Structural studies of the capsular antigen from Streptococcus pneumoniae type 26.

The structure of the capsular antigen from Pneumococcus type 26 has been determined by using methylation analysis, periodate-oxidation studies, and n.m.r. spectroscopy of the original and the dephosphorylated product. It is considered that the polysaccharide is composed of repeating-units having the following structure. (formula: see text): The only difference between this structure and that of the type-6 antigen is that the alpha-L-rhamnopyranosyl residue is linked to O-4 of D-ribitol in the former, but to O-3 in the latter.