Structure of the O-chain of the lipopolysaccharide of Haemophilus pleuropneumoniae serotype 1.

By phenol-water extraction an aqueous-phase soluble cellular lipopolysaccharide was isolated from Haemophilus pleuro-pneumoniae serotype 1. It was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, hydrolysis, methylation, and both one- and two-dimensional 1H and 13C nuclear magnetic resonance studies to be an S-type lipopolysaccharide, which could be cleaved to yield a lipid A and an O-chain polysaccharide identified as a high molecular weight branched polymer of a tetrasaccharide repeating unit having the structure: (Formula: see text).