title: Structural analysis of the polysaccharide from the lipopolysaccharide of Porphyromonas gingivalis strain W50.
abstract: The lipopolysaccharide (LPS) of Porphyromonas gingivalis is an important pro-inflammatory molecule in periodontal disease and a significant target of the host's specific immune response. In addition, we recently demonstrated using monoclonal antibodies that the Arg-gingipains of P. gingivalis are post-translationally modified with glycan chains that are immunologically related to an LPS preparation from this organism. In the present investigation, we determined the structure of the O-polysaccharide of P. gingivalis W50 that was fully characterized on the basis of 1D and 2D NMR (DQF-COSY, TOCSY, NOESY, ROESY, 1H-13C HSQC and 1H-31P HXTOCSY) and GC-MS data. These data allowed us to conclude that the O-polysaccharide is built up of the tetrasaccharide repeating sequence: -->6)-alpha-D-Glcp-(1-->4)-alpha-L-Rhap-(1-->3)-beta-D-GalNAc-(1-->3)-alpha-D-Galp-(1--> and carries a monophosphoethanolamine residue at position C-2 of the alpha-rhamnose residue in a nonstoichiometric (approximately 60%) amount. These data indicate that the O-polysaccharide of P. gingivalis LPS is composed of an unusually modified tetrasaccharide repeating unit.
authors.affiliation: MRC Molecular Pathogenesis Group, Department of Medical Microbiology, St. Bartholomew's and The Royal London School of Medicine and Dentistry, Queen Mary College, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Paramonov
authors.forename: D
authors.initials: D
authors.lastname: Bailey
authors.forename: M
authors.initials: M
authors.lastname: Rangarajan
authors.forename: A
authors.initials: A
authors.lastname: Hashim
authors.forename: G
authors.initials: G
authors.lastname: Kelly
authors.forename: M A
authors.initials: MA
authors.lastname: Curtis
authors.forename: E F
authors.initials: EF
authors.lastname: Hounsell
mesh_terms: D002236:Carbohydrate Conformation; D005936:Glucans / Q000737:chemistry* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D016966:Porphyromonas gingivalis / Q000737:chemistry*
chemical_list: D005936:Glucans; D008070:Lipopolysaccharides