title: Myosin V is a left-handed spiral motor on the right-handed actin helix.
abstract: Myosin V is a two-headed, actin-based molecular motor implicated in organelle transport. Previously, a single myosin V molecule has been shown to move processively along an actin filament in discrete approximately 36 nm steps. However, 36 nm is the helical repeat length of actin, and the geometry of the previous experiments may have forced the heads to bind to, or halt at, sites on one side of actin that are separated by 36 nm. To observe unconstrained motion, we suspended an actin filament in solution and attached a single myosin V molecule carrying a bead duplex. The duplex moved as a left-handed spiral around the filament, disregarding the right-handed actin helix. Our results indicate a stepwise walking mechanism in which myosin V positions and orients the unbound head such that the head will land at the 11th or 13th actin subunit on the opposing strand of the actin double helix.
authors: Center for Integrative Bioscience, Okazaki National Research Institutes, Higashiyama 5-1, Myodaiji, Okazaki 444-8585, Japan.
authors: M Yusuf
authors: MY
authors: Ali
authors: Sotaro
authors: S
authors: Uemura
authors: Kengo
authors: K
authors: Adachi
authors: Hiroyasu
authors: H
authors: Itoh
authors: Kazuhiko
authors: K
authors: Kinosita
authors: Shin'ichi
authors: S
authors: Ishiwata
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002642:Chick Embryo; D008863:Microspheres; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D009068:Movement; D024701:Myosin Type V / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D011137:Polystyrenes; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D011817:Rabbits; D012399:Rotation
chemical_list: D000199:Actins; D020409:Molecular Motor Proteins; D011137:Polystyrenes; D021122:Protein Subunits; D000255:Adenosine Triphosphate; D024701:Myosin Type V