title: Three-dimensional structures of the flagellar dynein-microtubule complex by cryoelectron microscopy.
abstract: The outer dynein arms (ODAs) of the flagellar axoneme generate forces needed for flagellar beating. Elucidation of the mechanisms underlying the chemomechanical energy conversion by the dynein arms and their orchestrated movement in cilia/flagella is of great importance, but the nucleotide-dependent three-dimensional (3D) movement of dynein has not yet been observed. In this study, we establish a new method for reconstructing the 3D structure of the in vitro reconstituted ODA-microtubule complex and visualize nucleotide-dependent conformational changes using cryoelectron microscopy and image analysis. As the complex went from the rigor state to the relaxed state, the head domain of the beta heavy chain shifted by 3.7 nm toward the B tubule and inclined 44 degrees inwards. These observations suggest that there is a mechanism that converts head movement into the axonemal sliding motion.
authors: Department of Cell Biology, University of Texas, Southwestern Medical Center, Dallas, TX 75390, USA.
authors: Toshiyuki
authors: T
authors: Oda
authors: Nobutaka
authors: N
authors: Hirokawa
authors: Masahide
authors: M
authors: Kikkawa
mesh_terms: D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D004398:Dyneins / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D005407:Flagella / Q000737:chemistry* / Q000648:ultrastructure*; D008870:Microtubules / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D009711:Nucleotides / Q000378:metabolism; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
chemical_list: D046912:Multiprotein Complexes; D009711:Nucleotides; D004398:Dyneins