Structural, biosynthetic and serological cross-reactive elucidation of capsular polysaccharides from Streptococcus pneumoniae serogroup 28

Chengxin Li, Katarzyna A. Duda, Pernille L. Elverdal, Ian C. Skovsted, Christian Kjeldsen, David Tezé, Jens Øllgaard Duus*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Capsular polysaccharides (CPS) are the key virulent factors in the pathogenesis of Streptococcus pneumoniae. The previously unknown CPS structures of the pneumococcal serotype 28F and 28A were thoroughly characterized by NMR spectroscopy, chemical analysis and AF4-MALS-dRI. The following repeat unit structures were determined: -4)[α-l-Rhap-[4-P-2-Gro]]-(1-3)-α-d-Sug-[6-P-Cho]-(1-3)-β-l-Rhap-[2-OAc]-(1-4)-β-d-Glcp-(1-; 28F: Sug = Glcp, Mw: 540.5 kDa; 28A: Sug = GlcpNAc, Mw: 421.9 kDa; The correlation of CPS structures with biosynthesis showed that glycosyltransferase WciU in serotypes 28F and 28A had different sugar donor specificity toward α-d-Glcp and α-d-GlcNAcp, respectively. Furthermore, latex agglutination tests of de-OAc and de-PO4 CPS were conducted to understand cross-reactions between serogroup 28 with factor antiserum 23d. Interestingly, the de-OAc 28F and 28A CPS can still weakly react with factor antiserum 23d, while de-PO4 CPS did not react with factor antiserum 23d. This indicated that OAc group could affect the affinity and P-2-Gro was crucial for cross-reacting with factor antiserum 23d.
Original languageEnglish
Article number117323
JournalCarbohydrate Polymers
Volume254
Number of pages8
ISSN0144-8617
DOIs
Publication statusPublished - 2021

Keywords

  • Streptococcus pneumoniae
  • Capsular polysaccharides
  • Serogroup 28
  • Structural characterization
  • Biosynthesis
  • Serological cross-reactivity

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