title: Structural analysis of lipopolysaccharide oligosaccharide epitopes expressed by non-typeable Haemophilus influenzae strain 176.
abstract: The structure of the lipopolysaccharide (LPS) from non-typeable Haemophilus influenzae strain 176 has been investigated. Electrospray ionization-mass spectrometry (ESIMS) on O-deacylated LPS (LPS-OH) and core oligosaccharide (OS) samples obtained after mild-acid hydrolysis of LPS provided information on the composition and relative abundance of the glycoforms. ESIMS tandem-mass spectrometry on LPS-OH confirmed the presence of minor sialylated and disialylated glycoforms. Oligosaccharide samples were studied in detail using high-field NMR techniques. It was found that the LPS contains the common inner-core element of H. influenzae, L-alpha-D-Hepp-(1-->2)-[PEtn-->6]-L-alpha-D-Hepp-(1-->3)-[beta-D-Glcp-(1-->4)]-L-alpha-D-Hepp-(1-->5)-[PPEtn-->4]-alpha-Kdop-(2-->6)-Lipid A having glycosyl substitution at the O-3 position of the terminal heptose as recently observed for non-typeable H. influenzae strain 486 [Månsson, M.; Bauer, S. H. J.; Hood, D. W.; Richards, J. C.; Moxon, E. R.; Schweda, E. K. H., Eur. J. Biochem. 2001, 268, 2148--2159]. The following LPS structures were identified as the major glycoforms, the most significant being indicated with an asterisk (*) (glycoforms are partly substituted with Gly at the terminal Hep):
authors.affiliation: Clinical Research Centre, Karolinska Institutet and University College of South Stockholm, NOVUM, S-141 86, Huddinge, Sweden. elke.schweda@kfc.ki.se
authors.forename: Elke K H
authors.initials: EK
authors.lastname: Schweda
authors.forename: Jianjun
authors.initials: J
authors.lastname: Li
authors.forename: E Richard
authors.initials: ER
authors.lastname: Moxon
authors.forename: James C
authors.initials: JC
authors.lastname: Richards
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D000939:Epitopes / Q000737:chemistry*; D006193:Haemophilus influenzae / Q000737:chemistry*; D006601:Hexoses / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D009844:Oligosaccharides / Q000737:chemistry*; D010767:Phosphorylcholine / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D000939:Epitopes; D006601:Hexoses; D008070:Lipopolysaccharides; D009844:Oligosaccharides; D010767:Phosphorylcholine