The primary structure of the acidic capsular antigen of Escherichia coli O8:K45:H9 was shown by glycose analysis, methylation analysis, and one- and two-dimensional 1H and 13C NMR spectroscopy to be composed of repeating branched tetrasaccharide units having the structure: [formula: see text] The polysaccharide contains the uncommon amino sugar 3-acetamido-3,6-dideoxy-D- galactopyranose, which has not been previously identified in a capsular antigen.
Acetylgalactosamine Acetylglucosamine