title: Comparative structural elucidation of the K18, K22, and K100 antigens of Escherichia coli as related ribosyl-ribitol phosphates.
abstract: The structures of the capsular K18, K22, and K100 antigens of E. coli O23:K18:H15, O23:K22:H15, and O75:K100:H5, respectively, were elucidated by determination of composition, 1H-, 13C-, and 31P-n.m.r. spectroscopy, periodate oxidation, alkaline hydrolysis followed by incubation with alkaline phosphatase, and methylation analysis of the polymers and their neutral fragmentation products. The polymers are poly(ribosyl-ribitol phosphates) related to the capsular antigen of H. influenzae (Hib). The K22 antigen has the repeating unit -P-2)-beta-Rib-(1----2)-RibOH-(5-, and the K18 antigen has the same polymer chain with partial 3-O-acetylation of the ribose moiety. The K100 antigen consists of repeating units of -P-3)-beta-Rib-(1----2)-RibOH-(5- and seems to have a secondary structure different from that of the other antigens. Together with the Hib capsular antigens, the structure of which was reported as -P-3)-beta-Rib-(1----1)-RibOH-(5-, these capsular antigens represent a structurally related group of capsular polymers.
authors.affiliation: Max-Planck-Institut für Immunobiologie, Freiburg-Zähringen, F.R.G.
authors.forename: M L
authors.initials: ML
authors.lastname: Rodriguez
authors.forename: B
authors.initials: B
authors.lastname: Jann
authors.forename: K
authors.initials: K
authors.lastname: Jann
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000276:immunology*; D006384:Hemagglutination; D007122:Immunoelectrophoresis; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008745:Methylation; D011135:Polysaccharides, Bacterial
chemical_list: D007202:Indicators and Reagents; D011135:Polysaccharides, Bacterial