title: Dissecting the kinematics of the kinesin step.
abstract: Kinesin walks processively on microtubules in an asymmetric hand-over-hand manner with each step spanning 16 nm. We used molecular simulations to determine the fraction of a single step due to conformational changes in the neck linker, and that due to diffusion of the tethered head. Stepping is determined largely by two energy scales, one favoring neck-linker docking and the other, ε(h)(MT-TH), between the trailing head (TH) and the microtubule. Neck-linker docking and an optimal value of ε(h)(MT-TH) are needed to minimize the probability that the TH takes side steps. There are three major stages in the kinematics of a step. In the first, the neck linker docks, resulting in ∼(5-6) nm movements of the trailing head. The TH moves an additional (6-8) nm in stage II by anisotropic translational diffusion. In the third stage, spanning ∼(3-4) nm, the step is complete with the TH binding to the αβ-tubulin binding site.
authors.affiliation: Biophysics Program, Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA.
authors.forename: Zhechun
authors.initials: Z
authors.lastname: Zhang
authors.forename: D
authors.initials: D
authors.lastname: Thirumalai
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D001665:Binding Sites; D001696:Biomechanical Phenomena; D004058:Diffusion; D016547:Kinesins / Q000737:chemistry*; D007700:Kinetics; D008870:Microtubules / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013816:Thermodynamics; D014404:Tubulin / Q000737:chemistry*
chemical_list: D014404:Tubulin; D000255:Adenosine Triphosphate; D016547:Kinesins