Structure and gene cluster of the O-antigen of Escherichia coli O36

•E. coli O36 strains were isolated from birds with respiratory tract disease and salpingitis.•The OPS structure of E. coli O36 was established by NMR spectroscopy and chemical methods.•The gene cluster of E. coli O36 was sequenced and found to be in full agreement with the OPS structure.

The O-polysaccharide (O-antigen) of Escherichia coli O36 was isolated from the lipopolysaccharide and studied by sugar analyses and Smith degradation along with 1H and 13C NMR spectroscopy. The following structure of the branched pentasaccharide repeating unit was established, which is unique among the known structures of bacterial polysaccharides:Figure optionsDownload full-size imageDownload as PowerPoint slideThe O-antigen gene cluster of E. coli O36 has been 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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