MOLECULAR ANGLE TRANSITIONS IN MUSCLE

描述：拟议工作的目的是阐明 通过测定肌球蛋白在肌肉收缩机制中的旋转 能量传递(三磷酸腺苷水解酶)过程中跨桥的运动轨迹 以及力量的产生。几个特定位置的光谱探针 将定位于肌球蛋白跨桥上空间分离的位置。 探针将检测到肽骨架的大规模运动 或与力量生产有关的全球跨桥旋转运动 局部跨桥构象变化与能量传递有关。 稳态和时间分辨光谱技术遵循 不同生理状态下的定向敏感探头信号 在机械扰动之后提供全局方向和 肌球蛋白的动力学。时间分辨技术，偏振荧光 光漂白恢复与时间分辨荧光偏振 (TRFP)，在亚毫秒时间内跟踪肌肉纤维中的探针运动 域。PFPR施加一个光学瞬变探测命令，松弛到 平衡，不会对肌肉纤维系统产生任何干扰。TRFP 跟随探头的旋转运动以响应机械扰动 肌肉纤维。这些技术，用于不同的生理 纤维的状态，提供独立但补充的信息 跨桥秩序和动态。新的数据组合方法 多个探测信号区分局部和全局跨桥 旋转。来自同一探测器的不同光谱信号的解释 在探针-蛋白质接触方面提供了局部构象 过桥。探针-蛋白质的耦合偶极振子模型 接触解释吸收、荧光和圆二向色性信号 从络合物的分子结构的角度来看。这个 跨桥的局部构象和全局构象的结合 制作活动周期中跨桥运动的全面地图 允许局部能量转导事件与全球 强制生成事件。

DESCRIPTION: The aim of the proposed work is to elucidate the role of myosin in the mechanism of muscle contraction by determining the rotational trajectory of the cross-bridge during energy transduction (ATP hydrolysis) and the generation of force. Several site-specific spectroscopic probes will be localized on spatially separated sites on the myosin cross-bridge. The probes will sense both the large scale movement of the peptide backbone or global cross-bridge rotational movement related to force production and local cross-bridge conformation change related to energy transduction. Steady-state and time-resolved spectroscopic techniques follow the orientation sensitive probe signals in various physiological states and after mechanical perturbations to provide the global orientation and dynamics of myosin. The time-resolved techniques, polarized fluorescence photobleaching recovery (PFPR) and time-resolved fluorescence polarization (TRFP), follow probe movement in muscle fibers on the submillisecond time domain. PFPR imposes an optical transient to probe order that relaxes to equilibrium without any perturbation of the muscle fiber system. TRFP follows probe rotational movement in response to a mechanical perturbation of the muscle fiber. These techniques, used on different physiological states of the fiber, provide independent but complementary information on cross-bridge order and dynamics. New methodology for combining data from multiple probe signals distinguishes local from global cross-bridge rotation. Different spectroscopic signals from the same probes interpreted in terms of probe-protein contacts provide the local conformation of the cross-bridge. A coupled dipole oscillator model of the probe-protein contacts interprets absorption, fluorescence, and circular dichroism signals from the probes in terms of the molecular structure of the complex. The combination of the local and global conformation of the cross-bridge will produce a comprehensive map of cross-bridge movement during the active cycle permitting the correlation of local energy transduction events with global force generating events.