Theory and Bio-Systems, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
Biophys J. 2011 Apr 6;100(7):1747-55. doi: 10.1016/j.bpj.2011.02.012.
The molecular motor myosin V has been studied extensively both in bulk and single molecule experiments. Based on the chemical states of the motor, we construct a systematic network theory that includes experimental observations about the stepping behavior of myosin V. We utilize constraints arising from nonequilibrium thermodynamics to determine motor parameters and demonstrate that the motor behavior is governed by three chemomechanical motor cycles. The competition between these cycles can be understood via the influence of external load forces onto the chemical transition rates for the binding of adenosine triphosphate and adenosine diphosphate. In addition, we also investigate the functional dependence of the mechanical stepping rates on these forces. For substall forces, the dominant pathway of the motor network is profoundly different from the one for superstall forces, which leads to a stepping behavior that is in agreement with the experimental observations. Our theory provides a unified description of the experimental data as obtained for myosin V in single motor experiments.
分子马达肌球蛋白 V 在大量和单分子实验中都得到了广泛研究。基于马达的化学状态，我们构建了一个系统的网络理论，其中包括关于肌球蛋白 V 步进行为的实验观察结果。我们利用非平衡热力学产生的约束来确定马达参数，并证明马达行为由三个化学机械马达循环控制。通过外部负载力对结合三磷酸腺苷和二磷酸腺苷的化学跃迁率的影响，可以理解这些循环之间的竞争。此外，我们还研究了机械步进速率对这些力的功能依赖性。对于亚稳力，马达网络的主导途径与超稳力的途径截然不同，这导致了与实验观察结果一致的步进行为。我们的理论为单分子实验中获得的肌球蛋白 V 的实验数据提供了一个统一的描述。
