Structural Characterization of the Extracellular Polysaccharide from Vibrio cholerae O1 El-Tor

The ability to form biofilms is important for environmental survival, transmission, and infectivity of Vibrio cholerae, the causative agent of cholera in humans. To form biofilms, V. cholerae produces an extracellular matrix composed of proteins, nucleic acids and a glycoconjugate, termed Vibrio exopolysaccharide (VPS). Here, we present the data on isolation and characterization of the polysaccharide part of the VPS (VPS-PS), which has the following structure: 4) alpha GulpNAcAGly3OAc (1 4) beta D Glcp (1 4) alpha Glcp (1 4) alpha D Galp (1 where alpha-D-Glc is partially (similar to 20%) replaced with alpha-D-GlcNAc. alpha-GulNAcAGly is an amide between 2-acetamido-2-deoxy-alpha-guluronic acid and glycine. Apparently, the polysaccharide is bound to a yet unidentified component, which gives it high viscosity and completely suppresses any NMR signals belonging to the sugar chains of the VPS. The only reliable method to remove this component at present is a treatment of the whole glycoconjugate with concentrated hydrochloric acid.