Structure of the O-antigen of Vibrio cholerae O155 that shares a putative D-galactose 4,6-cyclophosphate-associated epitope with V. cholerae O139 Bengal.

The O-specific polysaccharide of Vibrio cholerae 0155 was studied by sugar and methylation analyses, dephosphorylation with 48% hydrofluoric acid, 1H- and 13C-NMR spectroscopy, including two-dimensional COSY, TOCSY, NOESY, and heteronuclear single-quantum coherence (HSQC) experiments. The following structure of the pentasaccharide repeating unit of the polysaccharide was established: carbohydrate sequence [see text]. An unusual component, D-galactose 4,6-cyclophosphate, has been reported previously as a component of the capsular polysaccharide and O-antigen of V. cholerae O139 Bengal and appears to be responsible for the known serological cross-reactivity between V. cholerae O139 and O155.