Structure of the polysaccharide O-antigen of Salmonella O Antigen Group D

  The structure of the Salmonella O Antigen Group D antigen was determined from an analysis of the antigenic O-polysaccharide component of the lipopolysaccharide produced by Salmonella riogrande O:40. Using 1H- and 13C-NMR spectroscopy, methylation analysis, and periodate degradation methods, the O-polysaccharide was found to be a high molecular weight branched polymer of repeating pentasaccharide units having the structure:The reported human blood group

  A activity was concluded to reside in an epitope of a terminal trisaccharide portion of the O-chain involving alpha-D-GalpNAc and beta-D-GlcpNAc residues linked (1----3) and (1----2), respectively, to beta-D-Manp branched residues in which the alpha-D-GalpNAc residue would appear to be the critical antigenic factor recognized by polyclonal blood group A antisera.