Structure of the O-antigen of Yersinia pseudotuberculosis O:4a revised

The O-specific polysaccharide was isolated by mild acid degradation of the lipopolysaccharide of Yersinia pseudotuberculosis O:4a and studied by NMR spectroscopy, including 2D ROESY and 1H, 13C HMBC experiments. The following structure of the pentasaccharide repeating unit of the polysaccharide was established, which differs from the structure reported earlier [Gorshkova, R. P. et al., Bioorg. Khim. 1983, 9, 1401–1407] in the linkage modes between the monosaccharides: where Tyv stands for 3,6-dideoxy-d-arabino-hexose (tyvelose). The structure of the Y. pseudotuberculosis O:4a antigen resembles that of Y. pseudotuberculosis O:2c, which differs in the presence of abequose (3,6-dideoxy-d-xylo-hexose) in place of tyvelose only.