Full assignment of the 1H and 13C spectra and revision of the O-acetylation site of the capsular polysaccharide of Streptococcus pneumoniae Type 33F, a component of the current pneumococcal polysaccharide vaccine

The structure of the capsular polysaccharide from Streptococcus pneumoniae Type 33F was originally determined by a combination of chemical methods and limited use of NMR spectroscopy [Can. J. Biochem. Cell Biol.1984, 62, 666–677]. We report full 1H and 13C assignments and confirm the structure of the saccharide repeat unit, but find that the site of O-acetylation is O-2 of the →5)-β-d-Galf, rather than the →3)-β-d-Galf residue. We find that a slightly higher percentage of the repeat units are O-acetylated:

Graphical abstractFull NMR assignments and a revised location for the O-acetyl group in the capsular polysaccharide from Streptococcus pneumoniae Type 33F are reported. The O-acetyl group is attached to O-2 of the →5)-β-d-Galf residue, rather than the →3)-β-d-Galf as previously reported.Figure optionsDownload full-size imageDownload as PowerPoint slide