Sheshka R, Truskinovsky L
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.
LMS, CNRS-UMR 7649, École Polytechnique, Route de Saclay, 91128 Palaiseau, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2014 Jan;89(1):012708. doi: 10.1103/PhysRevE.89.012708. Epub 2014 Jan 13.
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.
在描述肌动球蛋白收缩的基于棘轮的模型中，活性通常与肌动蛋白结合潜力相关联，而存在于肌球蛋白头部内部的动力冲程机制则被视为被动的。为了表明收缩可以直接通过构象变化来推动，我们提出了一种替代模型，其中动力冲程是唯一的主动机制。确保定向运动的不对称性存在于外部驱动的动力冲程元件与被动非极性肌动蛋白丝之间的空间相互作用中。尽管该模型是根据连续的朗之万动力学来表述的，但它可以重现最小肌动球蛋白催化循环的所有四个离散状态。我们通过证明不仅连续运动分子马达而且非连续运动分子马达都可以使用结构转变作为主要驱动力，在连续运动和非连续运动分子马达之间建立了概念上的桥梁。
