[Antigenic polysaccharides of Shigella bacteria. Structure of the polysaccharide chain of the lipopolysaccharide from Shigella boydii, type 11].

On mild acid degradation of the Shigella boydii, type 11 lipopolysaccharide, the corresponding O-specific polysaccharide composed of D-glucuronic acid, 2-acetylamino-2-deoxy-D-glucose, D-ribose and L-rhamnose residues in the ratio 1:1:1:3 was obtained. Methylation, partial acid hydrolysis and 13C-NMR spectral data for the polysaccharide led to the structure of the oligosaccharide repeating unit as a branched hexasaccharide: [formula: see text]. Numerous O-acetyl groups attached non-stoichiometrically to the residues of D-glucuronic acid, L-rhamnose and 2-acetylamino-2-deoxy-D-glucose were located with the use of 13C-NMR spectroscopy.