[Structure of the repeating chain of the O-specific polysaccharide of Vibrio fluvialis]

O-Specific polysaccharide chain of the Vibrio fluvialis lipopolysaccharide is built up of pentasaccharide repeating units, containing one N-acetyl-D-glucosamine and four L-rhamnose residues. The structure of the polysaccharide was elucidated using two-dimensional correlation 1H-NMR-spectroscopy, 13C-NMR-spectroscopy and nuclear Overhauser effect and confirmed by methylation analysis and selective cleavage of N-acetylglucosamine residues by the N-deacetylation-deamination method which yielded linear L-rhamnan representing the backbone of the polysaccharide. Thus, the repeating unit of the O-specific polysaccharide has the following structure: (formula; see text)