Lipo-oligosaccharide of Campylobacter lari strain PC 637. Structure of the liberated oligosaccharide and an associated extracellular polysaccharide

Lipo-oligosaccharide from phenol-water extraction of cells of Campylobacter lari strain PC 637 was separated as a water-insoluble gel of low relative molecular mass (Mr) from a water-soluble extracellular polysaccharide of high Mr. Structural investigations were performed on the lipo-oligosaccharide and the extracellular polysaccharide, variously using 1H, 13C, and 31P NMR spectroscopy, linkage analysis, and fast atom bombardment-mass spectrometry of permethylated derivatives of the glycans and their products of chemical and enzymic degradation. The following structures are proposed for the highly branched oligosaccharide region: and for the tetraglycosyl phosphate repeating unit of the extracellular polysaccharide: