Abstract
Lipopolysaccharide from phenol-water extraction of cells of Campylobacter coli serotype O:30 was separated as a water-insoluble gel of low M(r) from a water-soluble antigenic polysaccharide of high M(r). Acetic acid hydrolysis of the ketosidic linkages to lipid A in the lipopolysaccharide furnished a core oligosaccharide. Structural investigations were performed using 1H and 13C NMR, fast atom bombardment-mass spectrometry of permethylated derivatives, and methylation linkage analysis on the core oligosaccharide and the products of two successive Smith degradations. It is concluded that the highly branched 3-deoxy-D-manno-octulosonic acid-terminated oligosaccharide chains carried at the nonreducing end disaccharide units of beta-D-Qui3NAc-(1-->2)-beta-D-Qui3NAc (where Qui3NAc represents 3-acylamino-3,6-dideoxy-D-glucose), in which N-acyl residues were either both (R)-3-hydroxybutanoyl or both 3-hydroxy-2,3-dimethyl-5-oxoprolyl. The demonstration of these unusual features provides further evidence for a wide variety of structures within the core oligosaccharide region of lipopolysaccharides from Campylobacter sp.