title: Structural studies and biosynthetic aspects of the O-antigen polysaccharide from Escherichia coli O174.
abstract: The structure of the repeating unit of the O-antigenic polysaccharide (PS) from Escherichia coli O174 has been determined. Component analysis together with (1)H and (13)C NMR spectroscopy experiments were employed to elucidate the structure. Inter-residue correlations were determined by (1)H,(13)C-heteronuclear multiple-bond correlation and (1)H,(1)H-NOESY experiments. The PS is composed of tetrasaccharide repeating units with the following structure: [formula see text] Cross-peaks of low intensity were present in the NMR spectra consistent with a β-D-GlcpNAc-(1→2)-β-D-GlcpA(1→ structural element at the terminal part of the polysaccharide, which on average is composed of ∼15 repeating units. Consequently the biological repeating unit has a 3-substituted N-acetyl-D-galactosamine residue at its reducing end.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
authors.forename: Carolina
authors.initials: C
authors.lastname: Fontana
authors.forename: Magnus
authors.initials: M
authors.lastname: Lundborg
authors.forename: Andrej
authors.initials: A
authors.lastname: Weintraub
authors.forename: Göran
authors.initials: G
authors.lastname: Widmalm
mesh_terms: D002236:Carbohydrate Conformation; D004926:Escherichia coli / Q000737:chemistry* / Q000254:growth & development; D009682:Magnetic Resonance Spectroscopy; D019081:O Antigens / Q000096:biosynthesis* / Q000737:chemistry*; D012015:Reference Standards
chemical_list: D019081:O Antigens