title: Structural elucidation of the novel core oligosaccharide from LPS of Burkholderia cepacia serogroup O4.
abstract: Lipopolysaccharide (LPS) is an important virulence factor of Burkholderia cepacia, an opportunistic bacterial pathogen that causes life-threatening disease in cystic fibrosis patients and immunocompromised individuals. B. cepacia LPS comprises an O-specific polysaccharide covalently linked to a core oligosaccharide (OS) which in turn is attached to a lipid A moiety. The complete structure of the LPS core oligosaccharide from B. cepacia serotype O4 was investigated by detailed NMR and mass spectrometry (MS) methods. High- (HMW) and low-molecular-weight (LMW) OSs were obtained by deacylation, dephosphorylation, and reducing-end reduction of the LPS. Glycan and NMR analyses established that both OSs contain a common inner-core structure consisting of D-glucose, L-glycero-D-manno-heptose, D-glycero-D-manno-heptose, 3-deoxy-D-manno-octulsonic acid, and D-glycero-D-talo-2-octulosonic acid. The structure of the LMW OS differed from that of the HMW OS in that it lacks a tetra-rhamnosyl GlcNAc OS extension. These structural conclusions were confirmed by tandem MS analyses of the two OS fractions as well as an OS fraction obtained by alkaline deacylation of the LPS. The location of a phosphoethanolamine substituent in the core region was determined by ESI-MS and methylation analysis of O-deacylated LPS and core OS samples. A polyclonal antibody to B. cepacia serotype O4 core OS was cross-reactive with several other serotypes indicating common structural features.
authors.affiliation: Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Hussein
authors.initials: H
authors.lastname: Masoud
authors.forename: Malcolm B
authors.initials: MB
authors.lastname: Perry
authors.forename: Jean-Robert
authors.initials: JR
authors.lastname: Brisson
authors.forename: Dusan
authors.initials: D
authors.lastname: Uhrin
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.forename: James C
authors.initials: JC
authors.lastname: Richards
mesh_terms: D016956:Burkholderia cepacia / Q000737:chemistry / Q000378:metabolism*; D004983:Ethanolamines / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D006539:Heptoses / Q000737:chemistry; D008050:Lipid A / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry*; D008745:Methylation; D008956:Models, Chemical; D019906:Nuclear Magnetic Resonance, Biomolecular; D019081:O Antigens / Q000737:chemistry*; D011135:Polysaccharides, Bacterial / Q000737:chemistry; D012703:Serotyping; D013400:Sugar Acids / Q000737:chemistry; D053719:Tandem Mass Spectrometry
chemical_list: D004983:Ethanolamines; D006539:Heptoses; D008050:Lipid A; D008070:Lipopolysaccharides; D019081:O Antigens; D011135:Polysaccharides, Bacterial; D013400:Sugar Acids; C002532:2-keto-3-deoxyoctonate; C051933:2-octulosonic acid; C026312:glycero-manno-heptose; C005448:phosphorylethanolamine; D005947:Glucose