title: 3D structure of eukaryotic flagella in a quiescent state revealed by cryo-electron tomography.
abstract: We have used cryo-electron tomography to investigate the 3D structure and macromolecular organization of intact, frozen-hydrated sea urchin sperm flagella in a quiescent state. The tomographic reconstructions provide information at a resolution better than 6 nm about the in situ arrangements of macromolecules that are key for flagellar motility. We have visualized the heptameric rings of the motor domains in the outer dynein arm complex and determined that they lie parallel to the plane that contains the axes of neighboring flagellar microtubules. Both the material associated with the central pair of microtubules and the radial spokes display a plane of symmetry that helps to explain the planar beat pattern of these flagella. Cryo-electron tomography has proven to be a powerful technique for helping us understand the relationships between flagellar structure and function and the design of macromolecular machines in situ.
authors.affiliation: Abteilung Molekulare Strukturbiologie, Max-Planck-Institut für Biochemie, 82152 Martinsried, Germany. nicastro@colorado.edu
authors.forename: Daniela
authors.initials: D
authors.lastname: Nicastro
authors.forename: J Richard
authors.initials: JR
authors.lastname: McIntosh
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Baumeister
mesh_terms: D000818:Animals; D020285:Cryoelectron Microscopy / Q000379:methods; D004398:Dyneins / Q000737:chemistry; D005057:Eukaryotic Cells / Q000166:cytology; D005407:Flagella / Q000737:chemistry*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008870:Microtubules / Q000737:chemistry; D020409:Molecular Motor Proteins / Q000737:chemistry; D017434:Protein Structure, Tertiary; D012617:Sea Urchins; D013094:Spermatozoa / Q000166:cytology*; D014054:Tomography
chemical_list: D020409:Molecular Motor Proteins; D004398:Dyneins