title: Escherichia coli O18ac antigen: structure of the O-specific polysaccharide moiety.
abstract: The O-specific polysaccharide moiety (O18ac polysaccharide) of the O18ac antigen (lipopolysaccharide) from Escherichia coli 2980 (O18ac:K5:Fim+:H-) was isolated in pure form by degradation of the lipopolysaccharide and chromatography on Sephadex G-50. The primary structure of the O18ac polysaccharide was elucidated by composition, fragmentation procedures, methylation analysis, and nuclear magnetic resonance spectroscopy. The polysaccharide consists of repeating units of the pentasaccharide: (formula; see text) which are joined in the polymer by alpha-1,2 linkages.
mesh_terms: D000942:Antigens, Bacterial / Q000302:isolation & purification*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002854:Chromatography, Paper; D004926:Escherichia coli / Q000276:immunology*; D008401:Gas Chromatography-Mass Spectrometry; D008070:Lipopolysaccharides / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D019081:O Antigens
chemical_list: D000942:Antigens, Bacterial; D008070:Lipopolysaccharides; D019081:O Antigens