STRUCTURE OF THE O-SPECIFIC SIDE-CHAIN OF THE ESCHERICHIA-COLI O128 LIPOPOLYSACCHARIDE

The O-specific polysaccharide isolated from Escherichia coli O128 lipo polysaccharide contains D-galactose, L-fucose, and 2-acetamido-2-deoxy -D-galactose in the molar ratios 2:1:2. The primary structure of the O -specific polysaccharide from E. coli was established by compositional analysis, methylation analysis, together with H-1 and C-13 NMR spectr oscopy including two-dimensional shift-correlated and one-dimensional NOE spectroscopy. The polysaccharide moiety was found to consist of a tetrasaccharide backbone containing D-galactose and 2-acetamido-2-deox y-D-galactose, with L-fucose as a side chain in a branched pentasaccha ride repeating unit having the following structure: --> 3)-beta-D-Gal pNAc-(1 --> 4)-alpha-D-Gal p-(1 --> 3)-beta-D-Gal pNAc-(1 --> 6)-beta- D-Gal p-(1 --> [GRAPHICS] APHICS]