Structure and gene cluster of the O-antigen of Escherichia coli O120

The acidic O-polysaccharide (O-antigen) of Escherichia coli O120 was isolated from the lipopolysaccharide and studied by sugar analysis and NMR spectroscopy. The following structure of the branched hexasaccharide repeating unit was established, which is unique among the known structures of bacterial polysaccharides:The O-antigen gene cluster of E. coli O120 was sequenced. The gene functions were tentatively assigned by comparison with sequences in the available databases and found to be in full agreement with the O-polysaccharide structure.

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