Department of Microbial Chemistry, Tokyo College of Pharmacy, 1432-1 Horinouchi, Hachioji, Tokyo 192-03 Japan
Abstract:
The structure of the capsular polysaccharide of Type XIX Streptococcus pneumoniae (S-XIX) has been elucidated by 1H- and 13C-n.m.r. spectroscopy. Mild hydrolysis of S-XIX with acid yielded a major oligosaccharide, the repeating unit of S-XIX, which was shown to be O-2-acetamido-2-deoxy-β-d-mannopyranosyl-(1→4)-O-α-d-glucopyranosyl-(1→2)-l-rhamnose 4′′-phosphate. Phosphoric acid forms a diester linkage in the S-XIX molecule, which explains the instability of S-XIX towards acid or alkali. The phosphodiester linkages in S-XIX join HO-1 of α-l-rhamnose and HO-4 of the 2-acetamido-2-deoxy-d-mannopyranosyl residue in the next repeating-unit. Treatment of S-XIX with alkali or alkaline-NaBH4 produced the repeating units in a lower yield. The proposed structure of S-XIX is
