Characterization of the serotype e polysaccharide antigen of Streptococcus mutans (original) (raw)

The structure of the Streptococcus mutuns serotype e polysaccharide was studied in order to determine the chemical basis of the immunological cross-reactions observed between it and the streptococcal group E polysaccharide. The chemical structure was established using methylation analysis, periodate oxidation, partial methanolysis and "C NMR spectroscopy. The polysaccharide was found to consist of a polyrhamnose backbone of alternating 2-and 3-linked cc-L-rhamnose units and sidechain /I-D-glucosyl units linked to the 2-position of rhamnose units in the backbone. This structure of the oligosaccharide repeating unit of the S. mutans serotype e polysaccharide was identical to that of the group-specific polysaccharide of group E Streptococcus. Possible explanations for the previously reported differences in these two polysaccharides are discussed.