title: Divergence of quaternary structures among bacterial flagellar filaments.
abstract: It has been widely assumed that the atomic structure of the flagellar filament from Salmonella typhimurium serves as a model for all bacterial flagellar filaments given the sequence conservation in the coiled-coil regions responsible for polymerization. On the basis of electron microscopic images, we show that the flagellar filaments from Campylobacter jejuni have seven protofilaments rather than the 11 in S. typhimurium. The vertebrate Toll-like receptor 5 (TLR5) recognizes a region of bacterial flagellin that is involved in subunit-subunit assembly in Salmonella and many other pathogenic bacteria, and this short region has diverged in Campylobacter and related bacteria, such as Helicobacter pylori, which are not recognized by TLR5. The driving force in the change of quaternary structure between Salmonella and Campylobacter may have been the evasion of TLR5.
authors.affiliation: Department of Biochemistry and Molecular Genetics, Box 800733, University of Virginia, Charlottesville, VA 22908-0733, USA.
authors.forename: Vitold E
authors.initials: VE
authors.lastname: Galkin
authors.forename: Xiong
authors.initials: X
authors.lastname: Yu
authors.forename: Jakub
authors.initials: J
authors.lastname: Bielnicki
authors.forename: John
authors.initials: J
authors.lastname: Heuser
authors.forename: Cheryl P
authors.initials: CP
authors.lastname: Ewing
authors.forename: Patricia
authors.initials: P
authors.lastname: Guerry
authors.forename: Edward H
authors.initials: EH
authors.lastname: Egelman
mesh_terms: D000595:Amino Acid Sequence; D016123:Campylobacter jejuni / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D019143:Evolution, Molecular; D005407:Flagella / Q000737:chemistry* / Q000648:ultrastructure*; D005408:Flagellin / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D008969:Molecular Sequence Data; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D012486:Salmonella typhimurium / Q000737:chemistry / Q000648:ultrastructure*; D051198:Toll-Like Receptor 5 / Q000276:immunology / Q000378:metabolism
chemical_list: D051198:Toll-Like Receptor 5; D005408:Flagellin