title: Structural studies of the O-antigenic polysaccharides from the enteroaggregative Escherichia coli strain 87/D2 and international type strains from E. coli O128.
abstract: The O-antigen of the lipopolysaccharide (LPS) from the enteroaggregative Escherichia coli strain 87/D2 has been determined by component analysis together with NMR spectroscopy. The polysaccharide has pentasaccharide repeating units in which all the residues have the galacto-configuration. The repeating unit of the O-antigen, elucidated using the O-deacylated LPS, is branched with the following structure: Analysis of the 1H NMR spectrum of the LPS revealed O-acetyl groups (approximately 0.7 per repeating unit) distributed over two positions. Subsequent analysis showed that the galactose residue carries acetyl groups at either O-3 or O-4 in a ratio of approximately 2:1. The international reference strain from E. coli O128ab was investigated and the repeating unit of the O-antigens has the following structure: Analysis of the 1H NMR spectrum of the LPS revealed O-acetyl groups (approximately one per repeating unit) distributed over two positions. The integrals of the resonances for the O-acetyl groups indicated similarities between the O-antigen from E. coli O128ab and that of E. coli strain 87/D2, whereas the O-acetyl substitution pattern in the E. coli O128ac O-antigen differed slightly. Enzyme immunoassay using specific anti-E. coli O128ab and anti-E. coli O128ac rabbit sera confirmed the results.
authors.affiliation: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, and Karolinska Institute, Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, S-141 86 Stockholm, 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: D000818:Animals; D002240:Carbohydrate Sequence; D004926:Escherichia coli / Q000737:chemistry* / Q000378:metabolism; D007124:Immunoenzyme Techniques; D009682:Magnetic Resonance Spectroscopy; D019081:O Antigens / Q000096:biosynthesis / Q000737:chemistry*; D011817:Rabbits
chemical_list: D019081:O Antigens