title: Structural determination of the O-antigenic polysaccharide from the Shiga toxin-producing Escherichia coli O171.
abstract: The structure of the O-antigenic part of the lipopolysaccharide (LPS) obtained from the verotoxin-producing Escherichia coli O171 has been determined. (1)H and (13)C NMR spectroscopy techniques in combination with component analysis were used to elucidate the O-antigen structure of O-deacylated LPS. Subsequent NMR analysis of the native LPS revealed acetylation at O-7/O-9 of the sialic acid residue. The sequence of sugars was determined by inter-residue correlations in (1)H,(1)H-NOESY and (1)H,(13)C-heteronuclear multiple-bond correlation spectra. The O-antigen is composed of pentasaccharide repeating units with one equivalent of O-acetyl groups distributed over two positions: -->4)-alpha-Neu5Ac7,9Ac-(2-->6)-beta-D-Galp-(1-->6)-beta-DGlcp-->(1-->3)-beta-D-Galp-(1-->3)-beta-D-GalpNAc-(1--> Based on biosynthetic considerations, this should also be the biological repeating unit.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Sweden.
authors.forename: Tara
authors.initials: T
authors.lastname: Ali
authors.forename: Andrej
authors.initials: A
authors.lastname: Weintraub
authors.forename: Göran
authors.initials: G
authors.lastname: Widmalm
mesh_terms: D000107:Acetylation; D002240:Carbohydrate Sequence; D002247:Carbon Isotopes; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000032:analysis / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019158:N-Acetylneuraminic Acid / Q000032:analysis / Q000737:chemistry; D019081:O Antigens / Q000032:analysis / Q000737:chemistry*; D022621:Shiga Toxin / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D008070:Lipopolysaccharides; D019081:O Antigens; D022621:Shiga Toxin; D019158:N-Acetylneuraminic Acid