STRUCTURAL-ANALYSIS OF THE LIPOPOLYSACCHARIDE FROM VIBRIO-CHOLERAE O139

The lipopolysaccharide (LPS) from Vibrio cholerae 0139 was deacylated with KOH. The following structure of the oligosaccharide resulting fro m this treatment was established on the basis of monosaccharide and me thylation analyses, H-1, C-13 and P-31 1D and 2D NMR experiments and 1 D analogues of 3D NOESY-TOCSY and 3D TOCSY-NOESY experiments. [GRAPHIC S] 'C' is a beta-L-threo-hex-4-enuronopyranosyl residue. Hep is L-glyc ero-D-manno-heptose, QuiN is 2-amino-2,6-dideoxy-D-glucose, GlcN is 2- amino-2-deoxy-D-glucose, Glc is D-glucose, Fru is D-fructose, and Kdo is 3-deoxy-D-manno-2-octulosonic acid. All sugars are pyranoses except fructose which is furanosidic. The fructose residue was localised aft er deacylation of the LPS with anhydrous hydrazine, methylation, acid methanolysis, and remethylation using deuterated iodomethane. The eluc idation of this structure allowed for a direct comparison to the previ ously determined structure for Vibrio cholerae 01 lipid A-core region. The two structures are almost identical, and, therefore, this study i s consistent with the genetic data for the biogenesis of strain 0139 f rom 01. Furthermore, the identification of a structural analogue to th e capsular polysaccharide of 0139 in the outer core of the LPS in conj unction with the identification of colitose as a constituent of the LP S, provides additional evidence that the O-antigen and capsular polysa ccharide of this strain may share the same repeat unit. (C) 1996 Elsev ier Science Ltd.