Computational and single molecule analysis of kinesin's atomistic machinery

驱动蛋白原子机制的计算和单分子分析

基本信息

批准号：
8330273
负责人：
Wonmuk Hwang
金额：
$ 22.26万
依托单位：
TEXAS ENGINEERING EXPERIMENT STATION
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-09-01 至 2014-08-31
项目状态：
已结题

项目摘要

Project Summary Kinesin is the smallest known biped motor protein that uses ATP as a fuel to walk processively along the microtubule track. Its proper function is critical for many vital tasks including intracellular cargo transport and cell division. A deeper insight into how kinesin functions is thus not only important for advancing fundamental knowledge of molecular motors, but also critical for developing novel therapeutics against diseases involving impaired intracellular transport. While past advances revealed many important aspects on its global motility characteristics, physical mechanism underling its stepping motion remains unclear. A major difficulty in studying kinesin motility or motor proteins in general, is that the molecule dynamically senses and generates force to move, which is difficult to contemplate based on static structural picture only. To investigate the dynamic aspect in atomistic detail, we take a synergistic approach between molecular dynamics simulation and single-molecule experiment. Using molecular dynamics simulations, we discovered that kinesin generates force by folding of a domain, which we named the cover-neck bundle. While the proposed mechanism is supported by our single- molecule motility experiments testing kinesin mutants designed to generate less force, the experiments led to further questions regarding energetics of the force generation as well as the role of the force-generating step in the overall kinesin mechanochemical cycle. Furthermore, our preliminary simulations identified two other crucial aspects of kinesin motility: (1) the structural pathway by which mechanical strain is transmitted through the motor head to modulate the nucleotide affinity, which is important for motor head coordination, and (2) the dynamic role of the C-terminal flexible E-hook domains of the microtubule in biasing the trajectory of a motor head, which is critical for how kinesin makes a step. These issues will be thoroughly investigated by further simulations. Mutant kinesins will be generated that specifically alter the physical mechanism found in simulations, and experimentally tested using state-of-the-art optical trap systems. Outcome of this work will provide a clearer atomistic picture of the mechanics underling kinesin motility. With our previous R21-funded project as a precursor, the proposed work will be developed via strong synergy between experiments and simulations, which will be the basis upon which a host of other motor proteins will be investigated as our long-term goal.

项目概要驱动蛋白是已知最小的双足运动蛋白，它使用 ATP 作为燃料沿着路径持续行走微管轨道。它的正确功能对于许多重要任务至关重要，包括细胞内货物运输和细胞分裂。因此，更深入地了解驱动蛋白的功能不仅对于推进基础研究很重要分子马达的知识，对于开发针对涉及疾病的新疗法也至关重要细胞内运输受损。虽然过去的进展揭示了其全球动力的许多重要方面特征、其步进运动的物理机制仍不清楚。学习上的一大困难一般而言，驱动蛋白运动或运动蛋白是分子动态感知并产生力以移动，仅根据静态结构图很难进行思考。研究动态方面在原子细节上，我们采用分子动力学模拟和单分子之间的协同方法实验。使用分子动力学模拟，我们发现驱动蛋白通过折叠产生力域，我们将其命名为颈盖束。虽然所提出的机制得到了我们单一的支持分子运动实验测试了旨在产生较小力的驱动蛋白突变体，该实验导致关于力产生的能量学以及力产生步骤的作用的进一步问题整个驱动蛋白机械化学循环。此外，我们的初步模拟还发现了另外两个关键因素驱动蛋白运动的方面：（1）机械应变通过电机传递的结构途径头调节核苷酸亲和力，这对于运动头协调很重要，以及（2）动态作用微管 C 端柔性 E-hook 结构域对电机头轨迹的偏置，即对于驱动蛋白如何迈出一步至关重要。这些问题将通过进一步的模拟进行彻底研究。突变体将生成专门改变模拟和实验中发现的物理机制的驱动蛋白使用最先进的光阱系统进行测试。这项工作的成果将提供更清晰的原子图驱动蛋白运动的机制。以我们之前的 R21 资助项目为先导，拟议的工作将通过实验和模拟之间的强大协同作用来开展，这将成为基础我们将研究许多其他运动蛋白作为我们的长期目标。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Modular aspects of kinesin force generation machinery.

驱动蛋白力产生机械的模块化方面。

DOI：
发表时间：
2013-05-07
期刊：
影响因子：
3.4
作者：
Hesse, William R;Steiner, Miriam;Wohlever, Matthew L;Kamm, Roger D;Hwang, Wonmuk;Lang, Matthew J
通讯作者：
Lang, Matthew J

Nucleotide-dependent control of internal strains in ring-shaped AAA+ motors.

环形 AAA 电机中内部应变的核苷酸依赖性控制。