Structure elucidation and analysis of biosynthesis genes of the O-antigen of Escherichia coli O131 containing N-acetylneuraminic acid.

The O-polysaccharide (O-antigen) of Escherichia coli O131 was studied by sugar analysis along with 1D and 2D 1H and 13C NMR spectroscopy. The following structure of the linear tetrasaccharide repeating unit of the polysaccharide was established: →8)-α-Neup5Ac-(2 → 6)-β-D-Galp-(1 → 6)-β-D-Galp-(1 → 3)-β-D-GalpNAc-(1→ The gene functions were tentatively assigned by comparison with sequences in the available databases and found to be in agreement with the E. coli O131-antigen structure.