title: Power-stroke-driven actomyosin contractility.
abstract: In ratchet-based models describing actomyosin contraction the activity is usually associated with actin binding potential while the power-stroke mechanism, residing inside myosin heads, is viewed as passive. To show that contraction can be propelled directly through a conformational change, we propose an alternative model where the power stroke is the only active mechanism. The asymmetry, ensuring directional motion, resides in steric interaction between the externally driven power-stroke element and the passive nonpolar actin filament. The proposed model can reproduce all four discrete states of the minimal actomyosin catalytic cycle even though it is formulated in terms of continuous Langevin dynamics. We build a conceptual bridge between processive and nonprocessive molecular motors by demonstrating that not only the former but also the latter can use structural transformation as the main driving force.
authors.affiliation: LMS, CNRS-UMR 7649, École Polytechnique, Route de Saclay, 91128 Palaiseau, France and LITEN, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble Cedex 9, France.
authors.forename: R
authors.initials: R
authors.lastname: Sheshka
authors.affiliation: LMS, CNRS-UMR 7649, École Polytechnique, Route de Saclay, 91128 Palaiseau, France.
authors.forename: L
authors.initials: L
authors.lastname: Truskinovsky
mesh_terms: D000205:Actomyosin / Q000737:chemistry / Q000502:physiology*; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000502:physiology*; D000818:Animals; D003198:Computer Simulation; D056966:Excitation Contraction Coupling / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D008956:Models, Chemical; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000502:physiology*; D018482:Muscle, Skeletal / Q000737:chemistry / Q000502:physiology*; D013314:Stress, Mechanical
chemical_list: D020409:Molecular Motor Proteins; D000205:Actomyosin; D000251:Adenosine Triphosphatases