1
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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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2
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Griffin ME, Klupt S, Espinosa J, Hang HC. Peptidoglycan NlpC/P60 peptidases in bacterial physiology and host interactions. Cell Chem Biol 2023; 30:436-456. [PMID: 36417916 PMCID: PMC10192474 DOI: 10.1016/j.chembiol.2022.11.001] [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: 05/18/2022] [Revised: 09/15/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022]
Abstract
The bacterial cell wall is composed of a highly crosslinked matrix of glycopeptide polymers known as peptidoglycan that dictates bacterial cell morphology and protects against environmental stresses. Regulation of peptidoglycan turnover is therefore crucial for bacterial survival and growth and is mediated by key protein complexes and enzyme families. Here, we review the prevalence, structure, and activity of NlpC/P60 peptidases, a family of peptidoglycan hydrolases that are crucial for cell wall turnover and division as well as interactions with antibiotics and different hosts. Understanding the molecular functions of NlpC/P60 peptidases should provide important insight into bacterial physiology, their interactions with different kingdoms of life, and the development of new therapeutic approaches.
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Affiliation(s)
- Matthew E Griffin
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA
| | - Steven Klupt
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA
| | - Juliel Espinosa
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY 10065, USA
| | - Howard C Hang
- Department of Immunology and Microbiology, Scripps Research, La Jolla, CA 92037, USA; Department of Chemistry, Scripps Research, La Jolla, CA 92037, USA.
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3
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Sanchez BC, Heckmann ER, Green SI, Clark JR, Kaplan HB, Ramig RF, Muldrew KL, Hines-Munson C, Skelton F, Trautner BW, Maresso AW. Development of Phage Cocktails to Treat E. coli Catheter-Associated Urinary Tract Infection and Associated Biofilms. Front Microbiol 2022; 13:796132. [PMID: 35620093 PMCID: PMC9127763 DOI: 10.3389/fmicb.2022.796132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 04/04/2022] [Indexed: 11/16/2022] Open
Abstract
High rates of antimicrobial resistance and formation of biofilms makes treatment of Escherichia coli catheter-associated urinary tract infections (CAUTI) particularly challenging. CAUTI affect 1 million patients per year in the United States and are associated with morbidity and mortality, particularly as an etiology for sepsis. Phage have been proposed as a potential therapeutic option. Here, we report the development of phage cocktails that lyse contemporary E. coli strains isolated from the urine of patients with spinal cord injury (SCI) and display strong biofilm-forming properties. We characterized E. coli phage against biofilms in two in vitro CAUTI models. Biofilm viability was measured by an MTT assay that determines cell metabolic activity and by quantification of colony forming units. Nine phage decreased cell viability by >80% when added individually to biofilms of two E. coli strains in human urine. A phage cocktail comprising six phage lyses 82% of the strains in our E. coli library and is highly effective against young and old biofilms and against biofilms on silicon catheter materials. Using antibiotics together with our phage cocktail prevented or decreased emergence of E. coli resistant to phage in human urine. We created an anti-biofilm phage cocktail with broad host range against E. coli strains isolated from urine. These phage cocktails may have therapeutic potential against CAUTI.
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Affiliation(s)
- Belkys C. Sanchez
- Tailored Antibacterials and Innovative Laboratories for Phage (Φ) Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Emmaline R. Heckmann
- Tailored Antibacterials and Innovative Laboratories for Phage (Φ) Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Sabrina I. Green
- Tailored Antibacterials and Innovative Laboratories for Phage (Φ) Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Justin R. Clark
- Tailored Antibacterials and Innovative Laboratories for Phage (Φ) Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Heidi B. Kaplan
- Department of Microbiology and Molecular Genetics, McGovern Medical School, UTHealth Houston, Houston, TX, United States
| | - Robert F. Ramig
- Tailored Antibacterials and Innovative Laboratories for Phage (Φ) Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - Kenneth L. Muldrew
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States,Pathology and Laboratory Medicine, Michael E. DeBakey VA Medical Center, Houston, TX, United States,Section of Infectious Diseases, Department of Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Casey Hines-Munson
- Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey VA Medical Center, Houston, TX, United States
| | - Felicia Skelton
- Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey VA Medical Center, Houston, TX, United States,H. Ben Taub Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, United States
| | - Barbara W. Trautner
- Center for Innovations in Quality, Effectiveness and Safety, Michael E. DeBakey VA Medical Center, Houston, TX, United States,Department of Medicine and Surgery, Baylor College of Medicine, Houston, TX, United States,Center for Translational Research on Inflammatory Diseases, Michael E. DeBakey VA Medical Center, Houston, TX, United States
| | - Anthony W. Maresso
- Tailored Antibacterials and Innovative Laboratories for Phage (Φ) Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States,*Correspondence: Anthony W. Maresso,
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4
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Biochemical reconstitution defines new functions for membrane-bound glycosidases in assembly of the bacterial cell wall. Proc Natl Acad Sci U S A 2021; 118:2103740118. [PMID: 34475211 DOI: 10.1073/pnas.2103740118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 07/30/2021] [Indexed: 01/25/2023] Open
Abstract
The peptidoglycan cell wall is a macromolecular structure that encases bacteria and is essential for their survival. Proper assembly of the cell wall requires peptidoglycan synthases as well as membrane-bound cleavage enzymes that control where new peptidoglycan is made and inserted. Previous studies have shown that two membrane-bound proteins in Streptococcus pneumoniae, here named MpgA and MpgB, are important in maintaining cell wall integrity. MpgA was predicted to be a lytic transglycosylase based on its homology to Escherichia coli MltG, while the enzymatic activity of MpgB was unclear. Using nascent peptidoglycan substrates synthesized in vitro from the peptidoglycan precursor Lipid II, we report that both MpgA and MpgB are muramidases. We show that replacing a single amino acid in E. coli MltG with the corresponding amino acid from MpgA results in muramidase activity, allowing us to predict from the presence of this amino acid that other putative lytic transglycosylases actually function as muramidases. Strikingly, we report that MpgA and MpgB cut nascent peptidoglycan at different positions along the sugar backbone relative to the reducing end, with MpgA producing much longer peptidoglycan oligomers. We show that the cleavage site selectivity of MpgA is controlled by the LysM-like subdomain, which is required for its full functionality in cells. We propose that MltG's ability to complement the loss of MpgA in S. pneumoniae despite performing different cleavage chemistry is because it can cleave nascent peptidoglycan at the same distance from the lipid anchor.
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5
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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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6
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Espinosa J, Lin TY, Estrella Y, Kim B, Molina H, Hang HC. Enterococcus NlpC/p60 Peptidoglycan Hydrolase SagA Localizes to Sites of Cell Division and Requires Only a Catalytic Dyad for Protease Activity. Biochemistry 2020; 59:4470-4480. [PMID: 33136372 DOI: 10.1021/acs.biochem.0c00755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peptidoglycan is a vital component of the bacterial cell wall, and its dynamic remodeling by NlpC/p60 hydrolases is crucial for proper cell division and survival. Beyond these essential functions, we previously discovered that Enterococcus species express and secrete the NlpC/p60 hydrolase-secreted antigen A (SagA), whose catalytic activity can modulate host immune responses in animal models. However, the localization and peptidoglycan hydrolase activity of SagA in Enterococcus was still unclear. In this study, we show that SagA contributes to a triseptal structure in dividing cells of enterococci and localizes to sites of cell division through its N-terminal coiled-coil domain. Using molecular modeling and site-directed mutagenesis, we identify amino acid residues within the SagA-NlpC/p60 domain that are crucial for catalytic activity and potential substrate binding. Notably, these studies revealed that SagA may function via a catalytic Cys-His dyad instead of the predicted Cys-His-His triad, which is conserved in SagA orthologs from other Enterococcus species. Our results provide key additional insight into peptidoglycan remodeling in Enterococcus by SagA NlpC/p60 hydrolases.
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Affiliation(s)
- Juliel Espinosa
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
| | - Ti-Yu Lin
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
| | - Yadyvic Estrella
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
| | - Byungchul Kim
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States
| | - Henrik Molina
- Proteomics Resource Center, The Rockefeller University, New York, New York 10065, United States
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, New York 10065, United States.,Departments of Immunology & Microbiology and Chemistry, Scripps Research, La Jolla, California 92037, United States
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7
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Abstract
The NlpC/p60-family of peptidoglycan hydrolases are key enzymes that facilitate bacterial cell division and also modulate microbe-host interactions. These endopeptidases utilize conserved Cys-His residues in their active site and are expressed in most bacterial species as well as some eukaryotes. Here we describe methods for biochemical analysis of Enterococcus faecium SagA-NlpC/p60 peptidoglycan hydrolase activity (Kim et al., 2019; Rangan et al., 2016), which includes recombinant protein preparation and biochemical analysis using both gel-based and LC-MS profiling of peptidoglycan fragments. These protocols should also facilitate the biochemical analysis of other NlpC/p60 peptidoglycan hydrolases.
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8
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Avello M, Davis KP, Grossman AD. Identification, characterization and benefits of an exclusion system in an integrative and conjugative element of Bacillus subtilis. Mol Microbiol 2019; 112:1066-1082. [PMID: 31361051 DOI: 10.1111/mmi.14359] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2019] [Indexed: 01/09/2023]
Abstract
Integrative and conjugative elements (ICEs) are mobile genetic elements that transfer from cell to cell by conjugation (like plasmids) and integrate into the chromosomes of bacterial hosts (like lysogenic phages or transposons). ICEs are prevalent in bacterial chromosomes and play a major role in bacterial evolution by promoting horizontal gene transfer. Exclusion prevents the redundant transfer of conjugative elements into host cells that already contain a copy of the element. Exclusion has been characterized mostly for conjugative elements of Gram-negative bacteria. Here, we report the identification and characterization of an exclusion mechanism in ICEBs1 from the Gram-positive bacterium Bacillus subtilis. We found that cells containing ICEBs1 inhibit the activity of the ICEBs1-encoded conjugation machinery in other cells. This inhibition (exclusion) was specific to the cognate conjugation machinery and the ICEBs1 gene yddJ was both necessary and sufficient to mediate exclusion by recipient cells. Through a mutagenesis and enrichment screen, we identified exclusion-resistant mutations in the ICEBs1 gene conG. Using genes from a heterologous but related ICE, we found that the exclusion specificity was determined by ConG and YddJ. Finally, we found that under conditions that support conjugation, exclusion provides a selective advantage to the element and its host cells.
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Affiliation(s)
- Monika Avello
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Kathleen P Davis
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Alan D Grossman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
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9
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Squeglia F, Moreira M, Ruggiero A, Berisio R. The Cell Wall Hydrolytic NlpC/P60 Endopeptidases in Mycobacterial Cytokinesis: A Structural Perspective. Cells 2019; 8:cells8060609. [PMID: 31216697 PMCID: PMC6628586 DOI: 10.3390/cells8060609] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/12/2019] [Accepted: 06/14/2019] [Indexed: 12/11/2022] Open
Abstract
In preparation for division, bacteria replicate their DNA and segregate the newly formed chromosomes. A division septum then assembles between the chromosomes, and the mother cell splits into two identical daughters due to septum degradation. A major constituent of bacterial septa and of the whole cell wall is peptidoglycan (PGN), an essential cell wall polymer, formed by glycan chains of β−(1-4)-linked-N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc), cross-linked by short peptide stems. Depending on the amino acid located at the third position of the peptide stem, PGN is classified as either Lys-type or meso-diaminopimelic acid (DAP)-type. Hydrolytic enzymes play a crucial role in the degradation of bacterial septa to split the cell wall material shared by adjacent daughter cells to promote their separation. In mycobacteria, a key PGN hydrolase, belonging to the NlpC/P60 endopeptidase family and denoted as RipA, is responsible for the degradation of septa, as the deletion of the gene encoding for this enzyme generates abnormal bacteria with multiple septa. This review provides an update of structural and functional data highlighting the central role of RipA in mycobacterial cytokinesis and the fine regulation of its catalytic activity, which involves multiple molecular partners.
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Affiliation(s)
- Flavia Squeglia
- Institute of Biostructures and Bioimaging (IBB), CNR, 80134 Naples, Italy.
| | - Miguel Moreira
- Institute of Biostructures and Bioimaging (IBB), CNR, 80134 Naples, Italy.
| | - Alessia Ruggiero
- Institute of Biostructures and Bioimaging (IBB), CNR, 80134 Naples, Italy.
| | - Rita Berisio
- Institute of Biostructures and Bioimaging (IBB), CNR, 80134 Naples, Italy.
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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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The cell wall hydrolase Pmp23 is important for assembly and stability of the division ring in Streptococcus pneumoniae. Sci Rep 2018; 8:7591. [PMID: 29765094 PMCID: PMC5954120 DOI: 10.1038/s41598-018-25882-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 04/13/2018] [Indexed: 12/02/2022] Open
Abstract
Bacterial division is intimately linked to synthesis and remodeling of the peptidoglycan, a cage-like polymer that surrounds the bacterial cell, providing shape and mechanical resistance. The bacterial division machinery, which is scaffolded by the cytoskeleton protein FtsZ, includes proteins with enzymatic, structural or regulatory functions. These proteins establish a complex network of transient functional and/or physical interactions which preserve cell shape and cell integrity. Cell wall hydrolases required for peptidoglycan remodeling are major contributors to this mechanism. Consistent with this, their deletion or depletion often results in morphological and/or division defects. However, the exact function of most of them remains elusive. In this work, we show that the putative lysozyme activity of the cell wall hydrolase Pmp23 is important for proper morphology and cell division in the opportunistic human pathogen Streptococcus pneumoniae. Our data indicate that active Pmp23 is required for proper localization of the Z-ring and the FtsZ-positioning protein MapZ. In addition, Pmp23 localizes to the division site and interacts directly with the essential peptidoglycan synthase PBP2x. Altogether, our data reveal a new regulatory function for peptidoglycan hydrolases.
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12
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Fukushima T, Uchida N, Ide M, Kodama T, Sekiguchi J. DL-endopeptidases function as both cell wall hydrolases and poly-γ-glutamic acid hydrolases. MICROBIOLOGY-SGM 2018; 164:277-286. [PMID: 29458655 DOI: 10.1099/mic.0.000609] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biopolymers on the cell surface are very important for protecting microorganisms from environmental stresses, as well as storing nutrients and minerals. Synthesis of biopolymers is well studied, while studies on the modification and degradation processes of biopolymers are limited. One of these biopolymers, poly-γ-glutamic acid (γ-PGA), is produced by Bacillus species. Bacillus subtilis PgdS, possessing three NlpC/P60 domains, hydrolyses γ-PGA. Here, we have demonstrated that several dl-endopeptidases with an NlpC/P60 domain (LytE, LytF, CwlS, CwlO, and CwlT) in B. subtilis digest not only an amide bond of d-γ-glutamyl-diaminopimelic acid in peptidoglycans but also linkages of γ-PGA produced by B. subtilis. The hydrolase activity of dl-endopeptidases towards γ-PGA was inhibited by IseA, which also inhibits their hydrolase activity towards peptidoglycans, while the hydrolysis of PgdS towards γ-PGA was not inhibited. PgdS hydrolysed only the d-/l-Glu‒d-Glu linkages of d-Glu-rich γ-PGA (d-Glu:l-Glu=7 : 3) and l-Glu-rich γ-PGA (d-Glu:l-Glu=1 : 9), indicating that PgdS can hydrolyse only restricted substrates. On the other hand, the dl-endopeptidases in B. subtilis cleaved d-/l-Glu‒d-/l-Glu linkages of d-Glu-rich γ-PGA (d-Glu:l-Glu=7 : 3), indicating that these enzymes show different substrate specificities. Thus, the dl-endopeptidases digest γ-PGA more flexibly than PgdS, even though they are annotated as "dl-endopeptidase, digesting the d-γ-glutamyl-diaminopimelic acid linkage (d‒l amino acid bond)".
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Affiliation(s)
- Tatsuya Fukushima
- Division of Gene Research, Department of Life Sciences, Research Center for Human and Environmental Sciences, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.,Present address: Fornia Biosolutions, Inc., 3876 Bay Center Place, Hayward, CA 94545, USA
| | - Natsuki Uchida
- Department of Applied Biology, Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda-shi, Nagano 386-8567, Japan
| | - Masatoshi Ide
- Department of Applied Biology, Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda-shi, Nagano 386-8567, Japan
| | - Takeko Kodama
- Kao Corporation, Biological Science Research, 1334 Minato, Wakayama-shi, Wakayama 640-8580, Japan
| | - Junichi Sekiguchi
- Department of Applied Biology, Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda-shi, Nagano 386-8567, Japan
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13
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Squeglia F, Ruggiero A, Berisio R. Chemistry of Peptidoglycan in Mycobacterium tuberculosis
Life Cycle: An off-the-wall Balance of Synthesis and Degradation. Chemistry 2017; 24:2533-2546. [DOI: 10.1002/chem.201702973] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Indexed: 12/22/2022]
Affiliation(s)
- Flavia Squeglia
- Institute of Biostructures and Bioimaging; CNR; Via Mezzocannone 16. 80134 Napoli Italy
| | - Alessia Ruggiero
- Institute of Biostructures and Bioimaging; CNR; Via Mezzocannone 16. 80134 Napoli Italy
| | - Rita Berisio
- Institute of Biostructures and Bioimaging; CNR; Via Mezzocannone 16. 80134 Napoli Italy
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14
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Wu X, Kwon SJ, Kim J, Kane RS, Dordick JS. Biocatalytic Nanocomposites for Combating Bacterial Pathogens. Annu Rev Chem Biomol Eng 2017; 8:87-113. [DOI: 10.1146/annurev-chembioeng-060816-101612] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Xia Wu
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Seok-Joon Kwon
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Jungbae Kim
- Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Ravi S. Kane
- School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Jonathan S. Dordick
- Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180
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15
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Auchtung JM, Aleksanyan N, Bulku A, Berkmen MB. Biology of ICEBs1, an integrative and conjugative element in Bacillus subtilis. Plasmid 2016; 86:14-25. [PMID: 27381852 DOI: 10.1016/j.plasmid.2016.07.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 06/21/2016] [Accepted: 07/01/2016] [Indexed: 10/21/2022]
Abstract
Horizontal gene transfer plays a profound role in bacterial evolution by propelling the rapid transfer of genes and gene cassettes. Integrative and conjugative elements (ICEs) are one important mechanism driving horizontal gene transfer. ICEs, also known as conjugative transposons, reside on the host chromosome but can excise to form a conjugative DNA circle that is capable of transfer to other cells. Analysis of the large number of completed bacterial genome sequences has revealed many previously unrecognized ICEs, including ICEBs1, found in the Gram-positive model bacterium Bacillus subtilis. The discovery of ICEBs1 in an organism with such an impressive array of molecular tools for genetics and molecular biology was fortuitous. Significant insights into ICE biology have resulted since its discovery <15years ago. In this review, we describe aspects of ICEBs1 biology, such as excision, conjugative transfer, and reintegration, likely to be conserved across many ICEs. We will also highlight some of the more unexpected aspects of ICEBs1 biology, such as its ability to undergo plasmid-like replication after excision and its ability to mobilize plasmids lacking dedicated mobilization functions. A molecular understanding of ICEBs1 has led to additional insights into signals and mechanisms that promote horizontal gene transfer and shape bacterial evolution.
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Affiliation(s)
- Jennifer M Auchtung
- Alkek Center for Metagenomics and Microbiome Research, Department of Molecular Virology and Microbiology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA.
| | - Naira Aleksanyan
- Department of Chemistry and Biochemistry, Suffolk University, 8 Ashburton Place, Boston, MA 02108, USA.
| | - Artemisa Bulku
- Department of Chemistry and Biochemistry, Suffolk University, 8 Ashburton Place, Boston, MA 02108, USA.
| | - Melanie B Berkmen
- Department of Chemistry and Biochemistry, Suffolk University, 8 Ashburton Place, Boston, MA 02108, USA.
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16
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The Composition of the Cell Envelope Affects Conjugation in Bacillus subtilis. J Bacteriol 2016; 198:1241-9. [PMID: 26833415 DOI: 10.1128/jb.01044-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 01/27/2016] [Indexed: 01/13/2023] Open
Abstract
UNLABELLED Conjugation in bacteria is the contact-dependent transfer of DNA from one cell to another via donor-encoded conjugation machinery. It is a major type of horizontal gene transfer between bacteria. Conjugation of the integrative and conjugative element ICEBs1 into Bacillus subtilis is affected by the composition of phospholipids in the cell membranes of the donor and recipient. We found that reduction (or elimination) of lysyl-phosphatidylglycerol caused by loss of mpr F caused a decrease in conjugation efficiency. Conversely, alterations that caused an increase in lysyl-phosphatidylglycerol, including loss of ugtP or overproduction of mprF, caused an increase in conjugation efficiency. In addition, we found that mutations that alter production of other phospholipids, e.g., loss of clsA and yfnI, also affected conjugation, apparently without substantively altering levels of lysyl-phosphatidylglycerol, indicating that there are multiple pathways by which changes to the cell envelope affect conjugation. We found that the contribution of mprF to conjugation was affected by the chemical environment. Wild-type cells were generally more responsive to addition of anions that enhanced conjugation, whereas mprF mutant cells were more sensitive to combinations of anions that inhibited conjugation at pH 7. Our results indicate that mprF and lysyl-phosphatidylglycerol allow cells to maintain relatively consistent conjugation efficiencies under a variety of ionic conditions. IMPORTANCE Horizontal gene transfer is a driving force in microbial evolution, enabling cells that receive DNA to acquire new genes and phenotypes. Conjugation, the contact-dependent transfer of DNA from a donor to a recipient by a donor-encoded secretion machine, is a prevalent type of horizontal gene transfer. Although critically important, it is not well understood how the recipient influences the success of conjugation. We found that the composition of phospholipids in the membranes of donors and recipients influences the success of transfer of the integrative and conjugative element ICEBs1 in Bacillus subtilis Specifically, the presence of lysyl-phosphatidylglycerol enables relatively constant conjugation efficiencies in a range of diverse chemical environments.
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17
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Abstract
Integrative and Conjugative Elements (ICEs) are bacterial mobile genetic elements that play a key role in bacterial genomes dynamics and evolution. ICEs are widely distributed among virtually all bacterial genera. Recent extensive studies have unraveled their high diversity and complexity. The present review depicts the general conserved features of ICEs and describes more precisely three major families of ICEs that have been extensively studied in the past decade for their biology, their evolution and their impact on genomes dynamics. First, the large SXT/R391 family of ICEs disseminates antibiotic resistance genes and drives the exchange of mobilizable genomic islands (MGIs) between many enteric pathogens such as Vibrio cholerae. Second, ICEBs1 of Bacillus subtilis is the most well understood ICE of Gram-positive bacteria, notably regarding the regulation of its dissemination and its initially unforeseen extrachromosomal replication, which could be a common feature of ICEs of both Gram-positive and Gram-negative bacteria. Finally, ICESt1 and ICESt3 of Streptococcus thermophilus are the prototypes of a large family of ICEs widely distributed among various streptococci. These ICEs carry an original regulation module that associates regulators related to those of both SXT/R391 and ICEBs1. Study of ICESt1 and ICESt3 uncovered the cis-mobilization of related genomic islands (CIMEs) by a mechanism called accretion-mobilization, which likely represents a paradigm for the evolution of many ICEs and genomic islands. These three major families of ICEs give a glimpse about ICEs dynamics and their high impact on bacterial adaptation.
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18
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Fukushima T, Sekiguchi J. Zymographic Techniques for the Analysis of Bacterial Cell Wall in Bacillus. Methods Mol Biol 2016; 1440:87-98. [PMID: 27311666 DOI: 10.1007/978-1-4939-3676-2_7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Zymography of cell wall hydrolases is a simple technique to specifically detect cell wall or peptidoglycan hydrolytic activity. The zymographic method can be used for assessing the hydrolytic activities of purified target proteins, cell surface proteins, and proteins secreted to culture. Here, methods of cell wall and peptidoglycan purification, extraction of cell surface proteins containing cell wall hydrolases, and zymographic analysis are described. The purified or extracted proteins are separated by electrophoresis using an SDS gel containing cell wall or peptidoglycan material and then the proteins are renatured in the gel. The renatured cell wall hydrolases in the gel hydrolyze the material around the proteins. The cell wall or peptidoglycan in the gel is stained by methylene blue and the hydrolyzed material cannot be stained, resulting in the detection of cell wall hydrolytic activities of the enzymes on the gel.
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Affiliation(s)
- Tatsuya Fukushima
- Division of Gene Research, Department of Life Sciences, Research Center for Human and Environmental Sciences, Shinshu University, 3-15-1 Tokida, Ueda, Nagano, 386-8567, Japan.
| | - Junichi Sekiguchi
- Department of Applied Biology, Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda-shi, Nagano, 386-8567, Japan.
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19
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Insights into Substrate Specificity of NlpC/P60 Cell Wall Hydrolases Containing Bacterial SH3 Domains. mBio 2015; 6:e02327-14. [PMID: 26374125 PMCID: PMC4600125 DOI: 10.1128/mbio.02327-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bacterial SH3 (SH3b) domains are commonly fused with papain-like Nlp/P60 cell wall hydrolase domains. To understand how the modular architecture of SH3b and NlpC/P60 affects the activity of the catalytic domain, three putative NlpC/P60 cell wall hydrolases were biochemically and structurally characterized. These enzymes all have γ-d-Glu-A2pm (A2pm is diaminopimelic acid) cysteine amidase (or dl-endopeptidase) activities but with different substrate specificities. One enzyme is a cell wall lysin that cleaves peptidoglycan (PG), while the other two are cell wall recycling enzymes that only cleave stem peptides with an N-terminal l-Ala. Their crystal structures revealed a highly conserved structure consisting of two SH3b domains and a C-terminal NlpC/P60 catalytic domain, despite very low sequence identity. Interestingly, loops from the first SH3b domain dock into the ends of the active site groove of the catalytic domain, remodel the substrate binding site, and modulate substrate specificity. Two amino acid differences at the domain interface alter the substrate binding specificity in favor of stem peptides in recycling enzymes, whereas the SH3b domain may extend the peptidoglycan binding surface in the cell wall lysins. Remarkably, the cell wall lysin can be converted into a recycling enzyme with a single mutation. Peptidoglycan is a meshlike polymer that envelops the bacterial plasma membrane and bestows structural integrity. Cell wall lysins and recycling enzymes are part of a set of lytic enzymes that target covalent bonds connecting the amino acid and amino sugar building blocks of the PG network. These hydrolases are involved in processes such as cell growth and division, autolysis, invasion, and PG turnover and recycling. To avoid cleavage of unintended substrates, these enzymes have very selective substrate specificities. Our biochemical and structural analysis of three modular NlpC/P60 hydrolases, one lysin, and two recycling enzymes, show that they may have evolved from a common molecular architecture, where the substrate preference is modulated by local changes. These results also suggest that new pathways for recycling PG turnover products, such as tracheal cytotoxin, may have evolved in bacteria in the human gut microbiome that involve NlpC/P60 cell wall hydrolases.
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20
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Jacquier N, Frandi A, Viollier PH, Greub G. Disassembly of a Medial Transenvelope Structure by Antibiotics during Intracellular Division. ACTA ACUST UNITED AC 2015; 22:1217-27. [PMID: 26364930 DOI: 10.1016/j.chembiol.2015.08.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/28/2015] [Accepted: 08/01/2015] [Indexed: 10/23/2022]
Abstract
Chlamydiales possess a minimal but functional peptidoglycan precursor biosynthetic and remodeling pathway involved in the assembly of the division septum by an atypical cytokinetic machine and cryptic or modified peptidoglycan-like structure (PGLS). How this reduced cytokinetic machine collectively coordinates the invagination of the envelope has not yet been explored in Chlamydiales. In other Gram-negative bacteria, peptidoglycan provides anchor points that connect the outer membrane to the peptidoglycan during constriction using the Pal-Tol complex. Purifying PGLS and associated proteins from the chlamydial pathogen Waddlia chondrophila, we unearthed the Pal protein as a peptidoglycan-binding protein that localizes to the chlamydial division septum along with other components of the Pal-Tol complex. Together, our PGLS characterization and peptidoglycan-binding assays support the notion that diaminopimelic acid is an important determinant recruiting Pal to the division plane to coordinate the invagination of all envelope layers with the conserved Pal-Tol complex, even during osmotically protected intracellular growth.
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Affiliation(s)
- Nicolas Jacquier
- Department of Laboratories, Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne 1011, Switzerland
| | - Antonio Frandi
- Department of Microbiology & Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Geneva 1211, Switzerland
| | - Patrick H Viollier
- Department of Microbiology & Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), Faculty of Medicine/CMU, University of Geneva, Geneva 1211, Switzerland.
| | - Gilbert Greub
- Department of Laboratories, Institute of Microbiology, University Hospital Center and University of Lausanne, Lausanne 1011, Switzerland.
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21
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The bifunctional cell wall hydrolase CwlT is needed for conjugation of the integrative and conjugative element ICEBs1 in Bacillus subtilis and B. anthracis. J Bacteriol 2014; 196:1588-96. [PMID: 24532767 DOI: 10.1128/jb.00012-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mobile genetic element ICEBs1 is an integrative and conjugative element (ICE) found in Bacillus subtilis. One of the ICEBs1 genes, cwlT, encodes a cell wall hydrolase with two catalytic domains, a muramidase and a peptidase. We found that cwlT is required for ICEBs1 conjugation. We examined the role of each of the two catalytic domains and found that the muramidase is essential, whereas the peptidase is partially dispensable for transfer of ICEBs1. We also found that the putative signal peptide in CwlT is required for CwlT to function in conjugation, consistent with the notion that CwlT is normally secreted from the cytoplasm. We found that alteration of the putative lipid attachment site on CwlT had no effect on its role in conjugation, indicating that if CwlT is a lipoprotein, the lipid attachment is not required for conjugation. Finally, we found conditions supporting efficient transfer of ICEBs1 into and out of Bacillus anthracis and that cwlT was needed for ICEBs1 to function in B. anthracis. The mature cell wall of B. anthracis is resistant to digestion by CwlT, indicating that CwlT might act during cell wall synthesis, before modifications of the peptidoglycan are complete.
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22
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PrgK, a multidomain peptidoglycan hydrolase, is essential for conjugative transfer of the pheromone-responsive plasmid pCF10. J Bacteriol 2013; 196:527-39. [PMID: 24244005 DOI: 10.1128/jb.00950-13] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peptidoglycan (PG) hydrolases associated with bacterial type IV secretion systems (T4SSs) are thought to generate localized lesions in the PG layer to facilitate assembly of the translocation channel. The pheromone-responsive plasmid pCF10 of Enterococcus faecalis encodes a putative cell wall hydrolase, PrgK, and here we report that a prgK deletion abolished functionality of the pCF10-encoded T4SS as monitored by pCF10 conjugative transfer. Expression in trans of wild-type prgK fully complemented this mutation. PrgK has three potential hydrolase motifs resembling staphylococcal LytM, soluble lytic transglycosylase (SLT), and cysteine-, histidine-dependent amidohydrolase/peptidase (CHAP) domains. Complementation analyses with mutant alleles established that PrgK bearing two hydrolase domains in any combination supported near-wild-type plasmid transfer, and PrgK bearing a single hydrolase domain supported at least a low level of transfer in filter matings. When exported to the Escherichia coli periplasm, each domain disrupted cell growth, and combinations of domains additionally induced cell rounding and blebbing and conferred enhanced sensitivity to osmotic shock. Each domain bound PG in vitro, but only the SLT domain exhibited detectable hydrolase activity, as shown by zymographic analyses and release of fluorescent PG fragments. Genes encoding three T4SS-associated, putative hydrolases, Lactococcus lactis CsiA, Tn925 Orf14, and pIP501 TraG, partially complemented the ΔprgK mutation. Our findings establish that PrgK is an essential component of the pCF10-encoded Prg/Pcf T4SS and that its hydrolase domains coordinate their activities for full PrgK function. PrgK is indispensable for plasmid transfer in liquid matings, suggestive of a role in formation or stabilization of mating junctions.
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23
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Ruggiero A, De Simone P, Smaldone G, Squeglia F, Berisio R. Bacterial cell division regulation by Ser/Thr kinases: a structural perspective. Curr Protein Pept Sci 2013; 13:756-66. [PMID: 23305362 PMCID: PMC3601408 DOI: 10.2174/138920312804871201] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/16/2012] [Accepted: 08/03/2012] [Indexed: 12/17/2022]
Abstract
Recent genetic, biochemical and structural studies have established that eukaryotic-like Ser/Thr protein-kinases are critical mediators of developmental changes and host pathogen interactions in bacteria. Although with lower abundance compared to their homologues from eukaryotes, Ser/Thr protein-kinases are widespread in gram-positive bacteria. These data underline a key role of reversible Ser/Thr phosphorylation in bacterial physiology and virulence. Numerous studies have revealed how phosphorylation/dephosphorylation of Ser/Thr protein-kinases governs cell division and cell wall biosynthesis and that Ser/Thr protein kinases are responsible for distinct phenotypes, dependent on different environmental signals. In this review we discuss the current understandings of Ser/Thr protein-kinases functional processes based on structural data.
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Affiliation(s)
- Alessia Ruggiero
- Institute of Biostructure and Bioimaging, CNR, Via Mezzocannone, 16. I-80134, Napoli, Italy.
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24
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Xu Q, Chiu HJ, Farr CL, Jaroszewski L, Knuth MW, Miller MD, Lesley SA, Godzik A, Elsliger MA, Deacon AM, Wilson IA. Structures of a bifunctional cell wall hydrolase CwlT containing a novel bacterial lysozyme and an NlpC/P60 DL-endopeptidase. J Mol Biol 2013; 426:169-84. [PMID: 24051416 DOI: 10.1016/j.jmb.2013.09.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 09/07/2013] [Accepted: 09/11/2013] [Indexed: 11/17/2022]
Abstract
Tn916-like conjugative transposons carrying antibiotic resistance genes are found in a diverse range of bacteria. Orf14 within the conjugation module encodes a bifunctional cell wall hydrolase CwlT that consists of an N-terminal bacterial lysozyme domain (N-acetylmuramidase, bLysG) and a C-terminal NlpC/P60 domain (γ-d-glutamyl-l-diamino acid endopeptidase) and is expected to play an important role in the spread of the transposons. We determined the crystal structures of CwlT from two pathogens, Staphylococcus aureus Mu50 (SaCwlT) and Clostridium difficile 630 (CdCwlT). These structures reveal that NlpC/P60 and LysG domains are compact and conserved modules, connected by a short flexible linker. The LysG domain represents a novel family of widely distributed bacterial lysozymes. The overall structure and the active site of bLysG bear significant similarity to other members of the glycoside hydrolase family 23 (GH23), such as the g-type lysozyme (LysG) and Escherichia coli lytic transglycosylase MltE. The active site of bLysG contains a unique structural and sequence signature (DxxQSSES+S) that is important for coordinating a catalytic water. Molecular modeling suggests that the bLysG domain may recognize glycan in a similar manner to MltE. The C-terminal NlpC/P60 domain contains a conserved active site (Cys-His-His-Tyr) that appears to be specific to murein tetrapeptide. Access to the active site is likely regulated by isomerism of a side chain atop the catalytic cysteine, allowing substrate entry or product release (open state), or catalysis (closed state).
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Affiliation(s)
- Qingping Xu
- Joint Center for Structural Genomics (http://www.jcsg.org); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Hsiu-Ju Chiu
- Joint Center for Structural Genomics (http://www.jcsg.org); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Carol L Farr
- Joint Center for Structural Genomics (http://www.jcsg.org); Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Lukasz Jaroszewski
- Joint Center for Structural Genomics (http://www.jcsg.org); Center for Research in Biological Systems, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Mark W Knuth
- Joint Center for Structural Genomics (http://www.jcsg.org); Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA
| | - Mitchell D Miller
- Joint Center for Structural Genomics (http://www.jcsg.org); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Scott A Lesley
- Joint Center for Structural Genomics (http://www.jcsg.org); Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Protein Sciences Department, Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121, USA
| | - Adam Godzik
- Joint Center for Structural Genomics (http://www.jcsg.org); Center for Research in Biological Systems, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Program on Bioinformatics and Systems Biology, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Marc-André Elsliger
- Joint Center for Structural Genomics (http://www.jcsg.org); Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ashley M Deacon
- Joint Center for Structural Genomics (http://www.jcsg.org); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Ian A Wilson
- Joint Center for Structural Genomics (http://www.jcsg.org); Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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25
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Bhatty M, Laverde Gomez JA, Christie PJ. The expanding bacterial type IV secretion lexicon. Res Microbiol 2013; 164:620-39. [PMID: 23542405 DOI: 10.1016/j.resmic.2013.03.012] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/01/2012] [Accepted: 02/05/2013] [Indexed: 02/06/2023]
Abstract
The bacterial type IV secretion systems (T4SSs) comprise a biologically diverse group of translocation systems functioning to deliver DNA or protein substrates from donor to target cells generally by a mechanism dependent on establishment of direct cell-to-cell contact. Members of one T4SS subfamily, the conjugation systems, mediate the widespread and rapid dissemination of antibiotic resistance and virulence traits among bacterial pathogens. Members of a second subfamily, the effector translocators, are used by often medically-important pathogens to deliver effector proteins to eukaryotic target cells during the course of infection. Here we summarize our current understanding of the structural and functional diversity of T4SSs and of the evolutionary processes shaping this diversity. We compare mechanistic and architectural features of T4SSs from Gram-negative and -positive species. Finally, we introduce the concept of the 'minimized' T4SSs; these are systems composed of a conserved set of 5-6 subunits that are distributed among many Gram-positive and some Gram-negative species.
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Affiliation(s)
- Minny Bhatty
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, 6431 Fannin, Houston, TX 77030, USA
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26
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Abstract
Peptidoglycan (PG) is the major structural component of the bacterial cell wall. Bacteria have autolytic PG hydrolases that allow the cell to grow and divide. A well-studied group of PG hydrolase enzymes are the bacteriophage endolysins. Endolysins are PG-degrading proteins that allow the phage to escape from the bacterial cell during the phage lytic cycle. The endolysins, when purified and exposed to PG externally, can cause "lysis from without." Numerous publications have described how this phenomenon can be used therapeutically as an effective antimicrobial against certain pathogens. Endolysins have a characteristic modular structure, often with multiple lytic and/or cell wall-binding domains (CBDs). They degrade the PG with glycosidase, amidase, endopeptidase, or lytic transglycosylase activities and have been shown to be synergistic with fellow PG hydrolases or a range of other antimicrobials. Due to the coevolution of phage and host, it is thought they are much less likely to invoke resistance. Endolysin engineering has opened a range of new applications for these proteins from food safety to environmental decontamination to more effective antimicrobials that are believed refractory to resistance development. To put phage endolysin work in a broader context, this chapter includes relevant studies of other well-characterized PG hydrolase antimicrobials.
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27
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Kobayashi K, Sudiarta IP, Kodama T, Fukushima T, Ara K, Ozaki K, Sekiguchi J. Identification and characterization of a novel polysaccharide deacetylase C (PdaC) from Bacillus subtilis. J Biol Chem 2012; 287:9765-9776. [PMID: 22277649 DOI: 10.1074/jbc.m111.329490] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cell wall metabolism and cell wall modification are very important processes that bacteria use to adjust to various environmental conditions. One of the main modifications is deacetylation of peptidoglycan. The polysaccharide deacetylase homologue, Bacillus subtilis YjeA (renamed PdaC), was characterized and found to be a unique deacetylase. The pdaC deletion mutant was sensitive to lysozyme treatment, indicating that PdaC acts as a deacetylase. The purified recombinant and truncated PdaC from Escherichia coli deacetylated B. subtilis peptidoglycan and its polymer, (-GlcNAc-MurNAc[-L-Ala-D-Glu]-)(n). Surprisingly, RP-HPLC and ESI-MS/MS analyses showed that the enzyme deacetylates N-acetylmuramic acid (MurNAc) not GlcNAc from the polymer. Contrary to Streptococcus pneumoniae PgdA, which shows high amino acid sequence similarity with PdaC and is a zinc-dependent GlcNAc deacetylase toward peptidoglycan, there was less dependence on zinc ion for deacetylation of peptidoglycan by PdaC than other metal ions (Mn(2+), Mg(2+), Ca(2+)). The kinetic values of the activity toward B. subtilis peptidoglycan were K(m) = 4.8 mM and k(cat) = 0.32 s(-1). PdaC also deacetylated N-acetylglucosamine (GlcNAc) oligomers with a K(m) = 12.3 mM and k(cat) = 0.24 s(-1) toward GlcNAc(4). Therefore, PdaC has GlcNAc deacetylase activity toward GlcNAc oligomers and MurNAc deacetylase activity toward B. subtilis peptidoglycan.
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Affiliation(s)
- Kaori Kobayashi
- Interdisciplinary Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - I Putu Sudiarta
- Interdisciplinary Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan
| | - Takeko Kodama
- Biological Science Laboratories, Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi 321-3497, Japan
| | - Tatsuya Fukushima
- Division of Gene Research, Department of Life Sciences, Research Center for Human and Environmental Sciences, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan and
| | - Katsutoshi Ara
- Biological Science Laboratories, Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi 321-3497, Japan
| | - Katsuya Ozaki
- Biological Science Laboratories, Kao Corporation, 2606 Akabane, Ichikai, Haga, Tochigi 321-3497, Japan
| | - Junichi Sekiguchi
- Interdisciplinary Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
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28
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Synthetic lethality of the lytE cwlO genotype in Bacillus subtilis is caused by lack of D,L-endopeptidase activity at the lateral cell wall. J Bacteriol 2011; 194:796-803. [PMID: 22139507 DOI: 10.1128/jb.05569-11] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial peptidoglycan acts as an exoskeleton to protect the bacterial cell. Although peptidoglycan biosynthesis by penicillin-binding proteins is well studied, few studies have described peptidoglycan disassembly, which is necessary for a dynamic structure that allows cell growth. In Bacillus subtilis, more than 35 genes encoding cell wall lytic enzymes have been identified; however, only two D,L-endopeptidases (lytE and cwlO) are involved in cell proliferation. In this study, we demonstrated that the D,L-endopeptidase activity at the lateral cell wall is essential for cell proliferation. Inactivation of LytE and CwlO by point mutation of the catalytic residues caused cell growth defects. However, the forced expression of LytF or CwlS, which are paralogs of LytE, did not suppress lytE cwlO synthetic lethality. Subcellular localization studies of these D,L-endopeptidases showed LytF and CwlS at the septa and poles, CwlO at the cylindrical part of the cell, and LytE at the septa and poles as well as the cylindrical part. Furthermore, construction of N-terminal and C-terminal domain-swapped enzymes of LytE, LytF, CwlS, and CwlO revealed that localization was dependent on the N-terminal domains. Only the chimeric proteins that were enzymatically active and localized to the sidewall were able to suppress the synthetic lethality, suggesting that the lack of D,L-endopeptidase activity at the cylindrical part of the cell leads to a growth defect. The functions of LytE and CwlO in cell morphogenesis were discussed.
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29
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Sudiarta IP, Fukushima T, Sekiguchi J. Bacillus subtilis CwlP of the SP-{beta} prophage has two novel peptidoglycan hydrolase domains, muramidase and cross-linkage digesting DD-endopeptidase. J Biol Chem 2010; 285:41232-43. [PMID: 20980266 DOI: 10.1074/jbc.m110.156273] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
For bacteria and bacteriophages, cell wall digestion by hydrolases is a very important event. We investigated one of the proteins involved in cell wall digestion, the yomI gene product (renamed CwlP). The gene is located in the SP-β prophage region of the Bacillus subtilis chromosome. Inspection of the Pfam database indicates that CwlP contains soluble lytic transglycosylase (SLT) and peptidase M23 domains, which are similar to Escherichia coli lytic transglycosylase Slt70, and the Staphylococcus aureus Gly-Gly endopeptidase LytM, respectively. The SLT domain of CwlP exhibits hydrolytic activity toward the B. subtilis cell wall; however, reverse phase (RP)-HPLC and mass spectrometry revealed that the CwlP-SLT domain has only muramidase activity. In addition, the peptidase M23 domain of CwlP exhibited hydrolytic activity and could cleave d-Ala-diaminopimelic acid cross-linkage, a property associated with dd-endopeptidases. Remarkably, the M23 domain of CwlP possessed a unique Zn(2+)-independent endopeptidase activity; this contrasts with all other characterized M23 peptidases (and enzymes similar to CwlP), which are Zn(2+) dependent. Both domains of CwlP could hydrolyze the peptidoglycan and cell wall of B. subtilis. However, the M23 domain digested neither the peptidoglycans nor the cell walls of S. aureus or Streptococcus thermophilus. The effect of defined point mutations in conserved amino acid residues of CwlP is also determined.
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Affiliation(s)
- I Putu Sudiarta
- Interdisciplinary Graduate School of Science and Technology, Department of Life Sciences, Research Center for Human and Environmental Sciences, Shinshu University, Nagano 386-8567, Japan
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Ruggiero A, Marasco D, Squeglia F, Soldini S, Pedone E, Pedone C, Berisio R. Structure and Functional Regulation of RipA, a Mycobacterial Enzyme Essential for Daughter Cell Separation. Structure 2010; 18:1184-90. [DOI: 10.1016/j.str.2010.06.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/09/2010] [Accepted: 06/17/2010] [Indexed: 10/19/2022]
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Bacillus subtilis CwlQ (previous YjbJ) is a bifunctional enzyme exhibiting muramidase and soluble-lytic transglycosylase activities. Biochem Biophys Res Commun 2010; 398:606-12. [PMID: 20609359 DOI: 10.1016/j.bbrc.2010.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Accepted: 07/01/2010] [Indexed: 11/22/2022]
Abstract
CwlQ (previous YjbJ) is one of the putative cell wall hydrolases in Bacillus subtilis. Its domain has an amino acid sequence similar to the soluble-lytic transglycosylase (SLT) of Escherichia coli Slt70 and also goose lysozyme (muramidase). To characterize the enzyme, the domain of CwlQ was cloned and expressed in E. coli. The purified CwlQ protein exhibited cell wall hydrolytic activity. Surprisingly, RP-HPLC, mass spectrometry (MS), and MS/MS analyses showed that CwlQ produces two products, 1,6-anhydro-N-acetylmuramic acid and N-acetylmuramic acid, thus indicating that CwlQ is a bifunctional enzyme. The site-directed mutagenesis revealed that glutamic acid 85 (Glu-85) is an amino acid residue essential to both activities.
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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: 60] [Impact Index Per Article: 4.3] [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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Conjugative transfer of the integrative and conjugative element ICEBs1 from Bacillus subtilis likely initiates at the donor cell pole. J Bacteriol 2010; 192:23-5. [PMID: 19854907 DOI: 10.1128/jb.01305-09] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Sharma RD, Lynn AM, Sharma PK, Rajnee, Jawaid S. High temperature unfolding of Bacillus anthracis amidase-03 by molecular dynamics simulations. Bioinformation 2009; 3:430-4. [PMID: 19759865 PMCID: PMC2737499 DOI: 10.6026/97320630003430] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2009] [Revised: 04/08/2009] [Accepted: 05/25/2009] [Indexed: 11/23/2022] Open
Abstract
The stability of amidase-03 structure (a cell wall hydrolase protein) from Bacillus anthracis was studied using classical molecular dynamics (MD) simulation. This protein (GenBank accession number: NP_844822) contains an amidase-03 domain which is known to exhibit the catalytic activity of N-acetylmuramoyl-L-alanine amidase (digesting MurNAc-Lalanine linkage of bacterial cell wall). The amidase-03 enzyme has stability at high temperature due to the core formed by the combination of several secondary structure elements made of beta-sheets. We used root-mean-square-displacement (RMSD) of the simulated structure from its initial state to demonstrate the unfolding of the enzyme using its secondary structural elements. Results show that amidase-03 unfolds in transition state ensemble (TSE). The data suggests that alpha-helices unfold before beta-sheets from the core during simulation.
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