Crossbridge Orientation and Dynamics in Muscle Contraction

肌肉收缩中的横桥方向和动力学

• 批准号: 9206658
• 负责人: Piotr Fajer
• 金额: $ 15.15万
• 依托单位: Florida State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-08-15 至 1995-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9206658&HistoricalAwards=false
• 关键词: Crossbridge; Orientation; Dynamics; Muscle; Contraction

The long term goal of this research is to determine the molecular mechanism of muscular contraction. In this proposal we hope to provide direct evidence for the "rotating myosin head" hypothesis of Huxley (1969), the widely accepted working model for the contractile mechanism. Our approach is to correlate the structural changes of the myosin head (orientation and mobility) with force production (mechanical cycle) and the utilization of ATP (biochemical cycle). In order to delineate physical changes taking place during different steps of the contractile cycle, steady- state equilibria will be perturbed mechanically and biochemically including "trapping" the cycle at certain steps. The orientation and mobility of muscle proteins will be measured using electron paramagnetic resonance spectroscopy (EPR) following the labeling of these proteins with paramagnetic probes. EPR is uniquely suited for this purpose because it is site-specific and it is sensitive to static orientation and rotational mobility of proteins. We have just developed a number of computational methods to extract the myosin head orientation (rather than the spin probe orientation) from EPR spectra. This new technology will give a detailed (3 degree resolution) picture of myosin head reorientation during transitions between the different states in the contractile cycle. We will be able to distinguish between pivoting and spinning motions of the myosin head.

这项研究的长期目标是确定 肌肉收缩的机制。在这份提案中，我们希望 为“旋转肌球蛋白头”假说提供了直接证据 赫胥黎（1969），广泛接受的工作模式， 收缩机制我们的方法是将结构 肌球蛋白头部（方向和移动性）随力的变化 生产（机械循环）和ATP的利用 （生化循环）。为了描述身体的变化， 在收缩周期的不同阶段放置，稳定- 状态平衡将受到机械和生物化学的扰动 包括在某些步骤“捕获”循环。 将测量肌肉蛋白质的方向和流动性 使用电子顺磁共振光谱（EPR）， 用顺磁性探针标记这些蛋白质。EPR是 因为它是特定于站点的， 它对静态方向和旋转移动性敏感， proteins. 我们刚刚开发了一些计算方法来提取 肌球蛋白头部方向（而不是自旋探针 取向）。这项新技术将为 肌球蛋白头部重新定向的详细（3度分辨率）图片 在收缩肌的不同状态之间的转换期间， 周期我们将能够区分旋转和旋转 肌球蛋白头部的运动。