title: Structural characterization of a novel branching pattern in the lipopolysaccharide from nontypeable Haemophilus influenzae.
abstract: Structural analysis of the lipopolysaccharide (LPS) from nontypeable Haemophilus influenzae strain 981 has been achieved using NMR spectroscopy and ESI-MS on O-deacylated LPS and core oligosaccharide (OS) material as well as by ESI-MSn on permethylated dephosphorylated OS. A heterogeneous glycoform population was identified, resulting from the variable length of the OS branches attached to the glucose residue in the common structural element of H. influenzae LPS, l-alpha-d-Hepp-(1-->2)-[PEtn-->6]-l-alpha-d-Hepp-(1-->3)-[beta-d-Glcxp-(1-->4)]-l-alpha-d-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdop-(2-->6)-Lipid A. Notably, the O-6 position of the beta-d-Glcp residue was either substituted by PCho or the disaccharide branch beta-d-Galp-(1-->4)-d-alpha-d-Hepp, while the O-4 position was substituted by the globotetraose unit, beta-d-GalpNAc-(1-->3)-alpha-d-Galp-(1-->4)-beta-d-Galp-(1-->4)-beta-d-Glcp, or sequentially truncated versions thereof. This is the first time a branching sugar residue has been reported in the outer-core region of H. influenzae LPS. Additionally, a PEtn group was identified at O-3 of the distal heptose residue in the inner-core.
authors.affiliation: Clinical Research Centre, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Månsson
authors.forename: Derek W
authors.initials: DW
authors.lastname: Hood
authors.forename: E Richard
authors.initials: ER
authors.lastname: Moxon
authors.forename: Elke K H
authors.initials: EK
authors.lastname: Schweda
mesh_terms: D000107:Acetylation; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006031:Glycosylation; D006193:Haemophilus influenzae / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006539:Heptoses / Q000032:analysis; D006601:Hexoses / Q000032:analysis; D006801:Humans; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010033:Otitis Media / Q000382:microbiology; D010766:Phosphorylation; D010767:Phosphorylcholine; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
chemical_list: D006539:Heptoses; D006601:Hexoses; D008070:Lipopolysaccharides; D010767:Phosphorylcholine