title: Structural studies of myosin:nucleotide complexes: a revised model for the molecular basis of muscle contraction.
abstract: The structures of the MgADP-beryllium fluoride and MgADP-aluminum fluoride complexes of the truncated myosin head from Dictyostelium myosin II are reported. These reveal the location of the nucleotide complex and define the amino acid residues that form the active site. The tertiary structure of the beryllium fluoride complex is essentially identical to that seen previously in the three-dimensional structure of chicken skeletal muscle myosin. By contrast, significant domain movements are observed in the aluminum fluoride complex. These structural findings form the basis of a revised model for the structural basis of the contractile cycle. It is now suggested that the narrow cleft that splits the central 50-kDa segment of the heavy chain provides not only the communication route between the nucleotide-binding pocket and actin but also transmits the conformational change necessary for movement.
authors.affiliation: Department of Biochemistry, University of Wisconsin, Madison 53705, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Fisher
authors.forename: C A
authors.initials: CA
authors.lastname: Smith
authors.forename: J
authors.initials: J
authors.lastname: Thoden
authors.forename: R
authors.initials: R
authors.lastname: Smith
authors.forename: K
authors.initials: K
authors.lastname: Sutoh
authors.forename: H M
authors.initials: HM
authors.lastname: Holden
authors.forename: I
authors.initials: I
authors.lastname: Rayment
mesh_terms: D000244:Adenosine Diphosphate; D017607:Aluminum Compounds; D000818:Animals; D001608:Beryllium; D001665:Binding Sites; D055592:Biophysical Phenomena; D001703:Biophysics; D004023:Dictyostelium; D005459:Fluorides; D008954:Models, Biological; D008958:Models, Molecular; D015394:Molecular Structure; D009119:Muscle Contraction / Q000502:physiology*; D015879:Myosin Subfragments / Q000737:chemistry* / Q000502:physiology; D009711:Nucleotides / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D017607:Aluminum Compounds; D015879:Myosin Subfragments; D009711:Nucleotides; C035982:beryllium fluoride; D000244:Adenosine Diphosphate; D001608:Beryllium; D005459:Fluorides; C032311:aluminum fluoride