Guerardel, Y., Sadovskaya, I., Maes, E. et al. (5 more authors) (2020) Complete structure of the enterococcal polysaccharide antigen (EPA) of vancomycin-resistant enterococcus faecalis V583 reveals that EPA decorations are teichoic acids covalently linked to a rhamnopolysaccharide backbone. mBio, 11 (2). e00277-20.
Abstract
All enterococci produce a complex polysaccharide called the enterococcal polysaccharide antigen (EPA). This polymer is required for normal cell growth and division and for resistance to cephalosporins and plays a critical role in host-pathogen interaction. The EPA contributes to host colonization and is essential for virulence, conferring resistance to phagocytosis during the infection. Recent studies revealed that the “decorations” of the EPA polymer, encoded by genetic loci that are variable between isolates, underpin the biological activity of this surface polysaccharide. In this work, we investigated the structure of the EPA polymer produced by the high-risk enterococcal clonal complex Enterococcus faecalis V583. We analyzed purified EPA from the wild-type strain and a mutant lacking decorations and elucidated the structure of the EPA backbone and decorations. We showed that the rhamnan backbone of EPA is composed of a hexasaccharide repeat unit of C2- and C3-linked rhamnan chains, partially substituted in the C3 position by α-glucose (α-Glc) and in the C2 position by β-N-acetylglucosamine (β-GlcNAc). The so-called “EPA decorations” consist of phosphopolysaccharide chains corresponding to teichoic acids covalently bound to the rhamnan backbone. The elucidation of the complete EPA structure allowed us to propose a biosynthetic pathway, a first essential step toward the design of antimicrobials targeting the synthesis of this virulence factor.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license. https://creativecommons.org/licenses/by/4.0/ |
Keywords: | E. faecalis; teichoic acids; cell wall polysaccharide; enterococcal polysaccharide antigen; Enterococcus faecalis; rhamnan |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Biosciences (Sheffield) > Department of Molecular Biology and Biotechnology (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 20 May 2020 09:12 |
Last Modified: | 20 May 2020 09:12 |
Status: | Published |
Publisher: | American Society for Microbiology |
Refereed: | Yes |
Identification Number: | 10.1128/mbio.00277-20 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:160889 |