Structural studies of the Escherichia coli O26 O-antigen polysaccharide

The structure of the O-specific side chain of the E. coli O26 lipopolysaccharide has been investigated. Based on sugar and methylation analyses, and 2D NMR spectroscopy employing HMBC experiments, it is concluded that the polysaccharide is composed of trisaccharide repeating units having the following structure: →3)-α-l-Rhap-(1→4)-α-l-FucpNAc-(1→3)-β-d-GlcpNAc-(1→