STRUCTURAL DETERMINATION OF THE O-ANTIGENIC POLYSACCHARIDE FROM ESCHERICHIA-COLI O35 AND CROSS-REACTIVITY TO SALMONELLA-ARIZONAE O62

The structure of the O-antigenic polysaccharide from Escherichia coli O35 has been investigated with the aid of NMR spectroscopy, sugar and methylation analyses. The sequence of the sugar residues could be dete rmined by NOESY and heteronuclear-multiple-bond-connectivity NMR exper iments. The polysaccharide is composed of hexasaccharide repeating uni ts with the following structure, where Rha and GalNAcAN represent rham nose and 2-acetamido-2-deoxy-galacturonamide, respectively: [GRAPHICS] The O-antigen of Escherichia coli O35 is similar to the O-specific po lysaccharide from Salmonella arizonae O62, which instead has a termina l 2-acetamido-2-deoxy-alpha-D-galacturonic acid residue. Immunochemica l analyses using a rabbit antiserum specific for the Salmonella arizon ae O62 O-antigen showed an identical reactivity with both lipopolysacc harides.