STRUCTURAL STUDIES OF THE VIBRIO-MIMICUS W-26768 O-ANTIGEN POLYSACCHARIDE

The structure of the Vibrio mimicus W-26768 O-antigen polysaccharide has been investigated by sugar and methylation analyses, Smith degradation, and NMR spectroscopy. It is proposed that it is composed of chains of beta-(1 --> 4)-linked 3,6-dideoxy-3-[(R)-3-hydroxybutyramido]-D-glucopyranosyl residues (D-Quip3NR), approximately 60% of which are substituted in the 2-position with 2-acetamido-2-deoxy-alpha-D-galactopyranosyl groups. The polysaccharide does not seem to be composed of oligosaccharide repeating units but has a less regular structure, schematically indicated below. [GRAPHICS]