Structural analysis of the O-antigenic polysaccharide from Vibrio mimicus N-1990

The O-antigenic polysaccharide part of the lipopolysaccharide from Vibrio mimicus N-1990 has been investigated. Sugar and methylation analysis of native and dephosphorylated polysaccharide together with NMR spectroscopy show that the polysaccharide is composed of tetrasaccharide repeating units. The structure of the repeating unit of the polysaccharide from V. mimicus N-1990 could be determined as: -->4)-alpha-D-GalpNAc-(1-->3)-beta-D-GalpNAc-(1-->2)-4,6-P-beta-D-Galp-( 1-->3)-alpha-D-GalpNAc-(1-->. The V. mimicus N-1990 strain cross-reacts with antibodies elicited against the Vibrio cholerae O139. The nature of this cross-reactivity resides in the partial structure comprising the galactosyl residue substituted with a cyclic phosphate. This element is present in the cell-wall-associated polysaccharides of both strains.