title: The structure of the LPS O-chain of Fusobacterium nucleatum strain 25586 containing two novel monosaccharides, 2-acetamido-2,6-dideoxy-l-altrose and a 5-acetimidoylamino-3,5,9-trideoxy-gluco-non-2-ulosonic acid.
abstract: Fusobacterium nucleatum is an anaerobic bacterium found in the human mouth where it causes periodontitis. Recently, it has been gaining attention as a potential causative agent for colorectal cancer and is strongly linked with pregnancy complications including pre-term and still births. Little is known about the virulence factors of this organism, and thus we have initiated studies to examine the bacterium's surface glycochemistry. We isolated lipopolysaccharide (LPS) from F. nucleatum strain 25586 and purified and performed structural analysis on the O-antigen polysaccharide. The polysaccharide contained two novel sugars, 2-acetamido-2,6-dideoxy-l-altrose (l-6dAltNAc) and a 5-acetimidoylamino-3,5,9-trideoxy-gluco-non-2-ulosonic acid (Non5Am), which was tentatively assigned the l-glycero-l-gluco configuration. The polysaccharide was found to have a trisaccharide repeating unit, which is phosphorylated with phosphocholine (PCho), and the following structure was established: -[-4-β-Nonp5Am-4-α-l-6dAltpNAc3PCho-3-β-d-QuipNAc-]- We propose the trivial name 'fusaminic acid' for the novel nonulosonic acid. It is the first occurrence of a 9-deoxynonulosonic acid with a hydroxyl group at C-7, which is occupied by an amino group in all monosaccharides of this class described so far.
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON K1A 0R6, Canada. Electronic address: Evgeny.Vinogradov@nrc-cnrc.gc.ca.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Vinogradov
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON K1A 0R6, Canada.
authors.forename: Frank
authors.initials: F
authors.lastname: St Michael
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON K1A 0R6, Canada.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Cox
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D016967:Fusobacterium nucleatum / Q000737:chemistry*; D006601:Hexoses / Q000737:chemistry* / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D019081:O Antigens / Q000737:chemistry* / Q000302:isolation & purification; D010766:Phosphorylation; D010767:Phosphorylcholine / Q000737:chemistry; D013400:Sugar Acids / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D006601:Hexoses; D019081:O Antigens; D013400:Sugar Acids; D010767:Phosphorylcholine
keywords: Fusaminic acid; Fusobacterium nucleatum; Lipopolysaccharide; NMR; Structure