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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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Pannullo AG, Zbylicki BR, Ellermeier CD. Identification of DraRS in Clostridioides difficile, a Two-Component Regulatory System That Responds to Lipid II-Interacting Antibiotics. J Bacteriol 2023; 205:e0016423. [PMID: 37439672 PMCID: PMC10601625 DOI: 10.1128/jb.00164-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 06/27/2023] [Indexed: 07/14/2023] Open
Abstract
Clostridioides difficile is a Gram-positive opportunistic pathogen that results in 220,000 infections, 12,000 deaths, and upwards of $1 billion in medical costs in the United States each year. C. difficile is highly resistant to a variety of antibiotics, but we have a poor understanding of how C. difficile senses and responds to antibiotic stress and how such sensory systems affect clinical outcomes. We have identified a spontaneous C. difficile mutant that displays increased daptomycin resistance. We performed whole-genome sequencing and found a nonsense mutation, S605*, in draS, which encodes a putative sensor histidine kinase of a two-component system (TCS). The draSS605* mutant has an ~4- to 8-fold increase in the daptomycin MIC compared to the wild type (WT). We found that the expression of constitutively active DraRD54E in the WT increases daptomycin resistance 8- to 16-fold and increases bacitracin resistance ~4-fold. We found that a selection of lipid II-inhibiting compounds leads to the increased activity of the luciferase-based reporter PdraR-slucopt, including vancomycin, bacitracin, ramoplanin, and daptomycin. Using RNA sequencing (RNA-seq), we identified the DraRS regulon. Interestingly, we found that DraRS can induce the expression of the previously identified hex locus required for the synthesis of a novel glycolipid produced in C. difficile. Our data suggest that the induction of the hex locus by DraR explains some, but not all, of the DraR-induced daptomycin and bacitracin resistance. IMPORTANCE Clostridioides difficile is a major cause of hospital-acquired diarrhea and represents an urgent concern due to the prevalence of antibiotic resistance and the rate of recurrent infections. C. difficile encodes ~50 annotated two-component systems (TCSs); however, only a few have been studied. The function of these unstudied TCSs is not known. Here, we show that the TCS DraRS plays a role in responding to a subset of lipid II-inhibiting antibiotics and mediates resistance to daptomycin and bacitracin in part by inducing the expression of the recently identified hex locus, which encodes enzymes required for the production of a novel glycolipid in C. difficile.
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Affiliation(s)
- Anthony G. Pannullo
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Brianne R. Zbylicki
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Craig D. Ellermeier
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
- Graduate Program in Genetics, University of Iowa, Iowa City, Iowa, USA
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3
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Strach M, Koch F, Fiedler S, Liebeton K, Graumann PL. Protein secretion zones during overexpression of amylase within the Gram-positive cell wall. BMC Biol 2023; 21:206. [PMID: 37794427 PMCID: PMC10552229 DOI: 10.1186/s12915-023-01684-1] [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: 12/14/2022] [Accepted: 08/16/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND Whereas the translocation of proteins across the cell membrane has been thoroughly investigated, it is still unclear how proteins cross the cell wall in Gram-positive bacteria, which are widely used for industrial applications. We have studied the secretion of α-amylase AmyE within two different Bacillus strains, B. subtilis and B. licheniformis. RESULTS We show that a C-terminal fusion of AmyE with the fluorescent reporter mCherry is secreted via discrete patches showing very low dynamics. These are visible at many places within the cell wall for many minutes. Expression from a high copy number plasmid was required to be able to see these structures we term "secretion zones". Zones corresponded to visualized AmyE activity on the surface of cells, showing that they release active enzymes. They overlapped with SecA signals but did not frequently co-localize with the secretion ATPase. Single particle tracking showed higher dynamics of SecA and of SecDF, involved in AmyE secretion, at the cell membrane than AmyE. These experiments suggest that SecA initially translocates AmyE molecules through the cell membrane, and then diffuses to a different translocon. Single molecule tracking of SecA suggests the existence of three distinct diffusive states of SecA, which change during AmyE overexpression, but increased AmyE secretion does not appear to overwhelm the system. CONCLUSIONS Because secretion zones were only found during the transition to and within the stationary phase, diffusion rather than passive transport based on cell wall growth from inside to outside may release AmyE and, thus, probably secreted proteins in general. Our findings suggest active transport through the cell membrane and slow, passive transition through the cell wall, at least for overexpressed proteins, in bacteria of the genus Bacillus.
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Affiliation(s)
- Manuel Strach
- Centre for Synthetic Microbiology (SYNMIKRO) and Fachbereich Chemie, Philipps-Universität Marburg, Marburg, 35032, Germany
| | - Felicitas Koch
- Centre for Synthetic Microbiology (SYNMIKRO) and Fachbereich Chemie, Philipps-Universität Marburg, Marburg, 35032, Germany
| | - Svenja Fiedler
- Centre for Synthetic Microbiology (SYNMIKRO) and Fachbereich Chemie, Philipps-Universität Marburg, Marburg, 35032, Germany
| | - Klaus Liebeton
- BRAIN Biotech AG, Darmstädter Str. 34-36, Zwingenberg, 64673, Germany
| | - Peter L Graumann
- Centre for Synthetic Microbiology (SYNMIKRO) and Fachbereich Chemie, Philipps-Universität Marburg, Marburg, 35032, Germany.
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Kormanová Ľ, Levarski Z, Minich A, Varga V, Levarská L, Struhárňanská E, Turňa J, Stuchlík S. Novel expression system based on enhanced permeability of Vibrio natriegens cells induced by D,D- carboxypeptidase overexpression. World J Microbiol Biotechnol 2023; 39:277. [PMID: 37568013 PMCID: PMC10421817 DOI: 10.1007/s11274-023-03723-z] [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: 02/02/2023] [Accepted: 08/06/2023] [Indexed: 08/13/2023]
Abstract
Vibrio natriegens is a fast-growing, non-pathogenic marine bacterium with promising features for biotechnological applications such as high-level recombinant protein production or fast DNA propagation. A remarkable short generation time (< 10 min), robust proteosynthetic activity and versatile metabolism with abilities to utilise wide range of substrates contribute to its establishment as a future industrial platform for fermentation processes operating with high productivity.D,D-carboxypeptidases are membrane-associated enzymes involved in peptidoglycan biosynthesis and cell wall formation. This study investigates the impact of overexpressed D,D-carboxypeptidases on membrane integrity and the increased leakage of intracellular proteins into the growth medium in V. natriegens. Our findings confirm that co-expression of these enzymes can enhance membrane permeability, thereby facilitating the transport of target proteins into the extracellular environment, without the need for secretion signals, tags, or additional permeabilization methods. Using only a single step IMAC chromatography, we were able to purify AfKatG, MDBP or Taq polymerase in total yields of 117.9 ± 56.0 mg/L, 36.5 ± 12.9 mg/L and 26.5 ± 6.0 mg/L directly from growth medium, respectively. These results demonstrate the feasibility of our V. natriegens based system as a broadly applicable extracellular tag-less recombinant protein producer.
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Affiliation(s)
- Ľubica Kormanová
- Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Bratislava, 811 04 Slovak Republic
| | - Zdenko Levarski
- Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Bratislava, 811 04 Slovak Republic
- Science Park, Comenius University in Bratislava, Ilkovičova 8, Bratislava, 811 04 Slovak Republic
| | - Andrej Minich
- Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Bratislava, 811 04 Slovak Republic
| | - Viktor Varga
- Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Bratislava, 811 04 Slovak Republic
| | - Lenka Levarská
- Science Park, Comenius University in Bratislava, Ilkovičova 8, Bratislava, 811 04 Slovak Republic
| | - Eva Struhárňanská
- Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Bratislava, 811 04 Slovak Republic
| | - Ján Turňa
- Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Bratislava, 811 04 Slovak Republic
| | - Stanislav Stuchlík
- Faculty of Natural Sciences, Comenius University in Bratislava, Ilkovičova 6, Bratislava, 811 04 Slovak Republic
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5
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Brčić J, Tong A, Wender PA, Cegelski L. Conjugation of Vancomycin with a Single Arginine Improves Efficacy against Mycobacteria by More Effective Peptidoglycan Targeting. J Med Chem 2023; 66:10226-10237. [PMID: 37477249 PMCID: PMC10783851 DOI: 10.1021/acs.jmedchem.3c00565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Drug resistant bacterial infections have emerged as one of the greatest threats to public health. The discovery and development of new antimicrobials and anti-infective strategies are urgently needed to address this challenge. Vancomycin is one of the most important antibiotics for the treatment of Gram-positive infections. Here, we introduce the vancomycin-arginine conjugate (V-R) as a highly effective antimicrobial against actively growing mycobacteria and difficult-to-treat mycobacterial biofilm populations. Further improvement in efficacy through combination treatment of V-R to inhibit peptidoglycan synthesis and ethambutol to inhibit arabinogalactan synthesis underscores the ability to identify compound synergies to more effectively target the Achilles heel of the cell-wall assembly. Moreover, we introduce mechanistic activity data and a molecular model derived from a d-Ala-d-Ala-bound vancomycin structure that we hypothesize underlies the molecular basis for the antibacterial improvement attributed to the arginine modification that is specific to peptidoglycan chemistry employed by mycobacteria and distinct from Gram-positive pathogens.
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Affiliation(s)
- Jasna Brčić
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Alan Tong
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Paul A. Wender
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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Pérez-Lorente AI, Molina-Santiago C, de Vicente A, Romero D. Sporulation Activated via σ W Protects Bacillus from a Tse1 Peptidoglycan Hydrolase Type VI Secretion System Effector. Microbiol Spectr 2023; 11:e0504522. [PMID: 36916921 PMCID: PMC10100999 DOI: 10.1128/spectrum.05045-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/21/2023] [Indexed: 03/16/2023] Open
Abstract
Within bacterial communities, community members engage in interactions employing diverse offensive and defensive tools to reach coexistence. Extracellular-matrix production and sporulation are defensive mechanisms used by Bacillus subtilis cells when they interact with Pseudomonas chlororaphis strains expressing a type VI secretion system (T6SS). Here, we define Tse1 as the main toxin mobilized by the Pseudomonas chlororaphis T6SS that triggers sporulation in Bacillus subtilis. We characterize Tse1 as a peptidoglycan hydrolase that indirectly alters the dynamics and functionality of the Bacillus cell membrane. We also delineate the response of Bacillus cells to Tse1, which through the coordinated actions of the extracellular sigma factor σW and the cytoplasmic histidine kinases KinA and KinB, culminates in activation of the sporulation cascade. We propose that this cellular developmental response permits bacilli to defend against the toxicity of T6SS-mobilized Tse1 effector. IMPORTANCE The study of bacterial interactions is helping to define species-specific strategies used to modulate the competition dynamics underlying the development of community compositions. In this study, we deciphered the role of Pseudomonas T6SS when competing with Bacillus and the mechanism by which a T6SS-toxin modifies Bacillus physiology. We found that Pseudomonas triggers Bacillus sporulation by injecting through T6SS a toxin that we called Tse1. We found that Tse1 is a hydrolase that degrades Bacillus peptidoglycan and indirectly damages Bacillus membrane functionality. In addition, we demonstrated the mechanism by which Bacillus cells increase the sporulation rate upon recognition of the presence of Tse1. Interestingly, asporogenic Bacillus cells are more sensitive to T6SS activity, which led us to propose sporulation as a last resort of bacilli to overcome this family of toxins.
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Affiliation(s)
- Alicia I. Pérez-Lorente
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
| | - Carlos Molina-Santiago
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
| | - Antonio de Vicente
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
| | - Diego Romero
- Instituto de Hortofruticultura Subtropical y Mediterránea La Mayora, Universidad de Málaga-Consejo Superior de Investigaciones Científicas, Departamento de Microbiología, Universidad de Málaga, Málaga, Spain
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7
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Transcriptional responses of human intestinal epithelial HT-29 cells to spore-displayed p40 derived from Lacticaseibacillus rhamnosus GG. BMC Microbiol 2022; 22:316. [PMID: 36550414 PMCID: PMC9772600 DOI: 10.1186/s12866-022-02735-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUNDS The aims of this study were to construct spore-displayed p40, a Lacticaseibacillus rhamnosus GG-derived soluble protein, using spore surface display technology and to evaluate transcriptional responses in human intestinal epithelial cells. RESULTS p40 was displayed on the surface of Bacillus subtilis spores using spore coat protein CotG as an anchor protein. Effects of spore-displayed p40 (CotG-p40) on gene expression of intestinal epithelial cell line HT-29 were evaluated by transcriptome analysis using RNA-sequencing. As a result of differentially expressed gene (DEG) analysis, 81 genes were up-regulated and 82 genes were down-regulated in CotG-p40 stimulated cells than in unstimulated cells. Gene ontology enrichment analysis showed that CotG-p40 affected biological processes such as developmental process, metabolic process, cell surface receptor linked signaling pathway, and retinoic acid metabolic process. Gene-gene network analysis suggested that 10 DEGs (EREG, FOXF1, GLI2, PTGS2, SPP1, MMP19, TNFRSF1B, PTGER4, CLDN18, and ALDH1A3) activated by CotG-p40 were associated with probiotic action. CONCLUSIONS This study demonstrates the regulatory effects of CotG-p40 on proliferation and homeostasis of HT-29 cells. This study provided comprehensive insights into the transcriptional response of human intestinal epithelial cells stimulated by CotG-p40.
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8
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Structure and Activity Relationships of the Two-Component Lantibiotic Bicereucin. ACS Infect Dis 2022; 8:2529-2539. [PMID: 36354217 DOI: 10.1021/acsinfecdis.2c00371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Identified from the pathogen Bacillus cereus SJ1, the two-component lantibiotic bicereucin is featured by the presence of a series of nonproteogenic amino acids and exhibits potent synergistic activity against a broad spectrum of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci, as well as hemolytic activity against mammalian cells. In this study, we performed site-directed mutagenesis on the nonproteogenic amino acids as well as truncation of dehydrobutyrine-rich N-terminal residues and evaluated the effects on both biological activities. We identified that D-Ala21 and D-Ala26 of Bsjα and D-Ala23 and D-Ala28 of Bsjβ play an essential role in the antimicrobial activity, while the N-termini of both peptides are important for both activities. We also determined that the integrity of both subunits is essential for hemolytic activity. Finally, we obtained two variants BsjαtS17A+Bsjβ and BsjαS30A+BsjβT19A, which retained the antimicrobial activity and exhibited greatly decreased hemolytic toxicity. Overall, our results provide a comprehensive understanding of the structure-activity relationships of bicereucin and insights into the mechanism of action thereof, facilitating the further exploration of the molecular basis of the binding receptor of bicereucin and genome mining of potential novel two-component lantibiotics.
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Zhang J, Zhu B, Xu X, Liu Y, Li Q, Li Y, Lu F. Remodeling Bacillus amyloliquefaciens Cell Wall Rigidity to Reduce Cell Lysis and Increase the Yield of Heterologous Proteins. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:10552-10562. [PMID: 35984403 DOI: 10.1021/acs.jafc.2c04454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Bacillus amyloliquefaciens has great potential as a host for heterologous protein production, but its severe autolytic behavior has precluded its industrial application to date. Because d,l-endopeptidase activity-guided cell wall rigidity is considered essential for autolysis resistance, we investigated the effects of d,l-endopeptidase genes lytE, lytF, cwlO, and cwlS play on the growth, lysis, and morphology remodeling of B. amyloliquefaciens strain TCCC11018. Individual and combinatorial deletion of lytE, lytF, and cwlS enhanced the cell growth and delayed cell lysis. For the best mutant with the lytF and cwlS double deletion, the viable cell number at 24 h increased by 11.90% and the cell wall thickness at 6 h increased by 25.87%. Transcriptomic and proteomic analyses indicated that the improvement was caused by enhanced peptidoglycan synthesis. With the lytF and cwlS double deletion, the extracellular green fluorescent protein and phospholipase D expression levels increased by 113 and 55.89%, respectively. This work broadens our understanding of the relationship between d,l-endopeptidases and B. amyloliquefaciens cell characteristics, which provides an effective strategy to improve the heterologous protein expression in B. amyloliquefaciens-based cell factories.
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Affiliation(s)
- Jinfang Zhang
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China
| | - Baoyue Zhu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China
| | - Xiaojian Xu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China
| | - Yihan Liu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China
| | - Qinggang Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China
| | - Yu Li
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China
| | - Fuping Lu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, P. R. China
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Riu F, Ruda A, Ibba R, Sestito S, Lupinu I, Piras S, Widmalm G, Carta A. Antibiotics and Carbohydrate-Containing Drugs Targeting Bacterial Cell Envelopes: An Overview. Pharmaceuticals (Basel) 2022; 15:942. [PMID: 36015090 PMCID: PMC9414505 DOI: 10.3390/ph15080942] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 02/07/2023] Open
Abstract
Certain bacteria constitute a threat to humans due to their ability to escape host defenses as they easily develop drug resistance. Bacteria are classified into gram-positive and gram-negative according to the composition of the cell membrane structure. Gram-negative bacteria have an additional outer membrane (OM) that is not present in their gram-positive counterpart; the latter instead hold a thicker peptidoglycan (PG) layer. This review covers the main structural and functional properties of cell wall polysaccharides (CWPs) and PG. Drugs targeting CWPs are discussed, both noncarbohydrate-related (β-lactams, fosfomycin, and lipopeptides) and carbohydrate-related (glycopeptides and lipoglycopeptides). Bacterial resistance to these drugs continues to evolve, which calls for novel antibacterial approaches to be developed. The use of carbohydrate-based vaccines as a valid strategy to prevent bacterial infections is also addressed.
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Affiliation(s)
- Federico Riu
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Alessandro Ruda
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden; (A.R.); (G.W.)
| | - Roberta Ibba
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Simona Sestito
- Department of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari, Via Vienna 2, 07100 Sassari, Italy;
| | - Ilenia Lupinu
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Sandra Piras
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden; (A.R.); (G.W.)
| | - Antonio Carta
- Department of Medicine, Surgery and Pharmacy, University of Sassari, Via Muroni 23/A, 07100 Sassari, Italy; (F.R.); (I.L.); (S.P.); (A.C.)
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11
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Pseudomonas aeruginosa Alters Peptidoglycan Composition under Nutrient Conditions Resembling Cystic Fibrosis Lung Infections. mSystems 2022; 7:e0015622. [PMID: 35545925 PMCID: PMC9239049 DOI: 10.1128/msystems.00156-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Epidemic strains of Pseudomonas aeruginosa are highly virulent opportunistic pathogens with increased transmissibility and enhanced antimicrobial resistance. Understanding the cellular mechanisms behind this heightened virulence and resistance is critical. Peptidoglycan (PG) is an integral component of P. aeruginosa cells that is essential to its survival and a target for antimicrobials. Here, we examined the global PG composition of two P. aeruginosa epidemic strains, LESB58 and LESlike1, and compared them to the common laboratory strains PAO1 and PA14. We also examined changes in PG composition when the strains were cultured under nutrient conditions that resembled cystic fibrosis lung infections. We identified 448 unique muropeptides and provide the first evidence for stem peptides modified with O-methylation, meso-diaminopimelic acid (mDAP) deamination, and novel substitutions of mDAP residues within P. aeruginosa PG. Our results also present the first evidence for both d,l- and l,d-endopeptidase activity on the PG sacculus of a Gram-negative organism. The PG composition of the epidemic strains varied significantly when grown under conditions resembling cystic fibrosis (CF) lung infections, showing increases in O-methylated stem peptides and decreases in l,d-endopeptidase activity as well as an increased abundance of de-N-acetylated sugars and l,d-transpeptidase activity, which are related to bacterial virulence and antibiotic resistance, respectively. We also identified strain-specific changes where LESlike1 increased the addition of unique amino acids to the terminus of the stem peptide and LESB58 increased amidase activity. Overall, this study demonstrates that P. aeruginosa PG composition is primarily influenced by nutrient conditions that mimic the CF lung; however, inherent strain-to-strain differences also exist. IMPORTANCE Using peptidoglycomics to examine the global composition of the peptidoglycan (PG) allows insights into the enzymatic activity that functions on this important biopolymer. Changes within the PG structure have implications for numerous physiological processes, including virulence and antimicrobial resistance. The identification of highly unique PG modifications illustrates the complexity of this biopolymer in Pseudomonas aeruginosa. Analyzing the PG composition of clinical P. aeruginosa epidemic strains provides insights into the increased virulence and antimicrobial resistance of these difficult-to-eradicate infections.
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Wang H, Liu Z, Lao J, Zhang S, Abzalimov R, Wang T, Chen X. High Energy and Power Density Peptidoglycan Muscles through Super-Viscous Nanoconfined Water. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104697. [PMID: 35285168 PMCID: PMC9130901 DOI: 10.1002/advs.202104697] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/23/2021] [Indexed: 06/14/2023]
Abstract
Water-responsive (WR) materials that reversibly deform in response to humidity changes show great potential for developing muscle-like actuators for miniature and biomimetic robotics. Here, it is presented that Bacillus (B.) subtilis' peptidoglycan (PG) exhibits WR actuation energy and power densities reaching 72.6 MJ m-3 and 9.1 MW m-3 , respectively, orders of magnitude higher than those of frequently used actuators, such as piezoelectric actuators and dielectric elastomers. PG can deform as much as 27.2% within 110 ms, and its actuation pressure reaches ≈354.6 MPa. Surprisingly, PG exhibits an energy conversion efficiency of ≈66.8%, which can be attributed to its super-viscous nanoconfined water that efficiently translates the movement of water molecules to PG's mechanical deformation. Using PG, WR composites that can be integrated into a range of engineering structures are developed, including a robotic gripper and linear actuators, which illustrate the possibilities of using PG as building blocks for high-efficiency WR actuators.
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Affiliation(s)
- Haozhen Wang
- Advanced Science Research Center (ASRC)The City University of New York85 St. Nicholas TerraceNew YorkNY10031USA
- PhD Program in PhysicsThe Graduate Center of the City University of New York365 5th Ave.New YorkNY10016USA
| | - Zhi‐Lun Liu
- Advanced Science Research Center (ASRC)The City University of New York85 St. Nicholas TerraceNew YorkNY10031USA
- Department of Chemical EngineeringThe City College of New York275 Convent Ave.New YorkNY10031USA
| | - Jianpei Lao
- Advanced Science Research Center (ASRC)The City University of New York85 St. Nicholas TerraceNew YorkNY10031USA
- Department of Chemical EngineeringThe City College of New York275 Convent Ave.New YorkNY10031USA
| | - Sheng Zhang
- Advanced Science Research Center (ASRC)The City University of New York85 St. Nicholas TerraceNew YorkNY10031USA
| | - Rinat Abzalimov
- Advanced Science Research Center (ASRC)The City University of New York85 St. Nicholas TerraceNew YorkNY10031USA
| | - Tong Wang
- Advanced Science Research Center (ASRC)The City University of New York85 St. Nicholas TerraceNew YorkNY10031USA
| | - Xi Chen
- Advanced Science Research Center (ASRC)The City University of New York85 St. Nicholas TerraceNew YorkNY10031USA
- PhD Program in PhysicsThe Graduate Center of the City University of New York365 5th Ave.New YorkNY10016USA
- Department of Chemical EngineeringThe City College of New York275 Convent Ave.New YorkNY10031USA
- PhD Program in ChemistryThe Graduate Center of the City University of New York365 5th Ave.New YorkNY10016USA
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Kwack KH, Lee JH, Moon JH. Whole genome and RNA sequencing of oral commensal bacterium Streptococcus anginosus subsp. anginosus with vancomycin tolerance. J Microbiol 2022; 60:167-176. [PMID: 34997538 DOI: 10.1007/s12275-022-1425-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/24/2022]
Abstract
"Antibiotic tolerance" promotes the rapid subsequent evolution of "antibiotic resistance," however, it is often overlooked because it is difficult to distinguish between tolerant and susceptible organisms. A commensal bacterium S. anginosus subsp. anginosus strain KHUD_S1, isolated from dental biofilm was found to exhibit a high MBC/MIC ratio of 32 against vancomycin. We observed KHUD_S1 cells exposed to vancomycin did not grow but maintained viability. Transmission electron microscope showed KHUD_S1 cells possessed a dense, thick capsule and maintained the cell wall integrity upon vancomycin exposure. To infer the underlying mechanisms of the vancomycin tolerance in KHUD_S1, we performed whole genome sequencing and RNA sequencing. The KHUD_S1 genome carried three genes encoding branching enzymes that can affect peptidoglycan structure through interpeptide bridge formation. Global gene expression profiling revealed that the vancomycin-induced downregulation of carbohydrate and inorganic ion transport/metabolism as well as translation is less prominent in KHUD_S1 than in the vancomycin susceptible strain KHUD_S3. Based on the transcriptional levels of genes related to peptidoglycan synthesis, KHUD_S1 was determined to have a 3D peptidoglycan architecture distinct from KHUD_S3. It was found that, under vancomycin exposure, the peptidoglycan was remodeled through changes in the interpeptide bridge and transpeptidation reactions. Collectively, these features of S. anginosus KHUD_S1, including a dense capsule and differential gene expression in peptidoglycan synthesis, may contribute to vancomycin tolerance. Our results showing the occurrence of vancomycin tolerance amongst oral commensal bacteria highlight the need for considering future strategies for screening of antibiotic tolerance as an effort to reduce antibiotic resistance.
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Affiliation(s)
- Kyu Hwan Kwack
- Department of Dentistry, Graduate School, Kyung Hee University, Seoul, 02447, Republic of Korea
- Present address: Department of Oral Biology, University at Buffalo School of Dental Medicine, Buffalo, New York, 14214, USA
| | - Jae-Hyung Lee
- Department of Oral Microbiology, School of Dentistry, Kyung Hee University, Seoul, 02447, Republic of Korea.
| | - Ji-Hoi Moon
- Department of Oral Microbiology, School of Dentistry, Kyung Hee University, Seoul, 02447, Republic of Korea.
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Magnesium rescues the morphology of Bacillus subtilis mreB mutants through its inhibitory effect on peptidoglycan hydrolases. Sci Rep 2022; 12:1137. [PMID: 35064120 PMCID: PMC8782873 DOI: 10.1038/s41598-021-04294-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/06/2021] [Indexed: 02/04/2023] Open
Abstract
Cell wall homeostasis in bacteria is tightly regulated by balanced synthesis and degradation of peptidoglycan (PG), allowing cells to expand their sacculus during growth while maintaining physical integrity. In rod-shaped bacteria, actin-like MreB proteins are key players of the PG elongation machinery known as the Rod complex. In the Gram-positive model bacterium Bacillus subtilis depletion of the essential MreB leads to loss of rod shape and cell lysis. However, millimolar concentrations of magnesium in the growth medium rescue the viability and morphological defects of mreB mutants by an unknown mechanism. Here, we used a combination of cytological, biochemical and biophysical approaches to investigate the cell surface properties of mreB null mutant cells and the interactions of Mg2+ with the cell wall of B. subtilis. We show that ∆mreB cells have rougher and softer surfaces, and changes in PG composition indicative of increased DL- and DD-endopeptidase activities as well as increased deacetylation of the sugar moieties. Increase in DL-endopeptidase activity is mitigated by excess Mg2+ while DD-endopeptidase activity remains high. Visualization of PG degradation in pulse-chase experiments showed anisotropic PG hydrolase activity along the sidewalls of ∆mreB cells, in particular at the sites of increased cell width and bulging, while PG synthesis remained isotropic. Overall, our data support a model in which divalent cations maintain rod shape in ∆mreB cells by inhibiting PG hydrolases, possibly through the formation of crosslinks with carboxyl groups of the PG meshwork that affect the capacity of PG hydrolases to act on their substrate.
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15
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A High-Content Microscopy Screening Identifies New Genes Involved in Cell Width Control in Bacillus subtilis. mSystems 2021; 6:e0101721. [PMID: 34846166 PMCID: PMC8631317 DOI: 10.1128/msystems.01017-21] [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] [Indexed: 11/28/2022] Open
Abstract
How cells control their shape and size is a fundamental question of biology. In most bacteria, cell shape is imposed by the peptidoglycan (PG) polymeric meshwork that surrounds the cell. Thus, bacterial cell morphogenesis results from the coordinated action of the proteins assembling and degrading the PG shell. Remarkably, during steady-state growth, most bacteria maintain a defined shape along generations, suggesting that error-proof mechanisms tightly control the process. In the rod-shaped model for the Gram-positive bacterium Bacillus subtilis, the average cell length varies as a function of the growth rate, but the cell diameter remains constant throughout the cell cycle and across growth conditions. Here, in an attempt to shed light on the cellular circuits controlling bacterial cell width, we developed a screen to identify genetic determinants of cell width in B. subtilis. Using high-content screening (HCS) fluorescence microscopy and semiautomated measurement of single-cell dimensions, we screened a library of ∼4,000 single knockout mutants. We identified 13 mutations significantly altering cell diameter, in genes that belong to several functional groups. In particular, our results indicate that metabolism plays a major role in cell width control in B. subtilis. IMPORTANCE Bacterial shape is primarily dictated by the external cell wall, a vital structure that, as such, is the target of countless antibiotics. Our understanding of how bacteria synthesize and maintain this structure is therefore a cardinal question for both basic and applied research. Bacteria usually multiply from generation to generation while maintaining their progenies with rigorously identical shapes. This implies that the bacterial cells constantly monitor and maintain a set of parameters to ensure this perpetuation. Here, our study uses a large-scale microscopy approach to identify at the whole-genome level, in a model bacterium, the genes involved in the control of one of the most tightly controlled cellular parameters, the cell width.
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16
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Sassine J, Pazos M, Breukink E, Vollmer W. Lytic transglycosylase MltG cleaves in nascent peptidoglycan and produces short glycan strands. Cell Surf 2021; 7:100053. [PMID: 34036206 PMCID: PMC8135044 DOI: 10.1016/j.tcsw.2021.100053] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/17/2021] [Accepted: 04/26/2021] [Indexed: 12/20/2022] Open
Abstract
Bacteria encase their cytoplasmic membrane with peptidoglycan (PG) to maintain the shape of the cell and protect it from bursting. The enlargement of the PG layer is facilitated by the coordinated activities of PG synthesising and -cleaving enzymes. In Escherichia coli, the cytoplasmic membrane-bound lytic transglycosylase MltG associates with PG synthases and was suggested to terminate the polymerisation of PG glycan strands. Using pull-down and surface plasmon resonance, we detected interactions between MltG from Bacillus subtilis and two PG synthases; the class A PBP1 and the class B PBP2B. Using in vitro PG synthesis assays with radio-labelled or fluorophore-labelled B. subtilis-type and/or E. coli-type lipid II, we showed that both, BsMltG and EcMltG, are lytic tranglycosylases and that their activity is higher during ongoing glycan strand polymerisation. MltG competed with the transpeptidase activity of class A PBPs, but had no effect on their glycosyltransferase activity, and produced glycan strands with a length of 7 disaccharide units from cleavage in the nascent strands. We hypothesize that MltG cleaves the nascent strands to produce short glycan strands that are used in the cell for a yet unknown process.
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Affiliation(s)
- Jad Sassine
- Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Manuel Pazos
- Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Eefjan Breukink
- Membrane Biochemistry and Biophysics, Bijvoet Centre of Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
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17
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Soltanmohammadi B, Piri‐Gavgani S, Basardeh E, Ghanei M, Azizi M, Khaksar Z, Sharifzadeh Z, Badmasti F, Soezi M, Fateh A, Azimi P, Siadat SD, Shooraj F, Bouzari S, Omrani MD, Rahimi‐Jamnani F. Bactericidal fully human single-chain fragment variable antibodies protect mice against methicillin-resistant Staphylococcus aureus bacteraemia. Clin Transl Immunology 2021; 10:e1302. [PMID: 34221401 PMCID: PMC8240403 DOI: 10.1002/cti2.1302] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/01/2021] [Accepted: 05/30/2021] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES The increasing prevalence of antibiotic-resistant Staphylococcus aureus, besides the inadequate numbers of effective antibiotics, emphasises the need to find new therapeutic agents against this lethal pathogen. METHODS In this study, to obtain antibody fragments against S. aureus, a human single-chain fragment variable (scFv) library was enriched against living methicillin-resistant S. aureus (MRSA) cells, grown in three different conditions, that is human peripheral blood mononuclear cells with plasma, whole blood and biofilm. The antibacterial activity of scFvs was evaluated by the growth inhibition assay in vitro. Furthermore, the therapeutic efficacy of anti-S. aureus scFvs was appraised in a mouse model of bacteraemia. RESULTS Three scFv antibodies, that is MEH63, MEH158 and MEH183, with unique sequences, were found, which exhibited significant binding to S. aureus and reduced the viability of S. aureus in in vitro inhibition assays. Based on the results, MEH63, MEH158 and MEH183, in addition to their combination, could prolong the survival rate, reduce the bacterial burden in the blood and prevent inflammation and tissue destruction in the kidneys and spleen of mice with MRSA bacteraemia compared with the vehicle group (treated with normal saline). CONCLUSION The combination therapy with anti-S. aureus scFvs and conventional antibiotics might shed light on the treatment of patients with S. aureus infections.
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Affiliation(s)
- Behnoush Soltanmohammadi
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Somayeh Piri‐Gavgani
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Eilnaz Basardeh
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Mostafa Ghanei
- Chemical Injuries Research CenterSystems Biology and Poisoning InstituteBaqiyatallah University of Medical SciencesTehranIran
| | - Masoumeh Azizi
- Molecular Medicine Department, Biotechnology Research CenterPasteur Institute of IranTehranIran
| | - Zabihollah Khaksar
- Department of Basic SciencesSchool of Veterinary MedicineShiraz UniversityShirazIran
| | | | - Farzad Badmasti
- Department of BacteriologyPasteur Institute of IranTehranIran
| | - Mahdieh Soezi
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Abolfazl Fateh
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Parisa Azimi
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Seyed Davar Siadat
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Fahimeh Shooraj
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
| | - Saeid Bouzari
- Molecular Biology DepartmentPasteur Institute of IranTehranIran
| | - Mir Davood Omrani
- Department of Medical GeneticsSchool of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Fatemeh Rahimi‐Jamnani
- Department of Mycobacteriology and Pulmonary ResearchPasteur Institute of IranTehranIran
- Microbiology Research CenterPasteur Institute of IranTehranIran
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18
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A synthetic 5,3-cross-link in the cell wall of rod-shaped Gram-positive bacteria. Proc Natl Acad Sci U S A 2021; 118:2100137118. [PMID: 33836615 DOI: 10.1073/pnas.2100137118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Gram-positive bacteria assemble a multilayered cell wall that provides tensile strength to the cell. The cell wall is composed of glycan strands cross-linked by nonribosomally synthesized peptide stems. Herein, we modify the peptide stems of the Gram-positive bacterium Bacillus subtilis with noncanonical electrophilic d-amino acids, which when in proximity to adjacent stem peptides form novel covalent 5,3-cross-links. Approximately 20% of canonical cell-wall cross-links can be replaced with synthetic cross-links. While a low level of synthetic cross-link formation does not affect B. subtilis growth and phenotype, at higher levels cell growth is perturbed and bacteria elongate. A comparison of the accumulation of synthetic cross-links over time in Gram-negative and Gram-positive bacteria highlights key differences between them. The ability to perturb cell-wall architecture with synthetic building blocks provides a novel approach to studying the adaptability, elasticity, and porosity of bacterial cell walls.
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19
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Delvaux C, Dauvin M, Boulanger M, Quinton L, Mengin-Lecreulx D, Joris B, Pauw ED, Far J. Use of Capillary Zone Electrophoresis Coupled to Electrospray Mass Spectrometry for the Detection and Absolute Quantitation of Peptidoglycan-Derived Peptides in Bacterial Cytoplasmic Extracts. Anal Chem 2021; 93:2342-2350. [PMID: 33470796 DOI: 10.1021/acs.analchem.0c04218] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptidoglycan (PGN) is an essential structure found in the bacterial cell wall. During the bacterial life cycle, PGN continuously undergoes biosynthesis and degradation to ensure bacterial growth and division. The resulting PGN fragments (muropeptides and peptides), which are generated by the bacterial autolytic system, are usually transported into the cytoplasm to be recycled. On the other hand, PGN fragments can act as messenger molecules involved in the bacterial cell wall stress response as in the case of β-lactamase induction in the presence of β-lactam antibiotic or in triggering mammalian innate immune response. During their cellular life, bacteria modulate their PGN degradation by their autolytic system or their recognition by the mammalian innate immune system by chemically modifying their PGN. Among these modifications, the amidation of the ε-carboxyl group of meso-diaminopimelic acid present in the PGN peptide chain is frequently observed. Currently, the detection and quantitation of PGN-derived peptides is still challenging because of the difficulty in separating these highly hydrophilic molecules by RP-HPLC as these compounds are eluted closely after the column void volume or coeluted in many cases. Here, we report the use of capillary zone electrophoresis coupled via an electrospray-based CE-MS interface to high-resolution mass spectrometry for the quantitation of three PGN peptides of interest and their amidated derivatives in bacterial cytoplasmic extracts. The absolute quantitation of the tripeptide based on the [13C,15N] isotopically labeled standard was also performed in crude cytoplasmic extracts of bacteria grown in the presence or absence of a β-lactam antibiotic (cephalosporin C). Despite the high complexity of the samples, the repeatability of the CZE-MS quantitation results was excellent, with relative standard deviations close to 1%. The global reproducibility of the method including biological handling was better than 20%.
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Affiliation(s)
- Cédric Delvaux
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Marjorie Dauvin
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Madeleine Boulanger
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Loïc Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Dominique Mengin-Lecreulx
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette 91198, France
| | - Bernard Joris
- Centre for Protein Engineering, InBioS Research Unit, Quartier Agora, University of Liège, Allée du Six Août 13, B-4000 Liège, Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Johann Far
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier Agora, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
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20
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Al-Mohammadi AR, Osman A, Enan G, Abdel-Shafi S, El-Nemer M, Sitohy M, Taha MA. Powerful Antibacterial Peptides from Egg Albumin Hydrolysates. Antibiotics (Basel) 2020; 9:antibiotics9120901. [PMID: 33322196 PMCID: PMC7763489 DOI: 10.3390/antibiotics9120901] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 01/18/2023] Open
Abstract
Native egg albumin (NEA) was isolated from hen eggs and hydrolyzed by pepsin to produce hydrolyzed egg albumin (HEA). HEA was chemically characterized and screened for its antibacterial activity against 10 pathogenic bacteria (6 Gram (+) and 4 Gram (−)). The SDS-PAGE pattern of NEA showed molecular weights of hen egg albumin subunits ranging from 30 to 180 kDa. The highest intensive bands appeared at a molecular mass of about 50 and 97 kDa. Ultra-performance liquid chromatography (UPLC) of the peptic HEA revealed 44 peptides, 17 of them were dipeptides, and the other 27 fractions corresponded to bigger peptides (3–9 amino acids). The dipeptides and big peptides represented 26% and 74% of the total hydrolysate, respectively. The MIC of HEA was about 100 μg/L for Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Salmonella typhimurium, Streptococcus pyogenes, and Klebsiella oxytoca and 150 μg/L for Pseudomonas aeruginosa, Bacillus subtilis, and Listeria ivanovii and 200 μg/L for Escherichia coli. L. monocytogenes was the most sensitive organism to HEA. Mixtures of HEA with antibiotics showed more significant antibacterial activity than individually using them. Transmission electron microscopy (TEM) revealed various signs of cellular deformation in the protein-treated bacteria. HEA may electrostatically and hydrophobically interact with the cell wall and cell membrane of the susceptible bacteria, engendering large pores and pore channels leading to cell wall and cell membrane disintegration. Higher cell permeability may, thus, occur, leading to cell emptiness, lysis, and finally death. Alternatively, no toxicity signs appeared when HEA was administrated to Wistar Albino rats as one single dose (2000, 5000 mg/kg body weight) or repeated daily dose (500 and 2500 mg/kg body weight/day) for 28 days to disclose the possible toxicity hazards. HEA did not produce any death.
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Affiliation(s)
- Abdul-Raouf Al-Mohammadi
- Department of Science, King Khalid Military Academy, P.O. Box 22140, Riyadh 11495, Saudi Arabia;
| | - Ali Osman
- Biochemistry Department, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt; (A.O.); (M.S.)
| | - Gamal Enan
- Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt; (M.E.-N.); (M.A.T.)
- Correspondence: (G.E.); (S.A.-S.); Tel.: +20-1009877015 (G.E.); +20-1289600036 (S.A.-S.)
| | - Seham Abdel-Shafi
- Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt; (M.E.-N.); (M.A.T.)
- Correspondence: (G.E.); (S.A.-S.); Tel.: +20-1009877015 (G.E.); +20-1289600036 (S.A.-S.)
| | - Mona El-Nemer
- Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt; (M.E.-N.); (M.A.T.)
| | - Mahmoud Sitohy
- Biochemistry Department, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt; (A.O.); (M.S.)
| | - Mohamed A. Taha
- Botany and Microbiology Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt; (M.E.-N.); (M.A.T.)
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21
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Cell morphology maintenance in Bacillus subtilis through balanced peptidoglycan synthesis and hydrolysis. Sci Rep 2020; 10:17910. [PMID: 33087775 PMCID: PMC7578834 DOI: 10.1038/s41598-020-74609-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/28/2020] [Indexed: 01/12/2023] Open
Abstract
The peptidoglycan layer is responsible for maintaining bacterial cell shape and permitting cell division. Cell wall growth is facilitated by peptidoglycan synthases and hydrolases and is potentially modulated by components of the central carbon metabolism. In Bacillus subtilis, UgtP synthesises the glucolipid precursor for lipoteichoic acid and has been suggested to function as a metabolic sensor governing cell size. Here we show that ugtP mutant cells have increased levels of cell wall precursors and changes in their peptidoglycan that suggest elevated DL-endopeptidase activity. The additional deletion of lytE, encoding a DL-endopeptidase important for cell elongation, in the ugtP mutant background produced cells with severe shape defects. Interestingly, the ugtP lytE mutant recovered normal rod-shape by acquiring mutations that decreased the expression of the peptidoglycan synthase PBP1. Together our results suggest that cells lacking ugtP must re-adjust the balance between peptidoglycan synthesis and hydrolysis to maintain proper cell morphology.
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22
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Kang SJ, Jun JS, Moon JA, Hong KW. Surface display of p75, a Lactobacillus rhamnosus GG derived protein, on Bacillus subtilis spores and its antibacterial activity against Listeria monocytogenes. AMB Express 2020; 10:139. [PMID: 32770428 PMCID: PMC7415045 DOI: 10.1186/s13568-020-01073-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 07/25/2020] [Indexed: 01/05/2023] Open
Abstract
Lactobacillus rhamnosus p75 protein with peptidoglycan hydrolase (PGH) activity is one of the key molecules exhibiting anti-apoptotic and cell-protective activity for human intestinal epithelial cells. In this study, with the goal of developing new probiotics, the p75 protein was displayed on the surface of Bacillus subtilis spores using spore coat protein CotG as an anchoring motif. The PGH activity, stability, and the antibacterial activity of the spore-displayed p75 (CotG-p75) protein were also investigated. The PGH activity of the CotG-p75 against peptidoglycan extracted from B. subtilis was confirmed by the ninhydrin test. Under various harsh conditions, compared to the control groups, the PGH activities of CotG-p75 were very stable in the range of pH 3–7 and maintained at 70% at 50 °C. In addition, the antibacterial activity of CotG-p75 against Listeria monocytogenes was evaluated by a time-kill assay. After 6 h incubation in phosphate-buffered saline, CotG-p75 reduced the number of viable cells of L. monocytogenes by up to 2.0 log. Scanning electron microscopy analysis showed that the cell wall of L. monocytogenes was partially damaged by the treatment with CotG-p75. Our preliminary results show that CotG-p75 could be a good candidate for further research to develop new genetically engineered probiotics.
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Sharifzadeh S, Dempwolff F, Kearns DB, Carlson EE. Harnessing β-Lactam Antibiotics for Illumination of the Activity of Penicillin-Binding Proteins in Bacillus subtilis. ACS Chem Biol 2020; 15:1242-1251. [PMID: 32155044 DOI: 10.1021/acschembio.9b00977] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Selective chemical probes enable individual investigation of penicillin-binding proteins (PBPs) and provide critical information about their enzymatic activity with spatial and temporal resolution. To identify scaffolds for novel probes to study peptidoglycan biosynthesis in Bacillus subtilis, we evaluated the PBP inhibition profiles of 21 β-lactam antibiotics from different structural subclasses using a fluorescence-based assay. Most compounds readily labeled PBP1, PBP2a, PBP2b, or PBP4. Almost all penicillin scaffolds were coselective for all or combinations of PBP2a, 2b, and 4. Cephalosporins, on the other hand, possessed the lowest IC50 values for PBP1 alone or along with PBP4 (ceftriaxone, cefoxitin) and 2b (cefotaxime) or 2a, 2b, and 4 (cephalothin). Overall, five selective inhibitors for PBP1 (aztreonam, faropenem, piperacillin, cefuroxime, and cefsulodin), one selective inhibitor for PBP5 (6-aminopenicillanic acid), and various coselective inhibitors for other PBPs in B. subtilis were discovered. Surprisingly, carbapenems strongly inhibited PBP3, formerly shown to have low affinity for β-lactams and speculated to be involved in β-lactam resistance in B. subtilis. To investigate the specific roles of PBP3, we developed activity-based probes based on the meropenem core and utilized them to monitor the activity of PBP3 in living cells. We showed that PBP3 activity localizes as patches in single cells and concentrates as a ring at the septum and the division site during the cell growth cycle. Our activity-based approach enabled spatial resolution of the transpeptidation activity of individual PBPs in this model microorganism, which was not possible with previous chemical and biological approaches.
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Affiliation(s)
| | - Felix Dempwolff
- Department of Biology, Indiana University, Bloomington, Indiana 47405, United States
| | - Daniel B. Kearns
- Department of Biology, Indiana University, Bloomington, Indiana 47405, United States
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Kuru E, Radkov A, Meng X, Egan A, Alvarez L, Dowson A, Booher G, Breukink E, Roper DI, Cava F, Vollmer W, Brun Y, VanNieuwenhze MS. Mechanisms of Incorporation for D-Amino Acid Probes That Target Peptidoglycan Biosynthesis. ACS Chem Biol 2019; 14:2745-2756. [PMID: 31743648 PMCID: PMC6929685 DOI: 10.1021/acschembio.9b00664] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
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Bacteria exhibit a myriad of different morphologies,
through the
synthesis and modification of their essential peptidoglycan (PG) cell
wall. Our discovery of a fluorescent D-amino acid (FDAA)-based PG labeling approach provided a powerful method
for observing how these morphological changes occur. Given that PG
is unique to bacterial cells and a common target for antibiotics,
understanding the precise mechanism(s) for incorporation of (F)DAA-based
probes is a crucial determinant in understanding the role of PG synthesis
in bacterial cell biology and could provide a valuable tool in the
development of new antimicrobials to treat drug-resistant antibacterial
infections. Here, we systematically investigate the mechanisms of
FDAA probe incorporation into PG using two model organisms Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive). Our in vitro and in vivo data unequivocally demonstrate
that these bacteria incorporate FDAAs using two extracytoplasmic pathways:
through activity of their D,D-transpeptidases, and,
if present, by their L,D-transpeptidases and not
via cytoplasmic incorporation into a D-Ala-D-Ala
dipeptide precursor. Our data also revealed the unprecedented finding
that the DAA-drug, D-cycloserine, can be incorporated into
peptide stems by each of these transpeptidases, in addition to its
known inhibitory activity against D-alanine racemase and D-Ala-D-Ala ligase. These mechanistic findings enabled
development of a new, FDAA-based, in vitro labeling approach that
reports on subcellular distribution of muropeptides, an especially
important attribute to enable the study of bacteria with poorly defined
growth modes. An improved understanding of the incorporation mechanisms
utilized by DAA-based probes is essential when interpreting results
from high resolution experiments and highlights the antimicrobial
potential of synthetic DAAs.
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Affiliation(s)
- Erkin Kuru
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Atanas Radkov
- Department of Biochemistry and Biophysics, UCSF School of Medicine, San Francisco, California 94158, United States
| | - Xin Meng
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Alexander Egan
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Laura Alvarez
- Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Amanda Dowson
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Garrett Booher
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Eefjan Breukink
- Department of Chemistry, Utrecht University, 3584 CH, Utrecht, Netherlands
| | - David I. Roper
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Felipe Cava
- Department of Molecular Biology, Umeå University, SE-901 87, Umeå, Sweden
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4AX, United Kingdom
| | - Yves Brun
- Department of Microbiology, Infectious Diseases, and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Canada
| | - Michael S. VanNieuwenhze
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, United States
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25
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Porfírio S, Carlson RW, Azadi P. Elucidating Peptidoglycan Structure: An Analytical Toolset. Trends Microbiol 2019; 27:607-622. [DOI: 10.1016/j.tim.2019.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/16/2019] [Accepted: 01/29/2019] [Indexed: 01/04/2023]
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26
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Boulanger M, Delvaux C, Quinton L, Joris B, De Pauw E, Far J. Bacillus licheniformispeptidoglycan characterization by CZE–MS: Assessment with the benchmark RP‐HPLC‐MS method. Electrophoresis 2019; 40:2672-2682. [DOI: 10.1002/elps.201900147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Madeleine Boulanger
- Center for Protein Engineering, InBioS Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Cédric Delvaux
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Loïc Quinton
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Bernard Joris
- Center for Protein Engineering, InBioS Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Edwin De Pauw
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
| | - Johann Far
- Mass Spectrometry Laboratory, MolSys Research Unit, Quartier AgoraUniversity of Liège Liège Belgium
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27
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Ealand CS, Asmal R, Mashigo L, Campbell L, Kana BD. Characterization of putative DD-carboxypeptidase-encoding genes in Mycobacterium smegmatis. Sci Rep 2019; 9:5194. [PMID: 30914728 PMCID: PMC6435803 DOI: 10.1038/s41598-019-41001-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 02/22/2019] [Indexed: 01/21/2023] Open
Abstract
Penicillin binding proteins (PBPs) are the target of numerous antimicrobial agents that disrupt bacterial cell wall synthesis. In mycobacteria, cell elongation occurs through insertion of nascent cell wall material in the sub-polar region, a process largely driven by High Molecular Weight PBPs. In contrast, the function of DD-carboxypeptidases (DD-CPases), which are Low Molecular Weight Class 1C PBPs, in mycobacteria remains poorly understood. Mycobacterium smegmatis encodes four putative DD-CPase homologues, which display homology to counterparts in Escherichia coli. Herein, we demonstrate that these are expressed in varying abundance during growth. Deletion of MSMEG_1661, MSMEG_2433 or MSMEG_2432, individually resulted in no defects in growth, cell morphology, drug susceptibility or spatial incorporation of new peptidoglycan. In contrast, deletion of MSMEG_6113 (dacB) was only possible in a merodiploid strain expressing the homologous M. tuberculosis operon encoding Rv3627c (dacB), Rv3626c, Rv3625c (mesJ) and Rv3624c (hpt), suggestive of essentiality. To investigate the role of this operon in mycobacterial growth, we depleted gene expression using anhydrotetracycline-responsive repressors and noted reduced bipolar peptidoglycan synthesis. These data point to a possible role for this four gene operon, which is highly conserved across all mycobacterial species, in regulating spatial localization of peptidoglycan synthesis.
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Affiliation(s)
- Christopher S Ealand
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, P.O. Box 1038, Johannesburg, 2000, South Africa
| | - Rukaya Asmal
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, P.O. Box 1038, Johannesburg, 2000, South Africa
| | - Lethabo Mashigo
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, P.O. Box 1038, Johannesburg, 2000, South Africa
| | - Lisa Campbell
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, P.O. Box 1038, Johannesburg, 2000, South Africa
| | - Bavesh D Kana
- DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, P.O. Box 1038, Johannesburg, 2000, South Africa.
- MRC-CAPRISA HIV-TB Pathogenesis and Treatment Research Unit, Centre for the AIDS Programme of Research in South Africa, CAPRISA, Durban, South Africa.
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28
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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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29
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Abstract
The peptidoglycan sacculus is a net-like polymer that surrounds the cytoplasmic membrane in most bacteria. It is essential to maintain the bacterial cell shape and protect from turgor. The peptidoglycan has a basic composition, common to all bacteria, with species-specific variations that can modify its biophysical properties or the pathogenicity of the bacteria. The synthesis of peptidoglycan starts in the cytoplasm and the precursor lipid II is flipped across the cytoplasmic membrane. The new peptidoglycan strands are synthesised and incorporated into the pre-existing sacculus by the coordinated activities of peptidoglycan synthases and hydrolases. In the model organism Escherichia coli there are two complexes required for the elongation and division. Each of them is regulated by different proteins from both the cytoplasmic and periplasmic sides that ensure the well-coordinated synthesis of new peptidoglycan.
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30
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Yadav AK, Espaillat A, Cava F. Bacterial Strategies to Preserve Cell Wall Integrity Against Environmental Threats. Front Microbiol 2018; 9:2064. [PMID: 30233540 PMCID: PMC6127315 DOI: 10.3389/fmicb.2018.02064] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 08/13/2018] [Indexed: 12/18/2022] Open
Abstract
Bacterial cells are surrounded by an exoskeleton-like structure, the cell wall, composed primarily of the peptidoglycan (PG) sacculus. This structure is made up of glycan strands cross-linked by short peptides generating a covalent mesh that shapes bacteria and prevents their lysis due to their high internal osmotic pressure. Even though the PG is virtually universal in bacteria, there is a notable degree of diversity in its chemical structure. Modifications in both the sugars and peptides are known to be instrumental for bacteria to cope with diverse environmental challenges. In this review, we summarize and discuss the cell wall strategies to withstand biotic and abiotic environmental insults such as the effect of antibiotics targeting cell wall enzymes, predatory PG hydrolytic proteins, and PG signaling systems. Finally we will discuss the opportunities that species-specific PG variability might open to develop antimicrobial therapies.
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Affiliation(s)
- Akhilesh K Yadav
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Akbar Espaillat
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
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31
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Li K, Yuan XX, Sun HM, Zhao LS, Tang R, Chen ZH, Qin QL, Chen XL, Zhang YZ, Su HN. Atomic Force Microscopy of Side Wall and Septa Peptidoglycan From Bacillus subtilis Reveals an Architectural Remodeling During Growth. Front Microbiol 2018; 9:620. [PMID: 29651285 PMCID: PMC5884923 DOI: 10.3389/fmicb.2018.00620] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 03/16/2018] [Indexed: 02/02/2023] Open
Abstract
Peptidoglycan is the fundamental structural constituent of the bacterial cell wall. Despite many years of research, the architecture of peptidoglycan is still largely elusive. Here, we report the high-resolution architecture of peptidoglycan from the model Gram-positive bacterium Bacillus subtilis. We provide high-resolution evidence of peptidoglycan architecture remodeling at different growth stages. Side wall peptidoglycan from B. subtilis strain AS1.398 changed from an irregular architecture in exponential growth phase to an ordered cable-like architecture in stationary phase. Thickness of side wall peptidoglycan was found to be related with growth stages, with a slight increase after transition to stationary phase. Septal disks were synthesized progressively toward the center, while the surface features were less clear than those imaged with side walls. Compared with previous studies, our results revealed slight differences in architecture of peptidoglycan from different B. subtilis strains, expanding our knowledge about the architectural features of B. subtilis peptidoglycan.
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Affiliation(s)
- Kang Li
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - Xiao-Xue Yuan
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - He-Min Sun
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - Long-Sheng Zhao
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - Ruocong Tang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - Zhi-Hua Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - Qi-Long Qin
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.,College of Marine Life Sciences, Ocean University of China, Qingdao, China
| | - Hai-Nan Su
- State Key Laboratory of Microbial Technology, Marine Biotechnology Research Center, Shandong University, Jinan, China.,College of Marine Life Sciences, Ocean University of China, Qingdao, China
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32
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Hashimoto M, Matsushima H, Suparthana IP, Ogasawara H, Yamamoto H, Teng C, Sekiguchi J. Digestion of peptidoglycan near the cross-link is necessary for the growth of Bacillus subtilis. Microbiology (Reading) 2018; 164:299-307. [DOI: 10.1099/mic.0.000614] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Masayuki Hashimoto
- Institute of Molecular Medicine, College of Medicine, National Cheng-Kung University, Tainan City 704-56, Taiwan, ROC
- Center of Infectious Disease and Signal Transduction, College of Medicine, National Cheng-Kung University, Tainan City 704-56, Taiwan, ROC
| | - Hiroaki Matsushima
- Department of Applied Biology, Graduated School of Science and technology, Shinshu University, Ueda, Japan
| | - I. Putu Suparthana
- Department of Applied Biology, Graduated School of Science and technology, Shinshu University, Ueda, Japan
- Present address: Department of Food Science and Technology, Faculty of Agricultural Technology, Udayana University, Bali, Indonesia
| | - Hiroshi Ogasawara
- Division of Gene Research, Department of Life Science, Research Center for Supports to Advanced Science, Shinshu University, Ueda, Japan
| | - Hiroki Yamamoto
- Department of Applied Biology, Graduated School of Science and technology, Shinshu University, Ueda, Japan
| | - ChingHao Teng
- Institute of Molecular Medicine, College of Medicine, National Cheng-Kung University, Tainan City 704-56, Taiwan, ROC
| | - Junichi Sekiguchi
- Department of Applied Biology, Graduated School of Science and technology, Shinshu University, Ueda, Japan
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33
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Pompeo F, Byrne D, Mengin-Lecreulx D, Galinier A. Dual regulation of activity and intracellular localization of the PASTA kinase PrkC during Bacillus subtilis growth. Sci Rep 2018; 8:1660. [PMID: 29374241 PMCID: PMC5786024 DOI: 10.1038/s41598-018-20145-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/15/2018] [Indexed: 12/13/2022] Open
Abstract
The activity of the PrkC protein kinase is regulated in a sophisticated manner in Bacillus subtilis cells. In spores, in the presence of muropeptides, PrkC stimulates dormancy exit. The extracellular region containing PASTA domains binds peptidoglycan fragments to probably enhance the intracellular kinase activity. During exponential growth, the cell division protein GpsB interacts with the intracellular domain of PrkC to stimulate its activity. In this paper, we have reinvestigated the regulation of PrkC during exponential and stationary phases. We observed that, during exponential growth, neither its septal localization nor its activity are influenced by the addition of peptidoglycan fragments or by the deletion of one or all PASTA domains. However, Dynamic Light Scattering experiments suggest that peptidoglycan fragments bind specifically to PrkC and induce its oligomerization. In addition, during stationary phase, PrkC appeared evenly distributed in the cell wall and the deletion of one or all PASTA domains led to a non-activated kinase. We conclude that PrkC activation is not as straightforward as previously suggested and that regulation of its kinase activity via the PASTA domains and peptidoglycan fragments binding occurs when PrkC is not concentrated to the bacterial septum, but all over the cell wall in non-dividing bacillus cells.
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Affiliation(s)
- Frédérique Pompeo
- Laboratoire de Chimie Bactérienne, UMR 7283, IMM, CNRS, Aix Marseille Univ, 31 Chemin Joseph Aiguier, 13009, Marseille, France.
| | - Deborah Byrne
- Protein Expression Facility, IMM, CNRS, Aix Marseille Univ, 31 Chemin Joseph Aiguier, 13009, Marseille, France
| | - Dominique Mengin-Lecreulx
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud and Université Paris-Saclay, 91198, Gif-sur-Yvette, France
| | - Anne Galinier
- Laboratoire de Chimie Bactérienne, UMR 7283, IMM, CNRS, Aix Marseille Univ, 31 Chemin Joseph Aiguier, 13009, Marseille, France
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34
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Abstract
Bacterial endospores possess multiple integument layers, one of which is the cortex peptidoglycan wall. The cortex is essential for the maintenance of spore core dehydration and dormancy and contains structural modifications that differentiate it from vegetative cell peptidoglycan and determine its fate during spore germination. Following the engulfment stage of sporulation, the cortex is synthesized within the intermembrane space surrounding the forespore. Proteins responsible for cortex synthesis are produced in both the forespore and mother cell compartments. While some of these proteins also contribute to vegetative cell wall synthesis, others are sporulation specific. In order for the bacterial endospore to germinate and resume metabolism, the cortex peptidoglycan must first be degraded through the action of germination-specific lytic enzymes. These enzymes are present, yet inactive, in the dormant spore and recognize the muramic-δ-lactam modification present in the cortex. Germination-specific lytic enzymes across Bacillaceae and Clostridiaceae share this specificity determinant, which ensures that the spore cortex is hydrolyzed while the vegetative cell wall remains unharmed. Bacillus species tend to possess two redundant enzymes, SleB and CwlJ, capable of sufficient cortex degradation, while the clostridia have only one, SleC. Additional enzymes are often present that cannot initiate the cortex degradation process, but which can increase the rate of release of small fragments into the medium. Between the two families, the enzymes also differ in the enzymatic activities they possess and the mechanisms acting to restrict their activation until germination has been initiated.
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35
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Zhao H, Patel V, Helmann JD, Dörr T. Don't let sleeping dogmas lie: new views of peptidoglycan synthesis and its regulation. Mol Microbiol 2017; 106:847-860. [PMID: 28975672 DOI: 10.1111/mmi.13853] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 12/24/2022]
Abstract
Bacterial cell wall synthesis is the target for some of our most powerful antibiotics and has thus been the subject of intense research focus for more than 50 years. Surprisingly, we still lack a fundamental understanding of how bacteria build, maintain and expand their cell wall. Due to technical limitations, directly testing hypotheses about the coordination and biochemistry of cell wall synthesis enzymes or architecture has been challenging, and interpretation of data has therefore often relied on circumstantial evidence and implicit assumptions. A number of recent papers have exploited new technologies, like single molecule tracking and real-time, high resolution temporal mapping of cell wall synthesis processes, to address fundamental questions of bacterial cell wall biogenesis. The results have challenged established dogmas and it is therefore timely to integrate new data and old observations into a new model of cell wall biogenesis in rod-shaped bacteria.
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Affiliation(s)
- Heng Zhao
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - Vaidehi Patel
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - Tobias Dörr
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA.,Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
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36
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Sassine J, Xu M, Sidiq KR, Emmins R, Errington J, Daniel RA. Functional redundancy of division specific penicillin-binding proteins in Bacillus subtilis. Mol Microbiol 2017; 106:304-318. [PMID: 28792086 PMCID: PMC5656894 DOI: 10.1111/mmi.13765] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2017] [Indexed: 12/30/2022]
Abstract
Bacterial cell division involves the dynamic assembly of a diverse set of proteins that coordinate the invagination of the cell membrane and synthesis of cell wall material to create the new cell poles of the separated daughter cells. Penicillin-binding protein PBP 2B is a key cell division protein in Bacillus subtilis proposed to have a specific catalytic role in septal wall synthesis. Unexpectedly, we find that a catalytically inactive mutant of PBP 2B supports cell division, but in this background the normally dispensable PBP 3 becomes essential. Phenotypic analysis of pbpC mutants (encoding PBP 3) shows that PBP 2B has a crucial structural role in assembly of the division complex, independent of catalysis, and that its biochemical activity in septum formation can be provided by PBP 3. Bioinformatic analysis revealed a close sequence relationship between PBP 3 and Staphylococcus aureus PBP 2A, which is responsible for methicillin resistance. These findings suggest that mechanisms for rescuing cell division when the biochemical activity of PBP 2B is perturbed evolved prior to the clinical use of β-lactams.
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Affiliation(s)
- Jad Sassine
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AH, UK
| | - Meizhu Xu
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AH, UK
| | - Karzan R Sidiq
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AH, UK
| | - Robyn Emmins
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AH, UK
| | - Jeff Errington
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AH, UK
| | - Richard A Daniel
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AH, UK
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37
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Hu Y, Zheng Q, Wanek W. Flux Analysis of Free Amino Sugars and Amino Acids in Soils by Isotope Tracing with a Novel Liquid Chromatography/High Resolution Mass Spectrometry Platform. Anal Chem 2017; 89:9192-9200. [PMID: 28776982 PMCID: PMC5605124 DOI: 10.1021/acs.analchem.7b01938] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Soil fluxomics analysis can provide
pivotal information for understanding
soil biochemical pathways and their regulation, but direct measurement
methods are rare. Here, we describe an approach to measure soil extracellular
metabolite (amino sugar and amino acid) concentrations and fluxes
based on a 15N isotope pool dilution technique via liquid
chromatography and high-resolution mass spectrometry. We produced
commercially unavailable 15N and 13C labeled
amino sugars and amino acids by hydrolyzing peptidoglycan isolated
from isotopically labeled bacterial biomass and used them as tracers
(15N) and internal standards (13C). High-resolution
(Orbitrap Exactive) MS with a resolution of 50 000 allowed
us to separate different stable isotope labeled analogues across a
large range of metabolites. The utilization of 13C internal
standards greatly improved the accuracy and reliability of absolute
quantification. We successfully applied this method to two types of
soils and quantified the extracellular gross fluxes of 2 amino sugars,
18 amino acids, and 4 amino acid enantiomers. Compared to the influx
and efflux rates of most amino acids, similar ones were found for
glucosamine, indicating that this amino sugar is released through
peptidoglycan and chitin decomposition and serves as an important
nitrogen source for soil microorganisms. d-Alanine and d-glutamic acid derived from peptidoglycan decomposition exhibited
similar turnover rates as their l-enantiomers. This novel
approach offers new strategies to advance our understanding of the
production and transformation pathways of soil organic N metabolites,
including the unknown contributions of peptidoglycan and chitin decomposition
to soil organic N cycling.
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Affiliation(s)
- Yuntao Hu
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Research Network "Chemistry meets Microbiology", University of Vienna , Althanstraße 14, 1090 Vienna, Austria
| | - Qing Zheng
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Research Network "Chemistry meets Microbiology", University of Vienna , Althanstraße 14, 1090 Vienna, Austria
| | - Wolfgang Wanek
- Division of Terrestrial Ecosystem Research, Department of Microbiology and Ecosystem Science, Research Network "Chemistry meets Microbiology", University of Vienna , Althanstraße 14, 1090 Vienna, Austria
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38
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Abstract
Cellular mechanical properties play an integral role in bacterial survival and adaptation. Historically, the bacterial cell wall and, in particular, the layer of polymeric material called the peptidoglycan were the elements to which cell mechanics could be primarily attributed. Disrupting the biochemical machinery that assembles the peptidoglycan (e.g., using the β-lactam family of antibiotics) alters the structure of this material, leads to mechanical defects, and results in cell lysis. Decades after the discovery of peptidoglycan-synthesizing enzymes, the mechanisms that underlie their positioning and regulation are still not entirely understood. In addition, recent evidence suggests a diverse group of other biochemical elements influence bacterial cell mechanics, may be regulated by new cellular mechanisms, and may be triggered in different environmental contexts to enable cell adaptation and survival. This review summarizes the contributions that different biomolecular components of the cell wall (e.g., lipopolysaccharides, wall and lipoteichoic acids, lipid bilayers, peptidoglycan, and proteins) make to Gram-negative and Gram-positive bacterial cell mechanics. We discuss the contribution of individual proteins and macromolecular complexes in cell mechanics and the tools that make it possible to quantitatively decipher the biochemical machinery that contributes to bacterial cell mechanics. Advances in this area may provide insight into new biology and influence the development of antibacterial chemotherapies.
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Affiliation(s)
- George K Auer
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Douglas B Weibel
- Department of Biomedical Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.,Department of Biochemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States.,Department of Chemistry, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
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39
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Inhibition of Staphylococcus aureus Cell Wall Biosynthesis by Desleucyl-Oritavancin: a Quantitative Peptidoglycan Composition Analysis by Mass Spectrometry. J Bacteriol 2017; 199:JB.00278-17. [PMID: 28507244 DOI: 10.1128/jb.00278-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 05/07/2017] [Indexed: 11/20/2022] Open
Abstract
Oritavancin is a lipoglycopeptide antibiotic that exhibits potent activities against vancomycin-resistant Gram-positive pathogens. Oritavancin differs from vancomycin by a hydrophobic side chain attached to the drug disaccharide, which forms a secondary binding site to enable oritavancin binding to the cross-linked peptidoglycan in the cell wall. The mode of action of secondary binding site was investigated by measuring the changes in the peptidoglycan composition of Staphylococcus aureus grown in the presence of desleucyl-oritavancin at subinhibitory concentration using liquid chromatography-mass spectrometry (LC-MS). Desleucyl-oritavancin is an Edman degradation product of oritavancin that exhibits potent antibacterial activities despite the damaged d-Ala-d-Ala binding site due to its functional secondary binding site. Accurate quantitative peptidoglycan composition analysis based on 83 muropeptide ions determined that cell walls of S. aureus grown in the presence of desleucyl-oritavancin showed a reduction of peptidoglycan cross-linking, increased muropeptides with a tetrapeptide-stem structure, decreased O-acetylation of MurNAc, and increased N-deacetylation of GlcNAc. The changes in peptidoglycan composition suggest that desleucyl-oritavancin targets the peptidoglycan template to induce cell wall disorder and interferes with cell wall maturation.IMPORTANCE Oritavancin is a lipoglycopeptide antibiotic with a secondary binding site that targets the cross-linked peptidoglycan bridge structure in the cell wall. Even after the loss of its primary d-Ala-d-Ala binding site through Edman degradation, desleucyl-oritavancin exhibits potent antimicrobial activities through its still-functioning secondary binding site. In this study, we characterized the mode of action for desleucyl-oritavancin's secondary binding site using LC-MS. Peptidoglycan composition analysis of desleucyl-oritavancin-treated S. aureus was performed by determining the relative abundances of 83 muropeptide ions matched from a precalculated library through integrating extracted ion chromatograms. Our work highlights the use of quantitative peptidoglycan composition analysis by LC-MS to provide insights into the mode of action of glycopeptide antibiotics.
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40
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Pidgeon SE, Pires MM. Vancomycin-Dependent Response in Live Drug-Resistant Bacteria by Metabolic Labeling. Angew Chem Int Ed Engl 2017; 56:8839-8843. [DOI: 10.1002/anie.201704851] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Indexed: 12/17/2022]
Affiliation(s)
- Sean E. Pidgeon
- Department of Chemistry; Lehigh University; 6 E. Packer Avenue Bethlehem PA 18015 USA
| | - Marcos M. Pires
- Department of Chemistry; Lehigh University; 6 E. Packer Avenue Bethlehem PA 18015 USA
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41
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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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42
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Dajkovic A, Tesson B, Chauhan S, Courtin P, Keary R, Flores P, Marlière C, Filipe SR, Chapot-Chartier MP, Carballido-Lopez R. Hydrolysis of peptidoglycan is modulated by amidation of meso-diaminopimelic acid and Mg 2+ in Bacillus subtilis. Mol Microbiol 2017; 104:972-988. [PMID: 28317238 PMCID: PMC5485061 DOI: 10.1111/mmi.13673] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2017] [Indexed: 12/27/2022]
Abstract
The ability of excess Mg2+ to compensate the absence of cell wall related genes in Bacillus subtilis has been known for a long time, but the mechanism has remained obscure. Here, we show that the rigidity of wild‐type cells remains unaffected with excess Mg2+, but the proportion of amidated meso‐diaminopimelic (mDAP) acid in their peptidoglycan (PG) is significantly reduced. We identify the amidotransferase AsnB as responsible for mDAP amidation and show that the gene encoding it is essential without added Mg2+. Growth without excess Mg2+ causes ΔasnB mutant cells to deform and ultimately lyse. In cell regions with deformations, PG insertion is orderly and indistinguishable from the wild‐type. However, PG degradation is unevenly distributed along the sidewalls. Furthermore, ΔasnB mutant cells exhibit increased sensitivity to antibiotics targeting the cell wall. These results suggest that absence of amidated mDAP causes a lethal deregulation of PG hydrolysis that can be inhibited by increased levels of Mg2+. Consistently, we find that Mg2+ inhibits autolysis of wild‐type cells. We suggest that Mg2+ helps to maintain the balance between PG synthesis and hydrolysis in cell wall mutants where this balance is perturbed in favor of increased degradation.
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Affiliation(s)
- Alex Dajkovic
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Benoit Tesson
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Smita Chauhan
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Pascal Courtin
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Ruth Keary
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Pierre Flores
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | | | - Sérgio R Filipe
- Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, 2829-516, Portugal
| | | | - Rut Carballido-Lopez
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
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43
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Cell surface engineering of Bacillus subtilis improves production yields of heterologously expressed α-amylases. Microb Cell Fact 2017; 16:56. [PMID: 28376879 PMCID: PMC5379735 DOI: 10.1186/s12934-017-0674-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/31/2017] [Indexed: 11/24/2022] Open
Abstract
Background Bacillus subtilis is widely used as a cell factory for numerous heterologous proteins of commercial value and medical interest. To explore the possibility of further enhancing the secretion potential of this model bacterium, a library of engineered strains with modified cell surface components was constructed, and the corresponding influences on protein secretion were investigated by analyzing the secretion of α-amylase variants with either low-, neutral- or high- isoelectric points (pI). Results Relative to the wild-type strain, the presence of overall anionic membrane phospholipids (phosphatidylglycerol and cardiolipin) increased dramatically in the PssA-, ClsA- and double KO mutants, which resulted in an up to 47% higher secretion of α-amylase. Additionally, we demonstrated that the appropriate net charge of secreted targets (AmyTS-23, AmyBs and AmyBm) was beneficial for secretion efficiency as well. Conclusions In B. subtilis, the characteristics of cell membrane phospholipid bilayer and the pIs of heterologous α-amylases appear to be important for their secretion efficiency. These two factors can be engineered to reduce the electrostatic interaction between each other during the secretion process, which finally leads to a better secretion yield of α-amylases.
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44
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Determining bacteriophage endopeptidase activity using either fluorophore-quencher labeled peptides combined with liquid chromatography-mass spectrometry (LC-MS) or Förster resonance energy transfer (FRET) assays. PLoS One 2017; 12:e0173919. [PMID: 28296948 PMCID: PMC5352010 DOI: 10.1371/journal.pone.0173919] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/28/2017] [Indexed: 12/03/2022] Open
Abstract
The necessity of identifying novel methods to combat infections caused by antibiotic resistant bacteria is increasing each year. Recent advancements in the development of peptidoglycan hydrolases (e.g. lysins) from bacterial viruses (bacteriophages) have revealed the efficiency of this class of enzymes in treating serious bacterial infections. Though promising results have been obtained regarding the lethal action of lysin on bacterial pathogens both in vitro and in vivo, an often-overlooked factor in these studies is precisely identifying their peptidoglycan cleavage site. This knowledge would be useful for following the activity of the enzyme during development, without the need for whole-organism lytic assays. However, more importantly, it would enable the selection of lysins with different cleavage activities that would act synergistically for enhanced efficacy. Here, we have developed two new methods to accurately identify the cleavage site of lysins using liquid chromatography mass spectrometry (LC-MS) on peptidoglycan-like fluorophore-quencher modified synthetic peptides, as well as determining the enzymatic action and kinetics of the enzymes on modified peptides in a Förster resonance energy transfer (FRET) assay. These methods should facilitate progress within the lysin field, accelerating the development of therapeutic lysins to combat antibiotic resistant bacterial infections.
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45
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Morales Angeles D, Liu Y, Hartman AM, Borisova M, de Sousa Borges A, de Kok N, Beilharz K, Veening JW, Mayer C, Hirsch AKH, Scheffers DJ. Pentapeptide-rich peptidoglycan at the Bacillus subtilis cell-division site. Mol Microbiol 2017; 104:319-333. [PMID: 28118510 DOI: 10.1111/mmi.13629] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2017] [Indexed: 11/28/2022]
Abstract
Peptidoglycan (PG), the major component of the bacterial cell wall, is one large macromolecule. To allow for the different curvatures of PG at cell poles and division sites, there must be local differences in PG architecture and eventually also chemistry. Here we report such local differences in the Gram-positive rod-shaped model organism Bacillus subtilis. Single-cell analysis after antibiotic treatment and labeling of the cell wall with a fluorescent analogue of vancomycin or the fluorescent D-amino acid analogue (FDAA) HCC-amino-D-alanine revealed that PG at the septum contains muropeptides with unprocessed stem peptides (pentapeptides). Whereas these pentapeptides are normally shortened after incorporation into PG, this activity is reduced at division sites indicating either a lower local degree of PG crosslinking or a difference in PG composition, which could be a topological marker for other proteins. The pentapeptides remain partially unprocessed after division when they form the new pole of a cell. The accumulation of unprocessed PG at the division site is not caused by the activity of the cell division specific penicillin-binding protein 2B. To our knowledge, this is the first indication of local differences in the chemical composition of PG in Gram-positive bacteria.
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Affiliation(s)
- Danae Morales Angeles
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, The Netherlands
| | - Yun Liu
- Stratingh Institute for Chemistry, University of Groningen, The Netherlands
| | - Alwin M Hartman
- Stratingh Institute for Chemistry, University of Groningen, The Netherlands
| | - Marina Borisova
- Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Anabela de Sousa Borges
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, The Netherlands
| | - Niels de Kok
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, The Netherlands
| | - Katrin Beilharz
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, The Netherlands
| | - Jan-Willem Veening
- Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, The Netherlands.,Department of Fundamental Microbiology, Faculty of Biology and Medicine, University of Lausanne, Biophore Building, Lausanne, CH-1015, Switzerland
| | - Christoph Mayer
- Department of Biology, Interfaculty Institute of Microbiology and Infection Medicine Tübingen, University of Tübingen, Tübingen, Germany
| | - Anna K H Hirsch
- Stratingh Institute for Chemistry, University of Groningen, The Netherlands
| | - Dirk-Jan Scheffers
- Department of Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute University of Groningen, The Netherlands
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46
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Bacterial peptidoglycan with amidated meso-diaminopimelic acid evades NOD1 recognition: an insight into NOD1 structure–recognition. Biochem J 2016; 473:4573-4592. [DOI: 10.1042/bcj20160817] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/04/2016] [Accepted: 10/14/2016] [Indexed: 12/16/2022]
Abstract
Nucleotide-binding oligomerization domain-containing protein 1 (NOD1) is an intracellular pattern recognition receptor that recognizes bacterial peptidoglycan (PG) containing meso-diaminopimelic acid (mesoDAP) and activates the innate immune system. Interestingly, a few pathogenic and commensal bacteria modify their PG stem peptide by amidation of mesoDAP (mesoDAPNH2). In the present study, NOD1 stimulation assays were performed using bacterial PG containing mesoDAP (PGDAP) and mesoDAPNH2 (PGDAPNH2) to understand the differences in their biomolecular recognition mechanism. PGDAP was effectively recognized, whereas PGDAPNH2 showed reduced recognition by the NOD1 receptor. Restimulation of the NOD1 receptor, which was initially stimulated with PGDAP using PGDAPNH2, did not show any further NOD1 activation levels than with PGDAP alone. But the NOD1 receptor initially stimulated with PGDAPNH2 responded effectively to restimulation with PGDAP. The biomolecular structure–recognition relationship of the ligand-sensing leucine-rich repeat (LRR) domain of human NOD1 (NOD1–LRR) with PGDAP and PGDAPNH2 was studied by different computational techniques to further understand the molecular basis of our experimental observations. The d-Glu–mesoDAP motif of GMTPDAP, which is the minimum essential motif for NOD1 activation, was found involved in specific interactions at the recognition site, but the interactions of the corresponding d-Glu–mesoDAP motif of PGDAPNH2 occur away from the recognition site of the NOD1 receptor. Hot-spot residues identified for effective PG recognition by NOD1–LRR include W820, G821, D826 and N850, which are evolutionarily conserved across different host species. These integrated results thus successfully provided the atomic level and biochemical insights on how PGs containing mesoDAPNH2 evade NOD1–LRR receptor recognition.
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47
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Mengin-Lecreulx D, Lemaitre B. Structure and metabolism of peptidoglycan and molecular requirements allowing its detection by the Drosophila innate immune system. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519050110020601] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Peptidoglycan (murein) is a major essential and specific constituent of the bacterial cell wall. Its main function is to protect cells against the internal osmotic pressure and to maintain the characteristic cell shape. It also serves as a platform for the anchoring of specific proteins and other cell wall components. This giant macromolecule is composed of long glycan chains cross-linked by short peptides. Any alteration of the disaccharide—peptide basic unit results in a global change of peptidoglycan structure and properties. Such global variations are encountered in nature as conserved variations along phyletic lines but have sometimes been acquired as a result of mutations or as a mechanism of resistance against cell-wall targeted antibiotics. During bacterial cell growth and division, the peptidoglycan mesh is constantly broken down by a set of highly specific hydrolases in a maturation process allowing insertion of newly synthesized units in the pre-existing polymerized material. Depending on the bacterial species considered, degradation fragments are either released in the growth medium or efficiently re-utilized for synthesis of new murein in a sequence of events termed the recycling pathway. Peptidoglycan is one of the main pathogen-associated molecular patterns recognized by the host innate immune system. Variations of the structure and metabolism of this cell wall component have been exploited by host defense mechanisms for detection/identification of invading bacterial species. Modification of the peptidoglycan structure could also represent a mechanism allowing bacteria to escape these host defense systems.
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Affiliation(s)
- Dominique Mengin-Lecreulx
- Institut de Biochimie et Biophysique Moléculaire et Cellulaire, CNRS, Université Paris-Sud, Paris, France, -psud.fr
| | - Bruno Lemaitre
- Centre de Génétique Moléculaire, CNRS, Gif-sur-Yvette, France
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48
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Towards an automated analysis of bacterial peptidoglycan structure. Anal Bioanal Chem 2016; 409:551-560. [PMID: 27520322 PMCID: PMC5203844 DOI: 10.1007/s00216-016-9857-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 07/21/2016] [Accepted: 08/01/2016] [Indexed: 12/11/2022]
Abstract
Peptidoglycan (PG) is an essential component of the bacterial cell envelope. This macromolecule consists of glycan chains alternating N-acetylglucosamine and N-acetylmuramic acid, cross-linked by short peptides containing nonstandard amino acids. Structural analysis of PG usually involves enzymatic digestion of glycan strands and separation of disaccharide peptides by reversed-phase HPLC followed by collection of individual peaks for MALDI-TOF and/or tandem mass spectrometry. Here, we report a novel strategy using shotgun proteomics techniques for a systematic and unbiased structural analysis of PG using high-resolution mass spectrometry and automated analysis of HCD and ETD fragmentation spectra with the Byonic software. Using the PG of the nosocomial pathogen Clostridium difficile as a proof of concept, we show that this high-throughput approach allows the identification of all PG monomers and dimers previously described, leaving only disambiguation of 3–3 and 4–3 cross-linking as a manual step. Our analysis confirms previous findings that C. difficile peptidoglycans include mainly deacetylated N-acetylglucosamine residues and 3–3 cross-links. The analysis also revealed a number of low abundance muropeptides with peptide sequences not previously reported. The bacterial cell envelope includes plasma membrane, peptidoglycan, and surface layer. Peptidoglycan is unique to bacteria and the target of the most important antibiotics; here it is analyzed by mass spectrometry. ![]()
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49
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Sarkar S, Libby EA, Pidgeon SE, Dworkin J, Pires MM. In Vivo Probe of Lipid II-Interacting Proteins. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603441] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Sourav Sarkar
- Department of Chemistry; Lehigh University; Bethlehem PA 18015 USA
| | - Elizabeth A. Libby
- Department of Microbiology & Immunology; Columbia University; New York NY 10032 USA
| | - Sean E. Pidgeon
- Department of Chemistry; Lehigh University; Bethlehem PA 18015 USA
| | - Jonathan Dworkin
- Department of Microbiology & Immunology; Columbia University; New York NY 10032 USA
| | - Marcos M. Pires
- Department of Chemistry; Lehigh University; Bethlehem PA 18015 USA
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50
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Sarkar S, Libby EA, Pidgeon SE, Dworkin J, Pires MM. In Vivo Probe of Lipid II-Interacting Proteins. Angew Chem Int Ed Engl 2016; 55:8401-4. [PMID: 27225706 DOI: 10.1002/anie.201603441] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 04/25/2016] [Indexed: 11/11/2022]
Abstract
β-Lactams represent one of the most important classes of antibiotics discovered to date. These agents block Lipid II processing and cell wall biosynthesis through inactivation of penicillin-binding proteins (PBPs). PBPs enzymatically load cell wall building blocks from Lipid II carrier molecules onto the growing cell wall scaffold during growth and division. Lipid II, a bottleneck in cell wall biosynthesis, is the target of some of the most potent antibiotics in clinical use. Despite the immense therapeutic value of this biosynthetic pathway, the PBP-Lipid II association has not been established in live cells. To determine this key interaction, we designed an unnatural d-amino acid dipeptide that is metabolically incorporated into Lipid II molecules. By hijacking the peptidoglycan biosynthetic machinery, photoaffinity probes were installed in combination with click partners within Lipid II, thereby allowing, for the first time, demonstration of PBP interactions in vivo with Lipid II.
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Affiliation(s)
- Sourav Sarkar
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Elizabeth A Libby
- Department of Microbiology & Immunology, Columbia University, New York, NY, 10032, USA
| | - Sean E Pidgeon
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA
| | - Jonathan Dworkin
- Department of Microbiology & Immunology, Columbia University, New York, NY, 10032, USA
| | - Marcos M Pires
- Department of Chemistry, Lehigh University, Bethlehem, PA, 18015, USA.
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