title: Structure of the Escherichia coli O24 and O56 O-specific sialic-acid-containing polysaccharides and linkage of these structures to the core region in lipopolysaccharides.
abstract: The lipopolysaccharides from Escherichia coli O24 and O56 could be separated into higher-molecular-mass and lower-molecular-mass fractions. Mild acid hydrolysis of lipopolysaccharides of both serotypes released an O-specific polysaccharide and a tetrasaccharide repeating unit. Oligomers of the repeating unit, the core and the oligosaccharide that contains a fragment of the repeating unit linked to the core region were also obtained according to hydrolysis conditions. On the basis of sugar and methylation analyses, Smith degradation, fast-atom-bombardment mass spectrometry and NMR spectroscopy of the hydrolysis products, the biological repeating units of the O-specific polysaccharides were shown to be the following tetrasaccharides: [formula: see text] The structures differ from the structures proposed previously by Kogan et al. [Kogan, G., Shashkov, A. S., Jann, B. & Jann, K. (1993) Carbohydr. Res. 238, 261-270; Kogan, G., Jann, B. & Jann, K. (1993) Carbohydr. Res. 238, 335-338]. The O-specific repeating unit in E. coli O24 lipopolysaccharide is linked to O6 of the terminal D-galactose in the core region, whereas in O56 LPS the repeating unit is linked to O4 of a subterminal D-glucose residue in an R2 type core.
authors.affiliation: Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław.
authors.forename: A
authors.initials: A
authors.lastname: Gamian
authors.forename: L
authors.initials: L
authors.lastname: Kenne
authors.forename: M
authors.initials: M
authors.lastname: Mieszała
authors.forename: J
authors.initials: J
authors.lastname: Ulrich
authors.forename: J
authors.initials: J
authors.lastname: Defaye
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D008969:Molecular Sequence Data; D015394:Molecular Structure; D019158:N-Acetylneuraminic Acid; D019081:O Antigens; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D012794:Sialic Acids / Q000737:chemistry; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D002241:Carbohydrates; D008070:Lipopolysaccharides; D019081:O Antigens; D011135:Polysaccharides, Bacterial; D012794:Sialic Acids; D019158:N-Acetylneuraminic Acid