title: Structure elucidation of capsular polysaccharides from Streptococcus pneumoniae serotype 33C, 33D, and revised structure of serotype 33B.
abstract: We report herein the previously unknown structures of the pneumococcal capsular polysaccharides serotype 33C and 33D, and a revised structure of serotype 33B. The syntenic pair 33B/33D has nearly identical polysaccharide repeat units with the exception of one sugar residue (→2-α-Glcp in 33B and →2-α-Galp in 33D). Serotype 33C is structurally more similar to 33B/33D than 33A/33F, in that it also possesses a backbone ribitol-phosphate group and a →3-β-GalpNAc residue, both of which are absent in the repeat units of 33A/33F. Serotype 33C is notably different from all other serogroup 33 polysaccharides, as there is no →3-β-Glcp residue and the location of the O-acetylation of the →5-β-Galf residue (O-6) differs from the other serogroup 33 polysaccharides (O-2). This completes the structural assignments of polysaccharides within serogroup 33 and provides a framework for understanding the recognition of epitopes by serogroup 33 typing sera based on observed cross-reactivities reported in the literature.
authors: Pfizer Vaccine Research, 401 N. Middletown Road, Pearl River, NY 10965, USA. Electronic address: fiona.lin@pfizer.com.
authors: Fiona L
authors: FL
authors: Lin
authors: Institute for Biological Sciences, National Research Council, 100 Sussex Dr., Ottawa, ON K1A 0R6, Canada.
authors: Evgeny
authors: E
authors: Vinogradov
authors: Pfizer Vaccine Research, 401 N. Middletown Road, Pearl River, NY 10965, USA.
authors: Chenghua
authors: C
authors: Deng
authors: Pfizer Vaccine Research, 401 N. Middletown Road, Pearl River, NY 10965, USA.
authors: Sandra
authors: S
authors: Zeller
authors: Pfizer Vaccine Research, 401 N. Middletown Road, Pearl River, NY 10965, USA.
authors: Lynn
authors: L
authors: Phelan
authors: Pfizer Vaccine Research, 401 N. Middletown Road, Pearl River, NY 10965, USA.
authors: Bruce A
authors: BA
authors: Green
authors: Pfizer Vaccine Research, 401 N. Middletown Road, Pearl River, NY 10965, USA.
authors: Kathrin U
authors: KU
authors: Jansen
authors: Pfizer Vaccine Research, 401 N. Middletown Road, Pearl River, NY 10965, USA.
authors: Viliam
authors: V
authors: Pavliak
mesh_terms: D000107:Acetylation; D016667:Bacterial Capsules / Q000737:chemistry*; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D011134:Polysaccharides / Q000737:chemistry*; D012255:Ribitol / Q000737:chemistry; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000737:chemistry* / Q000235:genetics / Q000276:immunology
chemical_list: D000939:Epitopes; D011134:Polysaccharides; D012255:Ribitol
keywords: Capsular polysaccharide structure; Serogroup 33; Serotype 33B; Serotype 33C; Serotype 33D; Streptococcus pneumoniae