title: High-resolution structures of kinesin on microtubules provide a basis for nucleotide-gated force-generation.
abstract: Microtubule-based transport by the kinesin motors, powered by ATP hydrolysis, is essential for a wide range of vital processes in eukaryotes. We obtained insight into this process by developing atomic models for no-nucleotide and ATP states of the monomeric kinesin motor domain on microtubules from cryo-EM reconstructions at 5-6 Å resolution. By comparing these models with existing X-ray structures of ADP-bound kinesin, we infer a mechanistic scheme in which microtubule attachment, mediated by a universally conserved 'linchpin' residue in kinesin (N255), triggers a clamshell opening of the nucleotide cleft and accompanying release of ADP. Binding of ATP re-closes the cleft in a manner that tightly couples to translocation of cargo, via kinesin's 'neck linker' element. These structural transitions are reminiscent of the analogous nucleotide-exchange steps in the myosin and F1-ATPase motors and inform how the two heads of a kinesin dimer 'gate' each other to promote coordinated stepping along microtubules.
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Shang
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.
authors.forename: Kaifeng
authors.initials: K
authors.lastname: Zhou
authors.affiliation: Department of Biology, Brandeis University, Waltham, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
authors.affiliation: Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, United States.
authors.forename: Roseann
authors.initials: R
authors.lastname: Csencsits
authors.affiliation: Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, United States.
authors.forename: Jared C
authors.initials: JC
authors.lastname: Cochran
authors.affiliation: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, United States.
authors.forename: Charles V
authors.initials: CV
authors.lastname: Sindelar
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D001696:Biomechanical Phenomena; D006801:Humans; D016547:Kinesins / Q000737:chemistry*; D008870:Microtubules / Q000378:metabolism*; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism*; D017354:Point Mutation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
chemical_list: D050505:Mutant Proteins; D009711:Nucleotides; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D016547:Kinesins
keywords: biophysics; cryo-EM; human; kinesin; molecular motors; myosin; structural biology