Investigation of the structure of the capsular polysaccharide of Escherichia coli K55 using Klebsiella bacteriophage phi 5.

The structure of the capsular polysaccharide from Escherichia coli O9:K55 (N 24c) has been studied, using methylation analysis, degradation by bacteriophage, and n.m.r. spectroscopy. Depolymerisation of the K55 polysaccharide, using the lyase enzyme borne by Klebsiella phi 5, yielded a tri- and a hexa-saccharide, analysis of which indicated the following repeating unit. (formula; see text) This structure differs from that for the repeating unit of the capsular polysaccharide of Klebsiella K5 only in the position of acetylation (position 2 of the glucose residue).