Structures of two polysaccharides of Campylobacter jejuni 81116

Campylobacter jejuni 81116 has been extensively investigated in studies on genes associated with the synthesis of Campylobacter lipopoly/lipooligosaccharides (LPS/LOS). Despite these investigations, data on the chemical structure of polysaccharides from C. jejuni 81116 have been absent. The present study was undertaken to fill that void. Biomass was grown in large quantities on agar medium, harvested and extracted by hot phenol-water extraction. Subsequently, extracts were treated by DNase, RNase and proteinase K to remove contaminants. After mild acid treatment, followed by preparative gel-permeation and anion-exchange chromatography, fractions were isolated and studied by 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, 1H,(13)C HMQC and HMBC experiments. These advanced investigations revealed the occurrence of two different polysaccharides in the approximate ratio of 3:1, each having a tetrasaccharide repeating unit. Polysaccharide A contained glucose, glucuronic acid and mannose, and is O-acetylated. Polysaccharide B contained glucose, galactose and N-acetylglucosamine. Importantly, polysaccharide A is acidic, whereas polysaccharide B is neutral. [carbohydrate structure: see text]