title: Structure of the LPS O-chain from Fusobacterium nucleatum strain 10953, containing sialic 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 virulence factors of this organism and thus we have initiated studies to examine the bacterial surface glycochemistry. Consistent with a recent paper suggesting that F. nucleatum strain 10593 can synthesize sialic acid, a staining technique identified sialic acid on the bacterial surface. We isolated lipopolysaccharide from this F. nucleatum strain and performed structural analysis on the O-antigen. Our studies identified a trisaccharide repeating unit of the O-antigen with the following structure: -[→4)-α-Neup5Ac-(2 → 4)-β-d-Galp-(1 → 3)-α-d-FucpNAc4NAc-(1-]- where Ac indicates 4-N-acetylation of ∼30% FucNAc4N residues. The presence of sialic acid as a constituent of the O-antigen is consistent with recent data identifying de novo sialic acid synthesis in this strain.
authors.affiliation: Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, ON, K1A 0R6, Canada. Electronic address: evguenii.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: Department of Oral Biology, University at Buffalo, Buffalo, NY, 14214, USA.
authors.forename: Kiyonobu
authors.initials: K
authors.lastname: Homma
authors.affiliation: Department of Oral Biology, University at Buffalo, Buffalo, NY, 14214, USA.
authors.forename: Ashu
authors.initials: A
authors.lastname: Sharma
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*; D009682:Magnetic Resonance Spectroscopy; D019158:N-Acetylneuraminic Acid / Q000737:chemistry* / Q000302:isolation & purification; D019081:O Antigens / Q000737:chemistry* / Q000302:isolation & purification; D013194:Staining and Labeling / Q000379:methods; D014312:Trisaccharides / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D019081:O Antigens; D014312:Trisaccharides; D019158:N-Acetylneuraminic Acid
keywords: Fusobacterium nucleatum; Lipopolysaccharide; Sialic acid