Structure and gene cluster of the O-antigen of Escherichia coli strain SDLZB008

Abstract The O-polysaccharide (O-antigen) of Escherichia coli SDLZB008 was isolated from the lipopolysaccharide and studied by sugar analyses 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: α - D - Fuc p 3 NAc 1 ↓ 2 → 3 ) - α - L - Rha p - ( 1 → 2 ) - α - L - Rha p - ( 1 → 3 ) - α - D - Man p - ( 1 → 3 ) - β - D - Gal p NAc - ( 1 → The O-antigen gene cluster of E. coli SDLZB008 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.