Structural investigation of Klebsiella serotype K46 polysaccharide

The structure of the capsular polysaccharide from Klebsiella type K46 has been investigated by using the techniques of methylation analysis, periodate oxidation, and partial hydrolysis. The anomeric linkages were determined by 1H- and 13C-n.m.r. spectroscopy of the polysaccharide and of derived poly- and oligo-saccharides obtained through degradative procedures. 1H-N.m.r. spectroscopy of the polysaccharide in D2O showed clearly a ratio of one (1-carboxyethylidene) group (CH3, delta 1.47) to six anomeric protons (delta 4.62--5.29). The polysaccharide was shown to consist of the following hexasaccharide repeating unit, which is unique in this series in having a (1-carboxyethylidene) acetal group on a lateral, but nonterminal, sugar residue. (Formula: see text).