Structural analysis of the specific capsular polysaccharide of Streptococcuspneumoniae type 22F

The structure of the specific capsular polysaccharide produced by Streptococcuspneumoniae type 22F (American type 22) was investigated by high-field 1 H and 13 C nuclear magnetic resonance spectroscopy, composition, methylation analysis, and periodate oxidation studies. The polysaccharide was found to be a high molecular weight acidic polymer composed of D-glucose, D-galactose, D-glucuronic acid, and L-rhamnose residues to form a regular repeating hexasaccharide unit having the structureFormula: see textin which the β-L-rhamnopyranosyl residues were substituted by O-acetyl groups in 80% of the repeating units. The 1 H and 13 C nmr resonances of the O-deacetylated type 22F polysaccharide were completely assigned by application of two-dimensional homo- and heteronuclear chemical shift correlation techniques. Keywords: Streptococcuspneumoniae polysaccharide, NMR analysis.