Structure elucidation and biosynthesis gene cluster organization of the O-antigen of Escherichia coli O170

• E. coli O170 belongs to the Enterotoxigenic virotype.
• The O-antigen repeating unit carries the β-d-Galf-(1→3)-β-d-GlcpNAc structural element twice.
• Structural elucidation was carried out on both poly- and oligosaccharides.

Enterotoxigenic Escherichia coli are causative agents of diarrhea in humans as well as animals, and E. coli O170 belongs to this virotype. Upon mild acid degradation of the lipopolysaccharide of E. coli O170, the branched O-polysaccharide chain was partially cleaved at β-d-glactofuranosidic linkages to give multiple products, including a linear tetrasaccharide and oligomers thereof. Studies of the acid degradation products and O-deacylated lipopolysaccharide by 1D and 2D 1H and 13C NMR spectroscopy enabled elucidation of the following O-polysaccharide structure:Figure optionsDownload as PowerPoint slideFunctions of genes in the O-antigen biosynthesis gene cluster were tentatively assigned and found to be in agreement with the O-polysaccharide structure.

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