Structure of the 3-deoxy-D-manno-octulosonic acid-containing polysaccharide (K6 antigen) from Escherichia coli LP 1092.

The acidic polysaccharide (K6) antigen from Escherichia coli LP 1092 contains D-ribose and 3-deoxy-D-manno-octulosonic acid in the molar ratio of 2:1, respectively. Spectroscopic data (13C- and 1H-n.m.r.), methylation analyses, and periodate oxidation indicate that the polysaccharide is composed of the foregoing components essentially in the following trisaccharide sequence: leads to 2)-beta-D-Ribf-(1 leads to 2)-beta-D-Ribf-(1 leads to 7)-alpha-D-KDO-(2 leads to. The polysaccharide also contains O-acetyl substituents (approximately 0.2-0.3 mol per KDO residue).