Structural studies of the capsular polysaccharide (S-21) from Klebsiella pneumoniae ATCC 31314.

The structure of the polysaccharide (S-21) elaborated by Klebsiella pneumoniae ATCC 31314 has been investigated. NMR spectroscopy, sugar and methylation analysis, uronic acid degradation, and partial hydrolysis to oligosaccharides were the main methods used. In order to obtain good NMR spectra, the polymer was subjected to non-specific degradation by treatment with fuming hydrochoric acid. It is concluded that S-21 is composed of pentasaccharide repeating units with the following structure. [formula: see text] Approximately 0.7 equivalent of O-acetyl group, distributed over at least three positions, was also present but not located. The carbohydrate backbone in S-21 is identical to that of Klebsiella K30 and K33 capsular polysaccharides.