title: Structural diversity of bacterial flagellar motors.
abstract: The bacterial flagellum is one of nature's most amazing and well-studied nanomachines. Its cell-wall-anchored motor uses chemical energy to rotate a microns-long filament and propel the bacterium towards nutrients and away from toxins. While much is known about flagellar motors from certain model organisms, their diversity across the bacterial kingdom is less well characterized, allowing the occasional misrepresentation of the motor as an invariant, ideal machine. Here, we present an electron cryotomographical survey of flagellar motor architectures throughout the Bacteria. While a conserved structural core was observed in all 11 bacteria imaged, surprisingly novel and divergent structures as well as different symmetries were observed surrounding the core. Correlating the motor structures with the presence and absence of particular motor genes in each organism suggested the locations of five proteins involved in the export apparatus including FliI, whose position below the C-ring was confirmed by imaging a deletion strain. The combination of conserved and specially-adapted structures seen here sheds light on how this complex protein nanomachine has evolved to meet the needs of different species.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena, CA, USA.
authors.forename: Songye
authors.initials: S
authors.lastname: Chen
authors.forename: Morgan
authors.initials: M
authors.lastname: Beeby
authors.forename: Gavin E
authors.initials: GE
authors.lastname: Murphy
authors.forename: Jared R
authors.initials: JR
authors.lastname: Leadbetter
authors.forename: David R
authors.initials: DR
authors.lastname: Hendrixson
authors.forename: Ariane
authors.initials: A
authors.lastname: Briegel
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Shi
authors.forename: Elitza I
authors.initials: EI
authors.lastname: Tocheva
authors.forename: Axel
authors.initials: A
authors.lastname: Müller
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Dobro
authors.forename: Grant J
authors.initials: GJ
authors.lastname: Jensen
mesh_terms: D001419:Bacteria / Q000737:chemistry* / Q000378:metabolism*; D002465:Cell Movement; D005407:Flagella / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D020409:Molecular Motor Proteins