement of PBPs by a β-lactam-insensitive L,D-transpeptidase to identify genes essential to mitigate the effects of PBP inactivation by β-lactams in actively dividing bacteria. The functions of the 179 conditionally essential genes identified by this approach extend far beyond L,D-transpeptidase partners for peptidoglycan polymerization to include proteins involved in stress response and in the assembly of outer membrane polymers. The unsuspected effects of β-lactams include loss of the lipoprotein-mediated covalent bond that links the outer membrane to the peptidoglycan, destabilization of the cell envelope in spite of effective peptidoglycan cross-linking, and increased permeability of the outer membrane. The latter effect indicates that the mode of action of β-lactams involves self-promoted penetration through the outer membrane.
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Affiliation(s)
- Henri Voedts
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
| | - Sean P. Kennedy
- Institut Pasteur, Université Paris Cité, Département Biologie Computationnelle, F-75015 Paris, France
| | - Guennadi Sezonov
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
| | - Michel Arthur
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
| | - Jean-Emmanuel Hugonnet
- grid.417925.cCentre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université Paris Cité, F-75006 Paris, France
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Atze H, Liang Y, Hugonnet JE, Gutierrez A, Rusconi F, Arthur M. Heavy isotope labeling and mass spectrometry reveal unexpected remodeling of bacterial cell wall expansion in response to drugs. eLife 2022; 11:72863. [PMID: 35678393 PMCID: PMC9249393 DOI: 10.7554/elife.72863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
Antibiotics of the β-lactam (penicillin) family inactivate target enzymes called D,D-transpeptidases or penicillin-binding proteins (PBPs) that catalyze the last cross-linking step of peptidoglycan synthesis. The resulting net-like macromolecule is the essential component of bacterial cell walls that sustains the osmotic pressure of the cytoplasm. In Escherichia coli, bypass of PBPs by the YcbB L,D-transpeptidase leads to resistance to these drugs. We developed a new method based on heavy isotope labeling and mass spectrometry to elucidate PBP- and YcbB-mediated peptidoglycan polymerization. PBPs and YcbB similarly participated in single-strand insertion of glycan chains into the expanding bacterial side wall. This absence of any transpeptidase-specific signature suggests that the peptidoglycan expansion mode is determined by other components of polymerization complexes. YcbB did mediate β-lactam resistance by insertion of multiple strands that were exclusively cross-linked to existing tripeptide-containing acceptors. We propose that this undocumented mode of polymerization depends upon accumulation of linear glycan chains due to PBP inactivation, formation of tripeptides due to cleavage of existing cross-links by a β-lactam-insensitive endopeptidase, and concerted cross-linking by YcbB.
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Affiliation(s)
- Heiner Atze
- INSERM, UMR-S 1138, Centre de Recherche des Cordeliers, Paris, France
| | | | | | - Arnaud Gutierrez
- INSERM, UMR-S 1138, Centre de Recherche des Cordeliers, Paris, France
| | | | - Michel Arthur
- INSERM, UMR-S 1138, Centre de Recherche des Cordeliers, Paris, France
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Voedts H, Dorchêne D, Lodge A, Vollmer W, Arthur M, Hugonnet JE. Role of endopeptidases in peptidoglycan synthesis mediated by alternative cross-linking enzymes in Escherichia coli. EMBO J 2021; 40:e108126. [PMID: 34382698 DOI: 10.15252/embj.2021108126] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 07/22/2021] [Accepted: 07/24/2021] [Indexed: 12/20/2022] Open
Abstract
Bacteria resist to the turgor pressure of the cytoplasm through a net-like macromolecule, the peptidoglycan, made of glycan strands connected via peptides cross-linked by penicillin-binding proteins (PBPs). We recently reported the emergence of β-lactam resistance resulting from a bypass of PBPs by the YcbB L,D-transpeptidase (LdtD), which form chemically distinct 3→3 cross-links compared to 4→3 formed by PBPs. Here we show that peptidoglycan expansion requires controlled hydrolysis of cross-links and identify among eight endopeptidase paralogues the minimum enzyme complements essential for bacterial growth with 4→3 (MepM) and 3→3 (MepM and MepK) cross-links. Purified Mep endopeptidases unexpectedly displayed a 4→3 and 3→3 dual specificity implying recognition of a common motif in the two cross-link types. Uncoupling of the polymerization of glycan chains from the 4→3 cross-linking reaction was found to facilitate the bypass of PBPs by YcbB. These results illustrate the plasticity of the peptidoglycan polymerization machinery in response to the selective pressure of β-lactams.
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Affiliation(s)
- Henri Voedts
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
| | - Delphine Dorchêne
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
| | - Adam Lodge
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle Upon Tyne, UK
| | - Michel Arthur
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
| | - Jean-Emmanuel Hugonnet
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, Paris, France
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