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Ruiz-Cruz S, Erazo Garzon A, Cambillau C, Ortiz Charneco G, Lugli GA, Ventura M, Mahony J, van Sinderen D. The tal gene of lactococcal bacteriophage TP901-1 is involved in DNA release following host adsorption. Appl Environ Microbiol 2024:e0069424. [PMID: 39132999 DOI: 10.1128/aem.00694-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Accepted: 07/10/2024] [Indexed: 08/13/2024] Open
Abstract
Temperate P335 phage TP901-1 represents one of the best-characterized Gram-positive phages regarding its structure and host interactions. Following its reversible adsorption to the polysaccharidic side-chain of the cell wall polysaccharide of its host Lactococcus cremoris 3107, TP901-1 requires a glucosylated cell envelope moiety to trigger its genome delivery into the host cytoplasm. Here, we demonstrate that three distinct single amino acid substitutions in the Tal protein of TP901-1 baseplate are sufficient to overcome the TP901-1 resistance of three L. cremoris 3107 derivatives, whose resistance is due to impaired DNA release of the phage. All of these Tal alterations are located in the N-terminally located gp27-like domain of the protein, conserved in many tailed phages. AlphaFold2 predictions of the Tal mutant proteins suggest that these mutations favor conformational changes necessary to reposition the Tal fiber and thus facilitate release of the tape measure protein from the tail tube and subsequent DNA ejection in the absence of the trigger otherwise required for phage genome release. IMPORTANCE Understanding the molecular mechanisms involved in phage-host interactions is essential to develop phage-based applications in the food and probiotic industries, yet also to reduce the risk of phage infections in fermentations. Lactococcus, extensively used in dairy fermentations, has been widely employed to unravel such interactions. Phage infection commences with the recognition of a suitable host followed by the release of its DNA into the bacterial cytoplasm. Details on this latter, irreversible step are still very scarce in lactococci and other Gram-positive bacteria. We demonstrate that a component of the baseplate of the lactococcal phage TP901-1, the tail-associated lysin (Tal), is involved in the DNA delivery into its host, L. cremoris 3107. Specifically, we have found that three amino acid changes in Tal appear to facilitate structural rearrangements in the baseplate necessary for the DNA release process, even in the absence of an otherwise required host trigger.
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Affiliation(s)
- Sofía Ruiz-Cruz
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Andrea Erazo Garzon
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Christian Cambillau
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork, Ireland
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IMM), Aix-Marseille Université-CNRS, Marseille, France
| | | | - Gabriele Andrea Lugli
- Department of Chemistry, Life Sciences, and Environmental Sustainability, Laboratory of Probiogenomics, University of Parma, Parma, Italy
| | - Marco Ventura
- Department of Chemistry, Life Sciences, and Environmental Sustainability, Laboratory of Probiogenomics, University of Parma, Parma, Italy
| | - Jennifer Mahony
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome Ireland, University College Cork, Cork, Ireland
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2
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Rahman MM, Zamakhaeva S, Rush JS, Chaton CT, Kenner CW, Hla YM, Tsui HCT, Uversky VN, Winkler ME, Korotkov KV, Korotkova N. O-glycosylation of intrinsically disordered regions regulates homeostasis of membrane proteins in streptococci. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.05.592596. [PMID: 38746434 PMCID: PMC11092751 DOI: 10.1101/2024.05.05.592596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Proteins harboring intrinsically disordered regions (IDRs) lacking stable secondary or tertiary structures are abundant across the three domains of life. These regions have not been systematically studied in prokaryotes. Our genome-wide analysis identifies extracytoplasmic serine/threonine-rich IDRs in several biologically important membrane proteins in streptococci. We demonstrate that these IDRs are O-glycosylated with glucose by glycosyltransferases GtrB and PgtC2 in Streptococcus pyogenes and Streptococcus pneumoniae, and with N-acetylgalactosamine by a Pgf-dependent mechanism in Streptococcus mutans. Absence of glycosylation leads to a defect in biofilm formation under ethanol-stressed conditions in S. mutans. We link this phenotype to the C-terminal IDR of a post-translocation secretion chaperone PrsA. O-glycosylation of the IDR protects this region from proteolytic degradation. The IDR length attenuates the efficiency of glycosylation and, consequently, the expression level of PrsA. Taken together, our data reveal that O-glycosylation of IDRs functions as a dynamic switch of protein homeostasis in streptococci.
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Affiliation(s)
- Mohammad M. Rahman
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Svetlana Zamakhaeva
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Jeffrey S. Rush
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Catherine T. Chaton
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Cameron W. Kenner
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
| | - Yin Mon Hla
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | | | - Vladimir N. Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Malcolm E. Winkler
- Department of Biology, Indiana University Bloomington, Bloomington, Indiana, USA
| | - Konstantin V. Korotkov
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Natalia Korotkova
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, Kentucky, USA
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, USA
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3
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Kelly SD, Duong NH, Nothof JT, Lowary TL, Whitfield C. Three-component systems represent a common pathway for extracytoplasmic addition of pentofuranose sugars into bacterial glycans. Proc Natl Acad Sci U S A 2024; 121:e2402554121. [PMID: 38748580 PMCID: PMC11127046 DOI: 10.1073/pnas.2402554121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Accepted: 04/18/2024] [Indexed: 05/27/2024] Open
Abstract
Cell surface glycans are major drivers of antigenic diversity in bacteria. The biochemistry and molecular biology underpinning their synthesis are important in understanding host-pathogen interactions and for vaccine development with emerging chemoenzymatic and glycoengineering approaches. Structural diversity in glycostructures arises from the action of glycosyltransferases (GTs) that use an immense catalog of activated sugar donors to build the repeating unit and modifying enzymes that add further heterogeneity. Classical Leloir GTs incorporate α- or β-linked sugars by inverting or retaining mechanisms, depending on the nucleotide sugar donor. In contrast, the mechanism of known ribofuranosyltransferases is confined to β-linkages, so the existence of α-linked ribofuranose in some glycans dictates an alternative strategy. Here, we use Citrobacter youngae O1 and O2 lipopolysaccharide O antigens as prototypes to describe a widespread, versatile pathway for incorporating side-chain α-linked pentofuranoses by extracytoplasmic postpolymerization glycosylation. The pathway requires a polyprenyl phosphoribose synthase to generate a lipid-linked donor, a MATE-family flippase to transport the donor to the periplasm, and a GT-C type GT (founding the GT136 family) that performs the final glycosylation reaction. The characterized system shares similarities, but also fundamental differences, with both cell wall arabinan biosynthesis in mycobacteria, and periplasmic glucosylation of O antigens first discovered in Salmonella and Shigella. The participation of auxiliary epimerases allows the diversification of incorporated pentofuranoses. The results offer insight into a broad concept in microbial glycobiology and provide prototype systems and bioinformatic guides that facilitate discovery of further examples from diverse species, some in currently unknown glycans.
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Affiliation(s)
- Steven D. Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Nam Ha Duong
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, National Tsing Hua University, Hsinchu300044, Taiwan
| | - Jeremy T. Nothof
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
| | - Todd L. Lowary
- Institute of Biological Chemistry, Academia Sinica, Nangang, Taipei11529, Taiwan
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
- Institute of Biochemical Sciences, National Taiwan University, Taipei10617, Taiwan
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
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4
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Guérin H, Courtin P, Guillot A, Péchoux C, Mahony J, van Sinderen D, Kulakauskas S, Cambillau C, Touzé T, Chapot-Chartier MP. Molecular mechanisms underlying the structural diversity of rhamnose-rich cell wall polysaccharides in lactococci. J Biol Chem 2024; 300:105578. [PMID: 38110036 PMCID: PMC10821137 DOI: 10.1016/j.jbc.2023.105578] [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: 10/18/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023] Open
Abstract
In Gram-positive bacteria, cell wall polysaccharides (CWPS) play critical roles in bacterial cell wall homeostasis and bacterial interactions with their immediate surroundings. In lactococci, CWPS consist of two components: a conserved rhamnan embedded in the peptidoglycan layer and a surface-exposed polysaccharide pellicle (PSP), which are linked together to form a large rhamnose-rich CWPS (Rha-CWPS). PSP, whose structure varies from strain to strain, is a receptor for many bacteriophages infecting lactococci. Here, we examined the first two steps of PSP biosynthesis, using in vitro enzymatic tests with lipid acceptor substrates combined with LC-MS analysis, AlfaFold2 modeling of protein 3D-structure, complementation experiments, and phage assays. We show that the PSP repeat unit is assembled on an undecaprenyl-monophosphate (C55P) lipid intermediate. Synthesis is initiated by the WpsA/WpsB complex with GlcNAc-P-C55 synthase activity and the PSP precursor GlcNAc-P-C55 is then elongated by specific glycosyltransferases that vary among lactococcal strains, resulting in PSPs with diverse structures. Also, we engineered the PSP biosynthesis pathway in lactococci to obtain a chimeric PSP structure, confirming the predicted glycosyltransferase specificities. This enabled us to highlight the importance of a single sugar residue of the PSP repeat unit in phage recognition. In conclusion, our results support a novel pathway for PSP biosynthesis on a lipid-monophosphate intermediate as an extracellular modification of rhamnan, unveiling an assembly machinery for complex Rha-CWPS with structural diversity in lactococci.
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Affiliation(s)
- Hugo Guérin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Pascal Courtin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Alain Guillot
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Christine Péchoux
- Université Paris-Saclay INRAE, AgroParisTech, GABI, Jouy-en-Josas, France
| | - Jennifer Mahony
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Christian Cambillau
- School of Microbiology and APC Microbiome Ireland, University College Cork, Cork, Ireland; Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IMM), Aix-Marseille Université - CNRS, UMR 7255, Marseille, France
| | - Thierry Touzé
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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5
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Ruiz‐Cruz S, Erazo Garzon A, Kelleher P, Bottacini F, Breum SØ, Neve H, Heller KJ, Vogensen FK, Palussière S, Courtin P, Chapot‐Chartier M, Vinogradov E, Sadovskaya I, Mahony J, van Sinderen D. Host genetic requirements for DNA release of lactococcal phage TP901-1. Microb Biotechnol 2022; 15:2875-2889. [PMID: 36259418 PMCID: PMC9733650 DOI: 10.1111/1751-7915.14156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/29/2022] [Accepted: 09/27/2022] [Indexed: 12/14/2022] Open
Abstract
The first step in phage infection is the recognition of, and adsorption to, a receptor located on the host cell surface. This reversible host adsorption step is commonly followed by an irreversible event, which involves phage DNA delivery or release into the bacterial cytoplasm. The molecular components that trigger this latter event are unknown for most phages of Gram-positive bacteria. In the current study, we present a comparative genome analysis of three mutants of Lactococcus cremoris 3107, which are resistant to the P335 group phage TP901-1 due to mutations that affect TP901-1 DNA release. Through genetic complementation and phage infection assays, a predicted lactococcal three-component glycosylation system (TGS) was shown to be required for TP901-1 infection. Major cell wall saccharidic components were analysed, but no differences were found. However, heterologous gene expression experiments indicate that this TGS is involved in the glucosylation of a cell envelope-associated component that triggers TP901-1 DNA release. To date, a saccharide modification has not been implicated in the DNA delivery process of a Gram-positive infecting phage.
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Affiliation(s)
- Sofía Ruiz‐Cruz
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Andrea Erazo Garzon
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Philip Kelleher
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Francesca Bottacini
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland,Department of Biological SciencesMunster Technological UniversityCorkIreland
| | - Solvej Østergaard Breum
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of ScienceUniversity of CopenhagenFrederiksbergDenmark,Present address:
Department of Virus & Microbiological Special Diagnostics, Division of Infectious Disease Preparedness, Statens Serum InstitutCopenhagenDenmark
| | - Horst Neve
- Department of Microbiology and Biotechnology, Max Rubner‐InstitutFederal Research Institute of Nutrition and FoodKielGermany
| | - Knut J. Heller
- Department of Microbiology and Biotechnology, Max Rubner‐InstitutFederal Research Institute of Nutrition and FoodKielGermany
| | - Finn K. Vogensen
- Section of Microbiology and Fermentation, Department of Food Science, Faculty of ScienceUniversity of CopenhagenFrederiksbergDenmark
| | - Simon Palussière
- Université Paris‐Saclay, INRAE, AgroParisTech, Micalis InstituteJouy‐en‐JosasFrance
| | - Pascal Courtin
- Université Paris‐Saclay, INRAE, AgroParisTech, Micalis InstituteJouy‐en‐JosasFrance
| | | | - Evgeny Vinogradov
- National Research Council CanadaInstitute for Biological SciencesOttawaOntarioCanada
| | - Irina Sadovskaya
- Equipe BPA, Université du Littoral‐Côte d'Opale, Institut Charles Violette EA 7394 USC AnsesBoulogne‐sur‐merFrance
| | - Jennifer Mahony
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
| | - Douwe van Sinderen
- School of Microbiology & APC Microbiome IrelandUniversity College CorkCorkIreland
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6
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Guérin H, Kulakauskas S, Chapot-Chartier MP. Structural variations and roles of rhamnose-rich cell wall polysaccharides in Gram-positive bacteria. J Biol Chem 2022; 298:102488. [PMID: 36113580 PMCID: PMC9574508 DOI: 10.1016/j.jbc.2022.102488] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 09/08/2022] [Accepted: 09/10/2022] [Indexed: 11/17/2022] Open
Abstract
Rhamnose-rich cell wall polysaccharides (Rha-CWPSs) have emerged as crucial cell wall components of numerous Gram-positive, ovoid-shaped bacteria—including streptococci, enterococci, and lactococci—of which many are of clinical or biotechnological importance. Rha-CWPS are composed of a conserved polyrhamnose backbone with side-chain substituents of variable size and structure. Because these substituents contain phosphate groups, Rha-CWPS can also be classified as polyanionic glycopolymers, similar to wall teichoic acids, of which they appear to be functional homologs. Recent advances have highlighted the critical role of these side-chain substituents in bacterial cell growth and division, as well as in specific interactions between bacteria and infecting bacteriophages or eukaryotic hosts. Here, we review the current state of knowledge on the structure and biosynthesis of Rha-CWPS in several ovoid-shaped bacterial species. We emphasize the role played by multicomponent transmembrane glycosylation systems in the addition of side-chain substituents of various sizes as extracytoplasmic modifications of the polyrhamnose backbone. We provide an overview of the contribution of Rha-CWPS to cell wall architecture and biogenesis and discuss current hypotheses regarding their importance in the cell division process. Finally, we sum up the critical roles that Rha-CWPS can play as bacteriophage receptors or in escaping host defenses, roles that are mediated mainly through their side-chain substituents. From an applied perspective, increased knowledge of Rha-CWPS can lead to advancements in strategies for preventing phage infection of lactococci and streptococci in food fermentation and for combating pathogenic streptococci and enterococci.
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Affiliation(s)
- Hugo Guérin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France
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7
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Furevi A, Udekwu KI, Widmalm G. Structural elucidation of the O-antigen polysaccharide from Escherichia coli O125ac and biosynthetic aspects thereof. Glycobiology 2022; 32:1089-1100. [PMID: 36087289 PMCID: PMC9680116 DOI: 10.1093/glycob/cwac061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 08/30/2022] [Accepted: 09/05/2022] [Indexed: 01/07/2023] Open
Abstract
Enteropathogenic Escherichia coli O125, the cause of infectious diarrheal disease, is comprised of two serogroups, viz., O125ab and O125ac, which display the aggregative adherence pattern with epithelial cells. Herein, the structure of the O-antigen polysaccharide from E. coli O125ac:H6 has been elucidated. Sugar analysis revealed the presence of fucose, mannose, galactose and N-acetyl-galactosamine as major components. Unassigned 1H and 13C NMR data from one- and two-dimensional NMR experiments of the O125ac O-antigen in conjunction with sugar components were used as input to the CASPER program, which can determine polysaccharide structure in a fully automated way, and resulted in the following branched pentasaccharide structure of the repeating unit: →4)[β-d-Galp-(1 → 3)]-β-d-GalpNAc-(1 → 2)-α-d-Manp-(1 → 3)-α-l-Fucp-(1 → 3)-α-d-GalpNAc-(1→, where the side chain is denoted by square brackets. The proposed O-antigen structure was confirmed by 1H and 13C NMR chemical shift assignments and determination of interresidue connectivities. Based on this structure, that of the O125ab O-antigen, which consists of hexasaccharide repeating units with an additional glucosyl group, was possible to establish in a semi-automated fashion by CASPER. The putative existence of gnu and gne in the gene clusters of the O125 serogroups is manifested by N-acetyl-d-galactosamine residues as the initial sugar residue of the biological repeating unit as well as within the repeating unit. The close similarity between O-antigen structures is consistent with the presence of two subgroups in the E. coli O125 serogroup.
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Affiliation(s)
- Axel Furevi
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Klas I Udekwu
- Department of Aquatic Sciences and Assessment, Swedish University of Agriculture, P.O. Box 7050, SE-750 07 Uppsala, Sweden
| | - Göran Widmalm
- To whom correspondence should be addressed: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden. e-mail:
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8
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The biosynthetic origin of ribofuranose in bacterial polysaccharides. Nat Chem Biol 2022; 18:530-537. [PMID: 35393575 DOI: 10.1038/s41589-022-01006-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/28/2022] [Indexed: 11/08/2022]
Abstract
Bacterial surface polysaccharides are assembled by glycosyltransferase enzymes that typically use sugar nucleotide or polyprenyl-monophosphosugar activated donors. Characterized representatives exist for many monosaccharides but neither the donor nor the corresponding glycosyltransferases have been definitively identified for ribofuranose residues found in some polysaccharides. Klebsiella pneumoniae O-antigen polysaccharides provided prototypes to identify dual-domain ribofuranosyltransferase proteins catalyzing a two-step reaction sequence. Phosphoribosyl-5-phospho-D-ribosyl-α-1-diphosphate serves as the donor for a glycan acceptor-specific phosphoribosyl transferase (gPRT), and a more promiscuous phosphoribosyl-phosphatase (PRP) then removes the residual 5'-phosphate. The 2.5-Å resolution crystal structure of a dual-domain ribofuranosyltransferase ortholog from Thermobacillus composti revealed a PRP domain that conserves many features of the phosphatase members of the haloacid dehalogenase family, and a gPRT domain that diverges substantially from all previously characterized phosphoribosyl transferases. The gPRT represents a new glycosyltransferase fold conserved in the most abundant ribofuranosyltransferase family.
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9
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Scarbrough BA, Eade CR, Reid AJ, Williams TC, Troutman JM. Lipopolysaccharide Is a 4-Aminoarabinose Donor to Exogenous Polyisoprenyl Phosphates through the Reverse Reaction of the Enzyme ArnT. ACS OMEGA 2021; 6:25729-25741. [PMID: 34632229 PMCID: PMC8495848 DOI: 10.1021/acsomega.1c04036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Indexed: 05/11/2023]
Abstract
Modification of the lipid A portion of LPS with cationic monosaccharides provides resistance to polymyxins, which are often employed as a last resort to treat multidrug-resistant bacterial infections. Here, we describe the use of fluorescent polyisoprenoids, liquid chromatography-mass spectrometry, and bacterial genetics to probe the activity of membrane-localized proteins that utilize the 55-carbon lipid carrier bactoprenyl phosphate (BP). We have discovered that a substantial background reaction occurs when B-strain E. coli cell membrane fractions are supplemented with exogenous BP. This reaction involves proteins associated with the arn operon, which is necessary for the covalent modification of lipid A with the cationic 4-aminoarabinose (Ara4N). Using a series of arn operon gene deletion mutants, we identified that the modification was dependent on ArnC, which is responsible for forming BP-linked Ara4N, or ArnT, which transfers Ara4N to lipid A. Surprisingly, we found that the majority of the Ara4N-modified isoprenoid was due to the reverse reaction catalyzed by ArnT and demonstrate this using heat-inactivated membrane fractions, isolated lipopolysaccharide fractions, and analyses of a purified ArnT. This work provides methods that will facilitate thorough and rapid investigation of bacterial outer membrane remodeling and the evaluation of polyisoprenoid precursors required for covalent glycan modifications.
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Affiliation(s)
- Beth A. Scarbrough
- Nanoscale
Science Program, The University of North
Carolina at Charlotte, Charlotte, North Carolina 28223-0001, United States
| | - Colleen R. Eade
- Department
of Chemistry, The University of North Carolina
at Charlotte, Charlotte, North Carolina 28223-0001, United States
| | - Amanda J. Reid
- Nanoscale
Science Program, The University of North
Carolina at Charlotte, Charlotte, North Carolina 28223-0001, United States
| | - Tiffany C. Williams
- Department
of Chemistry, The University of North Carolina
at Charlotte, Charlotte, North Carolina 28223-0001, United States
| | - Jerry M. Troutman
- Department
of Chemistry, The University of North Carolina
at Charlotte, Charlotte, North Carolina 28223-0001, United States
- Nanoscale
Science Program, The University of North
Carolina at Charlotte, Charlotte, North Carolina 28223-0001, United States
- . Phone: 704-687-5180
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10
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Martínez B, Rodríguez A, Kulakauskas S, Chapot-Chartier MP. Cell wall homeostasis in lactic acid bacteria: threats and defences. FEMS Microbiol Rev 2021; 44:538-564. [PMID: 32495833 PMCID: PMC7476776 DOI: 10.1093/femsre/fuaa021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
Lactic acid bacteria (LAB) encompasses industrially relevant bacteria involved in food fermentations as well as health-promoting members of our autochthonous microbiota. In the last years, we have witnessed major progresses in the knowledge of the biology of their cell wall, the outermost macrostructure of a Gram-positive cell, which is crucial for survival. Sophisticated biochemical analyses combined with mutation strategies have been applied to unravel biosynthetic routes that sustain the inter- and intra-species cell wall diversity within LAB. Interplay with global cell metabolism has been deciphered that improved our fundamental understanding of the plasticity of the cell wall during growth. The cell wall is also decisive for the antimicrobial activity of many bacteriocins, for bacteriophage infection and for the interactions with the external environment. Therefore, genetic circuits involved in monitoring cell wall damage have been described in LAB, together with a plethora of defence mechanisms that help them to cope with external threats and adapt to harsh conditions. Since the cell wall plays a pivotal role in several technological and health-promoting traits of LAB, we anticipate that this knowledge will pave the way for the future development and extended applications of LAB.
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Affiliation(s)
- Beatriz Martínez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Ana Rodríguez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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11
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Modifications of cell wall polymers in Gram-positive bacteria by multi-component transmembrane glycosylation systems. Curr Opin Microbiol 2021; 60:24-33. [PMID: 33578058 PMCID: PMC8035078 DOI: 10.1016/j.mib.2021.01.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/12/2021] [Accepted: 01/22/2021] [Indexed: 11/22/2022]
Abstract
Secondary cell wall polymers fulfil diverse and important functions within the cell wall of Gram-positive bacteria. Here, we will provide a brief overview of the principles of teichoic acid and complex secondary cell wall polysaccharide biosynthesis pathways in Firmicutes and summarize the recently revised mechanism for the decoration of teichoic acids with d-alanines. Many cell wall polymers are decorated with glycosyl groups, either intracellularly or extracellularly. The main focus of this review will be on the extracellular glycosylation mechanism and recent advances that have been made in the identification of enzymes involved in this process. Based on the proteins involved, we propose to rename the system to multi-component transmembrane glycosylation system in place of three-component glycosylation system.
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12
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The Impact of Insertion Sequences on O-Serotype Phenotype and Its O-Locus-Based Prediction in Klebsiella pneumoniae O2 and O1. Int J Mol Sci 2020; 21:ijms21186572. [PMID: 32911792 PMCID: PMC7556023 DOI: 10.3390/ijms21186572] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/04/2020] [Accepted: 09/05/2020] [Indexed: 12/14/2022] Open
Abstract
Klebsiella pneumoniae is a nosocomial pathogen, pointed out by the World Helth Organisation (WHO) as “critical” regarding the highly limited options of treatment. Lipopolysaccharide (LPS, O-antigen) and capsular polysaccharide (K-antigen) are its virulence factors and surface antigens, determining O- and K-serotypes and encoded by O- or K-loci. They are promising targets for antibody-based therapies (vaccines and passive immunization) as an alternative to antibiotics. To make such immunotherapy effective, knowledge about O/K-antigen structures, drift, and distribution among clinical isolates is needed. At present, the structural analysis of O-antigens is efficiently supported by bioinformatics. O- and K-loci-based genotyping by polymerase chain reaction (PCR) or whole genome sequencing WGS has been proposed as a diagnostic tool, including the Kaptive tool available in the public domain. We analyzed discrepancies for O2 serotyping between Kaptive-based predictions (O2 variant 2 serotype) and the actual phenotype (O2 variant 1) for two K. pneumoniae clinical isolates. Identified length discrepancies from the reference O-locus resulted from insertion sequences (ISs) within rfb regions of the O-loci. In silico analysis of 8130 O1 and O2 genomes available in public databases indicated a broader distribution of ISs in rfbs that may influence the actual O-antigen structure. Our results show that current high-throughput genotyping algorithms need to be further refined to consider the effects of ISs on the LPS O-serotype.
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13
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Whitfield C, Wear SS, Sande C. Assembly of Bacterial Capsular Polysaccharides and Exopolysaccharides. Annu Rev Microbiol 2020; 74:521-543. [PMID: 32680453 DOI: 10.1146/annurev-micro-011420-075607] [Citation(s) in RCA: 130] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polysaccharides are dominant features of most bacterial surfaces and are displayed in different formats. Many bacteria produce abundant long-chain capsular polysaccharides, which can maintain a strong association and form a capsule structure enveloping the cell and/or take the form of exopolysaccharides that are mostly secreted into the immediate environment. These polymers afford the producing bacteria protection from a wide range of physical, chemical, and biological stresses, support biofilms, and play critical roles in interactions between bacteria and their immediate environments. Their biological and physical properties also drive a variety of industrial and biomedical applications. Despite the immense variation in capsular polysaccharide and exopolysaccharide structures, patterns are evident in strategies used for their assembly and export. This review describes recent advances in understanding those strategies, based on a wealth of biochemical investigations of select prototypes, supported by complementary insight from expanding structural biology initiatives. This provides a framework to identify and distinguish new systems emanating from genomic studies.
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Affiliation(s)
- Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada;
| | - Samantha S Wear
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada;
| | - Caitlin Sande
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada;
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14
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Chateau A, Oh SY, Tomatsidou A, Brockhausen I, Schneewind O, Missiakas D. Distinct Pathways Carry Out α and β Galactosylation of Secondary Cell Wall Polysaccharide in Bacillus anthracis. J Bacteriol 2020; 202:e00191-20. [PMID: 32457049 PMCID: PMC7348550 DOI: 10.1128/jb.00191-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 05/15/2020] [Indexed: 12/26/2022] Open
Abstract
Bacillus anthracis, the causative agent of anthrax disease, elaborates a secondary cell wall polysaccharide (SCWP) that is required for the retention of surface layer (S-layer) and S-layer homology (SLH) domain proteins. Genetic disruption of the SCWP biosynthetic pathway impairs growth and cell division. B. anthracis SCWP is comprised of trisaccharide repeats composed of one ManNAc and two GlcNAc residues with O-3-α-Gal and O-4-β-Gal substitutions. UDP-Gal, synthesized by GalE1, is the substrate of galactosyltransferases that modify the SCWP repeat. Here, we show that the gtsE gene, which encodes a predicted glycosyltransferase with a GT-A fold, is required for O-4-β-Gal modification of trisaccharide repeats. We identify a DXD motif critical for GtsE activity. Three distinct genes, gtsA, gtsB, and gtsC, are required for O-3-α-Gal modification of trisaccharide repeats. Based on the similarity with other three-component glycosyltransferase systems, we propose that GtsA transfers Gal from cytosolic UDP-Gal to undecaprenyl phosphate (C55-P), GtsB flips the C55-P-Gal intermediate to the trans side of the membrane, and GtsC transfers Gal onto trisaccharide repeats. The deletion of galE1 does not affect growth in vitro, suggesting that galactosyl modifications are dispensable for the function of SCWP. The deletion of gtsA, gtsB, or gtsC leads to a loss of viability, yet gtsA and gtsC can be deleted in strains lacking galE1 or gtsE We propose that the loss of viability is caused by the accumulation of undecaprenol-bound precursors and present an updated model for SCWP assembly in B. anthracis to account for the galactosylation of repeat units.IMPORTANCE Peptidoglycan is a conserved extracellular macromolecule that protects bacterial cells from turgor pressure. Peptidoglycan of Gram-positive bacteria serves as a scaffold for the attachment of polymers that provide defined bacterial interactions with their environment. One such polymer, B. anthracis SCWP, is pyruvylated at its distal end to serve as a receptor for secreted proteins bearing the S-layer homology domain. Repeat units of SCWP carry three galactoses in B. anthracis Glycosylation is a recurring theme in nature and often represents a means to mask or alter conserved molecular signatures from intruders such as bacteriophages. Several glycosyltransferase families have been described based on bioinformatics prediction, but few have been studied. Here, we describe the glycosyltransferases that mediate the galactosylation of B. anthracis SCWP.
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Affiliation(s)
- Alice Chateau
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA
| | - So Young Oh
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA
| | - Anastasia Tomatsidou
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA
| | - Inka Brockhausen
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Olaf Schneewind
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA
| | - Dominique Missiakas
- Howard Taylor Ricketts Laboratory, Argonne National Laboratory, Lemont, Illinois, USA
- Department of Microbiology, University of Chicago, Chicago, Illinois, USA
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15
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Whitfield C, Williams DM, Kelly SD. Lipopolysaccharide O-antigens-bacterial glycans made to measure. J Biol Chem 2020; 295:10593-10609. [PMID: 32424042 DOI: 10.1074/jbc.rev120.009402] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/17/2020] [Indexed: 01/05/2023] Open
Abstract
Lipopolysaccharides are critical components of bacterial outer membranes. The more conserved lipid A part of the lipopolysaccharide molecule is a major element in the permeability barrier imposed by the outer membrane and offers a pathogen-associated molecular pattern recognized by innate immune systems. In contrast, the long-chain O-antigen polysaccharide (O-PS) shows remarkable structural diversity and fulfills a range of functions, depending on bacterial lifestyles. O-PS production is vital for the success of clinically important Gram-negative pathogens. The biological properties and functions of O-PSs are mostly independent of specific structures, but the size distribution of O-PS chains is particularly important in many contexts. Despite the vast O-PS chemical diversity, most are produced in bacterial cells by two assembly strategies, and the different mechanisms employed in these pathways to regulate chain-length distribution are emerging. Here, we review our current understanding of the mechanisms involved in regulating O-PS chain-length distribution and discuss their impact on microbial cell biology.
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Affiliation(s)
- Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Danielle M Williams
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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16
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Theodorou I, Courtin P, Sadovskaya I, Palussière S, Fenaille F, Mahony J, Chapot-Chartier MP, van Sinderen D. Three distinct glycosylation pathways are involved in the decoration of Lactococcus lactis cell wall glycopolymers. J Biol Chem 2020; 295:5519-5532. [PMID: 32169901 PMCID: PMC7170526 DOI: 10.1074/jbc.ra119.010844] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 03/10/2020] [Indexed: 12/16/2022] Open
Abstract
Extracytoplasmic sugar decoration of glycopolymer components of the bacterial cell wall contributes to their structural diversity. Typically, the molecular mechanism that underpins such a decoration process involves a three-component glycosylation system (TGS) represented by an undecaprenyl-phosphate (Und-P) sugar-activating glycosyltransferase (Und-P GT), a flippase, and a polytopic glycosyltransferase (PolM GT) dedicated to attaching sugar residues to a specific glycopolymer. Here, using bioinformatic analyses, CRISPR-assisted recombineering, structural analysis of cell wall-associated polysaccharides (CWPS) through MALDI-TOF MS and methylation analysis, we report on three such systems in the bacterium Lactococcus lactis On the basis of sequence similarities, we first identified three gene pairs, csdAB, csdCD, and csdEF, each encoding an Und-P GT and a PolM GT, as potential TGS component candidates. Our experimental results show that csdAB and csdCD are involved in Glc side-chain addition on the CWPS components rhamnan and polysaccharide pellicle (PSP), respectively, whereas csdEF plays a role in galactosylation of lipoteichoic acid (LTA). We also identified a potential flippase encoded in the L. lactis genome (llnz_02975, cflA) and confirmed that it participates in the glycosylation of the three cell wall glycopolymers rhamnan, PSP, and LTA, thus indicating that its function is shared by the three TGSs. Finally, we observed that glucosylation of both rhamnan and PSP can increase resistance to bacteriophage predation and that LTA galactosylation alters L. lactis resistance to bacteriocin.
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Affiliation(s)
- Ilias Theodorou
- School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
| | - Pascal Courtin
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - Irina Sadovskaya
- Équipe BPA, Université du Littoral Côte d'Opale, Institut Régional Charles Violette EA 7394, USC Anses-ULCO, 62202 Boulogne-sur-Mer, France
| | - Simon Palussière
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350 Jouy-en-Josas, France
| | - François Fenaille
- Université Paris-Saclay, Commissariat à l'Energie Atomique, INRAE, Médicaments et Technologies pour la Santé (MTS), MetaboHUB, 91191 Gif-sur-Yvette, France
| | - Jennifer Mahony
- School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
- APC Microbiome Ireland, University College Cork, Cork T12 K8AF, Ireland
| | | | - Douwe van Sinderen
- School of Microbiology, University College Cork, Cork T12 K8AF, Ireland
- APC Microbiome Ireland, University College Cork, Cork T12 K8AF, Ireland
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17
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Theodorou I, Courtin P, Palussière S, Kulakauskas S, Bidnenko E, Péchoux C, Fenaille F, Penno C, Mahony J, van Sinderen D, Chapot-Chartier MP. A dual-chain assembly pathway generates the high structural diversity of cell-wall polysaccharides in Lactococcus lactis. J Biol Chem 2019; 294:17612-17625. [PMID: 31582566 DOI: 10.1074/jbc.ra119.009957] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/30/2019] [Indexed: 12/12/2022] Open
Abstract
In Lactococcus lactis, cell-wall polysaccharides (CWPSs) act as receptors for many bacteriophages, and their structural diversity among strains explains, at least partially, the narrow host range of these viral predators. Previous studies have reported that lactococcal CWPS consists of two distinct components, a variable chain exposed at the bacterial surface, named polysaccharide pellicle (PSP), and a more conserved rhamnan chain anchored to, and embedded inside, peptidoglycan. These two chains appear to be covalently linked to form a large heteropolysaccharide. The molecular machinery for biosynthesis of both components is encoded by a large gene cluster, named cwps In this study, using a CRISPR/Cas-based method, we performed a mutational analysis of the cwps genes. MALDI-TOF MS-based structural analysis of the mutant CWPS combined with sequence homology, transmission EM, and phage sensitivity analyses enabled us to infer a role for each protein encoded by the cwps cluster. We propose a comprehensive CWPS biosynthesis scheme in which the rhamnan and PSP chains are independently synthesized from two distinct lipid-sugar precursors and are joined at the extracellular side of the cytoplasmic membrane by a mechanism involving a membrane-embedded glycosyltransferase with a GT-C fold. The proposed scheme encompasses a system that allows extracytoplasmic modification of rhamnan by complex substituting oligo-/polysaccharides. It accounts for the extensive diversity of CWPS structures observed among lactococci and may also have relevance to the biosynthesis of complex rhamnose-containing CWPSs in other Gram-positive bacteria.
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Affiliation(s)
- Ilias Theodorou
- School of Microbiology, University College Cork, Western Road, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
| | - Pascal Courtin
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Simon Palussière
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Saulius Kulakauskas
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Elena Bidnenko
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France
| | - Christine Péchoux
- INRA, UMR 1313 Génétique Animale et Biologie Intégrative (GABI), Plate-forme MIMA2, 78350 Jouy-en-Josas, France
| | - François Fenaille
- CEA, Institut Joliot, Service de Pharmacologie et d'Immunoanalyse, UMR 0496, Laboratoire d'Etude du Métabolisme des Médicaments, MetaboHUB-Paris, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Christophe Penno
- School of Microbiology, University College Cork, Western Road, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
| | - Jennifer Mahony
- School of Microbiology, University College Cork, Western Road, Cork, Ireland.,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
| | - Douwe van Sinderen
- School of Microbiology, University College Cork, Western Road, Cork, Ireland .,APC Microbiome Ireland, University College Cork, Western Road, Cork, Ireland
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18
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Salt-Induced Stress Stimulates a Lipoteichoic Acid-Specific Three-Component Glycosylation System in Staphylococcus aureus. J Bacteriol 2018; 200:JB.00017-18. [PMID: 29632092 DOI: 10.1128/jb.00017-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/03/2018] [Indexed: 01/01/2023] Open
Abstract
Lipoteichoic acid (LTA) in Staphylococcus aureus is a poly-glycerophosphate polymer anchored to the outer surface of the cell membrane. LTA has numerous roles in cell envelope physiology, including regulating cell autolysis, coordinating cell division, and adapting to environmental growth conditions. LTA is often further modified with substituents, including d-alanine and glycosyl groups, to alter cellular function. While the genetic determinants of d-alanylation have been largely defined, the route of LTA glycosylation and its role in cell envelope physiology have remained unknown, in part due to the low levels of basal LTA glycosylation in S. aureus We demonstrate here that S. aureus utilizes a membrane-associated three-component glycosylation system composed of an undecaprenol (Und) N-acetylglucosamine (GlcNAc) charging enzyme (CsbB; SAOUHSC_00713), a putative flippase to transport loaded substrate to the outside surface of the cell (GtcA; SAOUHSC_02722), and finally an LTA-specific glycosyltransferase that adds α-GlcNAc moieties to LTA (YfhO; SAOUHSC_01213). We demonstrate that this system is specific for LTA with no cross recognition of the structurally similar polyribitol phosphate containing wall teichoic acids. We show that while wild-type S. aureus LTA has only a trace of GlcNAcylated LTA under normal growth conditions, amounts are raised upon either overexpressing CsbB, reducing endogenous d-alanylation activity, expressing the cell envelope stress responsive alternative sigma factor SigB, or by exposure to environmental stress-inducing culture conditions, including growth media containing high levels of sodium chloride.IMPORTANCE The role of glycosylation in the structure and function of Staphylococcus aureus lipoteichoic acid (LTA) is largely unknown. By defining key components of the LTA three-component glycosylation pathway and uncovering stress-induced regulation by the alternative sigma factor SigB, the role of N-acetylglucosamine tailoring during adaptation to environmental stresses can now be elucidated. As the dlt and glycosylation pathways compete for the same sites on LTA and induction of glycosylation results in decreased d-alanylation, the interplay between the two modification systems holds implications for resistance to antibiotics and antimicrobial peptides.
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19
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Periplasmic depolymerase provides insight into ABC transporter-dependent secretion of bacterial capsular polysaccharides. Proc Natl Acad Sci U S A 2018; 115:E4870-E4879. [PMID: 29735649 PMCID: PMC6003464 DOI: 10.1073/pnas.1801336115] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Capsules are critical virulence determinants for bacterial pathogens. They are composed of capsular polysaccharides (CPSs) with diverse structures, whose assembly on the cell surface is often powered by a conserved ABC transporter. Current capsule-assembly models include a contiguous trans-envelope channel directing nascent CPSs from the transporter to the cell surface. This conserved apparatus is an attractive target for antivirulence antimicrobial development. This work describes a CPS depolymerizing lyase enzyme found in the Burkholderiales and unique structural features that define its mechanism, CPS specificity, and evolution to function in the periplasm in a noncatabolic role. The activity of this enzyme provides evidence that CPS assembled in an ABC transporter-dependent system is exposed to periplasm during translocation to the cell surface. Capsules are surface layers of hydrated capsular polysaccharides (CPSs) produced by many bacteria. The human pathogen Salmonella enterica serovar Typhi produces “Vi antigen” CPS, which contributes to virulence. In a conserved strategy used by bacteria with diverse CPS structures, translocation of Vi antigen to the cell surface is driven by an ATP-binding cassette (ABC) transporter. These transporters are engaged in heterooligomeric complexes proposed to form an enclosed translocation conduit to the cell surface, allowing the transporter to power the entire process. We identified Vi antigen biosynthesis genetic loci in genera of the Burkholderiales, which are paradoxically distinguished from S. Typhi by encoding VexL, a predicted pectate lyase homolog. Biochemical analyses demonstrated that VexL is an unusual metal-independent endolyase with an acidic pH optimum that is specific for O-acetylated Vi antigen. A 1.22-Å crystal structure of the VexL-Vi antigen complex revealed features which distinguish common secreted catabolic pectate lyases from periplasmic VexL, which participates in cell-surface assembly. VexL possesses a right-handed parallel β-superhelix, of which one face forms an electropositive glycan-binding groove with an extensive hydrogen bonding network that includes Vi antigen acetyl groups and confers substrate specificity. VexL provided a probe to interrogate conserved features of the ABC transporter-dependent export model. When introduced into S. Typhi, VexL localized to the periplasm and degraded Vi antigen. In contrast, a cytosolic derivative had no effect unless export was disrupted. These data provide evidence that CPS assembled in ABC transporter-dependent systems is actually exposed to the periplasm during envelope translocation.
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20
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Clarke BR, Ovchinnikova OG, Kelly SD, Williamson ML, Butler JE, Liu B, Wang L, Gou X, Follador R, Lowary TL, Whitfield C. Molecular basis for the structural diversity in serogroup O2-antigen polysaccharides in Klebsiella pneumoniae. J Biol Chem 2018; 293:4666-4679. [PMID: 29602878 DOI: 10.1074/jbc.ra117.000646] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 01/23/2018] [Indexed: 12/17/2022] Open
Abstract
Klebsiella pneumoniae is a major health threat. Vaccination and passive immunization are considered as alternative therapeutic strategies for managing Klebsiella infections. Lipopolysaccharide O antigens are attractive candidates because of the relatively small range of known O-antigen polysaccharide structures, but immunotherapeutic applications require a complete understanding of the structures found in clinical settings. Currently, the precise number of Klebsiella O antigens is unknown because available serological tests have limited resolution, and their association with defined chemical structures is sometimes uncertain. Molecular serotyping methods can evaluate clinical prevalence of O serotypes but require a full understanding of the genetic determinants for each O-antigen structure. This is problematic with Klebsiella pneumoniae because genes outside the main rfb (O-antigen biosynthesis) locus can have profound effects on the final structure. Here, we report two new loci encoding enzymes that modify a conserved polysaccharide backbone comprising disaccharide repeat units [→3)-α-d-Galp-(1→3)-β-d-Galf-(1→] (O2a antigen). We identified in serotype O2aeh a three-component system that modifies completed O2a glycan in the periplasm by adding 1,2-linked α-Galp side-group residues. In serotype O2ac, a polysaccharide comprising disaccharide repeat units [→5)-β-d-Galf-(1→3)-β-d-GlcpNAc-(1→] (O2c antigen) is attached to the non-reducing termini of O2a-antigen chains. O2c-polysaccharide synthesis is dependent on a locus encoding three glycosyltransferase enzymes. The authentic O2aeh and O2c antigens were recapitulated in recombinant Escherichia coli hosts to establish the essential gene set for their synthesis. These findings now provide a complete understanding of the molecular genetic basis for the known variations in Klebsiella O-antigen carbohydrate structures based on the O2a backbone.
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Affiliation(s)
- Bradley R Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Olga G Ovchinnikova
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Monica L Williamson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Jennifer E Butler
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Bin Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda St. TEDA, Tianjin 300457, China
| | - Lu Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda St. TEDA, Tianjin 300457, China
| | - Xi Gou
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda St. TEDA, Tianjin 300457, China
| | | | - Todd L Lowary
- Department of Chemistry and Alberta Glycomics Centre, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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21
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Rush JS, Edgar RJ, Deng P, Chen J, Zhu H, van Sorge NM, Morris AJ, Korotkov KV, Korotkova N. The molecular mechanism of N-acetylglucosamine side-chain attachment to the Lancefield group A carbohydrate in Streptococcus pyogenes. J Biol Chem 2017; 292:19441-19457. [PMID: 29021255 DOI: 10.1074/jbc.m117.815910] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/06/2017] [Indexed: 12/21/2022] Open
Abstract
In many Lactobacillales species (i.e. lactic acid bacteria), peptidoglycan is decorated by polyrhamnose polysaccharides that are critical for cell envelope integrity and cell shape and also represent key antigenic determinants. Despite the biological importance of these polysaccharides, their biosynthetic pathways have received limited attention. The important human pathogen, Streptococcus pyogenes, synthesizes a key antigenic surface polymer, the Lancefield group A carbohydrate (GAC). GAC is covalently attached to peptidoglycan and consists of a polyrhamnose polymer, with N-acetylglucosamine (GlcNAc) side chains, which is an essential virulence determinant. The molecular details of the mechanism of polyrhamnose modification with GlcNAc are currently unknown. In this report, using molecular genetics, analytical chemistry, and mass spectrometry analysis, we demonstrated that GAC biosynthesis requires two distinct undecaprenol-linked GlcNAc-lipid intermediates: GlcNAc-pyrophosphoryl-undecaprenol (GlcNAc-P-P-Und) produced by the GlcNAc-phosphate transferase GacO and GlcNAc-phosphate-undecaprenol (GlcNAc-P-Und) produced by the glycosyltransferase GacI. Further investigations revealed that the GAC polyrhamnose backbone is assembled on GlcNAc-P-P-Und. Our results also suggested that a GT-C glycosyltransferase, GacL, transfers GlcNAc from GlcNAc-P-Und to polyrhamnose. Moreover, GacJ, a small membrane-associated protein, formed a complex with GacI and significantly stimulated its catalytic activity. Of note, we observed that GacI homologs perform a similar function in Streptococcus agalactiae and Enterococcus faecalis In conclusion, the elucidation of GAC biosynthesis in S. pyogenes reported here enhances our understanding of how other Gram-positive bacteria produce essential components of their cell wall.
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Affiliation(s)
- Jeffrey S Rush
- From the Department of Molecular and Cellular Biochemistry and
| | - Rebecca J Edgar
- From the Department of Molecular and Cellular Biochemistry and
| | - Pan Deng
- Division of Cardiovascular Medicine and the Gill Heart Institute, University of Kentucky, Lexington, Kentucky 40536 and
| | - Jing Chen
- From the Department of Molecular and Cellular Biochemistry and
| | - Haining Zhu
- From the Department of Molecular and Cellular Biochemistry and
| | - Nina M van Sorge
- the Department of Medical Microbiology, University Medical Center Utrecht, Utrecht 3584 CX, The Netherlands
| | - Andrew J Morris
- Division of Cardiovascular Medicine and the Gill Heart Institute, University of Kentucky, Lexington, Kentucky 40536 and
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Wang M, Arbatsky NP, Xu L, Shashkov AS, Wang L, Knirel YA. O antigen of FranconibacterpulverisG3872 (O1) is a 4-deoxy-d-arabino-hexose-containing polysaccharide synthesized by the ABC-transporter-dependent pathway. MICROBIOLOGY-SGM 2016; 162:1103-1113. [PMID: 27166227 DOI: 10.1099/mic.0.000307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Franconibacter (Enterobacter, Cronobacter) pulveris bacteria share several typical characteristics with, and hence pose a challenge for the detection of, Cronobacter sakazakii, an emerging opportunistic pathogen, which can cause severe infections in neonates. A structurally variable O-specific polysaccharide (OPS) called O antigen provides the major basis for the typing of Gram-negative bacteria. We investigated the structure and genetics of the O antigen of F. pulveris G3872 (designated O1). An OPS was isolated by mild alkaline degradation of the LPS, whereas the same polysaccharide and its oligosaccharide fragments were obtained by mild acid degradation. Studies by sugar analysis and NMR spectroscopy showed that the OPS contained d-ribose, l-rhamnose (l-Rha) and a rarely occurring monosaccharide 4-deoxy-d-arabino-hexose, and the OPS structure was established. The O-antigen gene cluster of F. pulveris G3872 between JUMPStart and gnd genes includes putative genes for glycosyltransferases, ATP-binding cassette (ABC)-transporter genes wzm and wzt, and genes for the synthesis of l-Rha, but no genes for the synthesis of 4-deoxy-d-arabino-hexose. A mutation test with the wzm gene confirmed that the OPS is synthesized and exported by the ABC-transporter-dependent pathway. A trifunctional transferase was suggested to catalyse formation of two glycosidic linkages and add a methyl group to the non-reducing end of the OPS to terminate the chain elongation. A carbohydrate-binding module that presumably recognizes the terminal methyl-modified monosaccharide was found at the C-terminus of Wzt. Primers specific for F. pulveris G3872 were designed based on the wzm gene, which has potential to be used for identification and detection of the O1 serogroup.
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Affiliation(s)
- Min Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, 300457 Tianjin, China.,Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, 300071 Tianjin, China
| | - Nikolay P Arbatsky
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Lingling Xu
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, 300457 Tianjin, China.,Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, 300071 Tianjin, China
| | - Alexander S Shashkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
| | - Lei Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, 300457 Tianjin, China.,Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, 300071 Tianjin, China
| | - Yuriy A Knirel
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russia
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