Structure of Klebsiella type 61 capsular polysaccharide.

An aldotriouronic acid was isolated from the acid hydrolyzate of the polysaccharide from Klebsiella Type 61 (K-61), and its structure was established. Degradation of the permethylated polysaccharide with base established the identity of the sugar unit preceding the glucosyluronic acid residue. The modes of linkage and the sequence of different sugar residues were further confirmed by Smith degradation of K-61. The anomeric configurations of the different sugar residues were determined by oxidation of peracetylated native, and carboxyl-reduced, polysaccharides with chromium trioxide. The anomeric configuration of nonreducing D-galactosyl side-chains was further confirmed by enzymic degradation of K-61. Finally, gentiobiose was identified in the partial, acid hydrolyzate of K-61. Based on these results, the structure assigned the repeating unit of K-61 was as follows.