Chemical structures of the core region of Campylobacter jejuni O:3 lipopolysaccharide and an associated polysaccharide

Abstract

The complete structure for the core oligosaccharide region of the water-insoluble low-M(r) lipopolysaccharide of Campylobacter jejuni serotype O:3 from phenol/water extraction of bacterial cells was assigned through studies on derivatives of the liberated oligosaccharide. Structure determinations were performed using 1H-NMR and 31P-NMR spectroscopies, methylation analysis supported by fast-atom-bombardment mass spectrometry, and Smith degradation experiments. It was concluded that the complete chains in the core oligosaccharide had the following structure in which a proportion of the terminal residues were phosphorylated: [formula: see text] From a similar series of experiments, it was concluded that an associated polysaccharide, which was isolated from the water phase of the phenol/water extracts, had the following repeating unit in which a proportion of the previously unknown L-glycero-D-ido-heptose (L-alpha-D-ido-Hep) residues were present as 3-hydroxypropanoyl esters, and were not covalently linked to the lipopolysaccharide: [formula see: text]