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Anderson AC, Stangherlin S, Pimentel KN, Weadge JT, Clarke AJ. The SGNH hydrolase family: a template for carbohydrate diversity. Glycobiology 2022; 32:826-848. [PMID: 35871440 PMCID: PMC9487903 DOI: 10.1093/glycob/cwac045] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/20/2022] [Accepted: 07/05/2022] [Indexed: 11/14/2022] Open
Abstract
The substitution and de-substitution of carbohydrate materials are important steps in the biosynthesis and/or breakdown of a wide variety of biologically important polymers. The SGNH hydrolase superfamily is a group of related and well-studied proteins with a highly conserved catalytic fold and mechanism composed of 16 member families. SGNH hydrolases can be found in vertebrates, plants, fungi, bacteria, and archaea, and play a variety of important biological roles related to biomass conversion, pathogenesis, and cell signaling. The SGNH hydrolase superfamily is chiefly composed of a diverse range of carbohydrate-modifying enzymes, including but not limited to the carbohydrate esterase families 2, 3, 6, 12 and 17 under the carbohydrate-active enzyme classification system and database (CAZy.org). In this review, we summarize the structural and functional features that delineate these subfamilies of SGNH hydrolases, and which generate the wide variety of substrate preferences and enzymatic activities observed of these proteins to date.
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Affiliation(s)
- Alexander C Anderson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph N1G2W1, Canada
| | - Stefen Stangherlin
- Department of Chemistry & Biochemistry, Wilfrid Laurier University, Waterloo N2L3C5, Canada
| | - Kyle N Pimentel
- Department of Molecular and Cellular Biology, University of Guelph, Guelph N1G2W1, Canada
| | - Joel T Weadge
- Department of Biology, Wilfrid Laurier University, Waterloo N2L3C5, Canada
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph N1G2W1, Canada
- Department of Chemistry & Biochemistry, Wilfrid Laurier University, Waterloo N2L3C5, Canada
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2
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Riu F, Ruda A, Ibba R, Sestito S, Lupinu I, Piras S, Widmalm G, Carta A. Antibiotics and Carbohydrate-Containing Drugs Targeting Bacterial Cell Envelopes: An Overview. Pharmaceuticals (Basel) 2022; 15:942. [PMID: 36015090 PMCID: PMC9414505 DOI: 10.3390/ph15080942] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 02/07/2023] Open
Abstract
Certain bacteria constitute a threat to humans due to their ability to escape host defenses as they easily develop drug resistance. Bacteria are classified into gram-positive and gram-negative according to the composition of the cell membrane structure. Gram-negative bacteria have an additional outer membrane (OM) that is not present in their gram-positive counterpart; the latter instead hold a thicker peptidoglycan (PG) layer. This review covers the main structural and functional properties of cell wall polysaccharides (CWPs) and PG. Drugs targeting CWPs are discussed, both noncarbohydrate-related (β-lactams, fosfomycin, and lipopeptides) and carbohydrate-related (glycopeptides and lipoglycopeptides). Bacterial resistance to these drugs continues to evolve, which calls for novel antibacterial approaches to be developed. The use of carbohydrate-based vaccines as a valid strategy to prevent bacterial infections is also addressed.
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Affiliation(s)
- Federico Riu
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Alessandro Ruda
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden; (A.R.); (G.W.)
| | - Roberta Ibba
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Simona Sestito
- Department of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari, Via Vienna 2, 07100 Sassari, Italy;
| | - Ilenia Lupinu
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Sandra Piras
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden; (A.R.); (G.W.)
| | - Antonio Carta
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
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3
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Pearson C, Tindall S, Potts JR, Thomas GH, van der Woude MW. Diverse functions for acyltransferase-3 proteins in the modification of bacterial cell surfaces. Microbiology (Reading) 2022; 168. [PMID: 35253642 PMCID: PMC9558356 DOI: 10.1099/mic.0.001146] [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] [Indexed: 12/27/2022] Open
Abstract
The acylation of sugars, most commonly via acetylation, is a widely used mechanism in bacteria that uses a simple chemical modification to confer useful traits. For structures like lipopolysaccharide, capsule and peptidoglycan, that function outside of the cytoplasm, their acylation during export or post-synthesis requires transport of an activated acyl group across the membrane. In bacteria this function is most commonly linked to a family of integral membrane proteins – acyltransferase-3 (AT3). Numerous studies examining production of diverse extracytoplasmic sugar-containing structures have identified roles for these proteins in O-acylation. Many of the phenotypes conferred by the action of AT3 proteins influence host colonisation and environmental survival, as well as controlling the properties of biotechnologically important polysaccharides and the modification of antibiotics and antitumour drugs by Actinobacteria. Herein we present the first systematic review, to our knowledge, of the functions of bacterial AT3 proteins, revealing an important protein family involved in a plethora of systems of importance to bacterial function that is still relatively poorly understood at the mechanistic level. By defining and comparing this set of functions we draw out common themes in the structure and mechanism of this fascinating family of membrane-bound enzymes, which, due to their role in host colonisation in many pathogens, could offer novel targets for the development of antimicrobials.
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Affiliation(s)
| | - Sarah Tindall
- Department of Biology, University of York, Heslington, UK
| | | | - Gavin H. Thomas
- Department of Biology, University of York, Heslington, UK
- York Biomedical Institute, University of York, Heslington, UK
| | - Marjan W. van der Woude
- Hull York Medical School, Heslington, UK
- York Biomedical Institute, University of York, Heslington, UK
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4
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Parthasarathy S, Wang X, Carr KR, Varahan S, Hancock EB, Hancock LE. SigV Mediates Lysozyme Resistance in Enterococcus faecalis via RsiV and PgdA. J Bacteriol 2021; 203:e0025821. [PMID: 34370556 PMCID: PMC8459761 DOI: 10.1128/jb.00258-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Enterococcus faecalis is a gut commensal but transitions to a pathogenic state as a consequence of intestinal dysbiosis and/or the presence of indwelling medical devices, causing a wide range of infections. One of the unique features of E. faecalis is its ability to display high level resistance to lysozyme, an important host defense of the innate immune response. Lysozyme resistance in E. faecalis is known to be mediated by the extracytoplasmic function (ECF) sigma factor SigV. PgdA and RsiV expression is directly regulated by SigV, but pgdA and rsiV mutants display nominal changes in lysozyme resistance, suggesting that additional gene products in the SigV regulon contribute to lysozyme resistance. Using transcriptome sequencing (RNA-seq) analysis, we compared the transcriptional profile of the parental strain to that of an isogenic sigV mutant and show that apart from sigV, only rsiV and pgdA expression was induced upon lysozyme exposure. The combined deletion mutant of both rsiV and pgdA rendered E. faecalis sensitive to lysozyme at a level comparable to that of the sigV mutant, highlighting the limited SigV regulon. Several additional genes were also induced upon lysozyme exposure, but in a SigV-independent fashion. Overexpression of pgdA from a SigV-independent promoter restored lysozyme resistance in a sigV deletion mutant and also induced cell chaining. Overexpression of rsiV from a SigV-independent promoter only partially restored lysozyme resistance in a sigV mutant. Overall, we provide evidence for a simple adaptation to lysozyme stress, in which SigV controls the expression of rsiV and pgdA, and that both gene products contribute to lysozyme resistance. IMPORTANCE Enterococcus faecalis causes health care-associated infections and displays resistance to a variety of antibiotics and molecules of the innate immune system. SigV has been shown to play an important role in enterococcal lysozyme resistance. Even though several proteins have been implicated in enterococcal lysozyme resistance, a complete SigV-dependent regulon has not been functionally characterized as being responsible for the dramatic increase in lysozyme susceptibility displayed by a sigV mutant. Using RNA-seq, we have identified the SigV regulon to be comprised of two gene loci, sigV-rsiV and pgdA. Deletion of both rsiV and pgdA renders E. faecalis susceptible to lysozyme on par with a sigV mutant. We also demonstrate that overproduction of rsiV and pgdA contributes to lysozyme resistance in susceptible strains.
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Affiliation(s)
- Srivatsan Parthasarathy
- Department of Molecular Biosciences, University of Kansasgrid.266515.3, Lawrence, Kansas, USA
| | - Xiaofei Wang
- Department of Molecular Biosciences, University of Kansasgrid.266515.3, Lawrence, Kansas, USA
| | - Kristen R. Carr
- Department of Molecular Biosciences, University of Kansasgrid.266515.3, Lawrence, Kansas, USA
| | - Sriram Varahan
- Department of Molecular Biosciences, University of Kansasgrid.266515.3, Lawrence, Kansas, USA
| | - Elyssa B. Hancock
- Department of Molecular Biosciences, University of Kansasgrid.266515.3, Lawrence, Kansas, USA
| | - Lynn E. Hancock
- Department of Molecular Biosciences, University of Kansasgrid.266515.3, Lawrence, Kansas, USA
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5
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Lim KYL, Mullally CA, Haese EC, Kibble EA, McCluskey NR, Mikucki EC, Thai VC, Stubbs KA, Sarkar-Tyson M, Kahler CM. Anti-Virulence Therapeutic Approaches for Neisseria gonorrhoeae. Antibiotics (Basel) 2021; 10:antibiotics10020103. [PMID: 33494538 PMCID: PMC7911339 DOI: 10.3390/antibiotics10020103] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 01/15/2023] Open
Abstract
While antimicrobial resistance (AMR) is seen in both Neisseria gonorrhoeae and Neisseria meningitidis, the former has become resistant to commonly available over-the-counter antibiotic treatments. It is imperative then to develop new therapies that combat current AMR isolates whilst also circumventing the pathways leading to the development of AMR. This review highlights the growing research interest in developing anti-virulence therapies (AVTs) which are directed towards inhibiting virulence factors to prevent infection. By targeting virulence factors that are not essential for gonococcal survival, it is hypothesized that this will impart a smaller selective pressure for the emergence of resistance in the pathogen and in the microbiome, thus avoiding AMR development to the anti-infective. This review summates the current basis of numerous anti-virulence strategies being explored for N. gonorrhoeae.
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Affiliation(s)
- Katherine Y. L. Lim
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Christopher A. Mullally
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Ethan C. Haese
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Emily A. Kibble
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Nicolie R. McCluskey
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- School of Veterinary and Life Sciences, Murdoch University, Murdoch, WA 6150, Australia
| | - Edward C. Mikucki
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Van C. Thai
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Keith A. Stubbs
- School of Molecular Sciences, University of Western Australia, Crawley, WA 6009, Australia;
| | - Mitali Sarkar-Tyson
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
| | - Charlene M. Kahler
- Marshall Centre for Infectious Disease Research and Training, School of Biomedical Sciences, University of Western Australia, Crawley, WA 6009, Australia; (K.Y.L.L.); (C.A.M.); (E.C.H.); (E.A.K.); (N.R.M.); (E.C.M.); (V.C.T.); (M.S.-T.)
- Correspondence:
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6
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Secreted virulence factors from Heterorhabditis bacteriophora highlight its utility as a model parasite among Clade V nematodes. Int J Parasitol 2021; 51:321-325. [PMID: 33421438 DOI: 10.1016/j.ijpara.2020.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 11/23/2022]
Abstract
Much of the available knowledge of entomopathogenic virulence factors has been gleaned from studies in the nematode parasite Steinernema carpocapsae, but there is good reason to complement this knowledge with similar studies in Heterorhabditis bacteriophora. Three candidate virulence factors from H. bacteriophora have recently been characterised, and each was demonstrated to contribute to infection. This information can be used not only to advance efforts in the biocontrol of insect pests, but also to make inferences about the emergence of parasitism among Clade V nematodes.
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7
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Kenney E, Yaparla A, Hawdon JM, O' Halloran DM, Grayfer L, Eleftherianos I. A putative lysozyme and serine carboxypeptidase from Heterorhabditis bacteriophora show differential virulence capacities in Drosophila melanogaster. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 114:103820. [PMID: 32791175 DOI: 10.1016/j.dci.2020.103820] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 06/11/2023]
Abstract
Nematode virulence factors are of interest for a variety of applications including biocontrol against insect pests and the alleviation of autoimmune diseases with nematode-derived factors. In silico "omics" techniques have generated a wealth of candidate factors that may be important in the establishment of nematode infections, although the challenge of characterizing these individual factors in vivo remains. Here we provide a fundamental characterization of a putative lysozyme and serine carboxypeptidase from the host-induced transcriptome of Heterorhabditis bacteriophora. Both factors accelerated the mortality rate following Drosophila melanogaster infections with Photorhabdus luminescens, and both factors suppressed phenoloxidase activity in D. melanogaster hemolymph. Furthermore, the serine carboxypeptidase was lethal to a subpopulation of flies and suppressed the upregulation of antimicrobial peptides as well as phagocytosis. Together, our findings suggest that this serine carboxypeptidase possess both toxic and immunomodulatory properties while the lysozyme is likely to confer immunomodulatory, but not toxic effects.
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Affiliation(s)
- Eric Kenney
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA
| | - Amulya Yaparla
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA
| | - John M Hawdon
- Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, DC, USA
| | - Damien M O' Halloran
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA
| | - Leon Grayfer
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA
| | - Ioannis Eleftherianos
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA.
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8
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Grishin AV, Karyagina AS, Vasina DV, Vasina IV, Gushchin VA, Lunin VG. Resistance to peptidoglycan-degrading enzymes. Crit Rev Microbiol 2020; 46:703-726. [PMID: 32985279 DOI: 10.1080/1040841x.2020.1825333] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The spread of bacterial strains resistant to commonly used antibiotics urges the development of novel antibacterial compounds. Ideally, these novel antimicrobials should be less prone to the development of resistance. Peptidoglycan-degrading enzymes are a promising class of compounds with a fundamentally different mode of action compared to traditionally used antibiotics. The difference in the mechanism of action implies differences both in the mechanisms of resistance and the chances of its emergence. To critically assess the potential of resistance development to peptidoglycan-degrading enzymes, we review the available evidence for the development of resistance to these enzymes in vitro, along with the known mechanisms of resistance to lysozyme, bacteriocins, autolysins, and phage endolysins. We conclude that genetic determinants of resistance to peptidoglycan-degrading enzymes are unlikely to readily emerge de novo. However, resistance to these enzymes would probably spread by the horizontal transfer between intrinsically resistant and susceptible species. Finally, we speculate that the higher cost of the therapeutics based on peptidoglycan degrading enzymes compared to classical antibiotics might result in less misuse, which in turn would lead to lower selective pressure, making these antibacterials less prone to resistance development.
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Affiliation(s)
- Alexander V Grishin
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russia
| | - Anna S Karyagina
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russia.,A.N. Belozersky Institute of Physical and Chemical Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Daria V Vasina
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,A.N. Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow, Russia
| | - Irina V Vasina
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia
| | - Vladimir A Gushchin
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Vladimir G Lunin
- N.F. Gamaleya National Research Center for Epidemiology and Microbiology, Ministry of Health of the Russian Federation, Moscow, Russia.,All-Russia Research Institute of Agricultural Biotechnology, Russian Academy of Sciences, Moscow, Russia
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9
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Williams AH, Wheeler R, Deghmane AE, Santecchia I, Schaub RE, Hicham S, Moya Nilges M, Malosse C, Chamot-Rooke J, Haouz A, Dillard JP, Robins WP, Taha MK, Gomperts Boneca I. Defective lytic transglycosylase disrupts cell morphogenesis by hindering cell wall de- O-acetylation in Neisseria meningitidis. eLife 2020; 9:51247. [PMID: 32022687 PMCID: PMC7083599 DOI: 10.7554/elife.51247] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 02/04/2020] [Indexed: 12/17/2022] Open
Abstract
Lytic transglycosylases (LT) are enzymes involved in peptidoglycan (PG) remodeling. However, their contribution to cell-wall-modifying complexes and their potential as antimicrobial drug targets remains unclear. Here, we determined a high-resolution structure of the LT, an outer membrane lipoprotein from Neisseria species with a disordered active site helix (alpha helix 30). We show that deletion of the conserved alpha-helix 30 interferes with the integrity of the cell wall, disrupts cell division, cell separation, and impairs the fitness of the human pathogen Neisseria meningitidis during infection. Additionally, deletion of alpha-helix 30 results in hyperacetylated PG, suggesting this LtgA variant affects the function of the PG de-O-acetylase (Ape 1). Our study revealed that Ape 1 requires LtgA for optimal function, demonstrating that LTs can modulate the activity of their protein-binding partner. We show that targeting specific domains in LTs can be lethal, which opens the possibility that LTs are useful drug-targets.
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Affiliation(s)
- Allison Hillary Williams
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur; Groupe Avenir, INSERM 75015, Paris, France
| | - Richard Wheeler
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur; Groupe Avenir, INSERM 75015, Paris, France.,Tumour Immunology and Immunotherapy, Institut Gustave Roussy, Villejuif, France
| | | | - Ignacio Santecchia
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur; Groupe Avenir, INSERM 75015, Paris, France.,Universté Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Ryan E Schaub
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, United States
| | - Samia Hicham
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur; Groupe Avenir, INSERM 75015, Paris, France
| | - Maryse Moya Nilges
- Unité Technologie et Service BioImagerie Ultrastructural, Institut Pasteur, Paris, France
| | - Christian Malosse
- Unité Technologie et Service Spectrométrie de Masse pour la Biologie, Institut Pasteur; UMR 3528, CNRS 75015, Paris, France
| | - Julia Chamot-Rooke
- Unité Technologie et Service Spectrométrie de Masse pour la Biologie, Institut Pasteur; UMR 3528, CNRS 75015, Paris, France
| | - Ahmed Haouz
- Plate-forme de Cristallographie-C2RT, Institut Pasteur; UMR3528, CNRS 75015, Paris, France
| | - Joseph P Dillard
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, United States
| | - William P Robins
- Department of Microbiology, Harvard Medical School, Boston, United States
| | - Muhamed-Kheir Taha
- Unité des Infection Bactériennes Invasives, Institut Pasteur, Paris, France
| | - Ivo Gomperts Boneca
- Unité Biologie et Génétique de la Paroi Bactérienne, Institut Pasteur; Groupe Avenir, INSERM 75015, Paris, France
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10
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Brott AS, Clarke AJ. Peptidoglycan O-Acetylation as a Virulence Factor: Its Effect on Lysozyme in the Innate Immune System. Antibiotics (Basel) 2019; 8:antibiotics8030094. [PMID: 31323733 PMCID: PMC6783866 DOI: 10.3390/antibiotics8030094] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 07/11/2019] [Accepted: 07/13/2019] [Indexed: 11/16/2022] Open
Abstract
The peptidoglycan sacculus of both Gram-positive and Gram-negative bacteria acts as a protective mesh and provides structural support around the entirety of the cell. The integrity of this structure is of utmost importance for cell viability and so naturally is the first target for attack by the host immune system during bacterial infection. Lysozyme, a muramidase and the first line of defense of the innate immune system, targets the peptidoglycan sacculus hydrolyzing the β-(1→4) linkage between repeating glycan units, causing lysis and the death of the invading bacterium. The O-acetylation of N-acetylmuramoyl residues within peptidoglycan precludes the productive binding of lysozyme, and in doing so renders it inactive. This modification has been shown to be an important virulence factor in pathogens such as Staphylococcus aureus and Neisseria gonorrhoeae and is currently being investigated as a novel target for anti-virulence therapies. This article reviews interactions made between peptidoglycan and the host immune system, specifically with respect to lysozyme, and how the O-acetylation of the peptidoglycan interrupts these interactions, leading to increased pathogenicity.
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Affiliation(s)
- Ashley S Brott
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Anthony J Clarke
- Department of Molecular & Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
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11
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Getti GTM, Poole PL. Allicin causes fragmentation of the peptidoglycan coat in Staphylococcus aureus by effecting synthesis and aiding hydrolysis: a determination by MALDI-TOF mass spectrometry on whole cells. J Med Microbiol 2019; 68:667-677. [PMID: 30888314 DOI: 10.1099/jmm.0.000950] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To determine the effect of allicin on Staphylococcus aureus cell wall peptidoglycans by the application of MALDI-TOF mass spectrometry on whole cells and to relate this to current knowledge of wall-processing enzymes. METHODOLOGY Two different S. aureus strains were grown for 48 h after which period each culture was split into two, one part was then treated with sub-inhibitory levels of allicin while the other part left untreated as a control. After a further 24 h whole cells were recovered and analysed by MALDI-TOF mass spectrometry. RESULTS Changes in the mass spectra between the treated and untreated cells revealed fragmented peptidoglycans identified by mass calculation only in the treated cells. These peptidoglycan fragments where identified as the products of specific peptidoglycan hydrolases. CONCLUSIONS Allicin is known to target cysteine thiol groups. These are absent in peptidoglycan hydrolases and we might have expected identical results in both of the treated and untreated cells. Peptidoglycan synthesis enzymes such as the Fem family of enzymes do contain cysteines. Fem enzymes A, B and X all have a conserved conformation of 99 % for over 100 S. aureus strains and are therefore potential targets for allicin. Examination of FemA structure showed that cysteine102 is accessible from the surface. We propose that allicin has an inhibitory mechanism alongside others of targeting FemA and possibly other Fem enzymes by curtailing glycine bridging and leading to fragmentation. This study provided an insight into yet another antimicrobial mechanism of allicin.
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Affiliation(s)
- G T M Getti
- School of Health, Sport and Bioscience, University of East London, Water Lane, London E15 4LZ, UK
| | - P L Poole
- School of Health, Sport and Bioscience, University of East London, Water Lane, London E15 4LZ, UK
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12
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Schaub RE, Dillard JP. The Pathogenic Neisseria Use a Streamlined Set of Peptidoglycan Degradation Proteins for Peptidoglycan Remodeling, Recycling, and Toxic Fragment Release. Front Microbiol 2019; 10:73. [PMID: 30766523 PMCID: PMC6365954 DOI: 10.3389/fmicb.2019.00073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 01/15/2019] [Indexed: 12/26/2022] Open
Abstract
Neisseria gonorrhoeae and Neisseria meningitidis release peptidoglycan (PG) fragments from the cell as the bacteria grow. For N. gonorrhoeae these PG fragments are known to cause damage to human Fallopian tube tissue in organ culture that mimics the damage seen in patients with pelvic inflammatory disease. N. meningitidis also releases pro-inflammatory PG fragments, but in smaller amounts than those from N. gonorrhoeae. It is not yet known if PG fragment release contributes to the highly inflammatory conditions of meningitis and meningococcemia caused by N. meningitidis. Examination of the mechanisms of PG degradation and recycling identified proteins required for these processes. In comparison to the model organism E. coli, the pathogenic Neisseria have far fewer PG degradation proteins, and some of these proteins show differences in subcellular localization compared to their E. coli homologs. In particular, some N. gonorrhoeae PG degradation proteins were demonstrated to be in the outer membrane while their homologs in E. coli were found free in the periplasm or in the cytoplasm. The localization of two of these proteins was demonstrated to affect PG fragment release. Another major factor for PG fragment release is the allele of ampG. Gonococcal AmpG was found to be slightly defective compared to related PG fragment permeases, thus leading to increased release of PG. A number of additional PG-related factors affect other virulence functions in Neisseria. Endopeptidases and carboxypeptidases were found to be required for type IV pilus production and resistance to hydrogen peroxide. Also, deacetylation of PG was required for virulence of N. meningitidis as well as normal cell size. Overall, we describe the processes involved in PG degradation and recycling and how certain characteristics of these proteins influence the interactions of these pathogens with their host.
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Affiliation(s)
- Ryan E Schaub
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
| | - Joseph P Dillard
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States
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13
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Abstract
The peptidoglycan sacculus is a net-like polymer that surrounds the cytoplasmic membrane in most bacteria. It is essential to maintain the bacterial cell shape and protect from turgor. The peptidoglycan has a basic composition, common to all bacteria, with species-specific variations that can modify its biophysical properties or the pathogenicity of the bacteria. The synthesis of peptidoglycan starts in the cytoplasm and the precursor lipid II is flipped across the cytoplasmic membrane. The new peptidoglycan strands are synthesised and incorporated into the pre-existing sacculus by the coordinated activities of peptidoglycan synthases and hydrolases. In the model organism Escherichia coli there are two complexes required for the elongation and division. Each of them is regulated by different proteins from both the cytoplasmic and periplasmic sides that ensure the well-coordinated synthesis of new peptidoglycan.
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14
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Sychantha D, Brott AS, Jones CS, Clarke AJ. Mechanistic Pathways for Peptidoglycan O-Acetylation and De-O-Acetylation. Front Microbiol 2018; 9:2332. [PMID: 30327644 PMCID: PMC6174289 DOI: 10.3389/fmicb.2018.02332] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/11/2018] [Indexed: 12/22/2022] Open
Abstract
The post-synthetic O-acetylation of the essential component of bacterial cell walls, peptidoglycan (PG), is performed by many pathogenic bacteria to help them evade the lytic action of innate immunity responses. Occurring at the C-6 hydroxyl of N-acetylmuramoyl residues, this modification to the glycan backbone of PG sterically blocks the activity of lysozymes. As such, the enzyme responsible for this modification in Gram-positive bacteria is recognized as a virulence factor. With Gram-negative bacteria, the O-acetylation of PG provides a means of control of their autolysins at the substrate level. In this review, we discuss the pathways for PG O-acetylation and de-O-acetylation and the structure and function relationship of the O-acetyltransferases and O-acetylesterases that catalyze these reactions. The current understanding of their mechanisms of action is presented and the prospects of targeting these systems for the development of novel therapeutics are explored.
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Affiliation(s)
| | | | | | - Anthony J. Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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15
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Rameshwaram NR, Singh P, Ghosh S, Mukhopadhyay S. Lipid metabolism and intracellular bacterial virulence: key to next-generation therapeutics. Future Microbiol 2018; 13:1301-1328. [DOI: 10.2217/fmb-2018-0013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Lipid metabolism is thought to play a key role in the pathogenicity of several intracellular bacteria. Bacterial lipolytic enzymes hydrolyze lipids from the host cell to release free fatty acids which are used as an energy source and building blocks for the synthesis of cell envelope and also to modulate host immune responses. In this review, we discussed the role of lipid metabolism and lipolytic enzymes in the life cycle and virulence of Mycobacterium tuberculosis and other intracellular bacteria. The lipolytic enzymes appear to be potential candidates for developing novel therapeutics by targeting lipid metabolism for controlling M. tuberculosis and other intracellular pathogenic bacteria. [Formula: see text]
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Affiliation(s)
- Nagender Rao Rameshwaram
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting & Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad, India. 500 039
| | - Parul Singh
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting & Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad, India. 500 039
- Graduate Studies, Manipal University, Manipal, Karnataka, India. 576 104
| | - Sudip Ghosh
- Molecular Biology Division, National Institute of Nutrition (ICMR), Jamai-Osmania PO, Hyderabad, India. 500 007
| | - Sangita Mukhopadhyay
- Laboratory of Molecular Cell Biology, Centre for DNA Fingerprinting & Diagnostics (CDFD), Inner Ring Road, Uppal, Hyderabad, India. 500 039
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16
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Yadav AK, Espaillat A, Cava F. Bacterial Strategies to Preserve Cell Wall Integrity Against Environmental Threats. Front Microbiol 2018; 9:2064. [PMID: 30233540 PMCID: PMC6127315 DOI: 10.3389/fmicb.2018.02064] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 08/13/2018] [Indexed: 12/18/2022] Open
Abstract
Bacterial cells are surrounded by an exoskeleton-like structure, the cell wall, composed primarily of the peptidoglycan (PG) sacculus. This structure is made up of glycan strands cross-linked by short peptides generating a covalent mesh that shapes bacteria and prevents their lysis due to their high internal osmotic pressure. Even though the PG is virtually universal in bacteria, there is a notable degree of diversity in its chemical structure. Modifications in both the sugars and peptides are known to be instrumental for bacteria to cope with diverse environmental challenges. In this review, we summarize and discuss the cell wall strategies to withstand biotic and abiotic environmental insults such as the effect of antibiotics targeting cell wall enzymes, predatory PG hydrolytic proteins, and PG signaling systems. Finally we will discuss the opportunities that species-specific PG variability might open to develop antimicrobial therapies.
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Affiliation(s)
- Akhilesh K Yadav
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Akbar Espaillat
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - 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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17
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Pauly M, Ramírez V. New Insights Into Wall Polysaccharide O-Acetylation. FRONTIERS IN PLANT SCIENCE 2018; 9:1210. [PMID: 30186297 PMCID: PMC6110886 DOI: 10.3389/fpls.2018.01210] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/27/2018] [Indexed: 05/19/2023]
Abstract
The extracellular matrix of plants, algae, bacteria, fungi, and some archaea consist of a semipermeable composite containing polysaccharides. Many of these polysaccharides are O-acetylated imparting important physiochemical properties to the polymers. The position and degree of O-acetylation is genetically determined and varies between organisms, cell types, and developmental stages. Despite the importance of wall polysaccharide O-acetylation, only recently progress has been made to elucidate the molecular mechanism of O-acetylation. In plants, three protein families are involved in the transfer of the acetyl substituents to the various polysaccharides. In other organisms, this mechanism seems to be conserved, although the number of required components varies. In this review, we provide an update on the latest advances on plant polysaccharide O-acetylation and related information from other wall polysaccharide O-acetylating organisms such as bacteria and fungi. The biotechnological impact of understanding wall polysaccharide O-acetylation ranges from the design of novel drugs against human pathogenic bacteria to the development of improved lignocellulosic feedstocks for biofuel production.
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Affiliation(s)
| | - Vicente Ramírez
- Institute for Plant Cell Biology and Biotechnology – Cluster of Excellence on Plant Sciences, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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18
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Lentz CS, Sheldon JR, Crawford LA, Cooper R, Garland M, Amieva MR, Weerapana E, Skaar EP, Bogyo M. Identification of a S. aureus virulence factor by activity-based protein profiling (ABPP). Nat Chem Biol 2018; 14:609-617. [PMID: 29769740 PMCID: PMC6202179 DOI: 10.1038/s41589-018-0060-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 03/27/2018] [Indexed: 12/22/2022]
Abstract
Serine hydrolases play diverse roles in regulating host-pathogen interactions in a number of organisms, yet few have been characterized in the human pathogen Staphylococcus aureus. Here we describe a chemical proteomic screen that identified ten previously uncharacterized S. aureus serine hydrolases that mostly lack human homologs. We termed these enzymes fluorophosphonate-binding hydrolases (FphA-J). One hydrolase, FphB, can process short fatty acid esters, exhibits increased activity in response to host cell factors, is located predominantly on the bacterial cell surface in a subset of cells, and is concentrated in the division septum. Genetic disruption of fphB confirmed that the enzyme is dispensable for bacterial growth in culture but crucial for establishing infection in distinct sites in vivo. A selective small molecule inhibitor of FphB effectively reduced infectivity in vivo, suggesting that it may be a viable therapeutic target for the treatment or management of Staphylococcus infections.
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Affiliation(s)
- Christian S Lentz
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Jessica R Sheldon
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lisa A Crawford
- Department of Chemistry, Boston College, Chestnut Hill, MA, USA
| | - Rachel Cooper
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
| | - Megan Garland
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA
| | - Manuel R Amieva
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | | | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Matthew Bogyo
- Department of Pathology, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA.
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19
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Abstract
The innate immune system recognizes microbial products using germline-encoded receptors that initiate inflammatory responses to infection. The bacterial cell wall component peptidoglycan is a prime example of a conserved pathogen-associated molecular pattern (PAMP) for which the innate immune system has evolved sensing mechanisms. Peptidoglycan is a direct target for innate immune receptors and also regulates the accessibility of other PAMPs to additional innate immune receptors. Subtle structural modifications to peptidoglycan can influence the ability of the innate immune system to detect bacteria and can allow bacteria to evade or alter host defences. This Review focuses on the mechanisms of peptidoglycan recognition that are used by mammalian cells and discusses new insights into the role of peptidoglycan recognition in inflammation, metabolism, immune homeostasis and disease.
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Affiliation(s)
- Andrea J Wolf
- Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center
| | - David M Underhill
- Research Division of Immunology, Department of Biomedical Sciences, Cedars-Sinai Medical Center.,Inflammatory Bowel and Immunobiology Research Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, California 90048, USA
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20
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Sychantha D, Little DJ, Chapman RN, Boons GJ, Robinson H, Howell PL, Clarke AJ. PatB1 is an O-acetyltransferase that decorates secondary cell wall polysaccharides. Nat Chem Biol 2017; 14:79-85. [DOI: 10.1038/nchembio.2509] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 09/29/2017] [Indexed: 11/09/2022]
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21
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Bonnet J, Durmort C, Jacq M, Mortier-Barrière I, Campo N, VanNieuwenhze MS, Brun YV, Arthaud C, Gallet B, Moriscot C, Morlot C, Vernet T, Di Guilmi AM. Peptidoglycan O-acetylation is functionally related to cell wall biosynthesis and cell division in Streptococcus pneumoniae. Mol Microbiol 2017; 106:832-846. [PMID: 28960579 DOI: 10.1111/mmi.13849] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 09/11/2017] [Accepted: 09/23/2017] [Indexed: 12/12/2022]
Abstract
The peptidoglycan is a rigid matrix required to resist turgor pressure and to maintain the cellular shape. It is formed by linear glycan chains composed of N-acetylmuramic acid-(β-1,4)-N-acetylglucosamine (MurNAc-GlcNAc) disaccharides associated through cross-linked peptide stems. The peptidoglycan is continually remodelled by synthetic and hydrolytic enzymes and by chemical modifications, including O-acetylation of MurNAc residues that occurs in most Gram-positive and Gram-negative bacteria. This modification is a powerful strategy developed by pathogens to resist to lysozyme degradation and thus to escape from the host innate immune system but little is known about its physiological function. In this study, we have investigated to what extend peptidoglycan O-acetylation is involved in cell wall biosynthesis and cell division of Streptococcus pneumoniae. We show that O-acetylation driven by Adr protects the peptidoglycan of dividing cells from cleavage by the major autolysin LytA and occurs at the septal site. Our results support a function for Adr in the formation of robust and mature MurNAc O-acetylated peptidoglycan and infer its role in the division of the pneumococcus.
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Affiliation(s)
- Julie Bonnet
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Claire Durmort
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Maxime Jacq
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Isabelle Mortier-Barrière
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie intégrative (CBI). Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, UPS, F-31000 UMR Toulouse, France
| | - Nathalie Campo
- Laboratoire de Microbiologie et Génétique Moléculaires, Centre de Biologie intégrative (CBI). Centre National de la Recherche Scientifique (CNRS), Université de Toulouse, UPS, F-31000 UMR Toulouse, France
| | | | - Yves V Brun
- Departments of Biology, Indiana University, Bloomington, IN, USA
| | - Christopher Arthaud
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Benoit Gallet
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Christine Moriscot
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Cécile Morlot
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Thierry Vernet
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Anne Marie Di Guilmi
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
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22
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Peptidoglycan Acetylation of Campylobacter jejuni Is Essential for Maintaining Cell Wall Integrity and Colonization in Chicken Intestines. Appl Environ Microbiol 2016; 82:6284-6290. [PMID: 27520822 DOI: 10.1128/aem.02068-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 08/10/2016] [Indexed: 12/11/2022] Open
Abstract
Peptidoglycan (PG) acetylation of Gram-positive bacteria confers lysozyme resistance and contributes to survival in the host. However, the importance of PG acetylation in Gram-negative bacteria has not been fully elucidated. The genes encoding putative PG acetyltransferase A (PatA) and B (PatB) are highly conserved in Campylobacter jejuni, the predominant cause of bacterial diarrhea worldwide. To evaluate the importance of PatA and PatB of C. jejuni, we constructed patA and patB isogenic mutants and compared their phenotypes with those of the parental strains. Although transmission electron microscopy did not reveal morphological changes, both mutants exhibited decreased motility and biofilm formation in vitro The extent of acetylation of the PG purified from the patA and patB mutants was significantly lower than the PG acetylation in the parental strains. Both mutants exhibited decreased lysozyme resistance and intracellular survival in macrophage cells. In a chick colonization experiment, significant colonization deficiency was observed for both mutants. These results suggest that PatA and PatB of C. jejuni play important roles in maintaining cell wall integrity by catalyzing PG O-acetylation and that the loss of these enzymes causes decreased motility and biofilm formation, thus leading to colonization deficiency in chicken infection. IMPORTANCE The importance of peptidoglycan (PG) acetylation in Gram-negative bacteria has not been fully elucidated. The genes encoding putative PG acetyltransferase A (PatA) and B (PatB) are highly conserved in Campylobacter jejuni, the predominant cause of bacterial diarrhea worldwide. We evaluated the importance of these enzymes using isogenic mutants. The results of this study suggest that PatA and PatB of C. jejuni play important roles in maintaining cell wall integrity. The loss of these factors caused multiple phenotypic changes, leading to colonization deficiency in chicken infection. These data should be useful in developing novel control measures to prevent chicken colonization by C. jejuni Inhibitors of the PG acetylation enzymes PatA and PatB might serve as potent anti-C. jejuni agents.
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23
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Ha R, Frirdich E, Sychantha D, Biboy J, Taveirne ME, Johnson JG, DiRita VJ, Vollmer W, Clarke AJ, Gaynor EC. Accumulation of Peptidoglycan O-Acetylation Leads to Altered Cell Wall Biochemistry and Negatively Impacts Pathogenesis Factors of Campylobacter jejuni. J Biol Chem 2016; 291:22686-22702. [PMID: 27474744 PMCID: PMC5077204 DOI: 10.1074/jbc.m116.746404] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Indexed: 12/30/2022] Open
Abstract
Campylobacter jejuni is a leading cause of bacterial gastroenteritis in the developed world. Despite its prevalence, its mechanisms of pathogenesis are poorly understood. Peptidoglycan (PG) is important for helical shape, colonization, and host-pathogen interactions in C. jejuni Therefore, changes in PG greatly impact the physiology of this organism. O-acetylation of peptidoglycan (OAP) is a bacterial phenomenon proposed to be important for proper cell growth, characterized by acetylation of the C6 hydroxyl group of N-acetylmuramic acid in the PG glycan backbone. The OAP gene cluster consists of a PG O-acetyltransferase A (patA) for translocation of acetate into the periplasm, a PG O-acetyltransferase B (patB) for O-acetylation, and an O-acetylpeptidoglycan esterase (ape1) for de-O-acetylation. In this study, reduced OAP in ΔpatA and ΔpatB had minimal impact on C. jejuni growth and fitness under the conditions tested. However, accumulation of OAP in Δape1 resulted in marked differences in PG biochemistry, including O-acetylation, anhydromuropeptide levels, and changes not expected to result directly from Ape1 activity. This suggests that OAP may be a form of substrate level regulation in PG biosynthesis. Ape1 acetylesterase activity was confirmed in vitro using p-nitrophenyl acetate and O-acetylated PG as substrates. In addition, Δape1 exhibited defects in pathogenesis-associated phenotypes, including cell shape, motility, biofilm formation, cell surface hydrophobicity, and sodium deoxycholate sensitivity. Δape1 was also impaired for chick colonization and adhesion, invasion, intracellular survival, and induction of IL-8 production in INT407 cells in vitro The importance of Ape1 in C. jejuni biology makes it a good candidate as an antimicrobial target.
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Affiliation(s)
- Reuben Ha
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Emilisa Frirdich
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - David Sychantha
- the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Jacob Biboy
- the Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4AX, United Kingdom, and
| | - Michael E Taveirne
- the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Jeremiah G Johnson
- the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Victor J DiRita
- the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109
| | - Waldemar Vollmer
- the Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4AX, United Kingdom, and
| | - Anthony J Clarke
- the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Erin C Gaynor
- From the Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada,
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24
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Williams AH, Veyrier FJ, Bonis M, Michaud Y, Raynal B, Taha MK, White SW, Haouz A, Boneca IG. Visualization of a substrate-induced productive conformation of the catalytic triad of the Neisseria meningitidis peptidoglycan O-acetylesterase reveals mechanistic conservation in SGNH esterase family members. ACTA ACUST UNITED AC 2014; 70:2631-9. [PMID: 25286847 PMCID: PMC4188005 DOI: 10.1107/s1399004714016770] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/21/2014] [Indexed: 12/17/2022]
Abstract
Peptidoglycan O‐acetylesterase (Ape1), which is required for host survival in Neisseria sp., belongs to the diverse SGNH hydrolase superfamily, which includes important viral and bacterial virulence factors. Here, multi‐domain crystal structures of Ape1 with an SGNH catalytic domain and a newly identified putative peptidoglycan‐detection module are reported. Enzyme catalysis was performed in Ape1 crystals and key catalytic intermediates along the SGNH esterase hydrolysis reaction pathway were visualized, revealing a substrate‐induced productive conformation of the catalytic triad, a mechanistic detail that has not previously been observed. This substrate‐induced productive conformation of the catalytic triad shifts the established dogma on these enzymes, generating valuable insight into the structure‐based design of drugs targeting the SGNH esterase superfamily.
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Affiliation(s)
- Allison H Williams
- Institut Pasteur, Unité Biologie et génétique de la paroi bactérienne, Dept. Microbiologie, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Frédéric J Veyrier
- Institut Pasteur, Unité Biologie et génétique de la paroi bactérienne, Dept. Microbiologie, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Mathilde Bonis
- Institut Pasteur, Unité Biologie et génétique de la paroi bactérienne, Dept. Microbiologie, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Yann Michaud
- Institut Pasteur, Unité Biologie et génétique de la paroi bactérienne, Dept. Microbiologie, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Bertrand Raynal
- Institut Pasteur, CNRS-UMR3528, Plateforme de Biophysique, 25 Rue du Dr. Roux, 75724 Paris, France
| | - Muhamed Kheir Taha
- Institut Pasteur, Unité Infection Bactériennes Invasives, Dept. Infection et Epidémiologie, 28 Rue du Dr. Roux, 75015 Paris, France
| | - Stephen W White
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ahmed Haouz
- Institut Pasteur, CNRS-UMR3528, Plateforme de Cristallographie, 25 Rue du Dr. Roux, 75724 Paris, France
| | - Ivo G Boneca
- Institut Pasteur, Unité Biologie et génétique de la paroi bactérienne, Dept. Microbiologie, 28 Rue du Dr. Roux, 75015 Paris, France
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Moynihan PJ, Clarke AJ. Mechanism of action of peptidoglycan O-acetyltransferase B involves a Ser-His-Asp catalytic triad. Biochemistry 2014; 53:6243-51. [PMID: 25215566 DOI: 10.1021/bi501002d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The O-acetylation of the essential cell wall polymer peptidoglycan is essential in many bacteria for their integrity and survival, and it is catalyzed by peptidoglycan O-acetlytransferase B (PatB). Using PatB from Neisseria gonorrhoeae as the model, we have shown previously that the enzyme has specificity for polymeric muropeptides that possess tri- and tetrapeptide stems and that rates of reaction increase with increasing degrees of polymerization. Here, we present the catalytic mechanism of action of PatB, the first to be described for an O-acetyltransferase of any bacterial exopolysaccharide. The influence of pH on PatB activity was investigated, and pKa values of 6.4-6.45 and 6.25-6.35 for the enzyme-substrate complex (kcat vs pH) and the free enzyme (kcat·KM(-1) vs pH), respectively, were determined for the respective cosubstrates. The enzyme is partially inactivated by sulfonyl fluorides but not by EDTA, suggesting the participation of a serine residue in its catalytic mechanism. Alignment of the known and hypothetical PatB amino acid sequences identified Ser133, Asp302, and His305 as three invariant amino acid residues that could potentially serve as a catalytic triad. Replacement of Asp302 with Ala resulted in an enzyme with less than 20% residual activity, whereas activity was barely detectable with (His305 → Ala)PatB and (Ser133 → Ala)PatB was totally inactive. The reaction intermediate of the transferase reaction involving acetyl- and propionyl-acyl donors was trapped on both the wild-type and (Asp302 → Ala) enzymes and LC-MS/MS analysis of tryptic peptides identified Ser133 as the catalytic nucleophile. A transacetylase mechanism is proposed based on the mechanism of action of serine esterases.
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Affiliation(s)
- Patrick J Moynihan
- Department of Molecular and Cellular Biology, University of Guelph , Guelph, Ontario N1G 2W1 Canada
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26
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Chemical biology of peptidoglycan acetylation and deacetylation. Bioorg Chem 2014; 54:44-50. [DOI: 10.1016/j.bioorg.2014.03.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 03/25/2014] [Indexed: 12/16/2022]
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Moynihan PJ, Clarke AJ. Substrate specificity and kinetic characterization of peptidoglycan O-acetyltransferase B from Neisseria gonorrhoeae. J Biol Chem 2014; 289:16748-60. [PMID: 24795044 DOI: 10.1074/jbc.m114.567388] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The O-acetylation of the essential cell wall polymer peptidoglycan is a major virulence factor identified in many bacteria, both Gram-positive and Gram-negative, including Staphylococcus aureus, Bacillus anthracis, Neisseria gonorrhoeae, and Neisseria meningitidis. With Gram-negative bacteria, the translocation of acetyl groups from the cytoplasm is performed by an integral membrane protein, PatA, for its transfer to peptidoglycan by O-acetyltransferase PatB, whereas a single bimodal membrane protein, OatA, appears to catalyze both reactions of the process in Gram-positive bacteria. Only phenotypic evidence existed in support of these pathways because no in vitro biochemical assay was available for their analysis, which reflected the complexities of investigating integral membrane proteins that act on a totally insoluble and heterogeneous substrate, such as peptidoglycan. In this study, we present the first biochemical and kinetic analysis of a peptidoglycan O-acetyltransferase using PatB from N. gonorrhoeae as the model system. The enzyme has specificity for muropeptides that possess tri- and tetrapeptide stems on muramyl residues. With chitooligosaccharides as substrates, rates of reaction increase with increasing degrees of polymerization to 5/6. This information will be valuable for the identification and development of peptidoglycan O-acetyltransferase inhibitors that could represent potential leads to novel classes of antibiotics.
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Affiliation(s)
- Patrick J Moynihan
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Anthony J Clarke
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Sukhithasri V, Nisha N, Biswas L, Anil Kumar V, Biswas R. Innate immune recognition of microbial cell wall components and microbial strategies to evade such recognitions. Microbiol Res 2013; 168:396-406. [DOI: 10.1016/j.micres.2013.02.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 02/08/2013] [Accepted: 02/09/2013] [Indexed: 01/19/2023]
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Moynihan PJ, Clarke AJ. Assay for peptidoglycan O-acetyltransferase: a potential new antibacterial target. Anal Biochem 2013; 439:73-9. [PMID: 23660013 DOI: 10.1016/j.ab.2013.04.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 04/16/2013] [Indexed: 11/24/2022]
Abstract
The O-acetylation of peptidoglycan occurs at the C-6 hydroxyl group of muramoyl residues in many human pathogens, both gram positive and gram negative, such as Staphylococcus aureus and species of Campylobacter, Helicobacter, Neisseria, and Bacillus, including Bacillus anthracis. The process is a maturation event being catalyzed either by integral membrane O-acetylpeptidoglycan transferase (Oat) of gram-positive bacteria or by a two-component peptidoglycan O-acetyltransferase system (PatA/PatB) in gram-negative cells. Here, we describe the development of the first in vitro assay for any peptidoglycan O-acetyltransferase using PatB from Neisseria gonorrhoeae as the model enzyme. This assay is based on the use of chromogenic p-nitrophenyl acetate as the donor substrate and chitooligosaccharides as model acceptor substrates in place of peptidoglycan. The identity of the O-acetylated chitooligosaccharides was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Rates of transacetylations were determined spectrophotometrically by monitoring p-nitrophenol release after accounting for both spontaneous and enzyme-catalyzed hydrolysis of the acetate donor. Conditions were established for use of the assay in microtiter plate format, and its applicability was demonstrated by determining the first Michaelis-Menten kinetic parameters for PatB. The assay is readily amenable for application in the high-throughput screening for potential inhibitors of peptidoglycan O-acetyltransferases that may prove to be leads for novel classes of antibiotics.
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Affiliation(s)
- Patrick J Moynihan
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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Lunderberg JM, Nguyen-Mau SM, Richter GS, Wang YT, Dworkin J, Missiakas DM, Schneewind O. Bacillus anthracis acetyltransferases PatA1 and PatA2 modify the secondary cell wall polysaccharide and affect the assembly of S-layer proteins. J Bacteriol 2013; 195:977-89. [PMID: 23243307 PMCID: PMC3571321 DOI: 10.1128/jb.01274-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 12/09/2012] [Indexed: 11/20/2022] Open
Abstract
The envelope of Bacillus anthracis encompasses a proteinaceous S-layer with two S-layer proteins (Sap and EA1). Protein assembly in the envelope of B. anthracis requires S-layer homology domains (SLH) within S-layer proteins and S-layer-associated proteins (BSLs), which associate with the secondary cell wall polysaccharide (SCWP), an acetylated carbohydrate that is tethered to peptidoglycan. Here, we investigated the contributions of two putative acetyltransferases, PatA1 and PatA2, on SCWP acetylation and S-layer assembly. We show that mutations in patA1 and patA2 affect the chain lengths of B. anthracis vegetative forms and perturb the deposition of the BslO murein hydrolase at cell division septa. The patA1 and patA2 mutants are defective for the assembly of EA1 in the envelope but retain the ability of S-layer formation with Sap. SCWP isolated from the patA1 patA2 mutant lacked acetyl moieties identified in wild-type polysaccharide and failed to associate with the SLH domains of EA1. A model is discussed whereby patA1- and patA2-mediated acetylation of SCWP enables the deposition of EA1 as well as BslO near the septal region of the B. anthracis envelope.
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Affiliation(s)
- J. Mark Lunderberg
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois, USA
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Sao-Mai Nguyen-Mau
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois, USA
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - G. Stefan Richter
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois, USA
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Ya-Ting Wang
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois, USA
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Jonathan Dworkin
- Department of Microbiology and Immunology, Columbia University, New York, New York, USA
| | - Dominique M. Missiakas
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois, USA
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Olaf Schneewind
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Argonne, Illinois, USA
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
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Derbise A, Pierre F, Merchez M, Pradel E, Laouami S, Ricard I, Sirard JC, Fritz J, Lemaître N, Akinbi H, Boneca IG, Sebbane F. Inheritance of the lysozyme inhibitor Ivy was an important evolutionary step by Yersinia pestis to avoid the host innate immune response. J Infect Dis 2013; 207:1535-43. [PMID: 23402825 DOI: 10.1093/infdis/jit057] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Yersinia pestis (the plague bacillus) and its ancestor, Yersinia pseudotuberculosis (which causes self-limited bowel disease), encode putative homologues of the periplasmic lysozyme inhibitor Ivy and the membrane-bound lysozyme inhibitor MliC. The involvement of both inhibitors in virulence remains subject to debate. METHODS Mutants lacking ivy and/or mliC were generated. We evaluated the mutants' ability to counter lysozyme, grow in serum, and/or counter leukocytes; to produce disease in wild-type, neutropenic, or lysozyme-deficient rodents; and to induce host inflammation. RESULTS MliC was not required for lysozyme resistance and the development of plague. Deletion of ivy decreased Y. pestis' ability to counter lysozyme and polymorphonuclear neutrophils, but it did not affect the bacterium's ability to grow in serum or resist macrophages. Y. pestis lacking Ivy had attenuated virulence, unless animals were neutropenic or lysozyme deficient. The Ivy mutant induced inflammation to a degree similar to that of the parental strain. Last, Y. pseudotuberculosis did not require Ivy to counter lysozyme and for virulence. CONCLUSIONS Ivy is required to counter lysozyme during infection, but its role as a virulence factor is species dependent. Our study also shows that a gene that is not necessary for the virulence of an ancestral bacterium may become essential in the emergence of a new pathogen.
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Affiliation(s)
- Anne Derbise
- Equipe Peste et Yersinia pestis, INSERM U1019, Paris, France
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Veyrier FJ, Williams AH, Mesnage S, Schmitt C, Taha MK, Boneca IG. De-O-acetylation of peptidoglycan regulates glycan chain extension and affectsin vivosurvival ofNeisseria meningitidis. Mol Microbiol 2013; 87:1100-12. [DOI: 10.1111/mmi.12153] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2013] [Indexed: 01/21/2023]
Affiliation(s)
| | | | - Stéphane Mesnage
- Centre de Recherches des Cordeliers; Inserm U872; 15 rue de l'Ecole de Médecine; Paris; F-75006; France
| | - Christine Schmitt
- Institut Pasteur; Plate-forme de Microscopie Ultrastructurale; Département de Biologie Cellulaire et Infection; Paris; F-75015; France
| | - Muhamed-Kheir Taha
- Institut Pasteur; Infections Bactériennes Invasives; Département Infection et Epidémiologie; 28 Rue du Dr. Roux; Paris; F-75015; France
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Helicobacter pylori peptidoglycan modifications confer lysozyme resistance and contribute to survival in the host. mBio 2012; 3:e00409-12. [PMID: 23221800 PMCID: PMC3517862 DOI: 10.1128/mbio.00409-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The prominent host muramidase lysozyme cleaves bacterial peptidoglycan (PG), and the enzyme is abundant in mucosal secretions. The lytic enzyme susceptibility of Gram-negative bacteria and mechanisms they use to thwart lytic enzyme activity are poorly studied. We previously characterized a Helicobacter pylori PG modification enzyme, an N-deacetylase (PgdA) involved in lysozyme resistance. In this study, another PG modification enzyme, a putative PG O-acetyltransferase (PatA), was identified. Mass spectral analysis of the purified PG demonstrated that a patA strain contained a greatly reduced amount of acetylated muropeptides, indicating a role for PatA in H. pylori PG O-acetylation. The PG modification mutant strains (pgdA, patA, or pgdA patA) were more susceptible to lysozyme killing than the parent, but this assay required high lysozyme levels (up to 50 mg/ml). However, addition of host lactoferrin conferred lysozyme sensitivity to H. pylori, at physiologically relevant concentrations of both host components (3 mg/ml lactoferrin plus 0.3 mg/ml lysozyme). The pgdA patA double mutant strain was far more susceptible to lysozyme/lactoferrin killing than the parent. Peptidoglycan purified from a pgdA patA mutant was five times more sensitive to lysozyme than PG from the parent strain, while PG from both single mutants displayed intermediate sensitivity. Both sensitivity assays for whole cells and for purified PGs indicated that the modifications mediated by PgdA and PatA have a synergistic effect, conferring lysozyme tolerance. In a mouse infection model, significant colonization deficiency was observed for the double mutant at 3 weeks postinoculation. The results show that PG modifications affect the survival of a Gram-negative pathogen. Importance Pathogenic bacteria evade host antibacterial enzymes by a variety of mechanisms, which include resisting lytic enzymes abundant in the host. Enzymatic modifications to peptidoglycan (PG, the site of action of lysozyme) are a known mechanism used by Gram-positive bacteria to protect against host lysozyme attack. However, Gram-negative bacteria contain a thin layer of PG and a recalcitrant outer membrane permeability barrier to resist lysis, so molecular modifications to cell wall structure in order to combat lysis remain largely unstudied. Here we show that two Helicobacter pylori PG modification enzymes (PgdA and PatA) confer a clear protective advantage to a Gram-negative bacterium. They protect the bacterium from lytic enzyme degradation, albeit via different PG modification activities. Many pathogens are Gram negative, so some would be expected to have a similar cell wall-modifying strategy. Understanding such strategies may be useful for combating pathogen growth. Pathogenic bacteria evade host antibacterial enzymes by a variety of mechanisms, which include resisting lytic enzymes abundant in the host. Enzymatic modifications to peptidoglycan (PG, the site of action of lysozyme) are a known mechanism used by Gram-positive bacteria to protect against host lysozyme attack. However, Gram-negative bacteria contain a thin layer of PG and a recalcitrant outer membrane permeability barrier to resist lysis, so molecular modifications to cell wall structure in order to combat lysis remain largely unstudied. Here we show that two Helicobacter pylori PG modification enzymes (PgdA and PatA) confer a clear protective advantage to a Gram-negative bacterium. They protect the bacterium from lytic enzyme degradation, albeit via different PG modification activities. Many pathogens are Gram negative, so some would be expected to have a similar cell wall-modifying strategy. Understanding such strategies may be useful for combating pathogen growth.
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Pfeffer JM, Weadge JT, Clarke AJ. Mechanism of action of Neisseria gonorrhoeae O-acetylpeptidoglycan esterase, an SGNH serine esterase. J Biol Chem 2012; 288:2605-13. [PMID: 23209280 DOI: 10.1074/jbc.m112.436352] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
O-Acetylpeptidoglycan esterase from Neisseria gonorrhoeae functions to release O-acetyl groups from the C-6 position of muramoyl residues in O-acetylated peptidoglycan, thereby permitting the continued metabolism of this essential cell wall heteropolymer. It has been demonstrated to be a serine esterase with sequence similarity to the family CE-3 carbohydrate esterases of the CAZy classification system. In the absence of a three-dimensional structure for any Ape, further knowledge of its structure and function relationship is dependent on modeling and kinetic studies. In this study, we predicted Neisseria gonorrhoeae Ape1a to be an SGNH hydrolase with an adopted α/β-hydrolase fold containing a central twisted four-stranded parallel β-sheet flanked by six α-helices with the putative catalytic triad, Asp-366, His-369, and Ser-80 appropriately aligned within a pocket. The role of eight invariant and highly conserved residues localized to the active site was investigated by site-directed replacements coupled with kinetic characterization and binding studies of the resultant engineered enzymes. Based on these data and theoretical considerations, Gly-236 and Asn-268 were identified as participating at the oxyanion hole to stabilize the tetrahedral species in the reaction mechanism, whereas Gly-78, Asp-79, His-81, Asn-235, Thr-267, and Val-368 are proposed to position appropriately the catalytic residues and participate in substrate binding.
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Affiliation(s)
- John M Pfeffer
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Strating H, Vandenende C, Clarke AJ. Changes in peptidoglycan structure and metabolism during differentiation of Proteus mirabilis into swarmer cells. Can J Microbiol 2012; 58:1183-94. [PMID: 23051614 DOI: 10.1139/w2012-102] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The O-acetylation of peptidoglycan in Gram-negative bacteria occurs specifically at the C-6 hydroxyl group of muramoyl residues. The level of peptidoglycan O-acetylation was found to decrease from 51% to 29% upon differentiation of Proteus mirabilis vegetative cells to swarmers. This decrease was accompanied by a change in the muropeptide composition of the peptidoglycan. In particular, the content of anhydromuropeptides increased, while the amount of Lys-Lys-muropeptides arising from bound lipoprotein decreased. These changes together with a shift in proportion of larger muropeptides suggested a decrease in average chain length of the muropeptides from swarmer cells. Zymography using SDS-PAGE gels containing either O-acetylated or chemically de-O-acetylated peptidoglycan was used to monitor the activity of specific autolysins during the differentiation of vegetative to swarming cells of P. mirabilis. A 43 kDa autolysin with increased specificity for O-acetylated peptidoglycan was detected in vegetative cells, but its activity appeared to decrease as the cells began to differentiate, while the levels of 3 other autolysins with apparent specificity for non-O-acetylated peptidoglycan increased. These changes are discussed in relation to the autolysin profile of the bacteria and the changes in peptidoglycan composition with cell differentiation.
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Affiliation(s)
- Hendrik Strating
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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Frirdich E, Biboy J, Adams C, Lee J, Ellermeier J, Gielda LD, DiRita VJ, Girardin SE, Vollmer W, Gaynor EC. Peptidoglycan-modifying enzyme Pgp1 is required for helical cell shape and pathogenicity traits in Campylobacter jejuni. PLoS Pathog 2012; 8:e1002602. [PMID: 22457624 PMCID: PMC3310789 DOI: 10.1371/journal.ppat.1002602] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 02/08/2012] [Indexed: 11/18/2022] Open
Abstract
The impact of bacterial morphology on virulence and transmission attributes of pathogens is poorly understood. The prevalent enteric pathogen Campylobacter jejuni displays a helical shape postulated as important for colonization and host interactions. However, this had not previously been demonstrated experimentally. C. jejuni is thus a good organism for exploring the role of factors modulating helical morphology on pathogenesis. We identified an uncharacterized gene, designated pgp1 (peptidoglycan peptidase 1), in a calcofluor white-based screen to explore cell envelope properties important for C. jejuni virulence and stress survival. Bioinformatics showed that Pgp1 is conserved primarily in curved and helical bacteria. Deletion of pgp1 resulted in a striking, rod-shaped morphology, making pgp1 the first C. jejuni gene shown to be involved in maintenance of C. jejuni cell shape. Pgp1 contributes to key pathogenic and cell envelope phenotypes. In comparison to wild type, the rod-shaped pgp1 mutant was deficient in chick colonization by over three orders of magnitude and elicited enhanced secretion of the chemokine IL-8 in epithelial cell infections. Both the pgp1 mutant and a pgp1 overexpressing strain – which similarly produced straight or kinked cells – exhibited biofilm and motility defects. Detailed peptidoglycan analyses via HPLC and mass spectrometry, as well as Pgp1 enzyme assays, confirmed Pgp1 as a novel peptidoglycan DL-carboxypeptidase cleaving monomeric tripeptides to dipeptides. Peptidoglycan from the pgp1 mutant activated the host cell receptor Nod1 to a greater extent than did that of wild type. This work provides the first link between a C. jejuni gene and morphology, peptidoglycan biosynthesis, and key host- and transmission-related characteristics. Bacterial cell shape is dictated by the composition of the cell envelope component peptidoglycan. Some important pathogens have a characteristic helical corkscrew morphology that may help them burrow into mucus overlaying cells to initiate colonization and pathogenicity. One example is Campylobacter jejuni, the leading cause of bacterial-induced diarrheal disease in the developed world. Direct evidence supporting the hypothesis that C. jejuni shape is related to its pathogenicity traits has not previously been provided. We identified a gene encoding a peptidase modifying peptidoglycan that is essential for maintaining the C. jejuni corkscrew shape. We can now connect a C. jejuni gene with morphology and peptidoglycan biosynthesis. Loss of this gene was also found to affect pathogenic attributes such as chicken colonization, biofilms, motility, and activation of host inflammatory mediators. In addition, this is the first study to thoroughly characterize C. jejuni peptidoglycan structure and to identify a gene involved in peptidoglycan maintenance. Our findings highlight an emerging theme in bacterial pathogenesis research: the connection between bacterial cell biology and pathogenesis. Finally, our characterization of C. jejuni cell shape and peptidoglycan provides a starting point for further work in this area in C. jejuni and other bacteria with curved and helical morphologies.
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Affiliation(s)
- Emilisa Frirdich
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jacob Biboy
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Calvin Adams
- Wine Research Centre, Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jooeun Lee
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Jeremy Ellermeier
- Department of Microbiology and Immunology & Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Lindsay Davis Gielda
- Department of Microbiology and Immunology & Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Victor J. DiRita
- Department of Microbiology and Immunology & Unit for Laboratory Animal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Stephen E. Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Erin C. Gaynor
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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Pfeffer JM, Clarke AJ. Identification of the first known inhibitors of O-acetylpeptidoglycan esterase: a potential new antibacterial target. Chembiochem 2012; 13:722-31. [PMID: 22351512 DOI: 10.1002/cbic.201100744] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Indexed: 11/08/2022]
Abstract
The O-acetylation of peptidoglycan (PG) is now known to occur in 53 species, including numerous human pathogens such as, Staphylococcus aureus, Bacillus anthracis, species of Enterococcus, Campylobacter jejuni, Helicobacter pylori, Neisseria gonorrhoeae and N. meningitidis. This modification, which occurs at the C-6 hydroxyl of N-acetylmuramoyl residues within PG, serves to regulate autolytic activity during PG metabolism and contributes to pathogenesis and persistence within a host. O-Acetylpeptidoglycan esterase (Ape) was recently discovered as an enzyme responsible for the removal of O-acetyl groups from PG, thus permitting the continued maintenance and metabolism of the sacculus. Recombinant Ape1 from N. gonorrhoeae was purified to apparent homogeneity and optimal storage conditions for the enzyme were determined. Using 4-methylumbelliferyl acetate as substrate, a fluorogenic assay amenable for the high-throughput screening for potential inhibitors was developed and Ape1 was screened against a subset of compounds of the Canadian Compound Collection. The overall Z' score for the screen was 0.62, indicative of a well-suited assay with a sufficient signal window, and the threshold was set at 65 %. After eliminating a number of false-positives, seven compounds were identified as true inhibitors of Ape1, the first to be identified for this class of enzyme. Dose-response curves were generated leading to the identification of five of these compounds with IC(50) values ranging between 0.3 and 23 μM. Of these, purpurin was selected for further analysis and it was found to inhibit the growth of both Gram-positive and Gram-negative bacteria that produce both O-acetylated PG and Ape.
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Affiliation(s)
- John M Pfeffer
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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38
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Moynihan PJ, Clarke AJ. O-Acetylated peptidoglycan: Controlling the activity of bacterial autolysins and lytic enzymes of innate immune systems. Int J Biochem Cell Biol 2011; 43:1655-9. [DOI: 10.1016/j.biocel.2011.08.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 07/30/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022]
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39
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Hadi T, Pfeffer JM, Clarke AJ, Tanner ME. Water-soluble substrates of the peptidoglycan-modifying enzyme O-acetylpeptidoglycan esterase (Ape1) from Neisseria gonorrheae. J Org Chem 2011; 76:1118-25. [PMID: 21244065 DOI: 10.1021/jo102329c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peptidoglycan is the component of the bacterial cell wall that is essential for maintaining the shape and rigidity of the cell. As such, its polymeric structure, consisting of alternating units of N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc), is also a target for the action of host defense enzymes, such as lysozymes. Many bacteria have developed methods of masking their cell wall from these environmental dangers through the addition of aglycon moieties that prevent recognition or sterically hinder the degradative action of exogenous enzymes that would otherwise prove detrimental to the cell. Peptidoglycan acetyl-transferases (Pat's) and O-acetylpeptidoglycan esterases (Ape's) are the enzymes responsible for the controlled addition and removal of acetate onto the C-6 hydroxyl group of MurNAc residues in peptidoglycan. Studies on Ape1, an O-acetylpeptidoglycan esterase found in Neisseria gonorrheae, have suggested that this enzyme is essential for bacterial viability and thus presents an attractive target for antibacterial design. Previous studies on Ape1 have been hindered by the fact that Ape1's natural substrate is an insoluble polymer. In this paper we outline the design, synthesis, and testing of the water-soluble di- and monosaccharide substrate analogues 1 and 2. Both 1 and 2 serve as substrates of Ape1 with k(cat)/K(M) values of (5.1 ± 1.7) × 10(3) M(-1) s(-1) and (3.1 ± 0.8) × 10(3) M(-1) s(-1), respectively. It was determined that the substitution of the GlcNAc residue in compound 1 with an O-benzyl group in compound 2 did not significantly decrease the enzyme's affinity for the monosaccharide. These findings are important as they demonstrate that the catalytic prowess of Ape1 is not dependent on its binding to a polymeric substrate. This ensures that small molecule transition state/intermediate analogues can also capture the transition state binding energy of Ape1 and potentially serve as potent inhibitors. The synthetic route to compounds 1 and 2 could readily be modified to allow for the installation of a wide variety of functional groups at the MurNAc C-6 position in both the mono- and disaccharide scaffolds. This will serve as a general method for the construction of Ape1 substrates and inhibitors.
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Affiliation(s)
- Timin Hadi
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
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40
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Laaberki MH, Pfeffer J, Clarke AJ, Dworkin J. O-Acetylation of peptidoglycan is required for proper cell separation and S-layer anchoring in Bacillus anthracis. J Biol Chem 2010; 286:5278-88. [PMID: 21135105 DOI: 10.1074/jbc.m110.183236] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
O-Acetylation of the MurNAc moiety of peptidoglycan is typically associated with bacterial resistance to lysozyme, a muramidase that serves as a central component of innate immunity. Here, we report that the peptidoglycan of Bacillus anthracis, the etiological agent of anthrax, is O-acetylated and that, unusually, this modification is produced by two unrelated families of O-acetyltransferases. Also, in contrast to other bacteria, O-acetylation of B. anthracis peptidoglycan is combined with N-deacetylation to confer resistance of cells to lysozyme. Activity of the Pat O-acetyltransferases is required for the separation of the daughter cells following bacterial division and for anchoring of one of the major S-layer proteins. Our results indicate that peptidoglycan O-acetylation modulates endogenous muramidase activity affecting the cell-surface properties and morphology of this important pathogen.
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Affiliation(s)
- Maria-Halima Laaberki
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Clarke CA, Scheurwater EM, Clarke AJ. The vertebrate lysozyme inhibitor Ivy functions to inhibit the activity of lytic transglycosylase. J Biol Chem 2010; 285:14843-14847. [PMID: 20351104 DOI: 10.1074/jbc.c110.120931] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proteinaceous inhibitor of vertebrate lysozymes (Ivy) is produced by a collection of Gram-negative bacteria as a stress response to damage to their essential cell wall component peptidoglycan. A paralog of Ivy, Ivyp2 is produced exclusively by a number of pseudomonads, including Pseudomonas aeruginosa, but this protein does not inhibit the lysozymes, and its function was unknown. In this study, we demonstrate that the production of Ivy (homologs of both Ivyp1 and Ivyp2) correlates with bacteria that do not O-acetylate their peptidoglycan, a modification that controls the activity of the lytic transglycosylases. Furthermore, we show that both Ivy proteins are potent inhibitors of the lytic transglycoslyases, enzymes involved in the biosynthesis and maintenance of peptidoglycan. These data suggest that the true physiological function of the Ivy proteins is to control the autolytic activity of lytic transglycosylases within the periplasm of Gram-negative bacteria that do not produce O-acetylated peptidoglycan and that the inhibition of exogenous lysozyme by Ivy is simply a fortuitous coincidence.
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Affiliation(s)
- Chelsea A Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Edie M Scheurwater
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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Moynihan PJ, Clarke AJ. O-acetylation of peptidoglycan in gram-negative bacteria: identification and characterization of peptidoglycan O-acetyltransferase in Neisseria gonorrhoeae. J Biol Chem 2010; 285:13264-73. [PMID: 20178982 DOI: 10.1074/jbc.m110.107086] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ape2 gene encoding a hypothetical O-acetylpeptidoglycan esterase was amplified from genomic DNA of Neisseria gonorrhoeae FA1090 and cloned to encode either the full-length protein or a truncated version lacking its hypothetical signal sequence. Expression trials revealed that production of the full-length version possessing either an N-terminal or C-terminal His(6) tag was toxic to Escherichia coli transformants and that the host rapidly degraded the small amount of protein that was produced. An N-terminally truncated protein could be produced in sufficient yields for purification only if it possessed an N-terminal His(6) tag. This form of the protein was isolated and purified to apparent homogeneity, and its enzymatic properties were characterized. Whereas the protein could bind to insoluble peptidoglycan, it did not function as an esterase. Phenotypic characterization of E. coli transformants producing various forms of the protein revealed that it functions instead to O-acetylate peptidoglycan within the periplasm, and it was thus renamed peptidoglycan O-acetyltransferase B. This activity was found to be dependent upon a second protein, which functions to translocate acetate from the cytoplasm to the periplasm, demonstrating that the O-acetylation of peptidoglycan in N. gonorrhoeae, and other gram-negative bacteria, requires a two component system.
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Affiliation(s)
- Patrick J Moynihan
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Weadge JT, Weadge JT, Clarke AJ. Transacetylation of carbohydrates in organic solvent catalysed byO-acetylpeptidoglycan esterase fromNeisseria gonorrhoeae. BIOCATAL BIOTRANSFOR 2009. [DOI: 10.1080/10242420701801307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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44
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Abstract
The normal, unmodified glycan strands of bacterial peptidoglycan consist of alternating residues of beta-1,4-linked N-acetylmuramic acid and N-acetylglucosamine. In many species the glycan strands become modified after their insertion into the cell wall. This review describes the structure of secondary modifications and of attachment sites of surface polymers in the glycan strands of peptidoglycan. It also provides an overview of the occurrence of these modifications in various bacterial species. Recently, enzymes responsible for the N-deacetylation, N-glycolylation and O-acetylation of the glycan strands were identified. The presence of these modifications affects the hydrolysis of peptidoglycan and its enlargement during cell growth. Glycan strands are frequently deacetylated and/or O-acetylated in pathogenic species. These alterations affect the recognition of bacteria by host factors, and contribute to the resistance of bacteria to host defence factors such as lysozyme.
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Affiliation(s)
- Waldemar Vollmer
- Institute for Cell and Molecular Biosciences, Medical School, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
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45
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Veiga P, Bulbarela-Sampieri C, Furlan S, Maisons A, Chapot-Chartier MP, Erkelenz M, Mervelet P, Noirot P, Frees D, Kuipers OP, Kok J, Gruss A, Buist G, Kulakauskas S. SpxB Regulates O-Acetylation-dependent Resistance of Lactococcus lactis Peptidoglycan to Hydrolysis. J Biol Chem 2007; 282:19342-54. [PMID: 17485463 DOI: 10.1074/jbc.m611308200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endogenous peptidoglycan (PG)-hydrolyzing enzymes, the autolysins, are needed to relax the rigid PG sacculus to allow bacterial cell growth and separation. PGs of pathogens and commensal bacteria may also be degraded by hydrolases of animal origin (lysozymes), which act as antimicrobials. The genetic mechanisms regulating PG resistance to hydrolytic degradation were dissected in the Gram-positive bacterium Lactococcus lactis. We found that the ability of L. lactis to counteract PG hydrolysis depends on the degree of acetylation. Overexpression of PG O-acetylase (encoded by oatA) led to bacterial growth arrest, indicating the potential lethality of oatA and a need for its tight regulation. A novel regulatory factor, SpxB (previously denoted as YneH), exerted a positive effect on oatA expression. Our results indicate that SpxB binding to RNA polymerase constitutes a previously missing link in the multistep response to cell envelope stress, provoked by PG hydrolysis with lysozyme. We suggest that the two-component system CesSR responds to this stress by inducing SpxB, thus favoring its interactions with RNA polymerase. Induction of PG O-acetylation by this cascade renders it resistant to hydrolysis.
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Affiliation(s)
- Patrick Veiga
- Unité Bactéries Lactiques et Pathogènes Opportunistes, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas Cedex, France
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46
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Weadge JT, Clarke AJ. Neisseria gonorrheae O-Acetylpeptidoglycan Esterase, a Serine Esterase with a Ser-His-Asp Catalytic Triad. Biochemistry 2007; 46:4932-41. [PMID: 17388571 DOI: 10.1021/bi700254m] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
O-Acetylpeptidoglycan esterase from Neisseria gonorrheae FA1090 is similar in sequence to family CE-3 carbohydrate esterases of the CAZy classification system, and it functions to release O-linked acetyl groups from the C-6 position of muramoyl residues in O-acetylated peptidoglycan. Here, we characterize the peptidoglycan of N. gonorrheae FA1090 as being O-acetylated and find that it serves as a substrate for the esterase. The influence of pH on the activity of O-acetylpeptidoglycan esterase was determined, and pKa values of 6.38 and 6.78 for the enzyme-substrate complex (VEt-1) and free enzyme (VEt-1KM-1), respectively, were calculated. The enzyme was inactivated by sulfonyl fluorides but not by EDTA. Multiple-sequence alignment of the O-acetylpeptidoglycan esterase family 1 enzymes with members of the CE-3 enzymes and protein modeling studies identified Ser80, Asp366, and His369 as three invariant amino acid residues that could potentially serve as a catalytic triad. Replacement of each with alanine was accomplished by site-directed mutagenesis, and the resulting mutant proteins were purified to apparent homogeneity. The specific activity of each of the three esterase derivatives was greatly reduced on O-acetylpeptidoglycan. Using the artificial substrate p-nitrophenyl acetate, a kinetic analysis revealed that the turnover number (VEt-1) but not KM was affected by the replacements. These data thus indicate that N. gonorrheae O-acetylpeptidoglycan esterase, and by analogy the CE-3 family of enzymes, function as serine esterases involving a Ser-His-Asp catalytic triad.
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Affiliation(s)
- Joel T Weadge
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Pfeffer JM, Strating H, Weadge JT, Clarke AJ. Peptidoglycan O acetylation and autolysin profile of Enterococcus faecalis in the viable but nonculturable state. J Bacteriol 2006; 188:902-8. [PMID: 16428393 PMCID: PMC1347352 DOI: 10.1128/jb.188.3.902-908.2006] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The O acetylation of peptidoglycan occurs specifically at the C-6 hydroxyl group of muramoyl residues. Using a combination of high-performance liquid chromatography-based organic acid analysis and carbohydrate analysis by high-pH anion-exchange chromatography, we determined that strains of Entercoccus durans, E. faecalis, E. faecium, and E. hirae produce O-acetylated peptidoglycan. The levels of O acetylation ranged from 19% to 72% relative to the muramic acid content, and they were found to vary with the growth phase of the culture. Increases of 10 to 40% in O acetylation were observed with cultures entering the stationary phase. Cells of E. faecalis in the viable but nonculturable (VBNC) state had the highest levels of peptidoglycan O acetylation. The presence of this modification to peptidoglycan was shown to inhibit the action of hen egg white lysozyme in a concentration-dependent manner. Zymography using sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels containing either O-acetylated or chemically de-O-acetylated peptidoglycan was used to monitor the production of specific autolysins in E. faecalis. Differences in the expression of specific autolysins were observed with the age of the culture, and VBNC E. faecalis produced the highest levels of these enzymes. This technique also permitted classification of the enterococcal autolysins into enzymes that preferentially hydrolyze either O-acetylated or non-O-acetylated peptidoglycan and enzymes that show no apparent preference for either substrate type.
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Affiliation(s)
- John M Pfeffer
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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Weadge JT, Clarke AJ. Identification and Characterization of O-Acetylpeptidoglycan Esterase: A Novel Enzyme Discovered in Neisseria gonorrhoeae. Biochemistry 2005; 45:839-51. [PMID: 16411760 DOI: 10.1021/bi051679s] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Modification of the bacterial cell wall heteropolymer peptidoglycan by addition of an acetyl group to the C-6 hydroxyl group of N-acetylmuramoyl residues is known to inhibit the activity of muramidases (lysozymes) of innate immune systems. The O-acetylation of peptidoglycan also precludes the action of intrinsic lytic transglycosylases, enzymes that require a free C-6 hydroxyl group to generate their 1,6-anhydromuropeptide products. This class of autolysins is ubiquitous in peptidoglycan-synthesizing bacteria as they are responsible for insertion of pores and flagella, spore formation, and the general metabolism of peptidoglycan. We recently discovered a cluster of genes in the Neisseria gonorrhoeae chromosome that are proposed to participate in peptidoglycan O-acetylation (Weadge, J. T., Pfeffer, J. M., and Clarke, A. J. (2005) BMC Microb. 5, 49). In the current study, we demonstrate that one of these genes, ape1 functions as an O-acetylpeptidoglycan esterase. The ape1 gene was cloned and overexpressed in Escherichia coli as a fusion protein with a hexa-histidine tag. The expressed protein was purified to apparent homogeneity and assayed for activity as an esterase using three different assays involving high-performance liquid chromatography and chromogenic detection methods which measured the release of ester-linked acetate from a variety of polymer and soluble substrates. These assays demonstrated that Ape1 has a higher specific activity on O-acetylated peptidoglycan compared to O-acetylated xylan. Consequently, Ape1 represents the first enzyme characterized as an O-acetylpeptidoglycan esterase. The physicochemical and kinetic parameters of Ape1 were determined using soluble chromogenic substrates for convenience. Thus, its pH optima for stability and activity were observed to be 6.0 and 6.2, respectively, while its optimum temperature for activity was 55 degrees C. Two forms of truncated Ape1 are generated in E. coli, one lacked the complete predicted N-terminal signal sequence, while the second involved a proteolytic cleavage within this signal sequence. The smaller truncated form was localized predominantly to the periplasm, whereas the larger form was mainly associated with the outer membrane, and to a lesser extent, the cytoplasmic membrane, sites expected for the maintenance of peptidoglycan.
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Affiliation(s)
- Joel T Weadge
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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