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Liu X, de Bakker V, Heggenhougen MV, Mårli MT, Frøynes AH, Salehian Z, Porcellato D, Morales Angeles D, Veening JW, Kjos M. Genome-wide CRISPRi screens for high-throughput fitness quantification and identification of determinants for dalbavancin susceptibility in Staphylococcus aureus. mSystems 2024; 9:e0128923. [PMID: 38837392 PMCID: PMC11265419 DOI: 10.1128/msystems.01289-23] [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: 12/04/2023] [Accepted: 05/01/2024] [Indexed: 06/07/2024] Open
Abstract
Antibiotic resistance and tolerance remain a major problem for the treatment of staphylococcal infections. Identifying genes that influence antibiotic susceptibility could open the door to novel antimicrobial strategies, including targets for new synergistic drug combinations. Here, we developed a genome-wide CRISPR interference library for Staphylococcus aureus, demonstrated its use by quantifying gene fitness in different strains through CRISPRi-seq, and used it to identify genes that modulate susceptibility to the lipoglycopeptide dalbavancin. By exposing the library to sublethal concentrations of dalbavancin using both CRISPRi-seq and direct selection methods, we not only found genes previously reported to be involved in antibiotic susceptibility but also identified genes thus far unknown to affect antibiotic tolerance. Importantly, some of these genes could not have been detected by more conventional transposon-based knockout approaches because they are essential for growth, stressing the complementary value of CRISPRi-based methods. Notably, knockdown of a gene encoding the uncharacterized protein KapB specifically sensitizes the cells to dalbavancin, but not to other antibiotics of the same class, whereas knockdown of the Shikimate pathway showed the opposite effect. The results presented here demonstrate the promise of CRISPRi-seq screens to identify genes and pathways involved in antibiotic susceptibility and pave the way to explore alternative antimicrobial treatments through these insights.IMPORTANCEAntibiotic resistance is a challenge for treating staphylococcal infections. Identifying genes that affect how antibiotics work could help create new treatments. In our study, we made a CRISPR interference library for Staphylococcus aureus and used this to find which genes are critical for growth and also mapped genes that are important for antibiotic sensitivity, focusing on the lipoglycopeptide antibiotic dalbavancin. With this method, we identified genes that altered the sensitivity to dalbavancin upon knockdown, including genes involved in different cellular functions. CRISPRi-seq offers a means to uncover untapped antibiotic targets, including those that conventional screens would disregard due to their essentiality. This paves the way for the discovery of new ways to fight infections.
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Affiliation(s)
- Xue Liu
- Department of Pathogen, Biology, International Cancer Center, Shenzhen University Medical School, Shenzhen, Guangdong, China
- Department of Fundamental Microbiology, University of Lausanne, , Switzerland
| | - Vincent de Bakker
- Department of Fundamental Microbiology, University of Lausanne, , Switzerland
| | | | - Marita Torrissen Mårli
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Anette Heidal Frøynes
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Zhian Salehian
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Davide Porcellato
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Danae Morales Angeles
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, , Switzerland
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
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Litschko C, Di Domenico V, Schulze J, Li S, Ovchinnikova OG, Voskuilen T, Bethe A, Cifuente JO, Marina A, Budde I, Mast TA, Sulewska M, Berger M, Buettner FFR, Lowary TL, Whitfield C, Codée JDC, Schubert M, Guerin ME, Fiebig T. Transition transferases prime bacterial capsule polymerization. Nat Chem Biol 2024:10.1038/s41589-024-01664-8. [PMID: 38951648 DOI: 10.1038/s41589-024-01664-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 06/04/2024] [Indexed: 07/03/2024]
Abstract
Capsules are long-chain carbohydrate polymers that envelop the surfaces of many bacteria, protecting them from host immune responses. Capsule biosynthesis enzymes are potential drug targets and valuable biotechnological tools for generating vaccine antigens. Despite their importance, it remains unknown how structurally variable capsule polymers of Gram-negative pathogens are linked to the conserved glycolipid anchoring these virulence factors to the bacterial membrane. Using Actinobacillus pleuropneumoniae as an example, we demonstrate that CpsA and CpsC generate a poly(glycerol-3-phosphate) linker to connect the glycolipid with capsules containing poly(galactosylglycerol-phosphate) backbones. We reconstruct the entire capsule biosynthesis pathway in A. pleuropneumoniae serotypes 3 and 7, solve the X-ray crystal structure of the capsule polymerase CpsD, identify its tetratricopeptide repeat domain as essential for elongating poly(glycerol-3-phosphate) and show that CpsA and CpsC stimulate CpsD to produce longer polymers. We identify the CpsA and CpsC product as a wall teichoic acid homolog, demonstrating similarity between the biosynthesis of Gram-positive wall teichoic acid and Gram-negative capsules.
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Affiliation(s)
- Christa Litschko
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
- German Center for Infection Research, Partner Site Hannover-Braunschweig, Hannover, Germany
| | - Valerio Di Domenico
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Barakaldo, Spain
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology; Molecular Biology Institute of Barcelona, Spanish National Research Council, Barcelona Science Park, Tower R, Barcelona, Spain
| | - Julia Schulze
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Sizhe Li
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Olga G Ovchinnikova
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Thijs Voskuilen
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Andrea Bethe
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Javier O Cifuente
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Barakaldo, Spain
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Bizkaia Technology Park, Derio, Spain
| | - Alberto Marina
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Bizkaia Technology Park, Derio, Spain
| | - Insa Budde
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Tim A Mast
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Małgorzata Sulewska
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Monika Berger
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Falk F R Buettner
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
- Proteomics, Institute of Theoretical Medicine, Faculty of Medicine, University of Augsburg, Augsburg, Germany
| | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Jeroen D C Codée
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Mario Schubert
- Department of Biosciences and Medical Biology, University of Salzburg, Salzburg, Austria
- Department of Biology, Chemistry and Pharmacy, Free University of Berlin, Berlin, Germany
| | - Marcelo E Guerin
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, Barakaldo, Spain.
- Structural Glycobiology Laboratory, Department of Structural and Molecular Biology; Molecular Biology Institute of Barcelona, Spanish National Research Council, Barcelona Science Park, Tower R, Barcelona, Spain.
- Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Bizkaia Technology Park, Derio, Spain.
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain.
| | - Timm Fiebig
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany.
- German Center for Infection Research, Partner Site Hannover-Braunschweig, Hannover, Germany.
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Li FKK, Worrall LJ, Gale RT, Brown ED, Strynadka NCJ. Cryo-EM analysis of S. aureus TarL, a polymerase in wall teichoic acid biogenesis central to virulence and antibiotic resistance. SCIENCE ADVANCES 2024; 10:eadj3864. [PMID: 38416829 PMCID: PMC10901376 DOI: 10.1126/sciadv.adj3864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 01/23/2024] [Indexed: 03/01/2024]
Abstract
Wall teichoic acid (WTA), a covalent adduct of Gram-positive bacterial cell wall peptidoglycan, contributes directly to virulence and antibiotic resistance in pathogenic species. Polymerization of the Staphylococcus aureus WTA ribitol-phosphate chain is catalyzed by TarL, a member of the largely uncharacterized TagF-like family of membrane-associated enzymes. We report the cryo-electron microscopy structure of TarL, showing a tetramer that forms an extensive membrane-binding platform of monotopic helices. TarL is composed of an amino-terminal immunoglobulin-like domain and a carboxyl-terminal glycosyltransferase-B domain for ribitol-phosphate polymerization. The active site of the latter is complexed to donor substrate cytidine diphosphate-ribitol, providing mechanistic insights into the catalyzed phosphotransfer reaction. Furthermore, the active site is surrounded by electropositive residues that serve to retain the lipid-linked acceptor for polymerization. Our data advance general insight into the architecture and membrane association of the still poorly characterized monotopic membrane protein class and present molecular details of ribitol-phosphate polymerization that may aid in the design of new antimicrobials.
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Affiliation(s)
- Franco K K Li
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Liam J Worrall
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert T Gale
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Blood Research, The University of British Columbia, Vancouver, British Columbia, Canada
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Ye XX, Li KY, Li YF, Lu JN, Guo PT, Liu HY, Zhou LW, Xue SS, Huang CY, Fang SM, Gan QF. The effects of Clostridium butyricum on Ira rabbit growth performance, cecal microbiota and plasma metabolome. Front Microbiol 2022; 13:974337. [PMID: 36246250 PMCID: PMC9563143 DOI: 10.3389/fmicb.2022.974337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Clostridium butyricum (C. butyricum) can provide many benefits for animals’ growth performance and gut health. In this study, we investigated the effects of C. butyricum on the growth performance, cecal microbiota, and plasma metabolome in Ira rabbits. A total of 216 Ira rabbits at 32 days of age were randomly assigned to four treatments supplemented with basal diets containing 0 (CG), 200 (LC), 400 (MC), and 600 mg/kg (HC) C. butyricum for 35 days, respectively. In comparison with the CG group, C. butyricum supplementation significantly improved the average daily gain (ADG) and feed conversion rate (FCR) at 53 and 67 days of age (P < 0.05) and digestibilities of crude protein (CP) and crude fiber (CF) at 67 days of age (P < 0.05). The cellulase activity in the HC group was higher respectively by 50.14 and 90.13% at 53 and 67 days of age, than those in the CG groups (P < 0.05). Moreover, at 67 days of age, the diet supplemented with C. butyricum significantly increased the relative abundance of Verrucomicrobia at the phylum level (P < 0.05). Meanwhile, the concentrations of different metabolites, such as amino acids and purine, were significantly altered by C. butyricum (P < 0.05). In addition, 10 different genera were highly correlated with 52 different metabolites at 53-day-old and 6 different genera were highly correlated with 18 different metabolites at 67-day-old Ira rabbits. These findings indicated that the C. butyricum supplementation could significantly improve the growth performance by modifying the cecal microbiota structure and plasma metabolome of weaned Ira rabbits.
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Wall Teichoic Acids Facilitate the Release of Toxins from the Surface of Staphylococcus aureus. Microbiol Spectr 2022; 10:e0101122. [PMID: 35863033 PMCID: PMC9430763 DOI: 10.1128/spectrum.01011-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major feature of the pathogenicity of Staphylococcus aureus is its ability to secrete cytolytic toxins. This process involves the translocation of the toxins from the cytoplasm through the bacterial membrane and the cell wall to the external environment. The process of their movement through the membrane is relatively well defined, involving both general and toxin-specific secretory systems. Movement of the toxins through the cell wall was considered to involve the passive diffusion of the proteins through the porous cell wall structures; however, recent work suggests that this is more complex, and here we demonstrate a role for the wall teichoic acids (WTA) in this process. Utilizing a genome-wide association approach, we identified a polymorphism in the locus encoding the WTA biosynthetic machinery as associated with the cytolytic activity of the bacteria. We verified this association using an isogenic mutant set and found that WTA are required for the release of several cytolytic toxins from the bacterial cells. We show that this effect is mediated by a change in the electrostatic charge across the cell envelope that results from the loss of WTA. As a major target for the development of novel therapeutics, it is important that we fully understand the entire process of cytolytic toxin production and release. These findings open up a new aspect to the process of toxin release by a major human pathogen while also demonstrating that clinical isolates can utilize WTA production to vary their cytotoxicity, thereby altering their pathogenic capabilities. IMPORTANCE The production and release of cytolytic toxins is a critical aspect for the pathogenicity of many bacterial pathogens. In this study, we demonstrate a role for wall teichoic acids, molecules that are anchored to the peptidoglycan of the bacterial cell wall, in the release of toxins from S. aureus cells into the extracellular environment. Our findings suggest that this effect is mediated by a gradient of electrostatic charge which the presence of the negatively charged WTA molecules create across the cell envelope. This work brings an entirely new aspect to our understanding of the cytotoxicity of S. aureus and demonstrates a further means by which this major human pathogen can adapt its pathogenic capabilities.
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6
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Gao X, Yu Z, Tang X, Zhang H, Peng L, Li J. Augmented antibacterial mechanism of ZnO nanoparticles by labyrinthian-channel configuration of maize-stalk carbohydrate columns and sustainable strategy for water decontamination. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129258. [PMID: 35739777 DOI: 10.1016/j.jhazmat.2022.129258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/21/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Zinc oxide nanoparticles (ZnO NPs) as a broad-spectrum germicide in environmental remediation applications, is hindered by mild toxicity to organisms during water sterilization. To solve this dilemma, this work provided an eco-benign approach to utilize maize stalk with natural labyrinthine-channel configuration simultaneously acting as microbe trap and bactericide carrier to arouse bactericidal response of ZnO NPs. The preparation comprises in-situ growing ZnO NPs, accompanied by nanoscale delignification, leading to formed carbohydrate complex retaining the intricately porous structure of the stalk. Assembled by maize-stalk carbohydrate (MSC) composites with 9 short composites in serial, the elimination of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) reached up 6.7 and 4.8 orders of magnitude, respectively. Labyrinth-framework MSC provided favorable sites for fusiform flower-like ZnO NPs to strongly adsorb (adsorption energy 5.5-11.7 eV) phosphoryl-involved biomacromolecules of bacterial envelops, causing generation of stable Zn-P and Zn-O(H), then cell incompleteness, cellular redox imbalance and DNA damage. Breakthrough analysis exposed the MSC/ZnO-filter possessing remarkable features of antibacterial exhaustion rate (~ 1.06 g/L) and capacity (~ 9.6 × 109 CFU/g) which were comparable with Ag-based composites. As evaluated by the logistic and Gompertz models, the filters effectively sterilized 0.97-10 L of environmental waters to meet the requirements of drinking water.
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Affiliation(s)
- Xin Gao
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, PR China; CAS Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, Zhejiang, PR China
| | - Zhe Yu
- School of Materials, Sun Yat-Sen University, Guangzhou 510275, Guangdong, PR China
| | - Xiaoning Tang
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, PR China
| | - Heng Zhang
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, PR China
| | - Lincai Peng
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, PR China.
| | - Jiaqi Li
- Faculty of Chemical Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, PR China
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7
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Harden MM, Anderson ME, Grossman AD. A
CRISPR
interference screen reveals a role for cell wall teichoic acids in conjugation in
Bacillus subtilis. Mol Microbiol 2022; 117:1366-1383. [PMID: 35490406 PMCID: PMC9324163 DOI: 10.1111/mmi.14914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 11/30/2022]
Abstract
Conjugative elements are widespread in bacteria and include plasmids and integrative and conjugative elements (ICEs). They transfer from donor to recipient cells via an element‐encoded type IV secretion system. These elements interact with and utilize host functions for their lifecycles. We sought to identify essential host genes involved in the lifecycle of the integrative and conjugative element ICEBs1 of Bacillus subtilis. We constructed a library of strains for inducible knockdown of essential B. subtilis genes using CRISPR interference. Each strain expressed one guide RNA in ICEBs1. We induced partial interference of essential genes and identified those that caused an acute defect in acquisition of ICEBs1 by recipient cells. This screen revealed that reducing expression of genes needed for synthesis of cell wall teichoic acids caused a decrease in conjugation. Using three different ways to reduce their synthesis, we found that wall teichoic acids were necessary in both donors and recipients for efficient conjugative transfer of ICEBs1. Further, we found that depletion of wall teichoic acids caused cells involved in ICEBs1 conjugation to die, most likely from damage to the cell envelope. Our results indicate that wall teichoic acids help protect against envelope stress caused by active conjugation machines.
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Affiliation(s)
- M. Michael Harden
- Department of Biology Massachusetts Institute of Technology Cambridge, MA 02139
| | - Mary E. Anderson
- Department of Biology Massachusetts Institute of Technology Cambridge, MA 02139
| | - Alan D. Grossman
- Department of Biology Massachusetts Institute of Technology Cambridge, MA 02139
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Martinez OE, Mahoney BJ, Goring AK, Yi SW, Tran DP, Cascio D, Phillips ML, Muthana MM, Chen X, Jung ME, Loo JA, Clubb RT. Insight into the molecular basis of substrate recognition by the wall teichoic acid glycosyltransferase TagA. J Biol Chem 2021; 298:101464. [PMID: 34864059 PMCID: PMC8784642 DOI: 10.1016/j.jbc.2021.101464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/18/2021] [Accepted: 11/22/2021] [Indexed: 11/30/2022] Open
Abstract
Wall teichoic acid (WTA) polymers are covalently affixed to the Gram-positive bacterial cell wall and have important functions in cell elongation, cell morphology, biofilm formation, and β-lactam antibiotic resistance. The first committed step in WTA biosynthesis is catalyzed by the TagA glycosyltransferase (also called TarA), a peripheral membrane protein that produces the conserved linkage unit, which joins WTA to the cell wall peptidoglycan. TagA contains a conserved GT26 core domain followed by a C-terminal polypeptide tail that is important for catalysis and membrane binding. Here, we report the crystal structure of the Thermoanaerobacter italicus TagA enzyme bound to UDP-N-acetyl-d-mannosamine, revealing the molecular basis of substrate binding. Native MS experiments support the model that only monomeric TagA is enzymatically active and that it is stabilized by membrane binding. Molecular dynamics simulations and enzyme activity measurements indicate that the C-terminal polypeptide tail facilitates catalysis by encapsulating the UDP-N-acetyl-d-mannosamine substrate, presenting three highly conserved arginine residues to the active site that are important for catalysis (R214, R221, and R224). From these data, we present a mechanistic model of catalysis that ascribes functions for these residues. This work could facilitate the development of new antimicrobial compounds that disrupt WTA biosynthesis in pathogenic bacteria.
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Affiliation(s)
- Orlando E Martinez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
| | - Brendan J Mahoney
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
| | - Andrew K Goring
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
| | - Sung-Wook Yi
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
| | - Denise P Tran
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
| | - Duilio Cascio
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
| | - Martin L Phillips
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
| | - Musleh M Muthana
- Department of Chemistry, University of California, Davis, California, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, California, USA
| | - Michael E Jung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA; UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA.
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9
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Lavelle K, Sinderen DV, Mahony J. Cell wall polysaccharides of Gram positive ovococcoid bacteria and their role as bacteriophage receptors. Comput Struct Biotechnol J 2021; 19:4018-4031. [PMID: 34377367 PMCID: PMC8327497 DOI: 10.1016/j.csbj.2021.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 11/23/2022] Open
Abstract
Gram-positive bacterial cell walls are characterised by the presence of a thick peptidoglycan layer which provides protection from extracellular stresses, maintains cell integrity and determines cell morphology, while it also serves as a foundation to anchor a number of crucial polymeric structures. For ovococcal species, including streptococci, enterococci and lactococci, such structures are represented by rhamnose-containing cell wall polysaccharides, which at least in some instances appear to serve as a functional replacement for wall teichoic acids. The biochemical composition of several streptococcal, lactococcal and enterococcal rhamnose-containing cell wall polysaccharides have been elucidated, while associated functional genomic analyses have facilitated the proposition of models for individual biosynthetic pathways. Here, we review the genomic loci which encode the enzymatic machinery to produce rhamnose-containing, cell wall-associated polysaccharide (Rha cwps) structures of the afore-mentioned ovococcal bacteria with particular emphasis on gene content, biochemical structure and common biosynthetic steps. Furthermore, we discuss the role played by these saccharidic polymers as receptors for bacteriophages and the important role phages play in driving Rha cwps diversification and evolution.
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Affiliation(s)
- Katherine Lavelle
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland
| | - Jennifer Mahony
- School of Microbiology & APC Microbiome Ireland, University College Cork, Western Road, Cork T12 YT20, Ireland
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LytR-CpsA-Psr Glycopolymer Transferases: Essential Bricks in Gram-Positive Bacterial Cell Wall Assembly. Int J Mol Sci 2021; 22:ijms22020908. [PMID: 33477538 PMCID: PMC7831098 DOI: 10.3390/ijms22020908] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/28/2022] Open
Abstract
The cell walls of Gram-positive bacteria contain a variety of glycopolymers (CWGPs), a significant proportion of which are covalently linked to the peptidoglycan (PGN) scaffolding structure. Prominent CWGPs include wall teichoic acids of Staphylococcus aureus, streptococcal capsules, mycobacterial arabinogalactan, and rhamnose-containing polysaccharides of lactic acid bacteria. CWGPs serve important roles in bacterial cellular functions, morphology, and virulence. Despite evident differences in composition, structure and underlaying biosynthesis pathways, the final ligation step of CWGPs to the PGN backbone involves a conserved class of enzymes-the LytR-CpsA-Psr (LCP) transferases. Typically, the enzymes are present in multiple copies displaying partly functional redundancy and/or preference for a distinct CWGP type. LCP enzymes require a lipid-phosphate-linked glycan precursor substrate and catalyse, with a certain degree of promiscuity, CWGP transfer to PGN of different maturation stages, according to in vitro evidence. The prototype attachment mode is that to the C6-OH of N-acetylmuramic acid residues via installation of a phosphodiester bond. In some cases, attachment proceeds to N-acetylglucosamine residues of PGN-in the case of the Streptococcus agalactiae capsule, even without involvement of a phosphate bond. A novel aspect of LCP enzymes concerns a predicted role in protein glycosylation in Actinomyces oris. Available crystal structures provide further insight into the catalytic mechanism of this biologically important class of enzymes, which are gaining attention as new targets for antibacterial drug discovery to counteract the emergence of multidrug resistant bacteria.
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11
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Discovery of an antivirulence compound that reverses β-lactam resistance in MRSA. Nat Chem Biol 2019; 16:143-149. [PMID: 31768032 DOI: 10.1038/s41589-019-0401-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 09/17/2019] [Accepted: 10/07/2019] [Indexed: 02/06/2023]
Abstract
Staphylococcus aureus is the leading cause of infections worldwide, and methicillin-resistant strains (MRSA) are emerging. New strategies are urgently needed to overcome this threat. Using a cell-based screen of ~45,000 diverse synthetic compounds, we discovered a potent bioactive, MAC-545496, that reverses β-lactam resistance in the community-acquired MRSA USA300 strain. MAC-545496 could also serve as an antivirulence agent alone; it attenuates MRSA virulence in Galleria mellonella larvae. MAC-545496 inhibits biofilm formation and abrogates intracellular survival in macrophages. Mechanistic characterization revealed MAC-545496 to be a nanomolar inhibitor of GraR, a regulator that responds to cell-envelope stress and is an important virulence factor and determinant of antibiotic resistance. The small molecule discovered herein is an inhibitor of GraR function. MAC-545496 has value as a research tool to probe the GraXRS regulatory system and as an antibacterial lead series of a mechanism to combat drug-resistant Staphylococcal infections.
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12
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Hager FF, Sützl L, Stefanović C, Blaukopf M, Schäffer C. Pyruvate Substitutions on Glycoconjugates. Int J Mol Sci 2019; 20:E4929. [PMID: 31590345 PMCID: PMC6801904 DOI: 10.3390/ijms20194929] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/25/2019] [Accepted: 09/27/2019] [Indexed: 12/15/2022] Open
Abstract
Glycoconjugates are the most diverse biomolecules of life. Mostly located at the cell surface, they translate into cell-specific "barcodes" and offer a vast repertoire of functions, including support of cellular physiology, lifestyle, and pathogenicity. Functions can be fine-tuned by non-carbohydrate modifications on the constituting monosaccharides. Among these modifications is pyruvylation, which is present either in enol or ketal form. The most commonly best-understood example of pyruvylation is enol-pyruvylation of N-acetylglucosamine, which occurs at an early stage in the biosynthesis of the bacterial cell wall component peptidoglycan. Ketal-pyruvylation, in contrast, is present in diverse classes of glycoconjugates, from bacteria to algae to yeast-but not in humans. Mild purification strategies preventing the loss of the acid-labile ketal-pyruvyl group have led to a collection of elucidated pyruvylated glycan structures. However, knowledge of involved pyruvyltransferases creating a ring structure on various monosaccharides is scarce, mainly due to the lack of knowledge of fingerprint motifs of these enzymes and the unavailability of genome sequences of the organisms undergoing pyruvylation. This review compiles the current information on the widespread but under-investigated ketal-pyruvylation of monosaccharides, starting with different classes of pyruvylated glycoconjugates and associated functions, leading to pyruvyltransferases, their specificity and sequence space, and insight into pyruvate analytics.
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Affiliation(s)
- Fiona F Hager
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria.
| | - Leander Sützl
- Department of Food Science and Technology, Food Biotechnology Laboratory, Muthgasse 11, Universität für Bodenkultur Wien, A-1190 Vienna, Austria.
| | - Cordula Stefanović
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria.
| | - Markus Blaukopf
- Department of Chemistry, Division of Organic Chemistry, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria.
| | - Christina Schäffer
- Department of NanoBiotechnology, NanoGlycobiology unit, Universität für Bodenkultur Wien, Muthgasse 11, A-1190 Vienna, Austria.
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13
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Abstract
Bacteria in the genus Staphylococcus are important targets for phage therapy due to their prevalence as pathogens and increasing antibiotic resistance. Here we review Staphylococcus outer surface features and specific phage resistance mechanisms that define the host range, the set of strains that an individual phage can potentially infect. Phage infection goes through five distinct phases: attachment, uptake, biosynthesis, assembly, and lysis. Adsorption inhibition, encompassing outer surface teichoic acid receptor alteration, elimination, or occlusion, limits successful phage attachment and entry. Restriction-modification systems (in particular, type I and IV systems), which target phage DNA inside the cell, serve as the major barriers to biosynthesis as well as transduction and horizontal gene transfer between clonal complexes and species. Resistance to late stages of infection occurs through mechanisms such as assembly interference, in which staphylococcal pathogenicity islands siphon away superinfecting phage proteins to package their own DNA. While genes responsible for teichoic acid biosynthesis, capsule, and restriction-modification are found in most Staphylococcus strains, a variety of other host range determinants (e.g., clustered regularly interspaced short palindromic repeats, abortive infection, and superinfection immunity) are sporadic. The fitness costs of phage resistance through teichoic acid structure alteration could make staphylococcal phage therapies promising, but host range prediction is complex because of the large number of genes involved, and the roles of many of these are unknown. In addition, little is known about the genetic determinants that contribute to host range expansion in the phages themselves. Future research must identify host range determinants, characterize resistance development during infection and treatment, and examine population-wide genetic background effects on resistance selection.
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Affiliation(s)
- Abraham G Moller
- Program in Microbiology and Molecular Genetics (MMG), Graduate Division of Biological and Biomedical Sciences (GDBBS), Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Jodi A Lindsay
- Institute of Infection and Immunity, St. George's, University of London, London, United Kingdom
| | - Timothy D Read
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
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14
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Structure and mechanism of TagA, a novel membrane-associated glycosyltransferase that produces wall teichoic acids in pathogenic bacteria. PLoS Pathog 2019; 15:e1007723. [PMID: 31002736 PMCID: PMC6493773 DOI: 10.1371/journal.ppat.1007723] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 05/01/2019] [Accepted: 03/21/2019] [Indexed: 11/19/2022] Open
Abstract
Staphylococcus aureus and other bacterial pathogens affix wall teichoic acids (WTAs) to their surface. These highly abundant anionic glycopolymers have critical functions in bacterial physiology and their susceptibility to β-lactam antibiotics. The membrane-associated TagA glycosyltransferase (GT) catalyzes the first-committed step in WTA biosynthesis and is a founding member of the WecB/TagA/CpsF GT family, more than 6,000 enzymes that synthesize a range of extracellular polysaccharides through a poorly understood mechanism. Crystal structures of TagA from T. italicus in its apo- and UDP-bound states reveal a novel GT fold, and coupled with biochemical and cellular data define the mechanism of catalysis. We propose that enzyme activity is regulated by interactions with the bilayer, which trigger a structural change that facilitates proper active site formation and recognition of the enzyme's lipid-linked substrate. These findings inform upon the molecular basis of WecB/TagA/CpsF activity and could guide the development of new anti-microbial drugs.
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15
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El-Halfawy OM, Brown ED. High-Throughput Screening for Inhibitors of Wall Teichoic Acid Biosynthesis in Staphylococcus aureus. Methods Mol Biol 2019; 1954:297-308. [PMID: 30864141 DOI: 10.1007/978-1-4939-9154-9_23] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The world is heading toward a dangerous post-antibiotic era where antibiotics fail to treat infections. Staphylococcus aureus is the leading cause of healthcare-associated infections worldwide, and an ever-increasing percentage of them are methicillin-resistant (MRSA). New strategies are urgently needed to combat this pathogen. Wall teichoic acids (WTA) in S. aureus are polyribitol phosphate polymers that play important roles in virulence and resistance to β-lactam antibiotics. Here, we describe a high-throughput whole-cell screening platform for inhibitors targeting WTA biosynthesis. This platform takes advantage of the unique dispensability patterns of genes encoding WTA biosynthesis. We further describe follow-up dose-response assays to identify WTA inhibitors among the primary bioactives. WTA inhibitors offer an exciting opportunity for the development of novel antibacterial leads of unique mechanism in the fight against drug-resistant staphylococcal infections.
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Affiliation(s)
- Omar M El-Halfawy
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
- Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, ON, Canada
- Microbiology and Immunology Department, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.
- Michael G. DeGroote Institute of Infectious Disease Research, McMaster University, Hamilton, ON, Canada.
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16
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Hager FF, López-Guzmán A, Krauter S, Blaukopf M, Polter M, Brockhausen I, Kosma P, Schäffer C. Functional Characterization of Enzymatic Steps Involved in Pyruvylation of Bacterial Secondary Cell Wall Polymer Fragments. Front Microbiol 2018; 9:1356. [PMID: 29997588 PMCID: PMC6030368 DOI: 10.3389/fmicb.2018.01356] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 06/05/2018] [Indexed: 12/15/2022] Open
Abstract
Various mechanisms of protein cell surface display have evolved during bacterial evolution. Several Gram-positive bacteria employ S-layer homology (SLH) domain-mediated sorting of cell-surface proteins and concomitantly engage a pyruvylated secondary cell-wall polymer as a cell-wall ligand. Specifically, pyruvate ketal linked to β-D-ManNAc is regarded as an indispensable epitope in this cell-surface display mechanism. That secondary cell wall polymer (SCWP) pyruvylation and SLH domain-containing proteins are functionally coupled is supported by the presence of an ortholog of the predicted pyruvyltransferase CsaB in bacterial genomes, such as those of Bacillus anthracis and Paenibacillus alvei. The P. alvei SCWP, consisting of pyruvylated disaccharide repeats [→4)-β-D-GlcNAc-(1→3)-4,6-Pyr-β-D-ManNAc-(1→] serves as a model to investigate the widely unexplored pyruvylation reaction. Here, we reconstituted the underlying enzymatic pathway in vitro in combination with synthesized compounds, used mass spectrometry, and nuclear magnetic resonance spectroscopy for product characterization, and found that CsaB-catalyzed pyruvylation of β-D-ManNAc occurs at the stage of the lipid-linked repeat. We produced the P. alvei TagA (PAV_RS07420) and CsaB (PAV_RS07425) enzymes as recombinant, tagged proteins, and using a synthetic 11-phenoxyundecyl-diphosphoryl-α-GlcNAc acceptor, we uncovered that TagA is an inverting UDP-α-D-ManNAc:GlcNAc-lipid carrier transferase, and that CsaB is a pyruvyltransferase, with synthetic UDP-α-D-ManNAc and phosphoenolpyruvate serving as donor substrates. Next, to substitute for the UDP-α-D-ManNAc substrate, the recombinant UDP-GlcNAc-2-epimerase MnaA (PAV_RS07610) of P. alvei was included in this in vitro reconstitution system. When all three enzymes, their substrates and the lipid-linked GlcNAc primer were combined in a one-pot reaction, a lipid-linked SCWP repeat precursor analog was obtained. This work highlights the biochemical basis of SCWP biosynthesis and bacterial pyruvyl transfer.
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Affiliation(s)
- Fiona F Hager
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
| | - Arturo López-Guzmán
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
| | - Simon Krauter
- Division of Organic Chemistry, Department of Chemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Markus Blaukopf
- Division of Organic Chemistry, Department of Chemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Mathias Polter
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
| | - Inka Brockhausen
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Paul Kosma
- Division of Organic Chemistry, Department of Chemistry, Universität für Bodenkultur Wien, Vienna, Austria
| | - Christina Schäffer
- NanoGlycobiology Unit, Department of NanoBiotechnology, Universität für Bodenkultur Wien, Vienna, Austria
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17
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Caveney NA, Li FK, Strynadka NC. Enzyme structures of the bacterial peptidoglycan and wall teichoic acid biogenesis pathways. Curr Opin Struct Biol 2018; 53:45-58. [PMID: 29885610 DOI: 10.1016/j.sbi.2018.05.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/08/2018] [Accepted: 05/16/2018] [Indexed: 01/08/2023]
Abstract
The bacterial cell wall is a complex polymeric structure with essential roles in defence, survival and pathogenesis. Common to both Gram-positive and Gram-negative bacteria is the mesh-like peptidoglycan sacculus that surrounds the outer leaflet of the cytoplasmic membrane. Recent crystallographic studies of enzymes that comprise the peptidoglycan biosynthetic pathway have led to significant new understanding of all stages. These include initial multi-step cytosolic formation of sugar-pentapeptide precursors, transfer of the precursors to activated polyprenyl lipids at the membrane inner leaflet and flippase mediated relocalization of the resulting lipid II precursors to the outer leaflet where glycopolymerization and subsequent peptide crosslinking are finalized. Additional, species-specific enzymes allow customized peptidoglycan modifications and biosynthetic regulation that are important to bacterial virulence and survival. These studies have reinforced the unique and specific catalytic mechanisms at play in cell wall biogenesis and expanded the atomic foundation to develop novel, structure guided, antibacterial agents.
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Affiliation(s)
- Nathanael A Caveney
- University of British Columbia, Biochemistry and Molecular Biology and the Center for Blood Research, Rm 4350 Life Sciences Center, 2350 Health Sciences Mall, Vancouver V6T 1Z3 Canada
| | - Franco Kk Li
- University of British Columbia, Biochemistry and Molecular Biology and the Center for Blood Research, Rm 4350 Life Sciences Center, 2350 Health Sciences Mall, Vancouver V6T 1Z3 Canada
| | - Natalie Cj Strynadka
- University of British Columbia, Biochemistry and Molecular Biology and the Center for Blood Research, Rm 4350 Life Sciences Center, 2350 Health Sciences Mall, Vancouver V6T 1Z3 Canada.
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18
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Ng V, Kuehne SA, Chan WC. Rational Design and Synthesis of Modified Teixobactin Analogues: In Vitro Antibacterial Activity against Staphylococcus aureus
, Propionibacterium acnes
and Pseudomonas aeruginosa. Chemistry 2018; 24:9136-9147. [DOI: 10.1002/chem.201801423] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Vivian Ng
- School of Pharmacy; Centre for Biomolecular Sciences; University of Nottingham; University Park Nottingham NG7 2RD United Kingdom
| | - Sarah A. Kuehne
- School of Dentistry; Institute for Microbiology and Infection; University of Birmingham; Birmingham B5 7EG United Kingdom
| | - Weng C. Chan
- School of Pharmacy; Centre for Biomolecular Sciences; University of Nottingham; University Park Nottingham NG7 2RD United Kingdom
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19
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Abstract
Bacillus anthracis, the anthrax agent, is a member of the Bacillus cereus sensu lato group, which includes invasive pathogens of mammals or insects as well as nonpathogenic environmental strains. The genes for anthrax pathogenesis are located on two large virulence plasmids. Similar virulence plasmids have been acquired by other B. cereus strains and enable the pathogenesis of anthrax-like diseases. Among the virulence factors of B. anthracis is the S-layer-associated protein BslA, which endows bacilli with invasive attributes for mammalian hosts. BslA surface display and function are dependent on the bacterial S-layer, whose constituents assemble by binding to the secondary cell wall polysaccharide (SCWP) via S-layer homology (SLH) domains. B. anthracis and other pathogenic B. cereus isolates harbor genes for the secretion of S-layer proteins, for S-layer assembly, and for synthesis of the SCWP. We review here recent insights into the assembly and function of the S-layer and the SCWP.
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Affiliation(s)
- Dominique Missiakas
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois 60649.,Department of Microbiology, University of Chicago, Chicago, Illinois 60637;
| | - Olaf Schneewind
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois 60649.,Department of Microbiology, University of Chicago, Chicago, Illinois 60637;
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20
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Deficiency of RgpG Causes Major Defects in Cell Division and Biofilm Formation, and Deficiency of LytR-CpsA-Psr Family Proteins Leads to Accumulation of Cell Wall Antigens in Culture Medium by Streptococcus mutans. Appl Environ Microbiol 2017; 83:AEM.00928-17. [PMID: 28687645 DOI: 10.1128/aem.00928-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/29/2017] [Indexed: 12/20/2022] Open
Abstract
Streptococcus mutans is known to possess rhamnose-glucose polysaccharide (RGP), a major cell wall antigen. S. mutans strains deficient in rgpG, encoding the first enzyme of the RGP biosynthesis pathway, were constructed by allelic exchange. The rgpG deficiency had no effect on growth rate but caused major defects in cell division and altered cell morphology. Unlike the coccoid wild type, the rgpG mutant existed primarily in chains of swollen, "squarish" dividing cells. Deficiency of rgpG also causes significant reduction in biofilm formation (P < 0.01). Double and triple mutants with deficiency in brpA and/or psr, genes coding for the LytR-CpsA-Psr family proteins BrpA and Psr, which were previously shown to play important roles in cell envelope biogenesis, were constructed using the rgpG mutant. There were no major differences in growth rates between the wild-type strain and the rgpG brpA and rgpG psr double mutants, but the growth rate of the rgpG brpA psr triple mutant was reduced drastically (P < 0.001). Under transmission electron microscopy, both double mutants resembled the rgpG mutant, while the triple mutant existed as giant cells with multiple asymmetric septa. When analyzed by immunoblotting, the rgpG mutant displayed major reductions in cell wall antigens compared to the wild type, while little or no signal was detected with the double and triple mutants and the brpA and psr single mutants. These results suggest that RgpG in S. mutans plays a critical role in cell division and biofilm formation and that BrpA and Psr may be responsible for attachment of cell wall antigens to the cell envelope.IMPORTANCEStreptococcus mutans, a major etiological agent of human dental caries, produces rhamnose-glucose polysaccharide (RGP) as the major cell wall antigen. This study provides direct evidence that deficiency of RgpG, the first enzyme of the RGP biosynthesis pathway, caused major defects in cell division and morphology and reduced biofilm formation by S. mutans, indicative of a significant role of RGP in cell division and biofilm formation in S. mutans These results are novel not only in S. mutans, but also other streptococci that produce RGP. This study also shows that the LytR-CpsA-Psr family proteins BrpA and Psr in S. mutans are involved in attachment of RGP and probably other cell wall glycopolymers to the peptidoglycan. In addition, the results also suggest that BrpA and Psr may play a direct role in cell division and biofilm formation in S. mutans This study reveals new potential targets to develop anticaries therapeutics.
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21
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Matano LM, Morris HG, Hesser AR, Martin SES, Lee W, Owens TW, Laney E, Nakaminami H, Hooper D, Meredith TC, Walker S. Antibiotic That Inhibits the ATPase Activity of an ATP-Binding Cassette Transporter by Binding to a Remote Extracellular Site. J Am Chem Soc 2017; 139:10597-10600. [PMID: 28727445 DOI: 10.1021/jacs.7b04726] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Antibiotic-resistant strains of Staphylococcus aureus pose a major threat to human health and there is an ongoing need for new antibiotics to treat resistant infections. In a high throughput screen (HTS) of 230 000 small molecules designed to identify bioactive wall teichoic acid (WTA) inhibitors, we identified one hit, which was expanded through chemical synthesis into a small panel of potent compounds. We showed that these compounds target TarG, the transmembrane component of the two-component ATP-binding cassette (ABC) transporter TarGH, which exports WTA precursors to the cell surface for attachment to peptidoglycan. We purified, for the first time, a WTA transporter and have reconstituted ATPase activity in proteoliposomes. We showed that this new compound series inhibits TarH-catalyzed ATP hydrolysis even though the binding site maps to TarG near the opposite side of the membrane. These are the first ABC transporter inhibitors shown to block ATPase activity by binding to the transmembrane domain. The compounds have potential as therapeutic agents to treat S. aureus infections, and purification of the transmembrane transporter will enable further development.
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Affiliation(s)
- Leigh M Matano
- Department of Microbiology and Immunobiology, Harvard University , 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Heidi G Morris
- Department of Microbiology and Immunobiology, Harvard University , 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Anthony R Hesser
- Department of Microbiology and Immunobiology, Harvard University , 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Sara E S Martin
- Department of Microbiology and Immunobiology, Harvard University , 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Wonsik Lee
- Department of Microbiology and Immunobiology, Harvard University , 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Tristan W Owens
- Department of Chemistry and Chemical Biology, Harvard University , 12 Oxford Street, Cambridge, Massachusetts 02138, United States
| | - Emaline Laney
- Department of Microbiology and Immunobiology, Harvard University , 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
| | - Hidemasa Nakaminami
- Division of Infectious Diseases, Massachusetts General Hospital , 55 Fruit Street, Boston, Massachusetts 02114, United States
| | - David Hooper
- Division of Infectious Diseases, Massachusetts General Hospital , 55 Fruit Street, Boston, Massachusetts 02114, United States
| | - Timothy C Meredith
- Department of Biochemistry and Molecular Biology, Pennsylvania State University , 206 South Frear Laboratory, University Park, Pennsylvania 16802, United States
| | - Suzanne Walker
- Department of Microbiology and Immunobiology, Harvard University , 77 Avenue Louis Pasteur, Boston, Massachusetts 02115, United States
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22
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Lee SH, Wang H, Labroli M, Koseoglu S, Zuck P, Mayhood T, Gill C, Mann P, Sher X, Ha S, Yang SW, Mandal M, Yang C, Liang L, Tan Z, Tawa P, Hou Y, Kuvelkar R, DeVito K, Wen X, Xiao J, Batchlett M, Balibar CJ, Liu J, Xiao J, Murgolo N, Garlisi CG, Sheth PR, Flattery A, Su J, Tan C, Roemer T. TarO-specific inhibitors of wall teichoic acid biosynthesis restore β-lactam efficacy against methicillin-resistant staphylococci. Sci Transl Med 2016; 8:329ra32. [PMID: 26962156 DOI: 10.1126/scitranslmed.aad7364] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The widespread emergence of methicillin-resistant Staphylococcus aureus (MRSA) has dramatically eroded the efficacy of current β-lactam antibiotics and created an urgent need for new treatment options. We report an S. aureus phenotypic screening strategy involving chemical suppression of the growth inhibitory consequences of depleting late-stage wall teichoic acid biosynthesis. This enabled us to identify early-stage pathway-specific inhibitors of wall teichoic acid biosynthesis predicted to be chemically synergistic with β-lactams. We demonstrated by genetic and biochemical means that each of the new chemical series discovered, herein named tarocin A and tarocin B, inhibited the first step in wall teichoic acid biosynthesis (TarO). Tarocins do not have intrinsic bioactivity but rather demonstrated potent bactericidal synergy in combination with broad-spectrum β-lactam antibiotics against diverse clinical isolates of methicillin-resistant staphylococci as well as robust efficacy in a murine infection model of MRSA. Tarocins and other inhibitors of wall teichoic acid biosynthesis may provide a rational strategy to develop Gram-positive bactericidal β-lactam combination agents active against methicillin-resistant staphylococci.
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Affiliation(s)
- Sang Ho Lee
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Hao Wang
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Marc Labroli
- Merck Research Laboratories, West Point, PA 19486, USA
| | | | - Paul Zuck
- Merck Research Laboratories, West Point, PA 19486, USA
| | - Todd Mayhood
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Charles Gill
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Paul Mann
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Xinwei Sher
- Merck Research Laboratories, Boston, MA 02115, USA
| | - Sookhee Ha
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Shu-Wei Yang
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Mihir Mandal
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | - Lianzhu Liang
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Zheng Tan
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Paul Tawa
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Yan Hou
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | | | - Xiujuan Wen
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Jing Xiao
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | | | - Jenny Liu
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Jianying Xiao
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | | | | | - Payal R Sheth
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Amy Flattery
- Merck Research Laboratories, Kenilworth, NJ 07033, USA
| | - Jing Su
- Merck Research Laboratories, Kenilworth, NJ 07033, USA.
| | | | - Terry Roemer
- Merck Research Laboratories, Kenilworth, NJ 07033, USA.
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23
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Polydiglycosylphosphate Transferase PdtA (SCO2578) of Streptomyces coelicolor A3(2) Is Crucial for Proper Sporulation and Apical Tip Extension under Stress Conditions. Appl Environ Microbiol 2016; 82:5661-72. [PMID: 27422828 DOI: 10.1128/aem.01425-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/06/2016] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Although anionic glycopolymers are crucial components of the Gram-positive cell envelope, the relevance of anionic glycopolymers for vegetative growth and morphological differentiation of Streptomyces coelicolor A3(2) is unknown. Here, we show that the LytR-CpsA-Psr (LCP) protein PdtA (SCO2578), a TagV-like glycopolymer transferase, has a dual function in the S. coelicolor A3(2) life cycle. Despite the presence of 10 additional LCP homologs, PdtA is crucial for proper sporulation. The integrity of the spore envelope was severely affected in a pdtA deletion mutant, resulting in 34% nonviable spores. pdtA deletion caused a significant reduction in the polydiglycosylphosphate content of the spore envelope. Beyond that, apical tip extension and normal branching of vegetative mycelium were severely impaired on high-salt medium. This growth defect coincided with the mislocalization of peptidoglycan synthesis. Thus, PdtA itself or the polydiglycosylphosphate attached to the peptidoglycan by the glycopolymer transferase PdtA also has a crucial function in apical tip extension of vegetative hyphae under stress conditions. IMPORTANCE Anionic glycopolymers are underappreciated components of the Gram-positive cell envelope. They provide rigidity to the cell wall and position extracellular enzymes involved in peptidoglycan remodeling. Although Streptomyces coelicolor A3(2), the model organism for bacterial antibiotic production, is known to produce two distinct cell wall-linked glycopolymers, teichulosonic acid and polydiglycosylphosphate, the role of these glycopolymers in the S. coelicolor A3(2) life cycle has not been addressed so far. This study reveals a crucial function of the anionic glycopolymer polydiglycosylphosphate for the growth and morphological differentiation of S. coelicolor A3(2). Polydiglycosylphosphate is attached to the spore wall by the LytR-CpsA-Psr protein PdtA (SCO2578), a component of the Streptomyces spore wall-synthesizing complex (SSSC), to ensure the integrity of the spore envelope. Surprisingly, PdtA also has a crucial role in vegetative growth under stress conditions and is required for proper peptidoglycan incorporation during apical tip extension.
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Schade J, Weidenmaier C. Cell wall glycopolymers of Firmicutes and their role as nonprotein adhesins. FEBS Lett 2016; 590:3758-3771. [PMID: 27396949 DOI: 10.1002/1873-3468.12288] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 06/27/2016] [Accepted: 07/05/2016] [Indexed: 12/12/2022]
Abstract
Cell wall glycopolymers (CWGs) of gram-positive bacteria have gained increasing interest with respect to their role in colonization and infection. In most gram-positive pathogens they constitute a large fraction of the cell wall biomass and represent major cell envelope determinants. Depending on their chemical structure they modulate interaction with complement factors and play roles in immune evasion or serve as nonprotein adhesins that mediate, especially under dynamic conditions, attachment to different host cell types. In particular, covalently peptidoglycan-attached CWGs that extend well above the cell wall seem to interact with glyco-receptors on host cell surfaces. For example, in the case of Staphylococcus aureus, the cell wall-attached teichoic acid (WTA) has been identified as a major CWG adhesin. A recent report indicates that a type-F scavenger receptor, termed SR-F1 (SREC-I), is the predominant WTA receptor in the nasal cavity and that WTA-SREC-I interaction plays an important role in S. aureus nasal colonization. Therefore, understanding the role of CWGs in complex processes that mediate colonization and infection will allow novel insights into the mechanisms of host-microbiota interaction.
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Affiliation(s)
- Jessica Schade
- Interfaculty Institute for Microbiology and Infection Medicine (IMIT), University of Tübingen, Germany
| | - Christopher Weidenmaier
- Interfaculty Institute for Microbiology and Infection Medicine (IMIT), University of Tübingen, Germany.,German Center for Infection Research (DZIF), Partnersite Tübingen, Germany
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Mann PA, Müller A, Wolff KA, Fischmann T, Wang H, Reed P, Hou Y, Li W, Müller CE, Xiao J, Murgolo N, Sher X, Mayhood T, Sheth PR, Mirza A, Labroli M, Xiao L, McCoy M, Gill CJ, Pinho MG, Schneider T, Roemer T. Chemical Genetic Analysis and Functional Characterization of Staphylococcal Wall Teichoic Acid 2-Epimerases Reveals Unconventional Antibiotic Drug Targets. PLoS Pathog 2016; 12:e1005585. [PMID: 27144276 PMCID: PMC4856313 DOI: 10.1371/journal.ppat.1005585] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 03/29/2016] [Indexed: 11/18/2022] Open
Abstract
Here we describe a chemical biology strategy performed in Staphylococcus aureus and Staphylococcus epidermidis to identify MnaA, a 2-epimerase that we demonstrate interconverts UDP-GlcNAc and UDP-ManNAc to modulate substrate levels of TarO and TarA wall teichoic acid (WTA) biosynthesis enzymes. Genetic inactivation of mnaA results in complete loss of WTA and dramatic in vitro β-lactam hypersensitivity in methicillin-resistant S. aureus (MRSA) and S. epidermidis (MRSE). Likewise, the β-lactam antibiotic imipenem exhibits restored bactericidal activity against mnaA mutants in vitro and concomitant efficacy against 2-epimerase defective strains in a mouse thigh model of MRSA and MRSE infection. Interestingly, whereas MnaA serves as the sole 2-epimerase required for WTA biosynthesis in S. epidermidis, MnaA and Cap5P provide compensatory WTA functional roles in S. aureus. We also demonstrate that MnaA and other enzymes of WTA biosynthesis are required for biofilm formation in MRSA and MRSE. We further determine the 1.9Å crystal structure of S. aureus MnaA and identify critical residues for enzymatic dimerization, stability, and substrate binding. Finally, the natural product antibiotic tunicamycin is shown to physically bind MnaA and Cap5P and inhibit 2-epimerase activity, demonstrating that it inhibits a previously unanticipated step in WTA biosynthesis. In summary, MnaA serves as a new Staphylococcal antibiotic target with cognate inhibitors predicted to possess dual therapeutic benefit: as combination agents to restore β-lactam efficacy against MRSA and MRSE and as non-bioactive prophylactic agents to prevent Staphylococcal biofilm formation. Staphylococcus aureus and Staphylococcus epidermidis cause life-threatening infections that are commonly acquired in hospitals as well as the community and remain difficult to treat with current antibiotics. In part, this is due to the emergence of methicillin-resistant S. aureus and S. epidermidis (MRSA and MRSE), which exhibit broad resistance to β-lactams such as penicillin and other members of this important founding class of antibiotics. Compounding this problem, Staphylococci commonly colonize the surface of catheters and other medical devices, forming bacterial communities that are intrinsically resistant to antibiotics. Here we functionally characterize a family of 2-epimerases, named MnaA and Cap5P, that we demonstrate by genetic, biochemical, and X-ray crystallography means are essential for wall teichoic acid biosynthesis and that upon their genetic inactivation render methicillin-resistant Staphylococci unable to form biofilms as well as broadly hypersusceptible to β-lactam antibiotics both in vitro and in a host infection setting. WTA 2-epimerases therefore constitute a novel class of methicillin-resistant Staphylococcal drug targets.
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Affiliation(s)
- Paul A. Mann
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Anna Müller
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
- German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Kerstin A. Wolff
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Thierry Fischmann
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Hao Wang
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Patricia Reed
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Yan Hou
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Wenjin Li
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry, University of Bonn, Bonn, Germany
| | - Christa E. Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical Chemistry, University of Bonn, Bonn, Germany
| | - Jianying Xiao
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Nicholas Murgolo
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Xinwei Sher
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Todd Mayhood
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Payal R. Sheth
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Asra Mirza
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Marc Labroli
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Li Xiao
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Mark McCoy
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Charles J. Gill
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
| | - Mariana G. Pinho
- Laboratory of Bacterial Cell Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Tanja Schneider
- Institute for Pharmaceutical Microbiology, University of Bonn, Bonn, Germany
- German Centre for Infection Research (DZIF), partner site Bonn-Cologne, Bonn, Germany
| | - Terry Roemer
- Merck Research Laboratories, Kenilworth New Jersey, United States of America
- * E-mail:
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Klahn P, Brönstrup M. New Structural Templates for Clinically Validated and Novel Targets in Antimicrobial Drug Research and Development. Curr Top Microbiol Immunol 2016; 398:365-417. [PMID: 27704270 DOI: 10.1007/82_2016_501] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The development of bacterial resistance against current antibiotic drugs necessitates a continuous renewal of the arsenal of efficacious drugs. This imperative has not been met by the output of antibiotic research and development of the past decades for various reasons, including the declining efforts of large pharma companies in this area. Moreover, the majority of novel antibiotics are chemical derivatives of existing structures that represent mostly step innovations, implying that the available chemical space may be exhausted. This review negates this impression by showcasing recent achievements in lead finding and optimization of antibiotics that have novel or unexplored chemical structures. Not surprisingly, many of the novel structural templates like teixobactins, lysocin, griselimycin, or the albicidin/cystobactamid pair were discovered from natural sources. Additional compounds were obtained from the screening of synthetic libraries and chemical synthesis, including the gyrase-inhibiting NTBI's and spiropyrimidinetrione, the tarocin and targocil inhibitors of wall teichoic acid synthesis, or the boronates and diazabicyclo[3.2.1]octane as novel β-lactamase inhibitors. A motif that is common to most clinically validated antibiotics is that they address hotspots in complex biosynthetic machineries, whose functioning is essential for the bacterial cell. Therefore, an introduction to the biological targets-cell wall synthesis, topoisomerases, the DNA sliding clamp, and membrane-bound electron transport-is given for each of the leads presented here.
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Affiliation(s)
- Philipp Klahn
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
| | - Mark Brönstrup
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124, Braunschweig, Germany.
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Lunderberg JM, Liszewski Zilla M, Missiakas D, Schneewind O. Bacillus anthracis tagO Is Required for Vegetative Growth and Secondary Cell Wall Polysaccharide Synthesis. J Bacteriol 2015; 197:3511-20. [PMID: 26324447 PMCID: PMC4621081 DOI: 10.1128/jb.00494-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/17/2015] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED Bacillus anthracis elaborates a linear secondary cell wall polysaccharide (SCWP) that retains surface (S)-layer and associated proteins via their S-layer homology (SLH) domains. The SCWP is comprised of trisaccharide repeats [→4)-β-ManNAc-(1→4)-β-GlcNAc-(1→6)-α-GlcNAc-(1→] and tethered via acid-labile phosphodiester bonds to peptidoglycan. Earlier work identified UDP-GlcNAc 2-epimerases GneY (BAS5048) and GneZ (BAS5117), which act as catalysts of ManNAc synthesis, as well as a polysaccharide deacetylase (BAS5051), as factors contributing to SCWP synthesis. Here, we show that tagO (BAS5050), which encodes a UDP-N-acetylglucosamine:undecaprenyl-P N-acetylglucosaminyl 1-P transferase, the enzyme that initiates the synthesis of murein linkage units, is required for B. anthracis SCWP synthesis and S-layer assembly. Similar to gneY-gneZ mutants, B. anthracis strains lacking tagO cannot maintain cell shape or support vegetative growth. In contrast, mutations in BAS5051 do not affect B. anthracis cell shape, vegetative growth, SCWP synthesis, or S-layer assembly. These data suggest that TagO-mediated murein linkage unit assembly supports SCWP synthesis and attachment to the peptidoglycan via acid-labile phosphodiester bonds. Further, B. anthracis variants unable to synthesize SCWP trisaccharide repeats cannot sustain cell shape and vegetative growth. IMPORTANCE Bacillus anthracis elaborates an SCWP to support vegetative growth and envelope assembly. Here, we show that some, but not all, SCWP synthesis is dependent on tagO-derived murein linkage units and subsequent attachment of SCWP to peptidoglycan. The data implicate secondary polymer modifications of peptidoglycan and subcellular distributions as a key feature of the cell cycle in Gram-positive bacteria and establish foundations for work on the molecular functions of the SCWP and on inhibitors with antibiotic attributes.
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Affiliation(s)
- J Mark Lunderberg
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Megan Liszewski Zilla
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Dominique Missiakas
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA Department of Microbiology, University of Chicago, Chicago, Illinois, USA
| | - Olaf Schneewind
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA Department of Microbiology, University of Chicago, Chicago, Illinois, USA
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28
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Weidenmaier C, Lee JC. Structure and Function of Surface Polysaccharides of Staphylococcus aureus. Curr Top Microbiol Immunol 2015; 409:57-93. [PMID: 26728067 DOI: 10.1007/82_2015_5018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The major surface polysaccharides of Staphylococcus aureus include the capsular polysaccharide (CP), cell wall teichoic acid (WTA), and polysaccharide intercellular adhesin/poly-β(1-6)-N-acetylglucosamine (PIA/PNAG). These glycopolymers are important components of the staphylococcal cell envelope, but none of them is essential to S. aureus viability and growth in vitro. The overall biosynthetic pathways of CP, WTA, and PIA/PNAG have been elucidated, and the functions of most of the biosynthetic enzymes have been demonstrated. Because S. aureus CP and WTA (but not PIA/PNAG) utilize a common cell membrane lipid carrier (undecaprenyl-phosphate) that is shared by the peptidoglycan biosynthesis pathway, there is evidence that these processes are highly integrated and temporally regulated. Regulatory elements that control glycopolymer biosynthesis have been described, but the cross talk that orchestrates the biosynthetic pathways of these three polysaccharides remains largely elusive. CP, WTA, and PIA/PNAG each play distinct roles in S. aureus colonization and the pathogenesis of staphylococcal infection. However, they each promote bacterial evasion of the host immune defences, and WTA is being explored as a target for antimicrobial therapeutics. All the three glycopolymers are viable targets for immunotherapy, and each (conjugated to a carrier protein) is under evaluation for inclusion in a multivalent S. aureus vaccine. Future research findings that increase our understanding of these surface polysaccharides, how the bacterial cell regulates their expression, and their biological functions will likely reveal new approaches to controlling this important bacterial pathogen.
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Affiliation(s)
- Christopher Weidenmaier
- Interfaculty Institute for Microbiology and Infection Medicine Tübingen, University of Tübingen and German Center for Infection Research, Tübingen, Germany
| | - Jean C Lee
- Division of Infectious Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
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LytR-CpsA-Psr enzymes as determinants of Bacillus anthracis secondary cell wall polysaccharide assembly. J Bacteriol 2014; 197:343-53. [PMID: 25384480 DOI: 10.1128/jb.02364-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Bacillus anthracis, the causative agent of anthrax, replicates as chains of vegetative cells by regulating the separation of septal peptidoglycan. Surface (S)-layer proteins and associated proteins (BSLs) function as chain length determinants and bind to the secondary cell wall polysaccharide (SCWP). In this study, we identified the B. anthracis lcpD mutant, which displays increased chain length and S-layer assembly defects due to diminished SCWP attachment to peptidoglycan. In contrast, the B. anthracis lcpB3 variant displayed reduced cell size and chain length, which could be attributed to increased deposition of BSLs. In other bacteria, LytR-CpsA-Psr (LCP) proteins attach wall teichoic acid (WTA) and polysaccharide capsule to peptidoglycan. B. anthracis does not synthesize these polymers, yet its genome encodes six LCP homologues, which, when expressed in S. aureus, promote WTA attachment. We propose a model whereby B. anthracis LCPs promote attachment of SCWP precursors to discrete locations in the peptidoglycan, enabling BSL assembly and regulated separation of septal peptidoglycan.
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30
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Kollipara R, Downing C, Lee M, Guidry J, Curtis S, Tyring S. Current and emerging drugs for acute bacterial skin and skin structure infections: an update. Expert Opin Emerg Drugs 2014; 19:431-40. [DOI: 10.1517/14728214.2014.955015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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GneZ, a UDP-GlcNAc 2-epimerase, is required for S-layer assembly and vegetative growth of Bacillus anthracis. J Bacteriol 2014; 196:2969-78. [PMID: 24914184 DOI: 10.1128/jb.01829-14] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bacillus anthracis, the causative agent of anthrax, forms an S-layer atop its peptidoglycan envelope and displays S-layer proteins and Bacillus S-layer-associated (BSL) proteins with specific functions to support cell separation of vegetative bacilli and growth in infected mammalian hosts. S-layer and BSL proteins bind via the S-layer homology (SLH) domain to the pyruvylated secondary cell wall polysaccharide (SCWP) with the repeat structure [→4)-β-ManNAc-(1→4)-β-GlcNAc-(1→6)-α-GlcNAc-(1→]n, where α-GlcNAc and β-GlcNAc are substituted with two and one galactosyl residues, respectively. B. anthracis gneY (BAS5048) and gneZ (BAS5117) encode nearly identical UDP-GlcNAc 2-epimerase enzymes that catalyze the reversible conversion of UDP-GlcNAc and UDP-ManNAc. UDP-GlcNAc 2-epimerase enzymes have been shown to be required for the attachment of the phage lysin PlyG with the bacterial envelope and for bacterial growth. Here, we asked whether gneY and gneZ are required for the synthesis of the pyruvylated SCWP and for S-layer assembly. We show that gneZ, but not gneY, is required for B. anthracis vegetative growth, rod cell shape, S-layer assembly, and synthesis of pyruvylated SCWP. Nevertheless, inducible expression of gneY alleviated all the defects associated with the gneZ mutant. In contrast to vegetative growth, neither germination of B. anthracis spores nor the formation of spores in mother cells required UDP-GlcNAc 2-epimerase activity.
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32
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Fiebig A, Herrou J, Fumeaux C, Radhakrishnan SK, Viollier PH, Crosson S. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion. PLoS Genet 2014; 10:e1004101. [PMID: 24465221 PMCID: PMC3900383 DOI: 10.1371/journal.pgen.1004101] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 11/19/2013] [Indexed: 11/18/2022] Open
Abstract
In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA) that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ). Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.
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Affiliation(s)
- Aretha Fiebig
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (AF); (SC)
| | - Julien Herrou
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America
| | - Coralie Fumeaux
- Department of Microbiology and Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), University of Geneva Medical School, Geneva, Switzerland
| | - Sunish K. Radhakrishnan
- Department of Microbiology and Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), University of Geneva Medical School, Geneva, Switzerland
| | - Patrick H. Viollier
- Department of Microbiology and Molecular Medicine, Institute of Genetics & Genomics in Geneva (iGE3), University of Geneva Medical School, Geneva, Switzerland
| | - Sean Crosson
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, United States of America
- Committee on Microbiology, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (AF); (SC)
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Grover S, Alderwick LJ, Mishra AK, Krumbach K, Marienhagen J, Eggeling L, Bhatt A, Besra GS. Benzothiazinones mediate killing of Corynebacterineae by blocking decaprenyl phosphate recycling involved in cell wall biosynthesis. J Biol Chem 2014; 289:6177-87. [PMID: 24446451 PMCID: PMC3937683 DOI: 10.1074/jbc.m113.522623] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Benzothiazinones (BTZs) are a new class of sulfur containing heterocyclic compounds that target DprE1, an oxidoreductase involved in the epimerization of decaprenyl-phosphoribose (DPR) to decaprenyl-phosphoarabinose (DPA) in the Corynebacterineae, such as Corynebacterium glutamicum and Mycobacterium tuberculosis. As a result, BTZ inhibition leads to inhibition of cell wall arabinan biosynthesis. Previous studies have demonstrated the essentiality of dprE1. In contrast, Cg-UbiA a ribosyltransferase, which catalyzes the first step of DPR biosynthesis prior to DprE1, when genetically disrupted, produced a viable mutant, suggesting that although BTZ biochemically targets DprE1, killing also occurs through chemical synthetic lethality, presumably through the lack of decaprenyl phosphate recycling. To test this hypothesis, a derivative of BTZ, BTZ043, was examined in detail against C. glutamicum and C. glutamicum::ubiA. The wild type strain was sensitive to BTZ043; however, C. glutamicum::ubiA was found to be resistant, despite possessing a functional DprE1. When the gene encoding C. glutamicum Z-decaprenyl-diphosphate synthase (NCgl2203) was overexpressed in wild type C. glutamicum, resistance to BTZ043 was further increased. This data demonstrates that in the presence of BTZ, the bacilli accumulate DPR and fail to recycle decaprenyl phosphate, which results in the depletion of decaprenyl phosphate and ultimately leads to cell death.
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Affiliation(s)
- Shipra Grover
- From the School of Biosciences, Institute of Microbiology and Infection, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom and
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Sewell EWC, Brown ED. Taking aim at wall teichoic acid synthesis: new biology and new leads for antibiotics. J Antibiot (Tokyo) 2013; 67:43-51. [PMID: 24169797 DOI: 10.1038/ja.2013.100] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/04/2013] [Accepted: 09/10/2013] [Indexed: 11/09/2022]
Abstract
Wall teichoic acids are a major and integral component of the Gram-positive cell wall. These structures are present across all species of Gram-positive bacteria and constitute roughly half of the cell wall. Despite decades of careful investigation, a definitive physiological function for wall teichoic acids remains elusive. Advances in the genetics and biochemistry of wall teichoic acid synthesis have led to a new understanding of the complexity of cell wall synthesis in Gram-positive bacteria. Indeed, these innovations have provided new molecular tools available to probe the synthesis and function of these cell wall structures. Among recent discoveries are unexpected roles for wall teichoic acid in cell division, coordination of peptidoglycan synthesis and β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA). Notably, wall teichoic acid biogenesis has emerged as a bona fide drug target in S. aureus, where remarkable synthetic-viable interactions among biosynthetic genes have been leveraged for the discovery and characterization of novel inhibitors of the pathway.
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Affiliation(s)
- Edward W C Sewell
- Michael G DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Eric D Brown
- Michael G DeGroote Institute for Infectious Disease Research and the Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
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35
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Wang H, Gill CJ, Lee SH, Mann P, Zuck P, Meredith TC, Murgolo N, She X, Kales S, Liang L, Liu J, Wu J, Santa Maria J, Su J, Pan J, Hailey J, Mcguinness D, Tan CM, Flattery A, Walker S, Black T, Roemer T. Discovery of wall teichoic acid inhibitors as potential anti-MRSA β-lactam combination agents. ACTA ACUST UNITED AC 2013; 20:272-84. [PMID: 23438756 DOI: 10.1016/j.chembiol.2012.11.013] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 11/26/2012] [Accepted: 11/30/2012] [Indexed: 12/31/2022]
Abstract
Innovative strategies are needed to combat drug resistance associated with methicillin-resistant Staphylococcus aureus (MRSA). Here, we investigate the potential of wall teichoic acid (WTA) biosynthesis inhibitors as combination agents to restore β-lactam efficacy against MRSA. Performing a whole-cell pathway-based screen, we identified a series of WTA inhibitors (WTAIs) targeting the WTA transporter protein, TarG. Whole-genome sequencing of WTAI-resistant isolates across two methicillin-resistant Staphylococci spp. revealed TarG as their common target, as well as a broad assortment of drug-resistant bypass mutants mapping to earlier steps of WTA biosynthesis. Extensive in vitro microbiological analysis and animal infection studies provide strong genetic and pharmacological evidence of the potential effectiveness of WTAIs as anti-MRSA β-lactam combination agents. This work also highlights the emerging role of whole-genome sequencing in antibiotic mode-of-action and resistance studies.
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Affiliation(s)
- Hao Wang
- Infectious Disease Biology, Merck Research Laboratories, Kenilworth, NJ 07033, USA
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36
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Staphylococcus aureus mutants lacking the LytR-CpsA-Psr family of enzymes release cell wall teichoic acids into the extracellular medium. J Bacteriol 2013; 195:4650-9. [PMID: 23935043 DOI: 10.1128/jb.00544-13] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The LytR-CpsA-Psr (LCP) proteins are thought to transfer bactoprenol-linked biosynthetic intermediates of wall teichoic acid (WTA) to the peptidoglycan of Gram-positive bacteria. In Bacillus subtilis, mutants lacking all three LCP enzymes do not deposit WTA in the envelope, while Staphylococcus aureus Δlcp mutants display impaired growth and reduced levels of envelope phosphate. We show here that the S. aureus Δlcp mutant synthesized WTA yet released ribitol phosphate polymers into the extracellular medium. Further, Δlcp mutant staphylococci no longer restricted the deposition of LysM-type murein hydrolases to cell division sites, which was associated with defects in cell shape and increased autolysis. Mutations in S. aureus WTA synthesis genes (tagB, tarF, or tarJ2) inhibit growth, which is attributed to the depletion of bactoprenol, an essential component of peptidoglycan synthesis (lipid II). The growth defect of S. aureus tagB and tarFJ mutants was alleviated by inhibition of WTA synthesis with tunicamycin, whereas the growth defect of the Δlcp mutant was not relieved by tunicamycin treatment or by mutation of tagO, whose product catalyzes the first committed step of WTA synthesis. Further, sortase A-mediated anchoring of proteins to peptidoglycan, which also involves bactoprenol and lipid II, was not impaired in the Δlcp mutant. We propose a model whereby the S. aureus Δlcp mutant, defective in tethering WTA to the cell wall, cleaves WTA synthesis intermediates, releasing ribitol phosphate into the medium and recycling bactoprenol for peptidoglycan synthesis.
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37
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Pasquina LW, Santa Maria JP, Walker S. Teichoic acid biosynthesis as an antibiotic target. Curr Opin Microbiol 2013; 16:531-7. [PMID: 23916223 DOI: 10.1016/j.mib.2013.06.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/27/2013] [Accepted: 06/28/2013] [Indexed: 01/19/2023]
Abstract
The relentless spread of antibiotic-resistant pathogens makes it imperative to develop new chemotherapeutic strategies to overcome infection. The bacterial cell wall has served as a rich source for both validated and unexploited pathways that are essential for virulence and survival. Lipoteichoic acids (LTAs) and wall teichoic acids (WTAs) are cell wall polymers that play fundamental roles in Gram-positive bacterial physiology and pathogenesis, and both have been proposed as novel antibacterial targets. Here we describe recent progress toward the discovery of teichoic acid biosynthesis inhibitors and their potential as antibiotics to combat Staphylococcus aureus infections.
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Affiliation(s)
- Lincoln W Pasquina
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, United States
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38
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Roemer T, Schneider T, Pinho MG. Auxiliary factors: a chink in the armor of MRSA resistance to β-lactam antibiotics. Curr Opin Microbiol 2013; 16:538-48. [PMID: 23895826 DOI: 10.1016/j.mib.2013.06.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/28/2013] [Accepted: 06/28/2013] [Indexed: 12/20/2022]
Abstract
Combination agents provide an important orthogonal approach to treat infectious diseases, particularly those caused by drug resistant pathogens. Indeed, applying a biologically 'rational' and systems-level paradigm to discover potent, selective, and synergistic agents would augment current (and arguably overly relied upon) empirical and serendipitous approaches to such discovery efforts. Here, we review the cellular mechanisms of β-lactam drug resistance and tolerance achieved amongst methicillin-resistant Staphylococcus aureus (MRSA) as well as their molecular targets and strategies to identify cognate inhibitors as potential combination agents to restore β-lactam efficacy against MRSA.
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Affiliation(s)
- Terry Roemer
- Infectious Disease Research, Merck Research Laboratories, Kenilworth, NJ 07033, USA.
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39
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Farha MA, Leung A, Sewell EW, D’Elia MA, Allison SE, Ejim L, Pereira PM, Pinho MG, Wright GD, Brown ED. Inhibition of WTA synthesis blocks the cooperative action of PBPs and sensitizes MRSA to β-lactams. ACS Chem Biol 2013; 8:226-33. [PMID: 23062620 PMCID: PMC3552485 DOI: 10.1021/cb300413m] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Rising drug resistance is limiting treatment options
for infections
by methicillin-resistant Staphylococcus aureus (MRSA).
Herein we provide new evidence that wall teichoic acid (WTA) biogenesis
is a remarkable antibacterial target with the capacity to destabilize
the cooperative action of penicillin-binding proteins (PBPs) that
underlie β-lactam resistance in MRSA. Deletion of gene tarO, encoding the first step of WTA synthesis, resulted
in the restoration of sensitivity of MRSA to a unique profile of β-lactam
antibiotics with a known selectivity for penicillin binding protein
2 (PBP2). Of these, cefuroxime was used as a probe to screen for previously
approved drugs with a cryptic capacity to potentiate its activity
against MRSA. Ticlopidine, the antiplatelet drug Ticlid, strongly
potentiated cefuroxime, and this synergy was abolished in strains
lacking tarO. The combination was also effective
in a Galleria mellonella model of infection. Using
both genetic and biochemical strategies, we determined the molecular
target of ticlopidine as the N-acetylglucosamine-1-phosphate
transferase encoded in gene tarO and provide evidence
that WTA biogenesis represents an Achilles heel supporting the cooperative
function of PBP2 and PBP4 in creating highly cross-linked muropeptides
in the peptidoglycan of S. aureus. This approach
represents a new paradigm to tackle MRSA infection.
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Affiliation(s)
- Maya A. Farha
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Alexander Leung
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Edward W. Sewell
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Michael A. D’Elia
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Sarah E. Allison
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Linda Ejim
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Pedro M. Pereira
- Laboratory of Bacterial Cell
Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Mariana G. Pinho
- Laboratory of Bacterial Cell
Biology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Gerard D. Wright
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
| | - Eric D. Brown
- M. G. DeGroote
Institute for
Infectious Disease Research and Department of Biochemistry and Biomedical
Sciences, McMaster University, Hamilton,
Ontario, Canada L8N 3Z5
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40
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Abstract
The peptidoglycan layers of many gram-positive bacteria are densely functionalized with anionic glycopolymers known as wall teichoic acids (WTAs). These polymers play crucial roles in cell shape determination, regulation of cell division, and other fundamental aspects of gram-positive bacterial physiology. Additionally, WTAs are important in pathogenesis and play key roles in antibiotic resistance. We provide an overview of WTA structure and biosynthesis, review recent studies on the biological roles of these polymers, and highlight remaining questions. We also discuss prospects for exploiting WTA biosynthesis as a target for new therapies to overcome resistant infections.
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Affiliation(s)
- Stephanie Brown
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115;
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41
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Wall teichoic acids restrict access of bacteriophage endolysin Ply118, Ply511, and PlyP40 cell wall binding domains to the Listeria monocytogenes peptidoglycan. J Bacteriol 2012; 194:6498-506. [PMID: 23002226 DOI: 10.1128/jb.00808-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The C-terminal cell wall binding domains (CBDs) of phage endolysins direct the enzymes to their binding ligands on the bacterial cell wall with high affinity and specificity. The Listeria monocytogenes Ply118, Ply511, and PlyP40 endolysins feature related CBDs which recognize the directly cross-linked peptidoglycan backbone structure of Listeria. However, decoration with fluorescently labeled CBDs primarily occurs at the poles and septal regions of the rod-shaped cells. To elucidate the potential role of secondary cell wall-associated carbohydrates such as the abundant wall teichoic acid (WTA) on this phenomenon, we investigated CBD binding using L. monocytogenes serovar 1/2 and 4 cells deficient in WTA. Mutants were obtained by deletion of two redundant tagO homologues, whose products catalyze synthesis of the WTA linkage unit. While inactivation of either tagO1 (EGDe lmo0959) or tagO2 (EGDe lmo2519) alone did not affect WTA content, removal of both alleles following conditional complementation yielded WTA-deficient Listeria cells. Substitution of tagO from an isopropyl-β-d-thiogalactopyranoside-inducible single-copy integration vector restored the original phenotype. Although WTA-deficient cells are viable, they featured severe growth inhibition and an unusual coccoid morphology. In contrast to CBDs from other Listeria phage endolysins which directly utilize WTA as binding ligand, the data presented here show that WTAs are not required for attachment of CBD118, CBD511, and CBDP40. Instead, lack of the cell wall polymers enables unrestricted spatial access of CBDs to the cell wall surface, indicating that the abundant WTA can negatively regulate sidewall localization of the cell wall binding domains.
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42
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Dengler V, Meier PS, Heusser R, Kupferschmied P, Fazekas J, Friebe S, Staufer SB, Majcherczyk PA, Moreillon P, Berger-Bächi B, McCallum N. Deletion of hypothetical wall teichoic acid ligases in Staphylococcus aureus activates the cell wall stress response. FEMS Microbiol Lett 2012; 333:109-20. [PMID: 22640011 DOI: 10.1111/j.1574-6968.2012.02603.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 04/25/2012] [Accepted: 05/21/2012] [Indexed: 11/30/2022] Open
Abstract
The Staphylococcus aureus cell wall stress stimulon (CWSS) is activated by cell envelope-targeting antibiotics or depletion of essential cell wall biosynthesis enzymes. The functionally uncharacterized S. aureus LytR-CpsA-Psr (LCP) proteins, MsrR, SA0908 and SA2103, all belong to the CWSS. Although not essential, deletion of all three LCP proteins severely impairs cell division. We show here that VraSR-dependent CWSS expression was up to 250-fold higher in single, double and triple LCP mutants than in wild type S. aureus in the absence of external stress. The LCP triple mutant was virtually depleted of wall teichoic acids (WTA), which could be restored to different degrees by any of the single LCP proteins. Subinhibitory concentrations of tunicamycin, which inhibits the first WTA synthesis enzyme TarO (TagO), could partially complement the severe growth defect of the LCP triple mutant. Both of the latter findings support a role for S. aureus LCP proteins in late WTA synthesis, as in Bacillus subtilis where LCP proteins were recently proposed to transfer WTA from lipid carriers to the cell wall peptidoglycan. Intrinsic activation of the CWSS upon LCP deletion and the fact that LCP proteins were essential for WTA-loading of the cell wall, highlight their important role(s) in S. aureus cell envelope biogenesis.
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Affiliation(s)
- Vanina Dengler
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland.
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43
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Frankel MB, Schneewind O. Determinants of murein hydrolase targeting to cross-wall of Staphylococcus aureus peptidoglycan. J Biol Chem 2012; 287:10460-10471. [PMID: 22303016 DOI: 10.1074/jbc.m111.336404] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Cells of eukaryotic or prokaryotic origin express proteins with LysM domains that associate with the cell wall envelope of bacteria. The molecular properties that enable LysM domains to interact with microbial cell walls are not yet established. Staphylococcus aureus, a spherical microbe, secretes two murein hydrolases with LysM domains, Sle1 and LytN. We show here that the LysM domains of Sle1 and LytN direct murein hydrolases to the staphylococcal envelope in the vicinity of the cross-wall, the mid-cell compartment for peptidoglycan synthesis. LysM domains associate with the repeating disaccharide β-N-acetylmuramic acid, (1→4)-β-N-acetylglucosamine of staphylococcal peptidoglycan. Modification of N-acetylmuramic acid with wall teichoic acid, a ribitol-phosphate polymer tethered to murein linkage units, prevents the LysM domain from binding to peptidoglycan. The localization of LytN and Sle1 to the cross-wall is abolished in staphylococcal tagO mutants, which are defective for wall teichoic acid synthesis. We propose a model whereby the LysM domain ensures septal localization of LytN and Sle1 followed by processive cleavage of peptidoglycan, thereby exposing new LysM binding sites in the cross-wall and separating bacterial cells.
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Affiliation(s)
- Matthew B Frankel
- Department of Microbiology, University of Chicago, Chicago, Illinois 60637
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, Chicago, Illinois 60637.
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44
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An antibiotic that inhibits a late step in wall teichoic acid biosynthesis induces the cell wall stress stimulon in Staphylococcus aureus. Antimicrob Agents Chemother 2012; 56:1810-20. [PMID: 22290958 DOI: 10.1128/aac.05938-11] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Wall teichoic acids (WTAs) are phosphate-rich, sugar-based polymers attached to the cell walls of most Gram-positive bacteria. In Staphylococcus aureus, these anionic polymers regulate cell division, protect cells from osmotic stress, mediate host colonization, and mask enzymatically susceptible peptidoglycan bonds. Although WTAs are not required for survival in vitro, blocking the pathway at a late stage of synthesis is lethal. We recently discovered a novel antibiotic, targocil, that inhibits a late acting step in the WTA pathway. Its target is TarG, the transmembrane component of the ABC transporter (TarGH) that exports WTAs to the cell surface. We examined here the effects of targocil on S. aureus using transmission electron microscopy and gene expression profiling. We report that targocil treatment leads to multicellular clusters containing swollen cells displaying evidence of osmotic stress, strongly induces the cell wall stress stimulon, and reduces the expression of key virulence genes, including dltABCD and capsule genes. We conclude that WTA inhibitors that act at a late stage of the biosynthetic pathway may be useful as antibiotics, and we present evidence that they could be particularly useful in combination with beta-lactams.
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45
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Luo Y, Helmann JD. Analysis of the role of Bacillus subtilis σ(M) in β-lactam resistance reveals an essential role for c-di-AMP in peptidoglycan homeostasis. Mol Microbiol 2012; 83:623-39. [PMID: 22211522 DOI: 10.1111/j.1365-2958.2011.07953.x] [Citation(s) in RCA: 186] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The Bacillus subtilis extracytoplasmic function (ECF) σ factor σ(M) is inducible by, and confers resistance to, several cell envelope-acting antibiotics. Here, we demonstrate that σ(M) is responsible for intrinsic β-lactam resistance, with σ(X) playing a secondary role. Activation of σ(M) upregulates several cell wall biosynthetic enzymes including one, PBP1, shown here to be a target for the beta-lactam cefuroxime. However, σ(M) still plays a major role in cefuroxime resistance even in cells lacking PBP1. To better define the role of σ(M) in β-lactam resistance, we characterized suppressor mutations that restore cefuroxime resistance to a sigM null mutant. The most frequent suppressors inactivated gdpP (yybT) which encodes a cyclic-di-AMP phosphodiesterase (PDE). Intriguingly, σ(M) is a known activator of disA encoding one of three paralogous diadenylate cyclases (DAC). Overproduction of the GdpP PDE greatly sensitized cells to β-lactam antibiotics. Conversely, genetic studies indicate that at least one DAC is required for growth with depletion leading to cell lysis. These findings support a model in which c-di-AMP is an essential signal molecule required for cell wall homeostasis. Other suppressors highlight the roles of ECF σ factors in counteracting the deleterious effects of autolysins and reactive oxygen species in β-lactam-treated cells.
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Affiliation(s)
- Yun Luo
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
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46
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Kawai Y, Marles-Wright J, Cleverley RM, Emmins R, Ishikawa S, Kuwano M, Heinz N, Bui NK, Hoyland CN, Ogasawara N, Lewis RJ, Vollmer W, Daniel RA, Errington J. A widespread family of bacterial cell wall assembly proteins. EMBO J 2011; 30:4931-41. [PMID: 21964069 PMCID: PMC3243631 DOI: 10.1038/emboj.2011.358] [Citation(s) in RCA: 188] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 08/31/2011] [Indexed: 11/09/2022] Open
Abstract
Teichoic acids and acidic capsular polysaccharides are major anionic cell wall polymers (APs) in many bacteria, with various critical cell functions, including maintenance of cell shape and structural integrity, charge and cation homeostasis, and multiple aspects of pathogenesis. We have identified the widespread LytR-Cps2A-Psr (LCP) protein family, of previously unknown function, as novel enzymes required for AP synthesis. Structural and biochemical analysis of several LCP proteins suggest that they carry out the final step of transferring APs from their lipid-linked precursor to cell wall peptidoglycan (PG). In Bacillus subtilis, LCP proteins are found in association with the MreB cytoskeleton, suggesting that MreB proteins coordinate the insertion of the major polymers, PG and AP, into the cell wall.
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Affiliation(s)
- Yoshikazu Kawai
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Jon Marles-Wright
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Robert M Cleverley
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Robyn Emmins
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Shu Ishikawa
- Graduate School of Information Science, Nara Institute of Science and Technology, Nara, Japan
| | - Masayoshi Kuwano
- Graduate School of Information Science, Nara Institute of Science and Technology, Nara, Japan
| | - Nadja Heinz
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Nhat Khai Bui
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Christopher N Hoyland
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Naotake Ogasawara
- Graduate School of Information Science, Nara Institute of Science and Technology, Nara, Japan
| | - Richard J Lewis
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Richard A Daniel
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Jeff Errington
- Centre for Bacterial Cell Biology, Medical School, Newcastle University, Newcastle upon Tyne, UK
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47
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Allison SE, D'Elia MA, Arar S, Monteiro MA, Brown ED. Studies of the genetics, function, and kinetic mechanism of TagE, the wall teichoic acid glycosyltransferase in Bacillus subtilis 168. J Biol Chem 2011; 286:23708-16. [PMID: 21558268 DOI: 10.1074/jbc.m111.241265] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The biosynthetic enzymes involved in wall teichoic acid biogenesis in gram-positive bacteria have been the subject of renewed investigation in recent years with the benefit of modern tools of biochemistry and genetics. Nevertheless, there have been only limited investigations into the enzymes that glycosylate wall teichoic acid. Decades-old experiments in the model gram-positive bacterium, Bacillus subtilis 168, using phage-resistant mutants implicated tagE (also called gtaA and rodD) as the gene coding for the wall teichoic acid glycosyltransferase. This study and others have provided only indirect evidence to support a role for TagE in wall teichoic acid glycosylation. In this work, we showed that deletion of tagE resulted in the loss of α-glucose at the C-2 position of glycerol in the poly(glycerol phosphate) polymer backbone. We also reported the first kinetic characterization of pure, recombinant wall teichoic acid glycosyltransferase using clean synthetic substrates. We investigated the substrate specificity of TagE using a wide variety of acceptor substrates and found that the enzyme had a strong kinetic preference for the transfer of glucose from UDP-glucose to glycerol phosphate in polymeric form. Further, we showed that the enzyme recognized its polymeric (and repetitive) substrate with a sequential kinetic mechanism. This work provides direct evidence that TagE is the wall teichoic acid glycosyltransferase in B. subtilis 168 and provides a strong basis for further studies of the mechanism of wall teichoic acid glycosylation, a largely uncharted aspect of wall teichoic acid biogenesis.
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Affiliation(s)
- Sarah E Allison
- Department of Biochemistry and Biomedical Sciences and the Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario L8N 3Z5, Canada
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48
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Staphylococcus aureus and Bacillus subtilis W23 make polyribitol wall teichoic acids using different enzymatic pathways. ACTA ACUST UNITED AC 2011; 17:1101-10. [PMID: 21035733 DOI: 10.1016/j.chembiol.2010.07.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 05/17/2010] [Accepted: 07/16/2010] [Indexed: 12/22/2022]
Abstract
Wall teichoic acids (WTAs) are anionic polymers that play key roles in bacterial cell shape, cell division, envelope integrity, biofilm formation, and pathogenesis. B. subtilis W23 and S. aureus both make polyribitol-phosphate (RboP) WTAs and contain similar sets of biosynthetic genes. We use in vitro reconstitution combined with genetics to show that the pathways for WTA biosynthesis in B. subtilis W23 and S. aureus are different. S. aureus requires a glycerol-phosphate primase called TarF in order to make RboP-WTAs; B. subtilis W23 contains a TarF homolog, but this enzyme makes glycerol-phosphate polymers and is not involved in RboP-WTA synthesis. Instead, B. subtilis TarK functions in place of TarF to prime the WTA intermediate for chain extension by TarL. This work highlights the enzymatic diversity of the poorly characterized family of phosphotransferases involved in WTA biosynthesis in Gram-positive organisms.
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49
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Mendoza N, Tyring SK. Emerging drugs for complicated skin and skin-structure infections. Expert Opin Emerg Drugs 2010; 15:509-20. [PMID: 20557269 DOI: 10.1517/14728214.2010.497486] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
UNLABELLED IMPORTANCE OF THE FILED: With the worldwide surge of MRSA, skin and skin-structure infection (SSTI) treatment has become a challenge for physicians. Cultures and antibiotic susceptibility tests for SSTIs are the rule due to the implication in morbidity and mortality rates associated with MRSA infections. The need for new antibiotics is evident and the effort to decrease antibiotic resistance is a world priority. AREAS COVERED IN THIS REVIEW This manuscript accesses the actual treatments and the developing of antibiotics for MRSA SSTIs. WHAT THE READER WILL GAIN This is a review of the data on the available and emerging treatments for MRSA SSTIs. TAKE HOME MESSAGE There is an unmet medical need for new antibiotics in the new millennium. As physicians, we must assure all appropriate procedures are completed in order to reduce the bacterial resistance, especially for MRSA.
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Affiliation(s)
- Natalia Mendoza
- Center for Clinical Studies, 6655 Travis Suite 120, Houston, TX 77030, USA.
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50
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Kern J, Ryan C, Faull K, Schneewind O. Bacillus anthracis surface-layer proteins assemble by binding to the secondary cell wall polysaccharide in a manner that requires csaB and tagO. J Mol Biol 2010; 401:757-75. [PMID: 20603129 PMCID: PMC4652593 DOI: 10.1016/j.jmb.2010.06.059] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2010] [Revised: 06/09/2010] [Accepted: 06/25/2010] [Indexed: 10/19/2022]
Abstract
Bacillus anthracis, the causative agent of anthrax, requires surface (S)-layer proteins for the pathogenesis of infection. Previous work characterized S-layer protein binding via the surface layer homology domain to a pyruvylated carbohydrate in the envelope of vegetative forms. The molecular identity of this carbohydrate and the mechanism of its display in the bacterial envelope are still unknown. Analyzing acid-solubilized, purified carbohydrates by mass spectrometry and NMR spectroscopy, we identify secondary cell wall polysaccharide (SCWP) as the ligand of S-layer proteins. In agreement with the model that surface layer homology domains bind to pyruvylated carbohydrate, SCWP was observed to be linked to pyruvate in a manner requiring csaB, the only structural gene known to be required for S-layer assembly. B. anthracis does not elaborate wall teichoic acids; however, its genome harbors tagO and tagA, genes responsible for the synthesis of the linkage unit that tethers teichoic acids to the peptidoglycan layer. The tagO gene appears essential for B. anthracis growth and complements the tagO mutant phenotypes of staphylococci. Tunicamycin-mediated inhibition of TagO resulted in deformed, S-layer-deficient bacilli. Together, these results suggest that tagO-mediated assembly of linkage units tethers pyruvylated SCWP to the B. anthracis envelope, thereby enabling S-layer assembly and providing for the pathogenesis of anthrax infections.
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Affiliation(s)
- Justin Kern
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
| | - Christopher Ryan
- Pasarow Mass Spectrometry Laboratory, Neuropsychiatric Institute, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Kym Faull
- Pasarow Mass Spectrometry Laboratory, Neuropsychiatric Institute, Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Olaf Schneewind
- Department of Microbiology, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
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