Structure elucidation and gene cluster characterization of the O-antigen of Vibrio cholerae O14

Abstract

The O-polysaccharide (O-antigen) of Vibrio cholerae O14 was studied using chemical analyses and 1D and 2D NMR spectroscopy. The following structure of the repeating unit of the O-antigen was established: where GlcpN(SHb) indicates 2-deoxy-2-[(S)-3-hydroxybutanoylamino]-d-glucose. We found that Vibrio cholerae O14 is similar to that of O-polysaccharide of Azospirillum brasilense S17, which has been reported earlier. Moreover, we predicted functions of all the genes in the O-antigen gene cluster according to the structure established. Our study enriches the existing O-antigen database of Vibrio cholerae, and further facilitates the bacterial serotype identification.

Keywords: Bacterial polysaccharide structure; GRASS; Lipopolysaccharide; O-antigen; O-antigen gene cluster; O-specific polysaccharide; Vibrio cholerae.