Characterization of the specific O-polysaccharide structure and biosynthetic gene cluster of Yersinia pseudotuberculosis serotype O:15

Yersinia pseudotuberculosis serotyping scheme contains 21 serotypes based on the distribution of about 30 different O-factors within the species. The chemical structures of LPSs and the genetic basis of their biosynthesis has been determined for a number of Y. pseudotuberculosis strains representing different serotypes; thus, an overall picture of the relationship between genetics and structures is emerging. In this work, we have performed a structural and genetic analysis of the Y. pseudotuberculosis serotype O:15 O-specific polysaccharide. Our results showed that the set-up of the Y. pseudotuberculosis O:15 gene cluster is a hybrid between those of Y. pseudotuberculosis serotypes O:1b and O:5a, possibly due to a single recombination event. The hybrid nature could also be seen in the structure of the O-specific polysaccharide repeating unit pentasaccharide. It contains a tetrameric backbone identical to that of O:5a while the branching paratofuranose residue is identical to that of O:1b.