Chemical structure of a polysaccharide from Campylobacter jejuni 176.83 (serotype O:41) containing only furanose sugars

A neutral polysaccharide was obtained by hot phenol–water extraction of biomass from Campylobacter jejuni 176.83 and subsequently separated from acid-liberated core oligosaccharide of lipopolysaccharide by sequential GPC on Bio-Gel P6 and TSK-40 columns. All sugar components of the trisaccharide repeating unit of the polysaccharide were found to be of the furanose ring form. The major trisaccharide contained β-l-arabinose, 6-deoxy-β-d-altro-heptose (β-d-6d-altHep) and 6-deoxy-β-l-altrose (β-l-6d-Alt), whereas in the minor trisaccharide the β-l-6d-Alt is replaced by its C-5 epimer α-d-Fuc. On the basis of 1H and 13C NMR spectroscopic studies, including 2D ROESY, HMQC and HMQC-TOCSY experiments, the following structures of the repeating units were established:→2)-β-l-Araf-(1→2)-β-d-6d-altHepf-(1→2)-β-l-6d-Altf-(1→ (75%)→2)-β-l-Araf-(1→2)-β-d-6d-altHepf-(1→2)-α-d-Fucf-(1→ (25%)