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Wang L, Huang J, Chen S, Su X, Zhang X, Wang L, Zhang W, Wang Z, Zeng Q, Wang Q, Li Y. Endogenous cell wall degrading enzyme LytD is important for the biocontrol activity of Bacillus subtilis. FRONTIERS IN PLANT SCIENCE 2024; 15:1381018. [PMID: 38660441 PMCID: PMC11039861 DOI: 10.3389/fpls.2024.1381018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/14/2024] [Indexed: 04/26/2024]
Abstract
Autolysins are endogenous cell wall degrading enzymes (CWDEs) in bacteria that remodel the peptidoglycan layer of its own cell wall. In the Bacillus subtilis genome, at least 35 autolysin genes have been identified. However, the study of their roles in bacterial physiology has been hampered by their complexity and functional redundancy. B. subtilis GLB191 is an effective biocontrol strain against grape downy mildew disease, the biocontrol effect of which results from both direct effect against the pathogen and stimulation of the plant defense. In this study, we show that the autolysin N-acetylglucosaminidase LytD, a major autolysin of vegetative growth in B. subtilis, plays an important role in its biocontrol activity against grape downy mildew. Disruption of lytD resulted in reduced suppression of the pathogen Plasmopara viticola and stimulation of the plant defense. LytD is also shown to affect the biofilm formation and colonization of B. subtilis on grape leaves. This is the first report that demonstrates the role of an endogenous CWDE in suppressing plant disease infection of a biological control microorganism. These findings not only expand our knowledge on the biological function of autolysins but also provide a new target to promote the biocontrol activity of B. subtilis.
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Affiliation(s)
- Luotao Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Jianquan Huang
- The Research Institute of Forestry and Pomology, Tianjin Academy of Agricultural Sciences, Tianjin, China
| | - Si Chen
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xin Su
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Xun Zhang
- Airport Research Institute, China Academy of Civil Aviation Science and Technology, Beijing, China
| | - Lujun Wang
- Weinan Grapevine Research Institute, Weinan, China
| | - Wei Zhang
- Weinan Grapevine Research Institute, Weinan, China
| | - Zhenshuo Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qingchao Zeng
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Qi Wang
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
| | - Yan Li
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
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Wilson SA, Tank RKJ, Hobbs JK, Foster SJ, Garner EC. An exhaustive multiple knockout approach to understanding cell wall hydrolase function in Bacillus subtilis. mBio 2023; 14:e0176023. [PMID: 37768080 PMCID: PMC10653849 DOI: 10.1128/mbio.01760-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/03/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE In order to grow, bacterial cells must both create and break down their cell wall. The enzymes that are responsible for these processes are the target of some of our best antibiotics. Our understanding of the proteins that break down the wall- cell wall hydrolases-has been limited by redundancy among the large number of hydrolases many bacteria contain. To solve this problem, we identified 42 cell wall hydrolases in Bacillus subtilis and created a strain lacking 40 of them. We show that cells can survive using only a single cell wall hydrolase; this means that to understand the growth of B. subtilis in standard laboratory conditions, it is only necessary to study a very limited number of proteins, simplifying the problem substantially. We additionally show that the ∆40 strain is a research tool to characterize hydrolases, using it to identify three "helper" hydrolases that act in certain stress conditions.
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Affiliation(s)
- Sean A. Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Raveen K. J. Tank
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - Jamie K. Hobbs
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - Simon J. Foster
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Ethan C. Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA
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3
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Weaver A, Taguchi A, Dörr T. Masters of Misdirection: Peptidoglycan Glycosidases in Bacterial Growth. J Bacteriol 2023; 205:e0042822. [PMID: 36757204 PMCID: PMC10029718 DOI: 10.1128/jb.00428-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023] Open
Abstract
The dynamic composition of the peptidoglycan cell wall has been the subject of intense research for decades, yet how bacteria coordinate the synthesis of new peptidoglycan with the turnover and remodeling of existing peptidoglycan remains elusive. Diversity and redundancy within peptidoglycan synthases and peptidoglycan autolysins, enzymes that degrade peptidoglycan, have often made it challenging to assign physiological roles to individual enzymes and determine how those activities are regulated. For these reasons, peptidoglycan glycosidases, which cleave within the glycan strands of peptidoglycan, have proven veritable masters of misdirection over the years. Unlike many of the broadly conserved peptidoglycan synthetic complexes, diverse bacteria can employ unrelated glycosidases to achieve the same physiological outcome. Additionally, although the mechanisms of action for many individual enzymes have been characterized, apparent conserved homologs in other organisms can exhibit an entirely different biochemistry. This flexibility has been recently demonstrated in the context of three functions critical to vegetative growth: (i) release of newly synthesized peptidoglycan strands from their membrane anchors, (ii) processing of peptidoglycan turned over during cell wall expansion, and (iii) removal of peptidoglycan fragments that interfere with daughter cell separation during cell division. Finally, the regulation of glycosidase activity during these cell processes may be a cumulation of many factors, including protein-protein interactions, intrinsic substrate preferences, substrate availability, and subcellular localization. Understanding the true scope of peptidoglycan glycosidase activity will require the exploration of enzymes from diverse organisms with equally diverse growth and division strategies.
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Affiliation(s)
- Anna Weaver
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Atsushi Taguchi
- SANKEN (The Institute of Scientific and Industrial Research), Osaka University, Ibaraki, Osaka, Japan
| | - Tobias Dörr
- Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York, USA
- Department of Microbiology, Cornell University, Ithaca, New York, USA
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, New York, USA
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4
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Haubrich BA, Nayyab S, Gallati M, Hernandez J, Williams C, Whitman A, Zimmerman T, Li Q, Chen Y, Zhou CZ, Basu A, Reid CW. Inhibition of Streptococcus pneumoniae growth by masarimycin. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35467499 DOI: 10.1099/mic.0.001182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Despite renewed interest, development of chemical biology methods to study peptidoglycan metabolism has lagged in comparison to the glycobiology field in general. To address this, a panel of diamides were screened against the Gram-positive bacterium Streptococcus pneumoniae to identify inhibitors of bacterial growth. The screen identified the diamide masarimycin as a bacteriostatic inhibitor of S. pneumoniae growth with an MIC of 8 µM. The diamide inhibited detergent-induced autolysis in a concentration-dependent manner, indicating perturbation of peptidoglycan degradation as the mode-of-action. Cell based screening of masarimycin against a panel of autolysin mutants, identified a higher MIC against a ΔlytB strain lacking an endo-N-acetylglucosaminidase involved in cell division. Subsequent biochemical and phenotypic analyses suggested that the higher MIC was due to an indirect interaction with LytB. Further analysis of changes to the cell surface in masarimycin treated cells identified the overexpression of several moonlighting proteins, including elongation factor Tu which is implicated in regulating cell shape. Checkerboard assays using masarimycin in concert with additional antibiotics identified an antagonistic relationship with the cell wall targeting antibiotic fosfomycin, which further supports a cell wall mode-of-action.
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Affiliation(s)
- Brad A Haubrich
- Center for Health and Behavioral Sciences, Department of Science and Technology, Bryant University, 1150 Douglas Pike, Smithfield, RI 02917, USA.,Department of Basic Sciences, Touro University Nevada, College of Osteopathic Medicine, Henderson, NV 89014, USA
| | - Saman Nayyab
- Center for Health and Behavioral Sciences, Department of Science and Technology, Bryant University, 1150 Douglas Pike, Smithfield, RI 02917, USA.,Amherst Department of Molecular and Cellular Biology, University of Massachusetts, 230 Stockbridge Rd Amherst, MA, USA
| | - Mika Gallati
- Center for Health and Behavioral Sciences, Department of Science and Technology, Bryant University, 1150 Douglas Pike, Smithfield, RI 02917, USA
| | - Jazmeen Hernandez
- Center for Health and Behavioral Sciences, Department of Science and Technology, Bryant University, 1150 Douglas Pike, Smithfield, RI 02917, USA
| | - Caroline Williams
- Center for Health and Behavioral Sciences, Department of Science and Technology, Bryant University, 1150 Douglas Pike, Smithfield, RI 02917, USA
| | - Andrew Whitman
- Center for Health and Behavioral Sciences, Department of Science and Technology, Bryant University, 1150 Douglas Pike, Smithfield, RI 02917, USA
| | - Tahl Zimmerman
- Department of Family and Consumer Sciences, North Carolina A&T State University, Greensboro, NC, USA
| | - Qiong Li
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027, PR China
| | - Yuxing Chen
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027, PR China
| | - Cong-Zhao Zhou
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027, PR China
| | - Amit Basu
- Department of Chemistry, Brown University, Providence, RI, USA
| | - Christopher W Reid
- Center for Health and Behavioral Sciences, Department of Science and Technology, Bryant University, 1150 Douglas Pike, Smithfield, RI 02917, USA
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CwlQ Is Required for Swarming Motility but Not Flagellar Assembly in Bacillus subtilis. J Bacteriol 2021; 203:JB.00029-21. [PMID: 33649146 DOI: 10.1128/jb.00029-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/22/2021] [Indexed: 11/20/2022] Open
Abstract
Lytic enzymes play an essential role in the remodeling of bacterial peptidoglycan (PG), an extracellular mesh-like structure that retains the membrane in the context of high internal osmotic pressure. Peptidoglycan must be unfailingly stable to preserve cell integrity, but must also be dynamically remodeled for the cell to grow, divide, and insert macromolecular machines. The flagellum is one such macromolecular machine that transits the PG, and flagellar insertion is aided by localized activity of a dedicated PG lyase in Gram-negative bacteria. To date, there is no known dedicated lyase in Gram-positive bacteria for the insertion of flagella. Here, we take a reverse-genetic candidate-gene approach and find that cells mutated for the lytic transglycosylase CwlQ exhibit a severe defect in flagellum-dependent swarming motility. We further show that CwlQ is expressed by the motility sigma factor SigD and is secreted by the type III secretion system housed inside the flagellum. Nonetheless, cells with mutations of CwlQ remain proficient for flagellar biosynthesis even when mutated in combination with four other lyases related to motility (LytC, LytD, LytF, and CwlO). The PG lyase (or lyases) essential for flagellar synthesis in B. subtilis, if any, remains unknown.IMPORTANCE Bacteria are surrounded by a wall of peptidoglycan and early work in Bacillus subtilis was the first to suggest that bacteria needed to enzymatically remodel the wall to permit insertion of the flagellum. No PG remodeling enzyme alone or in combination, however, has been found to be essential for flagellar assembly in B. subtilis Here, we take a reverse-genetic candidate-gene approach and find that the PG lytic transglycosylase CwlQ is required for swarming motility. Subsequent characterization determined that while CwlQ was coexpressed with motility genes and is secreted by the flagellar secretion apparatus, it was not required for flagellar synthesis. The PG lyase needed for flagellar assembly in B. subtilis remains unknown.
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Alternative σ Factors Regulate Overlapping as Well as Distinct Stress Response and Metabolic Functions in Listeria monocytogenes under Stationary Phase Stress Condition. Pathogens 2021; 10:pathogens10040411. [PMID: 33915780 PMCID: PMC8066629 DOI: 10.3390/pathogens10040411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 12/13/2022] Open
Abstract
Listeria monocytogenes can regulate and fine-tune gene expression, to adapt to diverse stress conditions encountered during foodborne transmission. To further understand the contributions of alternative sigma (σ) factors to the regulation of L. monocytogenes gene expression, RNA-Seq was performed on L. monocytogenes strain 10403S and five isogenic mutants (four strains bearing in-frame null mutations in three out of four alternative σ factor genes, ΔCHL, ΔBHL, ΔBCL, and ΔBCH, and one strain bearing null mutations in all four genes, ΔBCHL), grown to stationary phase. Our data showed that 184, 35, 34, and 20 genes were positively regulated by σB, σL, σH, and σC (posterior probability > 0.9 and Fold Change (FC) > 5.0), respectively. Moreover, σB-dependent genes showed the highest FC (based on comparisons between the ΔCHL and the ΔBCHL strain), with 44 genes showing an FC > 100; only four σL-dependent, and no σH- or σC-dependent genes showed FC >100. While σB-regulated genes identified in this study are involved in stress-associated functions and metabolic pathways, σL appears to largely regulate genes involved in a few specific metabolic pathways, including positive regulation of operons encoding phosphoenolpyruvate (PEP)-dependent phosphotransferase systems (PTSs). Overall, our data show that (i) σB and σL directly and indirectly regulate genes involved in several energy metabolism-related functions; (ii) alternative σ factors are involved in complex regulatory networks and appear to have epistatic effects in stationary phase cells; and (iii) σB regulates multiple stress response pathways, while σL and σH positively regulate a smaller number of specific pathways.
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Müller M, Calvert M, Hottmann I, Kluj RM, Teufel T, Balbuchta K, Engelbrecht A, Selim KA, Xu Q, Borisova M, Titz A, Mayer C. The exo-β-N-acetylmuramidase NamZ from Bacillus subtilis is the founding member of a family of exo-lytic peptidoglycan hexosaminidases. J Biol Chem 2021; 296:100519. [PMID: 33684445 PMCID: PMC8054146 DOI: 10.1016/j.jbc.2021.100519] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/27/2021] [Accepted: 03/04/2021] [Indexed: 11/11/2022] Open
Abstract
Endo-β-N-acetylmuramidases, commonly known as lysozymes, are well-characterized antimicrobial enzymes that catalyze an endo-lytic cleavage of peptidoglycan; i.e., they hydrolyze the β-1,4-glycosidic bonds connecting N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc). In contrast, little is known about exo-β-N-acetylmuramidases, which catalyze an exo-lytic cleavage of β-1,4-MurNAc entities from the non-reducing ends of peptidoglycan chains. Such an enzyme was identified earlier in the bacterium Bacillus subtilis, but the corresponding gene has remained unknown so far. We now report that ybbC of B. subtilis, renamed namZ, encodes the reported exo-β-N-acetylmuramidase. A ΔnamZ mutant accumulated specific cell wall fragments and showed growth defects under starvation conditions, indicating a role of NamZ in cell wall turnover and recycling. Recombinant NamZ protein specifically hydrolyzed the artificial substrate para-nitrophenyl β-MurNAc and the peptidoglycan-derived disaccharide MurNAc-β-1,4-GlcNAc. Together with the exo-β-N-acetylglucosaminidase NagZ and the exo-muramoyl-l-alanine amidase AmiE, NamZ degraded intact peptidoglycan by sequential hydrolysis from the non-reducing ends. A structure model of NamZ, built on the basis of two crystal structures of putative orthologs from Bacteroides fragilis, revealed a two-domain structure including a Rossmann-fold-like domain that constitutes a unique glycosidase fold. Thus, NamZ, a member of the DUF1343 protein family of unknown function, is now classified as the founding member of a new family of glycosidases (CAZy GH171; www.cazy.org/GH171.html). NamZ-like peptidoglycan hexosaminidases are mainly present in the phylum Bacteroidetes and less frequently found in individual genomes within Firmicutes (Bacilli, Clostridia), Actinobacteria, and γ-proteobacteria.
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Affiliation(s)
- Maraike Müller
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Matthew Calvert
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Isabel Hottmann
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Robert Maria Kluj
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Tim Teufel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Katja Balbuchta
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alicia Engelbrecht
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Khaled A Selim
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany; Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Research Division, National Research Center, Giza, Egypt
| | - Qingping Xu
- GM/CA @ APS, Argonne National Laboratory, Lemont, Illinois, USA
| | - Marina Borisova
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Alexander Titz
- Chemical Biology of Carbohydrates, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Deutsches Zentrum für Infektionsforschung (DZIF), Standort Hannover-Braunschweig, Germany; Department of Chemistry, Saarland University, Saarbrücken, Germany
| | - Christoph Mayer
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany.
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Identification and Characterization of a Cell Wall Hydrolase for Sporangiospore Maturation in Actinoplanes missouriensis. J Bacteriol 2019; 201:JB.00519-19. [PMID: 31570527 DOI: 10.1128/jb.00519-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 09/23/2019] [Indexed: 11/20/2022] Open
Abstract
The rare actinomycete Actinoplanes missouriensis grows as substrate mycelium and forms terminal sporangia containing a few hundred spores as dormant cells. Upon contact with water, the sporangia open up and release spores to external environments. Here, we report a cell wall hydrolase, GsmA, that is required for sporangiospore maturation in A. missouriensis The gsmA gene is conserved among Actinoplanes species and several species of other rare actinomycetes. Transcription of gsmA is activated in the late stage of sporangium formation by the global transcriptional activator TcrA, which is involved in sporangium formation and dehiscence. GsmA is composed of an N-terminal signal peptide for the twin arginine translocation pathway, two tandem bacterial SH3-like domains, and a glucosaminidase domain. Zymographic analysis using a recombinant C-terminal glucosaminidase domain protein showed that GsmA is a hydrolase able to digest cell walls extracted from the vegetative mycelia of A. missouriensis and Streptomyces griseus A gsmA deletion mutant (ΔgsmA) formed apparently normal sporangia, but they released chains of 2 to 20 spores under sporangium dehiscence-inducing conditions, indicating that spores did not completely mature in the mutant sporangia. From these results, we concluded that GsmA is a cell wall hydrolase for digesting peptidoglycan at septum-forming sites to separate adjacent spores during sporangiospore maturation in A. missouriensis Unexpectedly, flagella were observed around the spore chains of the ΔgsmA mutant by transmission electron microscopy. The flagellar formation was strictly restricted to cell-cell interfaces, giving an important insight into the polarity of the flagellar biogenesis in a spherical spore.IMPORTANCE In streptomycetes, an aerial hypha is compartmentalized by multiple septations into prespores, which become spores through a series of maturation processes. However, little is known about these maturation processes. The rare actinomycete Actinoplanes missouriensis produces sporangiospores, which are assumed to be formed also from prespores generated by the compartmentalization of intrasporangium hyphae via septation. The identification of GsmA as a cell wall hydrolase for the separation of adjacent spores sheds light on the almost unknown processes of sporangiospore formation in A. missouriensis Furthermore, the fact that GsmA orthologues are conserved within the genus Actinoplanes but not in streptomycetes indicates that Actinoplanes has developed an original strategy for the spore maturation in a specific environment, that is, inside a sporangium.
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Vermassen A, Leroy S, Talon R, Provot C, Popowska M, Desvaux M. Cell Wall Hydrolases in Bacteria: Insight on the Diversity of Cell Wall Amidases, Glycosidases and Peptidases Toward Peptidoglycan. Front Microbiol 2019; 10:331. [PMID: 30873139 PMCID: PMC6403190 DOI: 10.3389/fmicb.2019.00331] [Citation(s) in RCA: 179] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 02/08/2019] [Indexed: 11/13/2022] Open
Abstract
The cell wall (CW) of bacteria is an intricate arrangement of macromolecules, at least constituted of peptidoglycan (PG) but also of (lipo)teichoic acids, various polysaccharides, polyglutamate and/or proteins. During bacterial growth and division, there is a constant balance between CW degradation and biosynthesis. The CW is remodeled by bacterial hydrolases, whose activities are carefully regulated to maintain cell integrity or lead to bacterial death. Each cell wall hydrolase (CWH) has a specific role regarding the PG: (i) cell wall amidase (CWA) cleaves the amide bond between N-acetylmuramic acid and L-alanine residue at the N-terminal of the stem peptide, (ii) cell wall glycosidase (CWG) catalyses the hydrolysis of the glycosidic linkages, whereas (iii) cell wall peptidase (CWP) cleaves amide bonds between amino acids within the PG chain. After an exhaustive overview of all known conserved catalytic domains responsible for CWA, CWG, and CWP activities, this review stresses that the CWHs frequently display a modular architecture combining multiple and/or different catalytic domains, including some lytic transglycosylases as well as CW binding domains. From there, direct physiological and collateral roles of CWHs in bacterial cells are further discussed.
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Affiliation(s)
- Aurore Vermassen
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | - Sabine Leroy
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | - Régine Talon
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
| | | | - Magdalena Popowska
- Department of Applied Microbiology, Faculty of Biology, Institute of Microbiology, University of Warsaw, Warsaw, Poland
| | - Mickaël Desvaux
- Université Clermont Auvergne, INRA, MEDiS, Clermont-Ferrand, France
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10
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Abstract
All Gram-negative bacteria release membrane vesicles. These vesicles contain a cargo of proteins and enzymes that include one or more autolysins. Autolysins are a group of enzymes with specificity for the different linkages within peptidoglycan sacculi that if uncontrolled cause bacteriolysis. This minireview, written in honor and memory of Terry Beveridge, presents an overview of autolytic activity and focuses on Beveridge's important original observations regarding predatory membrane vesicles and their associated autolysin cargo.
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Affiliation(s)
- Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.,Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada
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11
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Zhao L, Ye J, Fu J, Chen GQ. Engineering peptidoglycan degradation related genes of Bacillus subtilis for better fermentation processes. BIORESOURCE TECHNOLOGY 2018; 248:238-247. [PMID: 28811162 DOI: 10.1016/j.biortech.2017.05.134] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/19/2017] [Accepted: 05/21/2017] [Indexed: 06/07/2023]
Abstract
In this study, Bacillus subtilis 168 Δupp was engineered to change the bacterial shapes. Namely, some peptidoglycan hydrolase related genes were inactivated individually or in different combinations, including sigD, lytE, lytF, lytC, lytD and lytG. Inactivations of these genes resulted in various intensities of blockages on cell division, leading to elongation of bacterial cells. The resulted fiber phenotypes showed different lengths ranging from tens of microns to several millimeters. Mutants with multiple gene inactivations such as ΔsigDΔlytEΔlytD showed more easily precipitated phenomenon, obviously increased growth rate, more sensitive to antibiotics and improved α-amylase production compared with that of B. subtilis 168 Δupp. Mutants ΔsigDΔlytEΔlytD and ΔsigDΔlytEΔlytCΔlytD also showed an increased tolerance to high osmotic pressure of sodium chloride, allowing unsterile fermentation, all of which contributes to reduced processing cost.
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Affiliation(s)
- Liang Zhao
- Peking-Tsinghua Center for Life Sciences, School of Life Science, Tsinghua University, Beijing 100084, China; Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100081, China
| | - Jianwen Ye
- MOE Key Lab of Industrial Biocatalysis, Tsinghua University, Beijing 100081, China
| | - Jing Fu
- Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Guo-Qiang Chen
- Peking-Tsinghua Center for Life Sciences, School of Life Science, Tsinghua University, Beijing 100084, China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing 100084, China; MOE Key Lab of Industrial Biocatalysis, Tsinghua University, Beijing 100081, China.
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12
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The SPOR Domain, a Widely Conserved Peptidoglycan Binding Domain That Targets Proteins to the Site of Cell Division. J Bacteriol 2017; 199:JB.00118-17. [PMID: 28396350 DOI: 10.1128/jb.00118-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Sporulation-related repeat (SPOR) domains are small peptidoglycan (PG) binding domains found in thousands of bacterial proteins. The name "SPOR domain" stems from the fact that several early examples came from proteins involved in sporulation, but SPOR domain proteins are quite diverse and contribute to a variety of processes that involve remodeling of the PG sacculus, especially with respect to cell division. SPOR domains target proteins to the division site by binding to regions of PG devoid of stem peptides ("denuded" glycans), which in turn are enriched in septal PG by the intense, localized activity of cell wall amidases involved in daughter cell separation. This targeting mechanism sets SPOR domain proteins apart from most other septal ring proteins, which localize via protein-protein interactions. In addition to SPOR domains, bacteria contain several other PG-binding domains that can exploit features of the cell wall to target proteins to specific subcellular sites.
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Nayyab S, O’Connor M, Brewster J, Gravier J, Jamieson M, Magno E, Miller RD, Phelan D, Roohani K, Williard P, Basu A, Reid CW. Diamide Inhibitors of the Bacillus subtilis N-Acetylglucosaminidase LytG That Exhibit Antibacterial Activity. ACS Infect Dis 2017; 3:421-427. [PMID: 28448118 DOI: 10.1021/acsinfecdis.7b00005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
N-Acetylglucosaminidases (GlcNAcases) play an important role in the remodeling and recycling of bacterial peptidoglycan by degrading the polysaccharide backbone. Genetic deletions of autolysins can impair cell division and growth, suggesting an opportunity for using small molecule autolysin inhibitors both as tools for studying the chemical biology of autolysins and also as antibacterial agents. We report here the synthesis and evaluation of a panel of diamides that inhibit the growth of Bacillus subtilis. Two compounds, fgkc (21) and fgka (5), were found to be potent inhibitors (MIC 3.8 ± 1.0 and 21.3 ± 0.1 μM, respectively). These compounds inhibit the B. subtilis family 73 glycosyl hydrolase LytG, an exo GlcNAcase. Phenotypic analysis of fgkc (21)-treated cells demonstrates a propensity for cells to form linked chains, suggesting impaired cell growth and division.
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Affiliation(s)
- Saman Nayyab
- Department
of Science and Technology, Bryant University, Smithfield, Rhode Island 02917, United States
| | - Mary O’Connor
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912, United States
| | - Jennifer Brewster
- Department
of Science and Technology, Bryant University, Smithfield, Rhode Island 02917, United States
| | - James Gravier
- Department
of Science and Technology, Bryant University, Smithfield, Rhode Island 02917, United States
| | - Mitchell Jamieson
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912, United States
| | - Ethan Magno
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912, United States
| | - Ryan D. Miller
- Department
of Science and Technology, Bryant University, Smithfield, Rhode Island 02917, United States
| | - Drew Phelan
- Department
of Science and Technology, Bryant University, Smithfield, Rhode Island 02917, United States
| | - Keyana Roohani
- Department
of Science and Technology, Bryant University, Smithfield, Rhode Island 02917, United States
| | - Paul Williard
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912, United States
| | - Amit Basu
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912, United States
| | - Christopher W. Reid
- Department
of Science and Technology, Bryant University, Smithfield, Rhode Island 02917, United States
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Sawhney N, Crooks C, St. John F, Preston JF. Transcriptomic analysis of xylan utilization systems in Paenibacillus sp. strain JDR-2. Appl Environ Microbiol 2015; 81:1490-501. [PMID: 25527555 PMCID: PMC4309694 DOI: 10.1128/aem.03523-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 12/13/2014] [Indexed: 11/20/2022] Open
Abstract
Xylans, including methylglucuronoxylans (MeGX(n)) and methylglucuronoarabinoxylans (MeGAXn), are the predominant polysaccharidesin hemicellulose fractions of dicots and monocots available for conversion to biofuels and chemicals. Paenibacillus sp. strain JDR-2 (Pjdr2) efficiently depolymerizes MeGX(n) and MeGAX(n) and assimilates the generated oligosaccharides, resulting in efficient saccharification and subsequent metabolism of these polysaccharides. A xylan utilization regulon encoding a cellassociated GH10 (glycoside hydrolase family 10) endoxylanase, transcriptional regulators, ABC (ATP binding cassette) transporters, an intracellular GH67 -glucuronidase, and other glycoside hydrolases contributes to complete metabolism. This GH10/GH67 system has been proposed to account for preferential utilization of xylans compared to free oligo- and monosaccharides. To identify additional genes contributing to MeGX(n) and MeGAXn utilization, the transcriptome of Pjdr2 has been sequenced following growth on each of these substrates as well as xylose and arabinose. Increased expression of genes with different substrates identified pathways common or unique to the utilization of MeGX(n) or MeGAX(n). Coordinate upregulation of genes comprising the GH10/GH67 xylan utilization regulon is accompanied with upregulation of genes encoding a GH11 endoxylanase and a GH115 -glucuronidase, providing evidence for a novel complementary pathway for processing xylans. Elevated expression of genes encoding a GH43 arabinoxylan arabinofuranohydrolase and an arabinose ABC transporter on MeGAX(n) but not on MeGX(n) supports a process in which arabinose may be removed extracellularly followed by its rapid assimilation.Further development of Pjdr2 for direct conversion of xylans to targeted products or introduction of these systems into fermentative strains of related bacteria may lead to biocatalysts for consolidated bioprocessing of hemicelluloses released from lignocellulose.
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Affiliation(s)
- Neha Sawhney
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
| | - Casey Crooks
- U.S. Department of Agriculture, U.S. Forest Service, Forest Products Laboratory, Madison, Wisconsin, USA
| | - Franz St. John
- U.S. Department of Agriculture, U.S. Forest Service, Forest Products Laboratory, Madison, Wisconsin, USA
| | - James F. Preston
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA
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Lipski A, Hervé M, Lombard V, Nurizzo D, Mengin-Lecreulx D, Bourne Y, Vincent F. Structural and biochemical characterization of the β-N-acetylglucosaminidase from Thermotoga maritima: toward rationalization of mechanistic knowledge in the GH73 family. Glycobiology 2014; 25:319-30. [PMID: 25344445 DOI: 10.1093/glycob/cwu113] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Members of the GH73 glycosidase family cleave the β-1,4-glycosidic bond between the N-acetylglucosaminyl (GlcNAc) and N-acetylmuramyl (MurNAc) moieties in bacterial peptidoglycan. A catalytic mechanism has been proposed for members FlgJ, Auto, AcmA and Atl(WM) and the structural analysis of FlgJ and Auto revealed a conserved α/β fold reminiscent of the distantly related GH23 lysozyme. Comparison of the active site residues reveals variability in the nature of the catalytic general base suggesting two distinct catalytic mechanisms: an inverting mechanism involving two distant glutamate residues and a substrate-assisted mechanism involving anchimeric assistance by the C2-acetamido group of the GlcNAc moiety. Herein, we present the biochemical characterization and crystal structure of TM0633 from the hyperthermophilic bacterium Thermotoga maritima. TM0633 adopts the α/β fold of the family and displays β-N-acetylglucosaminidase activity on intact peptidoglycan sacculi. Site-directed mutagenesis identifies Glu34, Glu65 and Tyr118 as important residues for catalysis. A thorough bioinformatic analysis of the GH73 sequences identified five phylogenetic clusters. TM0633, FlgJ and Auto belong to a group of three clusters that conserve two carboxylate residues involved in a classical inverting acid-base mechanism. Members of the other two clusters lack a conserved catalytic general base supporting a substrate-assisted mechanism. Molecular modeling of representative members from each cluster suggests that variability in length of the β-hairpin region above the active site confers ligand-binding specificity and modulates the catalytic mechanisms within the GH73 family.
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Affiliation(s)
- Alexandra Lipski
- Laboratory for Biocrystallography and Structural Biology of Therapeutic Targets, Molecular and Structural Bases of Infectious Diseases, UMR 5086 CNRS and University of Lyon, 7 passage du Vercors, F-69367 Lyon Cedex 07, France CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
| | - Mireille Hervé
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, UMR 8619 CNRS, Université de Paris-Sud, 91405 Orsay, France
| | - Vincent Lombard
- CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France Aix-Marseille University, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
| | - Didier Nurizzo
- European Synchrotron Radiation Facility, Polygone Scientifique Louis Néel, 6 rue Jules Horowitz, 38000 Grenoble, France
| | - Dominique Mengin-Lecreulx
- Laboratoire des Enveloppes Bactériennes et Antibiotiques, Institut de Biochimie et Biophysique Moléculaire et Cellulaire, UMR 8619 CNRS, Université de Paris-Sud, 91405 Orsay, France
| | - Yves Bourne
- CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France Aix-Marseille University, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
| | - Florence Vincent
- CNRS, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France Aix-Marseille University, AFMB UMR7257, 163 avenue de luminy, 13288 Marseille cedex 09, France
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Wang Y, Chen Z, Zhao R, Jin T, Zhang X, Chen X. Deleting multiple lytic genes enhances biomass yield and production of recombinant proteins by Bacillus subtilis. Microb Cell Fact 2014; 13:129. [PMID: 25176138 PMCID: PMC4243946 DOI: 10.1186/s12934-014-0129-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/23/2014] [Indexed: 02/01/2023] Open
Abstract
Background Bacillus subtilis is widely used in agriculture and industrial biotechnology; however, cell autolysis significantly decreases its yield in liquid cultures. Numerous factors mediate the lysis of B. subtilis, such as cannibalism factors, prophages, and peptidoglycan (PG) hydrolases. The aim of this work was to use molecular genetic techniques to develop a new strategy to prevent cell lysis and enhance biomass as well as the production of recombinant proteins. Results Five genes or genetic elements representing three different functional categories were studied as follows: lytC encoding PG hydrolases, the prophage genes xpf and yqxG-yqxH-cwlA (yGlA), and skfA and sdpC that encode cannibalism factors. Cell lysis was reduced and biomass was enhanced by deleting individually skfA, sdpC, xpf, and lytC. We constructed the multiple deletion mutant LM2531 (skfA sdpC lytC xpf) and found that after 4 h of culture, its biomass yield was significantly increased compared with that of prototypical B. subtilis 168 (wild-type) strain and that 15% and 92% of the cells were lysed in cultures of LM2531 and wild-type, respectively. Moreover, two expression vectors were constructed for producing recombinant proteins (β-galactosidase and nattokinase) under the control of the P43 promoter. Cultures of LM2531 and wild-type transformants produced 13741 U/ml and 7991 U/ml of intracellular β-galactosidase, respectively (1.72-fold increase). Further, the level of secreted nattokinase produced by strain LM2531 increased by 2.6-fold compared with wild-type (5226 IU/ml vs. 2028 IU/ml, respectively). Conclusions Our novel, systematic multigene deletion approach designed to inhibit cell lysis significantly increased the biomass yield and the production of recombinant proteins by B. subtilis. These findings show promise for guiding efforts to manipulate the genomes of other B. subtilis strains that are used for industrial purposes. Electronic supplementary material The online version of this article (doi:10.1186/s12934-014-0129-9) contains supplementary material, which is available to authorized users.
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Kuhn H, Gutelius D, Black E, Nadolny C, Basu A, Reid C. Anti-bacterial glycosyl triazoles - Identification of an N-acetylglucosamine derivative with bacteriostatic activity against Bacillus. MEDCHEMCOMM 2014; 5:1213-1217. [PMID: 25431647 PMCID: PMC4241850 DOI: 10.1039/c4md00127c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
N-acetylglucosaminidases (GlcNAcases) play an important role in the remodeling and recycling of bacterial peptidoglycan. Inhibitors of bacterial GlcNAcases can serve as antibacterial agents and provide an opportunity for the development of new antibiotics. We report the synthesis of triazole derivatives of N-acetylglucosamine using a copper promoted azide-alkyne coupling reaction between 1-azido-N-acetylglucosamine and a small library of terminal alkynes prepared via the Ugi reaction. These compounds were evaluated for their ability to inhibit the growth of bacteria. Two compounds that show bacteriostatic activity against Bacillus were identified, with MIC values of approximately 60 μM in both cases. Bacillus subtilis cultured in the presence of sub-MIC amounts of the glycosyl triazole inhibitors exhibit an elongated phenotype characteristic of impaired cell division. This represents the first report of inhibitors of bacterial cell wall GlcNAcases that demonstrate inhibition of cell growth in whole cell assays.
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Affiliation(s)
| | | | - Eimear Black
- Department of Chemistry, Brown University, Providence RI 02912; Department of Science and Technology, Bryant University, Providence RI 02917
| | - Christina Nadolny
- Department of Chemistry, Brown University, Providence RI 02912; Department of Science and Technology, Bryant University, Providence RI 02917
| | - Amit Basu
- Department of Chemistry, Brown University, Providence RI 02912; Department of Science and Technology, Bryant University, Providence RI 02917
| | - Christopher Reid
- Department of Chemistry, Brown University, Providence RI 02912; Department of Science and Technology, Bryant University, Providence RI 02917
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Zhang X, Paganelli FL, Bierschenk D, Kuipers A, Bonten MJM, Willems RJL, van Schaik W. Genome-wide identification of ampicillin resistance determinants in Enterococcus faecium. PLoS Genet 2012; 8:e1002804. [PMID: 22761597 PMCID: PMC3386183 DOI: 10.1371/journal.pgen.1002804] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 05/17/2012] [Indexed: 01/03/2023] Open
Abstract
Enterococcus faecium has become a nosocomial pathogen of major importance, causing infections that are difficult to treat owing to its multi-drug resistance. In particular, resistance to the β-lactam antibiotic ampicillin has become ubiquitous among clinical isolates. Mutations in the low-affinity penicillin binding protein PBP5 have previously been shown to be important for ampicillin resistance in E. faecium, but the existence of additional resistance determinants has been suggested. Here, we constructed a high-density transposon mutant library in E. faecium and developed a transposon mutant tracking approach termed Microarray-based Transposon Mapping (M-TraM), leading to the identification of a compendium of E. faecium genes that contribute to ampicillin resistance. These genes are part of the core genome of E. faecium, indicating a high potential for E. faecium to evolve towards β-lactam resistance. To validate the M-TraM results, we adapted a Cre-lox recombination system to construct targeted, markerless mutants in E. faecium. We confirmed the role of four genes in ampicillin resistance by the generation of targeted mutants and further characterized these mutants regarding their resistance to lysozyme. The results revealed that ddcP, a gene predicted to encode a low-molecular-weight penicillin binding protein with D-alanyl-D-alanine carboxypeptidase activity, was essential for high-level ampicillin resistance. Furthermore, deletion of ddcP sensitized E. faecium to lysozyme and abolished membrane-associated D,D-carboxypeptidase activity. This study has led to the development of a broadly applicable platform for functional genomic-based studies in E. faecium, and it provides a new perspective on the genetic basis of ampicillin resistance in this organism. Enterococcus faecium has emerged as an important nosocomial pathogen around the world. Clinical E. faecium isolates are often resistant to multiple antibiotics, thereby complicating therapeutic interventions. However, the molecular mechanisms that contribute to the recent emergence of E. faecium as a nosocomial pathogen of major importance are only poorly understood, which is, at least partially, due to the lack of appropriate genetic tools for the study of this organism. Here, we developed a systematic genome-wide strategy, based on transposon mutagenesis and microarray-based screening, to identify E. faecium genes that contribute to ampicillin resistance. We also adapted the Cre-lox recombination system to construct targeted, markerless mutants in E. faecium. These tools enabled us to perform both high-throughput genome-wide analysis and specific targeted investigations in a clinical E. faecium isolate. We comprehensively identified, confirmed, and characterized a compendium of genes affecting the sensitivity to ampicillin in E. faecium. The identified intrinsic ampicillin resistance determinants are highly conserved among E. faecium, indicating that this organism has a high potential to evolve towards ampicillin resistance. These ampicillin-resistance determinants may serve as targets for the development of novel antimicrobial therapeutics.
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Affiliation(s)
- Xinglin Zhang
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Fernanda L. Paganelli
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Damien Bierschenk
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Annemarie Kuipers
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marc J. M. Bonten
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rob J. L. Willems
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Willem van Schaik
- Department of Medical Microbiology, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
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Ronholm J, Wang L, Hayashi I, Sugai M, Zhang Z, Cao X, Lin M. The Listeria monocytogenes serotype 4b autolysin IspC has N-acetylglucosaminidase activity. Glycobiology 2012; 22:1311-20. [DOI: 10.1093/glycob/cws100] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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Muropeptide rescue in Bacillus subtilis involves sequential hydrolysis by beta-N-acetylglucosaminidase and N-acetylmuramyl-L-alanine amidase. J Bacteriol 2010; 192:3132-43. [PMID: 20400549 DOI: 10.1128/jb.01256-09] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We identified a pathway in Bacillus subtilis that is used for recovery of N-acetylglucosamine (GlcNAc)-N-acetylmuramic acid (MurNAc) peptides (muropeptides) derived from the peptidoglycan of the cell wall. This pathway is encoded by a cluster of six genes, the first three of which are orthologs of Escherichia coli genes involved in N-acetylmuramic acid dissimilation and encode a MurNAc-6-phosphate etherase (MurQ), a MurNAc-6-phosphate-specific transcriptional regulator (MurR), and a MurNAc-specific phosphotransferase system (MurP). Here we characterized two other genes of this cluster. The first gene was shown to encode a cell wall-associated beta-N-acetylglucosaminidase (NagZ, formerly YbbD) that cleaves the terminal nonreducing N-acetylglucosamine of muropeptides and also accepts chromogenic or fluorogenic beta-N-acetylglucosaminides. The second gene was shown to encode an amidase (AmiE, formerly YbbE) that hydrolyzes the N-acetylmuramyl-L-Ala bond of MurNAc peptides but not this bond of muropeptides. Hence, AmiE requires NagZ, and in conjunction these enzymes liberate MurNAc by sequential hydrolysis of muropeptides. NagZ expression was induced at late exponential phase, and it was 6-fold higher in stationary phase. NagZ is noncovalently associated with lysozyme-degradable particulate material and can be released from it with salt. A nagZ mutant accumulates muropeptides in the spent medium and displays a lytic phenotype in late stationary phase. The evidence for a muropeptide catabolic pathway presented here is the first evidence for cell wall recovery in a Gram-positive organism, and this pathway is distinct from the cell wall recycling pathway of E. coli and other Gram-negative bacteria.
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YneA, an SOS-induced inhibitor of cell division in Bacillus subtilis, is regulated posttranslationally and requires the transmembrane region for activity. J Bacteriol 2010; 192:3159-73. [PMID: 20400548 DOI: 10.1128/jb.00027-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cell viability depends on the stable transmission of genetic information to each successive generation. Therefore, in the event of intrinsic or extrinsic DNA damage, it is important that cell division be delayed until DNA repair has been completed. In Bacillus subtilis, this is accomplished in part by YneA, an inhibitor of division that is induced as part of the SOS response. We sought to gain insight into the mechanism by which YneA blocks cell division and the processes involved in shutting off YneA activity. Our data suggest that YneA is able to inhibit daughter cell separation as well as septum formation. YneA contains a LysM peptidoglycan binding domain and is predicted to be exported. We established that the YneA signal peptide is rapidly cleaved, resulting in secretion of YneA into the medium. Mutations within YneA affect both the rate of signal sequence cleavage and the activity of YneA. YneA does not stably associate with the cell wall and is rapidly degraded by extracellular proteases. Based on these results, we hypothesize that exported YneA is active prior to signal peptide cleavage and that proteolysis contributes to the inactivation of YneA. Finally, we identified mutations in the transmembrane segment of YneA that abolish the ability of YneA to inhibit cell division, while having little or no effect on YneA export or stability. These data suggest that protein-protein interactions mediated by the transmembrane region may be required for YneA activity.
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Characterization of Acp, a peptidoglycan hydrolase of Clostridium perfringens with N-acetylglucosaminidase activity that is implicated in cell separation and stress-induced autolysis. J Bacteriol 2010; 192:2373-84. [PMID: 20190047 DOI: 10.1128/jb.01546-09] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This work reports the characterization of the first known peptidoglycan hydrolase (Acp) produced mainly during vegetative growth of Clostridium perfringens. Acp has a modular structure with three domains: a signal peptide domain, an N-terminal domain with repeated sequences, and a C-terminal catalytic domain. The purified recombinant catalytic domain of Acp displayed lytic activity on the cell walls of several Gram-positive bacterial species. Its hydrolytic specificity was established by analyzing the Bacillus subtilis peptidoglycan digestion products by coupling reverse phase-high-pressure liquid chromatography (RP-HPLC) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis, which displayed an N-acetylglucosaminidase activity. The study of acp expression showed a constant expression during growth, which suggested an important role of Acp in growth of C. perfringens. Furthermore, cell fractionation and indirect immunofluorescence staining using anti-Acp antibodies revealed that Acp is located at the septal peptidoglycan of vegetative cells during exponential growth phase, indicating a role in cell separation or division of C. perfringens. A knockout acp mutant strain was obtained by using the insertion of mobile group II intron strategy (ClosTron). The microscopic examination indicated a lack of vegetative cell separation in the acp mutant strain, as well as the wild-type strain incubated with anti-Acp antibodies, demonstrating the critical role of Acp in cell separation. The comparative responses of wild-type and acp mutant strains to stresses induced by Triton X-100, bile salts, and vancomycin revealed an implication of Acp in autolysis induced by these stresses. Overall, Acp appears as a major cell wall N-acetylglucosaminidase implicated in both vegetative growth and stress-induced autolysis.
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Molecular properties of the glucosaminidase AcmA from Lactococcus lactis MG1363: mutational and biochemical analyses. Gene 2009; 447:61-71. [PMID: 19686822 DOI: 10.1016/j.gene.2009.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 08/05/2009] [Accepted: 08/11/2009] [Indexed: 11/21/2022]
Abstract
The major autolysin AcmA of Lactococcus lactis ssp. cremoris MG1363 is a modular protein consisting of an N-terminal signal sequence, a central enzymatic region (glu(acma) as a glucosaminidase), and a C-terminal cell-recognition domain (LysM123). glu(acma) (about 160 amino acids) belongs to the glycoside hydrolase (GH) 73 family, and the two acidic residues E128 and D153 have been thought to be catalytically important. In this study, amino-acid substitution analysis of AcmA was first carried out in the Escherichia coli system. Point mutations E94A, E94Q, E128A, D153A, and Y191A markedly reduced cell-lytic activity (3.8%, 1.1%, 4.2%, 4.8%, and 2.4%, respectively), whereas E128Q and D153N retained significant residual activities (32.1% and 44.0%, respectively). On the other hand, Y191F and Y191W mutations retained high activities (66.2% and 46.0%, respectively). These results showed that E94 (rather than E128 and D153) and the aromatic residue Y191 probably play important roles in catalysis of AcmA. Together with mutational analysis of another GH73 glucoaminidase Glu(atlwm) from the Staphylococcus warneri M autolysin Atl(WM), these results suggested that the GH73 members cleave a glycosidic bond via a substrate-assisted mechanism, as postulated in the GH20 members. AcmA and Glu(atlwm) were purified from E. coli recombinant cells, and their enzymatic properties were studied.
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Bublitz M, Polle L, Holland C, Heinz DW, Nimtz M, Schubert WD. Structural basis for autoinhibition and activation of Auto, a virulence-associated peptidoglycan hydrolase ofListeria monocytogenes. Mol Microbiol 2009; 71:1509-22. [DOI: 10.1111/j.1365-2958.2009.06619.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Hashimoto W, Ochiai A, Momma K, Itoh T, Mikami B, Maruyama Y, Murata K. Crystal structure of the glycosidase family 73 peptidoglycan hydrolase FlgJ. Biochem Biophys Res Commun 2009; 381:16-21. [PMID: 19351587 DOI: 10.1016/j.bbrc.2009.01.186] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 01/27/2009] [Indexed: 10/21/2022]
Abstract
Glycoside hydrolase (GH) categorized into family 73 plays an important role in degrading bacterial cell wall peptidoglycan. The flagellar protein FlgJ contains N- and C-terminal domains responsible for flagellar rod assembly and peptidoglycan hydrolysis, respectively. A member of family GH-73, the C-terminal domain (SPH1045-C) of FlgJ from Sphingomonas sp. strain A1 was expressed in Escherichia coli, purified, and characterized. SPH1045-C exhibited bacterial cell lytic activity most efficiently at pH 6.0 and 37 degrees C. The X-ray crystallographic structure of SPH1045-C was determined at 1.74 A resolution by single-wavelength anomalous diffraction. The enzyme consists of two lobes, alpha and beta. A deep cleft located between the two lobes can accommodate polymer molecules, suggesting that the active site is located in the cleft. Although SPH1045-C shows a structural homology with family GH-22 and GH-23 lysozymes, the arrangement of the nucleophile/base residue in the active site is specific to each peptidoglycan hydrolase.
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Affiliation(s)
- Wataru Hashimoto
- Laboratory of Basic and Applied Molecular Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan
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Vollmer W, Joris B, Charlier P, Foster S. Bacterial peptidoglycan (murein) hydrolases. FEMS Microbiol Rev 2008; 32:259-86. [PMID: 18266855 DOI: 10.1111/j.1574-6976.2007.00099.x] [Citation(s) in RCA: 609] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Most bacteria have multiple peptidoglycan hydrolases capable of cleaving covalent bonds in peptidoglycan sacculi or its fragments. An overview of the different classes of peptidoglycan hydrolases and their cleavage sites is provided. The physiological functions of these enzymes include the regulation of cell wall growth, the turnover of peptidoglycan during growth, the separation of daughter cells during cell division and autolysis. Specialized hydrolases enlarge the pores in the peptidoglycan for the assembly of large trans-envelope complexes (pili, flagella, secretion systems), or they specifically cleave peptidoglycan during sporulation or spore germination. Moreover, peptidoglycan hydrolases are involved in lysis phenomena such as fratricide or developmental lysis occurring in bacterial populations. We will also review the current view on the regulation of autolysins and on the role of cytoplasm hydrolases in peptidoglycan recycling and induction of beta-lactamase.
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Affiliation(s)
- Waldemar Vollmer
- Institute for Cell and Molecular Biosciences, University of Newcastle upon Tyne, Newcastle upon Tyne, UK.
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27
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Carballido-López R, Formstone A. Shape determination in Bacillus subtilis. Curr Opin Microbiol 2007; 10:611-6. [PMID: 17981078 DOI: 10.1016/j.mib.2007.09.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2007] [Accepted: 09/14/2007] [Indexed: 11/19/2022]
Abstract
The discovery of cytoskeletal elements in prokaryotes has dramatically changed the way we think about bacterial cell morphogenesis. The rod shape of Bacillus subtilis is maintained by the two major polymers (peptidoglycan and teichoic acids) of its thick cell wall and determined by the way these are inserted during growth. The current view is that the dynamic tubulin-like (FtsZ) and actin-like (MreB) cytoskeletons orchestrate, both in time and space, the assembly of macromolecular machineries that effect cell wall synthesis and hydrolysis during cell division and cell elongation, respectively.
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Affiliation(s)
- Rut Carballido-López
- Génétique Microbienne, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas Cedex, France.
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28
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Fukushima T, Yao Y, Kitajima T, Yamamoto H, Sekiguchi J. Characterization of new l,d-endopeptidase gene product CwlK (previous YcdD) that hydrolyzes peptidoglycan in Bacillus subtilis. Mol Genet Genomics 2007; 278:371-83. [PMID: 17588176 DOI: 10.1007/s00438-007-0255-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Accepted: 05/23/2007] [Indexed: 10/23/2022]
Abstract
Bacillus subtilis has various cell wall hydrolases, however, the functions and hydrolase activities of some enzymes are still unknown. B. subtilis CwlK (YcdD) exhibits high sequence similarity with the peptidoglycan hydrolytic L,D-endopeptidase (PLY500) of Listeria monocytogenes phage and CwlK has the VanY motif which is a D-alanyl-D-alanine carboxypeptidase (Pfam: http://www.sanger.ac.uk/Software/Pfam/). The beta-galactosidase activity observed on cwlK-lacZ fusion indicated that the cwlK gene was expressed during the vegetative growth phase, and Western blotting suggested that CwlK seems to be localized in the membrane. Truncated CwlK fused with a histidine-tag (h-DeltaCwlK) was produced in Escherichia coli and purified on a nickel column. The h-DeltaCwlK protein hydrolyzed the peptidoglycan of B. subtilis, and the optimal pH, temperature and NaCl concentration for h-DeltaCwlK were pH 6.5, 37 degrees C, and 0 M, respectively. Interestingly, h-DeltaCwlK could hydrolyze the linkage of L-alanine-D-glutamic acid in the stem of the peptidoglycan, however, this enzyme could not hydrolyze the linkage of D-alanine-D-alanine, suggesting that CwlK is an L,D-endopeptidase not a D,D-carboxypeptidase. CwlK could not hydrolyze polyglutamate from B. natto or peptidoglycan of Staphylococcus aureus. This is the first report describing the characterization of an L,D-endopeptidase in B. subtilis and also the first report in bacteria of the characterization of a PLY500 family protein encoded in chromosomal DNA.
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Affiliation(s)
- Tatsuya Fukushima
- Department of Bioscience and Textile Technology, Interdisciplinary Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda-shi, Nagano, 386-8567, Japan
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Kobayashi K. Bacillus subtilis pellicle formation proceeds through genetically defined morphological changes. J Bacteriol 2007; 189:4920-31. [PMID: 17468240 PMCID: PMC1913431 DOI: 10.1128/jb.00157-07] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biofilms are structured multicellular communities of bacteria that form through a developmental process. In standing culture, undomesticated strains of Bacillus subtilis produce a floating biofilm, called a pellicle, with a distinct macroscopic architecture. Here we report on a comprehensive analysis of B. subtilis pellicle formation, with a focus on transcriptional regulators and morphological changes. To date, 288 known or putative transcriptional regulators encoded by the B. subtilis genome have been identified or assigned based on similarity to other known proteins. The genes encoding these regulators were systematically disrupted, and the effects of the mutations on pellicle formation were examined, resulting in the identification of 19 regulators involved in pellicle formation. In addition, morphological analysis revealed that pellicle formation begins with the formation of cell chains, which is followed by clustering and degradation of cell chains. Genetic and morphological evidence showed that each stage of morphological change can be defined genetically, based on mutants of transcriptional regulators, each of which blocks pellicle formation at a specific morphological stage. Formation and degradation of cell chains are controlled by down- and up-regulation of sigma(D)- and sigma(H)-dependent autolysins expressed at specific stages during pellicle formation. Transcriptional analysis revealed that the transcriptional activation of sigH depends on the formation of cell clusters, which in turn activates transcription of sigma(H)-dependent autolysin in cell clusters. Taken together, our results reveal relationships between transcriptional regulators and morphological development during pellicle formation by B. subtilis.
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Affiliation(s)
- Kazuo Kobayashi
- Graduate School of Information Science, Nara Institute of Science and Technology, Takayama 8916-5, Ikoma, Nara 630-0192, Japan.
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30
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Eckert C, Magnet S, Mesnage S. The Enterococcus hirae Mur-2 enzyme displays N-acetylglucosaminidase activity. FEBS Lett 2007; 581:693-6. [PMID: 17258207 PMCID: PMC1965491 DOI: 10.1016/j.febslet.2007.01.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 01/09/2007] [Accepted: 01/12/2007] [Indexed: 11/21/2022]
Abstract
Enterococcus hirae produces two autolytic enzymes named Mur-1 and Mur-2, both previously described as N-acetylmuramidases. We used tandem mass spectrometry to show that Mur-2 in fact displays N-acetylglucosaminidase activity. This result reveals that Mur-2 and its counterparts studied to date, which are members of glycosyl hydrolase family 73 from the CAZy (Carbohydrate-Active enZyme) database, display the same catalytic activity.
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Affiliation(s)
- Catherine Eckert
- Structures Bacteriennes Impliquees Dans la Modulation de la Resistance Aux Antibiotiques
INSERM : U655 IFR58Université Pierre et Marie Curie - Paris VIInstitut Biomedical Des Cordeliers
15, Rue de L'Ecole de Medecine
75270 PARIS CEDEX 06,FR
- Faculté de Médecine
Université René Descartes - Paris VParis,FR
- AP-HP
Hôpital européen Georges PompidouFR
| | - Sophie Magnet
- Structures Bacteriennes Impliquees Dans la Modulation de la Resistance Aux Antibiotiques
INSERM : U655 IFR58Université Pierre et Marie Curie - Paris VIInstitut Biomedical Des Cordeliers
15, Rue de L'Ecole de Medecine
75270 PARIS CEDEX 06,FR
- Faculté de Médecine
Université René Descartes - Paris VParis,FR
| | - Stéphane Mesnage
- Structures Bacteriennes Impliquees Dans la Modulation de la Resistance Aux Antibiotiques
INSERM : U655 IFR58Université Pierre et Marie Curie - Paris VIInstitut Biomedical Des Cordeliers
15, Rue de L'Ecole de Medecine
75270 PARIS CEDEX 06,FR
- Faculté de Médecine
Université René Descartes - Paris VParis,FR
- * Correspondence should be adressed to: Stéphane Mesnage
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Kodama T, Endo K, Ara K, Ozaki K, Kakeshita H, Yamane K, Sekiguchi J. Effect of Bacillus subtilis spo0A mutation on cell wall lytic enzymes and extracellular proteases, and prevention of cell lysis. J Biosci Bioeng 2007; 103:13-21. [PMID: 17298895 DOI: 10.1263/jbb.103.13] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 10/02/2006] [Indexed: 11/17/2022]
Abstract
The Bacillus subtilis spo0A mutant is an adequate host for extracellular protein production (e.g., alpha-amylase). However the mutant was prone to cell lysis. SDS-PAGE and zymography of cell wall lytic proteins indicated that the spo0A mutant contained high amounts of two major autolysins (LytC [CwlB] and LytD [CwlG]) and two minor cell wall lytic enzymes (LytE [CwlF] and LytF [CwlE]). On the other hand, the expression of eight extracellular protease genes was very poor or absent in the spo0A mutant. An eight-extracellular-protease-deficient mutant (Dpr8 strain) was constructed and the strain also exhibited cell lysis. The autolysins from the spo0A mutant were degraded by the supernatant of the wild type but not degraded by that of the Dpr8 mutant. These results suggest that the extensive cell lysis of the spo0A mutant was partially caused by the stability of autolysins via the decrease of the extracellular proteases. The introduction of a major autolysin and/or SigD mutations into the spo0A mutant was effective for preventing cell lysis.
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Affiliation(s)
- Takeko Kodama
- Tochigi Research Laboratories of Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi 321-3497, Japan
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32
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Eckert C, Lecerf M, Dubost L, Arthur M, Mesnage S. Functional analysis of AtlA, the major N-acetylglucosaminidase of Enterococcus faecalis. J Bacteriol 2006; 188:8513-9. [PMID: 17041059 PMCID: PMC1698247 DOI: 10.1128/jb.01145-06] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The major peptidoglycan hydrolase of Enterococcus faecalis, AtlA, has been identified, but its enzyme activity remains unknown. We have used tandem mass spectrometry analysis of peptidoglycan hydrolysis products obtained using the purified protein to show that AtlA is an N-acetylglucosaminidase. To gain insight into the regulation of its enzyme activity, the three domains of AtlA were purified alone or in combination following expression of truncated forms of the atlA gene in Escherichia coli or partial digestion of AtlA by proteinase K. The central domain of AtlA was catalytically active, but its activity was more than two orders of magnitude lower than that of the complete protein. Partial proteolysis of AtlA was detected in vivo: zymograms of E. faecalis extracts revealed two catalytically active protein bands of 62 and 72 kDa that were both absent in extracts from an atlA null mutant. Limited digestion of AtlA by proteinase K in vitro suggested that the proteolytic cleavage of AtlA in E. faecalis extracts corresponds to the truncation of the N-terminal domain, which is rich in threonine and glutamic acid residues. We show that the truncation of the N-terminal domain from recombinant AtlA has no impact on enzyme activity. The C-terminal domain of the protein, which contains six LysM modules bound to highly purified peptidoglycan, was required for optimal enzyme activity. These data indicate that AtlA is not produced as a proenzyme and that control of the AtlA glucosaminidase activity is likely to occur at the level of LysM-mediated binding to peptidoglycan.
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Affiliation(s)
- Catherine Eckert
- Centre de Recherches Biomédicales des Cordeliers, INSERM U655-LRMA, Université paris 6, 15 rue de l'Ecole de Médecine, 75254 Paris Cédex 06, France
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33
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Fukushima T, Afkham A, Kurosawa SI, Tanabe T, Yamamoto H, Sekiguchi J. A new D,L-endopeptidase gene product, YojL (renamed CwlS), plays a role in cell separation with LytE and LytF in Bacillus subtilis. J Bacteriol 2006; 188:5541-50. [PMID: 16855244 PMCID: PMC1540035 DOI: 10.1128/jb.00188-06] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A new peptidoglycan hydrolase, Bacillus subtilis YojL (cell wall-lytic enzyme associated with cell separation, renamed CwlS), exhibits high amino acid sequence similarity to LytE (CwlF) and LytF (CwlE), which are associated with cell separation. The N-terminal region of CwlS has four tandem repeat regions (LysM repeats) predicted to be a peptidoglycan-binding module. The C-terminal region exhibits high similarity to the cell wall hydrolase domains of LytE and LytF at their C-terminal ends. The C-terminal region of CwlS produced in Escherichia coli could hydrolyze the linkage of d-gamma-glutamyl-meso-diaminopimelic acid in the cell wall of B. subtilis, suggesting that CwlS is a d,l-endopeptidase. beta-Galactosidase fusion experiments and Northern hybridization analysis suggested that the cwlS gene is transcribed during the late vegetative and early stationary phases. A cwlS mutant exhibited a cell shape similar to that of the wild type; however, a lytE lytF cwlS triple mutant exhibited aggregated microfiber formation. Moreover, immunofluorescence microscopy showed that FLAG-tagged CwlS was localized at cell separation sites and cell poles during the late vegetative phase. The localization sites are similar to those of LytF and LytE, indicating that CwlS is involved in cell separation with LytF and LytE. These specific localizations may be dependent on the LysM repeats in their N-terminal domains. The roles of CwlS, LytF, and LytE in cell separation are discussed.
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Affiliation(s)
- Tatsuya Fukushima
- Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda-shi, Nagano 386-8567, Japan
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34
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Kuo TH, Chuang SC, Chang SY, Liang PH. Ligand specificities and structural requirements of two Tachypleus plasma lectins for bacterial trapping. Biochem J 2006; 393:757-66. [PMID: 16229681 PMCID: PMC1360729 DOI: 10.1042/bj20051108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TPL (Tachypleus plasma lectin)-1 was purified by using a Sepharose column and TPL-2 was purified from an LPS-Sepharose (LPS coupled to Sepharose matrix) affinity column, as described previously [Chiou, Chen, Y.-W., Chen, S.-C., Chao and Liu (2000) J. Biol. Chem. 275, 1630-1634] and the corresponding genes were cloned [Chen, Yen, Yeh, Huang and Liu (2001) J. Biol. Chem. 276, 9631-9639]. In the present study, TPL-1 and -2 were produced in yeast, and the recombinant proteins secreted into the media were purified and characterized. The proteins show specific PGN (peptidoglycan)- and LPS-binding activity, suggesting a role in trapping Gram-positive and Gram-negative bacteria respectively in innate immunity. Using BIAcore assays, the dissociation constant for the TPL-1-PGN complex was measured as 8x10(-8) M. Replacement of Asn74, the N-glycosylation site of TPL-1, with Asp abolishes the PGN-binding affinity, whereas the unglycosylated TPL-2 N3D mutant retains LPS-binding activity. DTT (dithiothreitol) treatment to break disulphide linkages abrogates TPL-2 activity but does not interfere with TPL-1 function. Cys4 in TPL-2 may form an intermolecular disulphide bond, which is essential for activity. As a result, the TPL-2 C4S mutant is inactive and is eluted as a monomer on a non-reducing gel. TPL-2 C6S is active and forms a non-covalently linked dimer. A model describing TPL-2 binding with LPS is proposed. These two plasma lectins that have different ligand specificities can be used for the detection and discrimination of bacteria and removal of endotoxins.
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Affiliation(s)
- Tun-Hsun Kuo
- *Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Shiao-Cheng Chuang
- *Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Sing-Yang Chang
- *Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
| | - Po-Huang Liang
- *Institute of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan
- †Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan
- To whom correspondence should be addressed (email )
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Nambu T, Inagaki Y, Kutsukake K. Plasticity of the domain structure in FlgJ, a bacterial protein involved in flagellar rod formation. Genes Genet Syst 2006; 81:381-9. [PMID: 17283383 DOI: 10.1266/ggs.81.381] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bacterial flagellar rod structure is built across the peptidoglycan (PG) layer. A Salmonella enterica flagellar protein FlgJ is believed to consist of two functional domains, the N-terminal half acting as a scaffold or cap essential for rod assembly and the C-terminal half acting as a PG hydrolase (PGase) that makes a hole in the PG layer to facilitate rod penetration. In this study, molecular data analyses were conducted on FlgJ data sets sampled from a variety of bacterial species, and three types of FlgJ homologs were identified: (i) "canonical dual-domain" type found in beta- and gamma-proteobacteria that has a domain for one of the PGases, acetylmuramidase (Acm), at the C terminus, (ii) "non-canonical dual-domain" type found in the genus Desulfovibrio (delta-proteobacteria) that bears a domain for another PGase, M23/M37-family peptidase (Pep), at the C terminus and (iii) "single-domain" type found in phylogenetically diverged lineages that lacks the Acm or Pep domain. FlgJ phylogeny, together with the domain architecture, suggested that the single-domain type was the original form of FlgJ and the canonical dual-domain type had evolved from the single-domain type by fusion of the Acm domain to its C terminus in the common ancestor of beta- and gamma-proteobacteria. The non-canonical dual-domain type may have been formed by fusion of the Pep domain to the single-domain type in the ancestor of Desulfovibrio. In some lineages of gamma-proteobacteria, the Acm domain appeared to be lost secondarily from the dual-domain type FlgJ to yield again a single-domain type one. To rationalize the underlying mechanism that gave rise to the two different types of dual-domain FlgJ homologs, we propose a model assuming the lineage-specific co-option of flagellum-specific PGase from diverged housekeeping PGases in bacteria.
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Affiliation(s)
- Takayuki Nambu
- Department of Bioscience, Nagahama Institute of Bioscience and Technology, 1266 Tamura, Nagahama, Shiga 526-0829, Japan
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36
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Abstract
Flagellar biosynthesis has been studied most thoroughly in laboratory strains of Escherichia coli and Salmonella enterica. However, genome sequencing has uncovered flagellar loci in distantly related bacteria. We have used homology searches to determine how far the E. coli/S. enterica paradigm can be generalised to other flagellar systems. Numerous previously unrecognized homologues of flagellar components were discovered, including novel FlgM, FlgN, FliK and FliO homologues. Homology was found between the FliK proteins and a molecular ruler, YscP, from a virulence-associated type-III secretion system. Also described is a new family of flagellar proteins, the FlhX proteins, which resemble the cytoplasmic domain of FlhB.
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Affiliation(s)
- Mark J Pallen
- Bacterial Pathogenesis and Genomics Unit, Division of Immunity and Infection, Medical School, University of Birmingham, Birmingham, UK B15 2TT.
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Dhalluin A, Bourgeois I, Pestel-Caron M, Camiade E, Raux G, Courtin P, Chapot-Chartier MP, Pons JL. Acd, a peptidoglycan hydrolase of Clostridium difficile with N-acetylglucosaminidase activity. Microbiology (Reading) 2005; 151:2343-2351. [PMID: 16000724 DOI: 10.1099/mic.0.27878-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A gene encoding a putative peptidoglycan hydrolase was identified by sequence similarity searching in the Clostridium difficile 630 genome sequence, and the corresponding protein, named Acd (autolysin of C. difficile) was expressed in Escherichia coli. The deduced amino acid sequence of Acd shows a modular structure with two main domains: an N-terminal domain exhibiting repeated sequences and a C-terminal catalytic domain. The C-terminal domain exhibits sequence similarity with the glucosaminidase domains of Staphylococcus aureus Atl and Bacillus subtilis LytD autolysins. Purified recombinant Acd produced in E. coli was confirmed to be a cell-wall hydrolase with lytic activity on the peptidoglycan of several Gram-positive bacteria, including C. difficile. The hydrolytic specificity of Acd was studied by RP-HPLC analysis and MALDI-TOF MS using B. subtilis cell-wall extracts. Muropeptides generated by Acd hydrolysis demonstrated that Acd hydrolyses peptidoglycan bonds between N-acetylglucosamine and N-acetylmuramic acid, confirming that Acd is an N-acetylglucosaminidase. The transcription of the acd gene increased during vegetative cellular growth of C. difficile 630. The sequence of the acd gene appears highly conserved in C. difficile strains. Regarding deduced amino acid sequences, the C-terminal domain with enzymic function appears to be the most conserved of the two main domains. Acd is the first known autolysin involved in peptidoglycan hydrolysis of C. difficile.
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Affiliation(s)
- Anne Dhalluin
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Ingrid Bourgeois
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Martine Pestel-Caron
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Emilie Camiade
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
| | - Gregory Raux
- INSERM U 614 (IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 76183 Rouen Cedex, France
| | - Pascal Courtin
- Unité de Biochimie et Structure des Protéines, INRA, 78352 Jouy-en-Josas Cedex, France
| | | | - Jean-Louis Pons
- Groupe de Recherche sur les Antimicrobiens et les Micro-organismes (UPRES EA 2656, IFR 23), Université de Rouen, UFR Médecine-Pharmacie, 22 Boulevard Gambetta, F-76183 Rouen Cedex, France
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Steen A, Buist G, Horsburgh GJ, Venema G, Kuipers OP, Foster SJ, Kok J. AcmA of Lactococcus lactis is an N-acetylglucosaminidase with an optimal number of LysM domains for proper functioning. FEBS J 2005; 272:2854-68. [PMID: 15943817 DOI: 10.1111/j.1742-4658.2005.04706.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AcmA, the major autolysin of Lactococcus lactis MG1363 is a modular protein consisting of an N-terminal active site domain and a C-terminal peptidoglycan-binding domain. The active site domain is homologous to that of muramidase-2 of Enterococcus hirae, however, RP-HPLC analysis of muropeptides released from Bacillus subtilis peptidoglycan, after digestion with AcmA, shows that AcmA is an N-acetylglucosaminidase. In the C-terminus of AcmA three highly similar repeated regions of 45 amino acid residues are present, which are separated by short nonhomologous sequences. The repeats of AcmA, which belong to the lysine motif (LysM) domain family, were consecutively deleted, removed, or, alternatively, one additional repeat was added, without destroying the cell wall-hydrolyzing activity of the enzyme in vitro, although AcmA activity was reduced in all cases. In vivo, proteins containing no or only one repeat did not give rise to autolysis of lactococcal cells, whereas separation of the producer cells from the chains was incomplete. Exogenously added AcmA deletion derivatives carrying two repeats or four repeats bound to lactococcal cells, whereas the derivative with no or one repeat did not. In conclusion, these results show that AcmA needs three LysM domains for optimal peptidoglycan binding and biological functioning.
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Affiliation(s)
- Anton Steen
- Department of Genetics, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Kerklaan, NN Haren, Netherlands
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Huard C, Miranda G, Redko Y, Wessner F, Foster SJ, Chapot-Chartier MP. Analysis of the peptidoglycan hydrolase complement of Lactococcus lactis: identification of a third N-acetylglucosaminidase, AcmC. Appl Environ Microbiol 2004; 70:3493-9. [PMID: 15184148 PMCID: PMC427759 DOI: 10.1128/aem.70.6.3493-3499.2004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The peptidoglycan hydrolase (PGH) complement of Lactococcus lactis was identified by amino acid sequence similarity searching of the L. lactis IL-1403 complete genome sequence. Five PGHs that are not encoded by prophages were detected, including the previously characterized AcmA and AcmB proteins. Four of these PGHs, AcmA to AcmD, contain a catalytic domain homologous to that of enterococcal muramidase, but they have different domain structures. The fifth one (YjgB) has sequence similarity with the active-site domain of peptidoglycan-specific endopeptidases. The three new PGH-encoding genes identified in this study are all actively transcribed in L. lactis subsp. cremoris MG1363. The relative abundance of their transcripts varied during growth and was maximal during the early exponential growth phase. The three encoded proteins have peptidoglycan-hydrolyzing activities which are detected only at acidic pHs by zymography. Like AcmA and AcmB, AcmC has N-acetylglucosaminidase activity rather than the N-acetylmuramidase activity predicted by sequence similarity.
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Affiliation(s)
- Carine Huard
- Unité de Biochimie et Structure des Protéines, INRA, 78352 Jouy-en-Josas Cedex, France
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