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de Oliveira AS, Inácio MM, de Oliveira LS, Elias Moreira AL, Alves Silva GA, Silva LOS, de Oliveira MAP, Giambiagi-deMarval M, Borges CL, Soares CMDA, Parente-Rocha JA. Immunoproteomic and immunoinformatic approaches identify secreted antigens and epitopes from Staphylococcus saprophyticus. Microb Pathog 2023:106171. [PMID: 37244490 DOI: 10.1016/j.micpath.2023.106171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 05/29/2023]
Abstract
Urinary tract infections (UTIs) are common human infections that compromise women's health around the world, even though they can affect men and women of all ages. Bacterial species are the primary causative agents of UTIs, while Staphylococcus saprophyticus, a gram-positive bacterium, is especially important for uncomplicated infections in young women. Despite the number of antigenic proteins identified in Staphylococcus aureus and other bacteria of the genus, there is no immunoproteomic study in S. saprophyticus. In this context, since pathogenic microorganisms secrete important proteins that interact with hosts during infection, the present work aims to identify the exoantigens from S. saprophyticus ATCC 15305 by immunoproteomic and immunoinformatic approaches. We identified 32 antigens on the exoproteome of S. saprophyticus ATCC 15305 by immunoinformatic tools. By using 2D-IB immunoproteomic analysis, it was possible to identify 3 antigenic proteins: transglycosylase IsaA, enolase and the secretory antigen Q49ZL8. In addition, 5 antigenic proteins were detected by immunoprecipitation (IP) approach, where the most abundant were bifunctional autolysin and transglycosylase IsaA proteins. The transglycosylase IsaA was the only protein detected by all the tools approaches used in this study. In this work it was possible to describe a total of 36 S. saprophyticus exoantigens. Immunoinformatic analysis allowed the identification of 5 exclusive linear B cell epitopes from S. saprophyticus and 5 epitopes presenting homology with other bacteria that cause UTIs. This work describes, for the first time, the profile of exoantigens secreted by S. saprophyticus and can contribute to the identification of new diagnostic targets of UTIs, as well as to develop vaccines and immunotherapies against bacterial urinary infections.
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Affiliation(s)
- Andrea Santana de Oliveira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - Moisés Morais Inácio
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - Lucas Silva de Oliveira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - André Luís Elias Moreira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - Guilherme Algusto Alves Silva
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - Lana O'Hara Souza Silva
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | | | - Marcia Giambiagi-deMarval
- Laboratório de Microbiologia Molecular, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
| | - Clayton Luiz Borges
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - Célia Maria de Almeida Soares
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
| | - Juliana Alves Parente-Rocha
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil.
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2
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Tan S, Cho K, Nodwell JR. A defect in cell wall recycling confers antibiotic resistance and sensitivity in Staphylococcus aureus. J Biol Chem 2022; 298:102473. [PMID: 36089064 PMCID: PMC9547203 DOI: 10.1016/j.jbc.2022.102473] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 09/02/2022] [Accepted: 09/03/2022] [Indexed: 11/17/2022] Open
Abstract
WalKR is a two-component system that is essential for viability in Gram-positive bacteria that regulates the all-important autolysins in cell wall homeostasis. Further investigation of this essential system is important for identifying ways to address antibiotic resistance. Here, we show that a T101M mutation in walR confers a defect in autolysis, a thickened cell wall, and decreased susceptibility to antibiotics that target lipid II cycle, a phenotype that is reminiscent of the clinical resistance form known as vancomycin intermediate-resistant Staphylococcus aureus. Importantly, this is accompanied by dramatic sensitization to tunicamycin. We demonstrate that this phenotype is due to partial collapse of a pathway consisting of autolysins, AtlA and Sle1, a transmembrane sugar permease, MurP, and GlcNAc recycling enzymes, MupG and MurQ. We suggest that this causes a shortage of substrate for the peptidoglycan biosynthesis enzyme MraY, causing it to be hypersensitive to competitive inhibition by tunicamycin. In conclusion, our results constitute a new molecular model for antibiotic sensitivity in S. aureus and a promising new route for antibiotic discovery.
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Affiliation(s)
- Stephanie Tan
- Department of Biochemistry, MaRS Discovery District, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada, M5G 1M1
| | - Kelvin Cho
- Department of Biochemistry, MaRS Discovery District, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada, M5G 1M1
| | - Justin R Nodwell
- Department of Biochemistry, MaRS Discovery District, University of Toronto, 661 University Avenue, Toronto, Ontario, Canada, M5G 1M1.
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3
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Hantke K, Friz S. The TonB dependent uptake of pyrroloquinoline‐quinone (PQQ) and secretion of gluconate by
Escherichia coli
K‐12. Mol Microbiol 2022; 118:417-425. [DOI: 10.1111/mmi.14975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/11/2022] [Accepted: 08/16/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Klaus Hantke
- University of Tübingen, IMIT Institute Tübingen Germany
| | - Simon Friz
- University of Tübingen, IMIT Institute Tübingen Germany
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4
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Mendes SS, Marques J, Mesterházy E, Straetener J, Arts M, Pissarro T, Reginold J, Berscheid A, Bornikoel J, Kluj RM, Mayer C, Oesterhelt F, Friães S, Royo B, Schneider T, Brötz-Oesterhelt H, Romão CC, Saraiva LM. Synergetic Antimicrobial Activity and Mechanism of Clotrimazole-Linked CO-Releasing Molecules. ACS BIO & MED CHEM AU 2022; 2:419-436. [PMID: 35996473 PMCID: PMC9389576 DOI: 10.1021/acsbiomedchemau.2c00007] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
Several metal-based
carbon monoxide-releasing molecules (CORMs)
are active CO donors with established antibacterial activity. Among
them, CORM conjugates with azole antibiotics of type [Mn(CO)3(2,2′-bipyridyl)(azole)]+ display important synergies
against several microbes. We carried out a structure–activity
relationship study based upon the lead structure of [Mn(CO)3(Bpy)(Ctz)]+ by producing clotrimazole (Ctz) conjugates
with varying metal and ligands. We concluded that the nature of the
bidentate ligand strongly influences the bactericidal activity, with
the substitution of bipyridyl by small bicyclic ligands leading to
highly active clotrimazole conjugates. On the contrary, the metal
did not influence the activity. We found that conjugate [Re(CO)3(Bpy)(Ctz)]+ is more than the sum of its parts:
while precursor [Re(CO)3(Bpy)Br] has no antibacterial activity
and clotrimazole shows only moderate minimal inhibitory concentrations,
the potency of [Re(CO)3(Bpy)(Ctz)]+ is one order
of magnitude higher than that of clotrimazole, and the spectrum of
bacterial target species includes Gram-positive and Gram-negative
bacteria. The addition of [Re(CO)3(Bpy)(Ctz)]+ to Staphylococcus aureus causes a
general impact on the membrane topology, has inhibitory effects on
peptidoglycan biosynthesis, and affects energy functions. The mechanism
of action of this kind of CORM conjugates involves a sequence of events
initiated by membrane insertion, followed by membrane disorganization,
inhibition of peptidoglycan synthesis, CO release, and break down
of the membrane potential. These results suggest that conjugation
of CORMs to known antibiotics may produce useful structures with synergistic
effects that increase the conjugate’s activity relative to
that of the antibiotic alone.
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Affiliation(s)
- Sofia S Mendes
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Joana Marques
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Edit Mesterházy
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Jan Straetener
- Interfaculty Institute of Microbiology and Infection Medicine, Dept. of Microbial Bioactive Compounds, Cluster of Excellence Controlling Microbes to Fight Infection. University of Tuebingen, Auf der Morgenstelle 28, 72070 Tuebingen, Germany
| | - Melina Arts
- Institute for Pharmaceutical Microbiology, University of Bonn, University Clinic Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany
| | - Teresa Pissarro
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Jorgina Reginold
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Anne Berscheid
- Interfaculty Institute of Microbiology and Infection Medicine, Dept. of Microbial Bioactive Compounds, Cluster of Excellence Controlling Microbes to Fight Infection. University of Tuebingen, Auf der Morgenstelle 28, 72070 Tuebingen, Germany
| | - Jan Bornikoel
- Interfaculty Institute of Microbiology and Infection Medicine, Dept. of Microbial Bioactive Compounds, Cluster of Excellence Controlling Microbes to Fight Infection. University of Tuebingen, Auf der Morgenstelle 28, 72070 Tuebingen, Germany
| | - Robert M Kluj
- Institute of Microbiology and Infection Medicine, Dept. of Organismic Interactions, University of Tuebingen, Auf der Morgenstelle 28, 72070 Tuebingen, Germany
| | - Christoph Mayer
- Institute of Microbiology and Infection Medicine, Dept. of Organismic Interactions, University of Tuebingen, Auf der Morgenstelle 28, 72070 Tuebingen, Germany
| | - Filipp Oesterhelt
- Interfaculty Institute of Microbiology and Infection Medicine, Dept. of Microbial Bioactive Compounds, Cluster of Excellence Controlling Microbes to Fight Infection. University of Tuebingen, Auf der Morgenstelle 28, 72070 Tuebingen, Germany
| | - Sofia Friães
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Beatriz Royo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Tanja Schneider
- Institute for Pharmaceutical Microbiology, University of Bonn, University Clinic Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany
| | - Heike Brötz-Oesterhelt
- Interfaculty Institute of Microbiology and Infection Medicine, Dept. of Microbial Bioactive Compounds, Cluster of Excellence Controlling Microbes to Fight Infection. University of Tuebingen, Auf der Morgenstelle 28, 72070 Tuebingen, Germany
| | - Carlos C Romão
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
| | - Lígia M Saraiva
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Avenida da República (EAN), 2780-157 Oeiras, Portugal
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5
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Wang M, Buist G, van Dijl JM. Staphylococcus aureus cell wall maintenance - the multifaceted roles of peptidoglycan hydrolases in bacterial growth, fitness, and virulence. FEMS Microbiol Rev 2022; 46:6604383. [PMID: 35675307 PMCID: PMC9616470 DOI: 10.1093/femsre/fuac025] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/22/2022] [Accepted: 05/25/2022] [Indexed: 01/07/2023] Open
Abstract
Staphylococcus aureus is an important human and livestock pathogen that is well-protected against environmental insults by a thick cell wall. Accordingly, the wall is a major target of present-day antimicrobial therapy. Unfortunately, S. aureus has mastered the art of antimicrobial resistance, as underscored by the global spread of methicillin-resistant S. aureus (MRSA). The major cell wall component is peptidoglycan. Importantly, the peptidoglycan network is not only vital for cell wall function, but it also represents a bacterial Achilles' heel. In particular, this network is continuously opened by no less than 18 different peptidoglycan hydrolases (PGHs) encoded by the S. aureus core genome, which facilitate bacterial growth and division. This focuses attention on the specific functions executed by these enzymes, their subcellular localization, their control at the transcriptional and post-transcriptional levels, their contributions to staphylococcal virulence and their overall importance in bacterial homeostasis. As highlighted in the present review, our understanding of the different aspects of PGH function in S. aureus has been substantially increased over recent years. This is important because it opens up new possibilities to exploit PGHs as innovative targets for next-generation antimicrobials, passive or active immunization strategies, or even to engineer them into effective antimicrobial agents.
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Affiliation(s)
- Min Wang
- Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, PO Box 30001, 9700 RB Groningen, the Netherlands
| | | | - Jan Maarten van Dijl
- Corresponding author: Department of Medical Microbiology, University of Groningen, University Medical Center Groningen, Hanzeplein 1, P.O. box 30001, HPC EB80, 9700 RB Groningen, the Netherlands, Tel. +31-50-3615187; Fax. +31-50-3619105; E-mail:
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6
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Yang D, Zheng X, Jiang L, Ye M, He X, Jin Y, Wu R. Functional Mapping of Phenotypic Plasticity of Staphylococcus aureus Under Vancomycin Pressure. Front Microbiol 2021; 12:696730. [PMID: 34566908 PMCID: PMC8458881 DOI: 10.3389/fmicb.2021.696730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 08/23/2021] [Indexed: 11/17/2022] Open
Abstract
Phenotypic plasticity is the exhibition of various phenotypic traits produced by a single genotype in response to environmental changes, enabling organisms to adapt to environmental changes by maintaining growth and reproduction. Despite its significance in evolutionary studies, we still know little about the genetic control of phenotypic plasticity. In this study, we designed and conducted a genome-wide association study (GWAS) to reveal genetic architecture of how Staphylococcus aureus strains respond to increasing concentrations of vancomycin (0, 2, 4, and 6 μg/mL) in a time course. We implemented functional mapping, a dynamic model for genetic mapping using longitudinal data, to map specific loci that mediate the growth trajectories of abundance of vancomycin-exposed S. aureus strains. 78 significant single nucleotide polymorphisms were identified following analysis of the whole growth and development process, and seven genes might play a pivotal role in governing phenotypic plasticity to the pressure of vancomycin. These seven genes, SAOUHSC_00020 (walR), SAOUHSC_00176, SAOUHSC_00544 (sdrC), SAOUHSC_02998, SAOUHSC_00025, SAOUHSC_00169, and SAOUHSC_02023, were found to help S. aureus regulate antibiotic pressure. Our dynamic gene mapping technique provides a tool for dissecting the phenotypic plasticity mechanisms of S. aureus under vancomycin pressure, emphasizing the feasibility and potential of functional mapping in the study of bacterial phenotypic plasticity.
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Affiliation(s)
- Dengcheng Yang
- Center for Computational Biology, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xuyang Zheng
- College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Libo Jiang
- Center for Computational Biology, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Meixia Ye
- Center for Computational Biology, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Xiaoqing He
- Center for Computational Biology, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Yi Jin
- Center for Computational Biology, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China
| | - Rongling Wu
- Center for Computational Biology, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.,Department of Public Health Sciences and Statistics, Center for Statistical Genetics, The Pennsylvania State University, Hershey, PA, United States
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7
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Walter A, Friz S, Mayer C. Chitin, Chitin Oligosaccharide, and Chitin Disaccharide Metabolism of Escherichia coli Revisited: Reassignment of the Roles of ChiA, ChbR, ChbF, and ChbG. Microb Physiol 2021; 31:178-194. [PMID: 33794535 DOI: 10.1159/000515178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/05/2021] [Indexed: 11/19/2022]
Abstract
Escherichia coli is unable to grow on polymeric and oligomeric chitin, but grows on chitin disaccharide (GlcNAc-GlcNAc; N,N'-diacetylchitobiose) and chitin trisaccharide (GlcNAc-GlcNAc-GlcNAc; N,N',N''-triacetylchitotriose) via expression of the chb operon (chbBCARFG). The phosphotransferase system (PTS) transporter ChbBCA facilitates transport of both saccharides across the inner membrane and their concomitant phosphorylation at the non-reducing end, intracellularly yielding GlcNAc 6-phosphate-GlcNAc (GlcNAc6P-GlcNAc) and GlcNAc6P-GlcNAc-GlcNAc, respectively. We revisited the intracellular catabolism of the PTS products, thereby correcting the reported functions of the 6-phospho-glycosidase ChbF, the monodeacetylase ChbG, and the transcriptional regulator ChbR. Intracellular accumulation of glucosamine 6P-GlcNAc (GlcN6P-GlcNAc) and GlcN6P-GlcNAc-GlcNAc in a chbF mutant unraveled a role for ChbG as a monodeacetylase that removes the N-acetyl group at the non-reducing end. Consequently, GlcN6P- but not GlcNAc6P-containing saccharides likely function as coactivators of ChbR. Furthermore, ChbF removed the GlcN6P from the non-reducing terminus of the former saccharides, thereby degrading the inducers of the chb operon and facilitating growth on the saccharides. Consequently, ChbF was unable to hydrolyze GlcNAc6P-residues from the non-reducing end, contrary to previous assumptions but in agreement with structural modeling data and with the unusual catalytic mechanism of the family 4 of glycosidases, to which ChbF belongs. We also refuted the assumption that ChiA is a bifunctional endochitinase/lysozyme ChiA, and show that it is unable to degrade peptidoglycans but acts as a bona fide chitinase in vitro and in vivo, enabling growth of E. coli on chitin oligosaccharides when ectopically expressed. Overall, this study revises our understanding of the chitin, chitin oligosaccharide, and chitin disaccharide metabolism of E. coli.
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Affiliation(s)
- Axel Walter
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions/Glycobiology, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Simon Friz
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions/Glycobiology, Eberhard Karls Universität Tübingen, Tübingen, Germany
| | - Christoph Mayer
- Interfaculty Institute of Microbiology and Infection Medicine, Organismic Interactions/Glycobiology, Eberhard Karls Universität Tübingen, Tübingen, Germany
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8
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Fisher JF, Mobashery S. β-Lactams against the Fortress of the Gram-Positive Staphylococcus aureus Bacterium. Chem Rev 2021; 121:3412-3463. [PMID: 33373523 PMCID: PMC8653850 DOI: 10.1021/acs.chemrev.0c01010] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The biological diversity of the unicellular bacteria-whether assessed by shape, food, metabolism, or ecological niche-surely rivals (if not exceeds) that of the multicellular eukaryotes. The relationship between bacteria whose ecological niche is the eukaryote, and the eukaryote, is often symbiosis or stasis. Some bacteria, however, seek advantage in this relationship. One of the most successful-to the disadvantage of the eukaryote-is the small (less than 1 μm diameter) and nearly spherical Staphylococcus aureus bacterium. For decades, successful clinical control of its infection has been accomplished using β-lactam antibiotics such as the penicillins and the cephalosporins. Over these same decades S. aureus has perfected resistance mechanisms against these antibiotics, which are then countered by new generations of β-lactam structure. This review addresses the current breadth of biochemical and microbiological efforts to preserve the future of the β-lactam antibiotics through a better understanding of how S. aureus protects the enzyme targets of the β-lactams, the penicillin-binding proteins. The penicillin-binding proteins are essential enzyme catalysts for the biosynthesis of the cell wall, and understanding how this cell wall is integrated into the protective cell envelope of the bacterium may identify new antibacterials and new adjuvants that preserve the efficacy of the β-lactams.
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Affiliation(s)
- Jed F Fisher
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, McCourtney Hall, University of Notre Dame, Notre Dame Indiana 46556, United States
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9
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Müller M, Calvert M, Hottmann I, Kluj RM, Teufel T, Balbuchta K, Engelbrecht A, Selim KA, Xu Q, Borisova M, Titz A, Mayer C. The exo-β-N-acetylmuramidase NamZ from Bacillus subtilis is the founding member of a family of exo-lytic peptidoglycan hexosaminidases. J Biol Chem 2021; 296:100519. [PMID: 33684445 PMCID: PMC8054146 DOI: 10.1016/j.jbc.2021.100519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/27/2021] [Accepted: 03/04/2021] [Indexed: 11/11/2022] Open
Abstract
Endo-β-N-acetylmuramidases, commonly known as lysozymes, are well-characterized antimicrobial enzymes that catalyze an endo-lytic cleavage of peptidoglycan; i.e., they hydrolyze the β-1,4-glycosidic bonds connecting N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc). In contrast, little is known about exo-β-N-acetylmuramidases, which catalyze an exo-lytic cleavage of β-1,4-MurNAc entities from the non-reducing ends of peptidoglycan chains. Such an enzyme was identified earlier in the bacterium Bacillus subtilis, but the corresponding gene has remained unknown so far. We now report that ybbC of B. subtilis, renamed namZ, encodes the reported exo-β-N-acetylmuramidase. A ΔnamZ mutant accumulated specific cell wall fragments and showed growth defects under starvation conditions, indicating a role of NamZ in cell wall turnover and recycling. Recombinant NamZ protein specifically hydrolyzed the artificial substrate para-nitrophenyl β-MurNAc and the peptidoglycan-derived disaccharide MurNAc-β-1,4-GlcNAc. Together with the exo-β-N-acetylglucosaminidase NagZ and the exo-muramoyl-l-alanine amidase AmiE, NamZ degraded intact peptidoglycan by sequential hydrolysis from the non-reducing ends. A structure model of NamZ, built on the basis of two crystal structures of putative orthologs from Bacteroides fragilis, revealed a two-domain structure including a Rossmann-fold-like domain that constitutes a unique glycosidase fold. Thus, NamZ, a member of the DUF1343 protein family of unknown function, is now classified as the founding member of a new family of glycosidases (CAZy GH171; www.cazy.org/GH171.html). NamZ-like peptidoglycan hexosaminidases are mainly present in the phylum Bacteroidetes and less frequently found in individual genomes within Firmicutes (Bacilli, Clostridia), Actinobacteria, and γ-proteobacteria.
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Affiliation(s)
- Maraike Müller
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Matthew Calvert
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Isabel Hottmann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Robert Maria Kluj
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Tim Teufel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Katja Balbuchta
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alicia Engelbrecht
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Khaled A Selim
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany; Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Center, Giza, Egypt
| | - Qingping Xu
- GM/CA @ APS, Argonne National Laboratory, Lemont, Illinois, USA
| | - Marina Borisova
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Christoph Mayer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.
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10
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Differential Induction of Type I and III Interferons by Staphylococcus aureus. Infect Immun 2020; 88:IAI.00352-20. [PMID: 32690637 DOI: 10.1128/iai.00352-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus is a leading cause of bacterial pneumonia, and we have shown previously that type I interferon (IFN) contributes to the pathogenesis of this disease. In this study, we screened 75 S. aureus strains for their ability to induce type I and III IFN. Both cytokine pathways were differentially stimulated by various S. aureus strains independently of their isolation sites or methicillin resistance profiles. These induction patterns persisted over time, and type I and III IFN generation differentially correlated with tumor necrosis factor alpha production. Investigation of one isolate, strain 126, showed a significant defect in type I IFN induction that persisted over several time points. The lack of induction was not due to differential phagocytosis, subcellular location, or changes in endosomal acidification. A correlation between reduced type I IFN induction levels and decreased autolysis and lysostaphin sensitivity was found between strains. Strain 126 had a decreased rate of autolysis and increased resistance to lysostaphin degradation and host cell-mediated killing. This strain displayed decreased virulence in a murine model of acute pneumonia compared to USA300 (current epidemic strain and commonly used in research) and had reduced capacity to induce multiple cytokines. We observed this isolate to be a vancomycin-intermediate S. aureus (VISA) strain, and reduced Ifnb was observed with a defined mutation in walK that induces a VISA phenotype. Overall, this study demonstrates the heterogeneity of IFN induction by S. aureus and uncovered an interesting property of a VISA strain in its inability to induce type I IFN production.
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Maitra A, Munshi T, Healy J, Martin LT, Vollmer W, Keep NH, Bhakta S. Cell wall peptidoglycan in Mycobacterium tuberculosis: An Achilles' heel for the TB-causing pathogen. FEMS Microbiol Rev 2020; 43:548-575. [PMID: 31183501 PMCID: PMC6736417 DOI: 10.1093/femsre/fuz016] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/07/2019] [Indexed: 02/06/2023] Open
Abstract
Tuberculosis (TB), caused by the intracellular pathogen Mycobacterium tuberculosis, remains one of the leading causes of mortality across the world. There is an urgent requirement to build a robust arsenal of effective antimicrobials, targeting novel molecular mechanisms to overcome the challenges posed by the increase of antibiotic resistance in TB. Mycobacterium tuberculosis has a unique cell envelope structure and composition, containing a peptidoglycan layer that is essential for maintaining cellular integrity and for virulence. The enzymes involved in the biosynthesis, degradation, remodelling and recycling of peptidoglycan have resurfaced as attractive targets for anti-infective drug discovery. Here, we review the importance of peptidoglycan, including the structure, function and regulation of key enzymes involved in its metabolism. We also discuss known inhibitors of ATP-dependent Mur ligases, and discuss the potential for the development of pan-enzyme inhibitors targeting multiple Mur ligases.
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Affiliation(s)
- Arundhati Maitra
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Tulika Munshi
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Jess Healy
- Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Liam T Martin
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne, NE2 4AX, UK
| | - Nicholas H Keep
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
| | - Sanjib Bhakta
- Mycobacteria Research Laboratory, Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, UK
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Shaku M, Ealand C, Matlhabe O, Lala R, Kana BD. Peptidoglycan biosynthesis and remodeling revisited. ADVANCES IN APPLIED MICROBIOLOGY 2020; 112:67-103. [PMID: 32762868 DOI: 10.1016/bs.aambs.2020.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The bacterial peptidoglycan layer forms a complex mesh-like structure that surrounds the cell, imparting rigidity to withstand cytoplasmic turgor and the ability to tolerate stress. As peptidoglycan has been the target of numerous clinically successful antimicrobials such as penicillin, the biosynthesis, remodeling and recycling of this polymer has been the subject of much interest. Herein, we review recent advances in the understanding of peptidoglycan biosynthesis and remodeling in a variety of different organisms. In order for bacterial cells to grow and divide, remodeling of cross-linked peptidoglycan is essential hence, we also summarize the activity of important peptidoglycan hydrolases and how their functions differ in various species. There is a growing body of evidence highlighting complex regulatory mechanisms for peptidoglycan metabolism including protein interactions, phosphorylation and protein degradation and we summarize key recent findings in this regard. Finally, we provide an overview of peptidoglycan recycling and how components of this pathway mediate resistance to drugs. In the face of growing antimicrobial resistance, these recent advances are expected to uncover new drug targets in peptidoglycan metabolism, which can be used to develop novel therapies.
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Affiliation(s)
- Moagi Shaku
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Christopher Ealand
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Ofentse Matlhabe
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Rushil Lala
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa
| | - Bavesh D Kana
- Department of Science and Technology/National Research Foundation Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg, South Africa.
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Walter A, Unsleber S, Rismondo J, Jorge AM, Peschel A, Gründling A, Mayer C. Phosphoglycerol-type wall and lipoteichoic acids are enantiomeric polymers differentiated by the stereospecific glycerophosphodiesterase GlpQ. J Biol Chem 2020; 295:4024-4034. [PMID: 32047114 PMCID: PMC7086022 DOI: 10.1074/jbc.ra120.012566] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 02/11/2020] [Indexed: 12/23/2022] Open
Abstract
The cell envelope of Gram-positive bacteria generally comprises two types of polyanionic polymers linked to either peptidoglycan (wall teichoic acids; WTA) or to membrane glycolipids (lipoteichoic acids; LTA). In some bacteria, including Bacillus subtilis strain 168, both WTA and LTA are glycerolphosphate polymers yet are synthesized through different pathways and have distinct but incompletely understood morphogenetic functions during cell elongation and division. We show here that the exolytic sn-glycerol-3-phosphodiesterase GlpQ can discriminate between B. subtilis WTA and LTA. GlpQ completely degraded unsubstituted WTA, which lacks substituents at the glycerol residues, by sequentially removing glycerolphosphates from the free end of the polymer up to the peptidoglycan linker. In contrast, GlpQ could not degrade unsubstituted LTA unless it was partially precleaved, allowing access of GlpQ to the other end of the polymer, which, in the intact molecule, is protected by a connection to the lipid anchor. Differences in stereochemistry between WTA and LTA have been suggested previously on the basis of differences in their biosynthetic precursors and chemical degradation products. The differential cleavage of WTA and LTA by GlpQ reported here represents the first direct evidence that they are enantiomeric polymers: WTA is made of sn-glycerol-3-phosphate, and LTA is made of sn-glycerol-1-phosphate. Their distinct stereochemistries reflect the dissimilar physiological and immunogenic properties of WTA and LTA. It also enables differential degradation of the two polymers within the same envelope compartment in vivo, particularly under phosphate-limiting conditions, when B. subtilis specifically degrades WTA and replaces it with phosphate-free teichuronic acids.
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Affiliation(s)
- Axel Walter
- Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Sandra Unsleber
- Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Jeanine Rismondo
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Ana Maria Jorge
- Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Andreas Peschel
- Infection Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72076 Tübingen, Germany
| | - Angelika Gründling
- Section of Molecular Microbiology and Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Christoph Mayer
- Microbiology/Glycobiology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, 72076 Tübingen, Germany
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Fisher JF, Mobashery S. Constructing and deconstructing the bacterial cell wall. Protein Sci 2020; 29:629-646. [PMID: 31747090 PMCID: PMC7021008 DOI: 10.1002/pro.3737] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 09/17/2019] [Accepted: 09/18/2019] [Indexed: 12/11/2022]
Abstract
The history of modern medicine cannot be written apart from the history of the antibiotics. Antibiotics are cytotoxic secondary metabolites that are isolated from Nature. The antibacterial antibiotics disproportionately target bacterial protein structure that is distinct from eukaryotic protein structure, notably within the ribosome and within the pathways for bacterial cell-wall biosynthesis (for which there is not a eukaryotic counterpart). This review focuses on a pre-eminent class of antibiotics-the β-lactams, exemplified by the penicillins and cephalosporins-from the perspective of the evolving mechanisms for bacterial resistance. The mechanism of action of the β-lactams is bacterial cell-wall destruction. In the monoderm (single membrane, Gram-positive staining) pathogen Staphylococcus aureus the dominant resistance mechanism is expression of a β-lactam-unreactive transpeptidase enzyme that functions in cell-wall construction. In the diderm (dual membrane, Gram-negative staining) pathogen Pseudomonas aeruginosa a dominant resistance mechanism (among several) is expression of a hydrolytic enzyme that destroys the critical β-lactam ring of the antibiotic. The key sensing mechanism used by P. aeruginosa is monitoring the molecular difference between cell-wall construction and cell-wall deconstruction. In both bacteria, the resistance pathways are manifested only when the bacteria detect the presence of β-lactams. This review summarizes how the β-lactams are sensed and how the resistance mechanisms are manifested, with the expectation that preventing these processes will be critical to future chemotherapeutic control of multidrug resistant bacteria.
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Affiliation(s)
- Jed F. Fisher
- Department of Chemistry and BiochemistryUniversity of Notre DameSouth BendIndiana
| | - Shahriar Mobashery
- Department of Chemistry and BiochemistryUniversity of Notre DameSouth BendIndiana
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Mayer C, Kluj RM, Mühleck M, Walter A, Unsleber S, Hottmann I, Borisova M. Bacteria's different ways to recycle their own cell wall. Int J Med Microbiol 2019; 309:151326. [PMID: 31296364 DOI: 10.1016/j.ijmm.2019.06.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/28/2019] [Accepted: 06/30/2019] [Indexed: 01/05/2023] Open
Abstract
The ability to recover components of their own cell wall is a common feature of bacteria. This was initially recognized in the Gram-negative bacterium Escherichia coli, which recycles about half of the peptidoglycan of its cell wall during one cell doubling. Moreover, E. coli was shown to grow on peptidoglycan components provided as nutrients. A distinguished recycling enzyme of E. coli required for both, recovery of the cell wall sugar N-acetylmuramic acid (MurNAc) of the own cell wall and for growth on external MurNAc, is the MurNAc 6-phosphate (MurNAc 6P) lactyl ether hydrolase MurQ. We revealed however, that most Gram-negative bacteria lack a murQ ortholog and instead harbor a pathway, absent in E. coli, that channels MurNAc directly to peptidoglycan biosynthesis. This "anabolic recycling pathway" bypasses the initial steps of peptidoglycan de novo synthesis, including the target of the antibiotic fosfomycin, thus providing intrinsic resistance to the antibiotic. The Gram-negative oral pathogen Tannerella forsythia is auxotrophic for MurNAc and apparently depends on the anabolic recycling pathway to synthesize its own cell wall by scavenging cell wall debris of other bacteria. In contrast, Gram-positive bacteria lack the anabolic recycling genes, but mostly contain one or two murQ orthologs. Quantification of MurNAc 6P accumulation in murQ mutant cells by mass spectrometry allowed us to demonstrate for the first time that Gram-positive bacteria do recycle their own peptidoglycan. This had been questioned earlier, since peptidoglycan turnover products accumulate in the spent media of Gram-positives. We showed, that these fragments are recovered during nutrient limitation, which prolongs starvation survival of Bacillus subtilis and Staphylococcus aureus. Peptidoglycan recycling in these bacteria however differs, as the cell wall is either cleaved exhaustively and monosaccharide building blocks are taken up (B. subtilis) or disaccharides are released and recycled involving a novel phosphomuramidase (MupG; S.aureus). In B. subtilis also the teichoic acids, covalently bound to the peptidoglycan (wall teichoic acids; WTAs), are recycled. During phosphate limitation, the sn-glycerol-3-phosphate phosphodiesterase GlpQ specifically degrades WTAs of B. subtilis. In S. aureus, in contrast, GlpQ is used to scavenge external teichoic acid sources. Thus, although bacteria generally recover their own cell wall, they apparently apply distinct strategies for breakdown and reutilization of cell wall fragments. This review summarizes our work on this topic funded between 2011 and 2019 by the DFG within the collaborative research center SFB766.
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Affiliation(s)
- Christoph Mayer
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany.
| | - Robert Maria Kluj
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Maraike Mühleck
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Axel Walter
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Sandra Unsleber
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Isabel Hottmann
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
| | - Marina Borisova
- Mikrobiologie/Biotechnologie, Interfakultäres Institut für Mikrobiologie und Infektionsmedizin Tübingen (IMIT), Eberhard Karls Universität Tübingen, Auf der Morgenstelle 28, 72076, Tübingen, Germany
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Irazoki O, Hernandez SB, Cava F. Peptidoglycan Muropeptides: Release, Perception, and Functions as Signaling Molecules. Front Microbiol 2019; 10:500. [PMID: 30984120 PMCID: PMC6448482 DOI: 10.3389/fmicb.2019.00500] [Citation(s) in RCA: 107] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 02/27/2019] [Indexed: 12/12/2022] Open
Abstract
Peptidoglycan (PG) is an essential molecule for the survival of bacteria, and thus, its biosynthesis and remodeling have always been in the spotlight when it comes to the development of antibiotics. The peptidoglycan polymer provides a protective function in bacteria, but at the same time is continuously subjected to editing activities that in some cases lead to the release of peptidoglycan fragments (i.e., muropeptides) to the environment. Several soluble muropeptides have been reported to work as signaling molecules. In this review, we summarize the mechanisms involved in muropeptide release (PG breakdown and PG recycling) and describe the known PG-receptor proteins responsible for PG sensing. Furthermore, we overview the role of muropeptides as signaling molecules, focusing on the microbial responses and their functions in the host beyond their immunostimulatory activity.
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Affiliation(s)
| | | | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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