Structure of the O-chain polysaccharide of the phenol-phase soluble lipopolysaccharide of Escherichia coli 0:157:H7.

The phenol-phase soluble lipopolysaccharide isolated from Escherichia coli 0:157 by the hot phenol-water extraction procedure was shown by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, periodate oxidation, methylation, and 13C and 1H nuclear magnetic resonance studies to be an unbranched linear polysaccharide with a tetrasaccharide repeating unit having the structure: (formula; see text) The serological cross-reactivity of E. coli 0:157 with Brucella abortus, Yersinia enterocolitica (serotype 0:9), group N Salmonella, and some other E. coli species can be related immunochemically to the presence of 1,2-glycosylated N-acylated 4-amino-4, 6-dideoxy-alpha-D-mannopyranosyl residues in the O-chains of their respective lipopolysaccharides.