title: A novel glycan modifies the flagellar filament proteins of the oral bacterium Treponema denticola.
abstract: While protein glycosylation has been reported in several spirochetes including the syphilis bacterium Treponema pallidum and Lyme disease pathogen Borrelia burgdorferi, the pertinent glycan structures and their roles remain uncharacterized. Herein, a novel glycan with an unusual chemical composition and structure in the oral spirochete Treponema denticola, a keystone pathogen of periodontitis was reported. The identified glycan of mass 450.2 Da is composed of a monoacetylated nonulosonic acid (Non) with a novel extended N7 acyl modification, a 2-methoxy-4,5,6-trihydroxy-hexanoyl residue in which the Non has a pseudaminic acid configuration (L-glycero-L-manno) and is β-linked to serine or threonine residues. This novel glycan modifies the flagellin proteins (FlaBs) of T. denticola by O-linkage at multiple sites near the D1 domain, a highly conserved region of bacterial flagellins that interact with Toll-like receptor 5. Furthermore, mutagenesis studies demonstrate that the glycosylation plays an essential role in the flagellar assembly and motility of T. denticola. To our knowledge, this novel glycan and its unique modification sites have not been reported previously in any bacteria.
authors.affiliation: Department of Oral Biology, The State University of New York at Buffalo, New York, NY, 14214, USA.
authors.forename: Kurni
authors.initials: K
authors.lastname: Kurniyati
authors.affiliation: Vaccine Program, Human Health Therapeutics, National Research Council, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: John F
authors.initials: JF
authors.lastname: Kelly
authors.affiliation: Vaccine Program, Human Health Therapeutics, National Research Council, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Evgeny
authors.initials: E
authors.lastname: Vinogradov
authors.affiliation: Vaccine Program, Human Health Therapeutics, National Research Council, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Anna
authors.initials: A
authors.lastname: Robotham
authors.affiliation: Department of Oral Biology, The State University of New York at Buffalo, New York, NY, 14214, USA.
authors.forename: Youbing
authors.initials: Y
authors.lastname: Tu
authors.affiliation: Department of Pathology and Laboratory Medicine, McGovern Medical School at UT Health Science Center, Houston, TX, 77030, USA.
authors.forename: Juyu
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Pathology and Laboratory Medicine, McGovern Medical School at UT Health Science Center, Houston, TX, 77030, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Vaccine Program, Human Health Therapeutics, National Research Council, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Logan
authors.affiliation: Department of Oral Biology, The State University of New York at Buffalo, New York, NY, 14214, USA.|Department of Microbiology and Immunology, The State University of New York at Buffalo, New York, NY, 14214, USA.
authors.forename: Chunhao
authors.initials: C
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000378:metabolism; D005407:Flagella / Q000235:genetics / Q000378:metabolism; D005408:Flagellin / Q000378:metabolism; D006031:Glycosylation; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism*; D013329:Structure-Activity Relationship; D048373:Treponema denticola / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D011134:Polysaccharides; D005408:Flagellin