KINETICS OF THE MUSCLE CONTRACTILE APPARATUS

这项研究的总体目标是了解分子 肌肉蛋白质将化学能转化为 机械功，并获得精确的相关性 肌肉的生理、生化和结构事件 收缩。新的方法将应用于横纹肌纤维以 探讨肌肉收缩的生化反应之间的关系 蛋白质，跨桥循环的基本机械步骤和 相应的构造运动。化学物质的快速变化 相关生化物种的浓度，如三磷酸腺苷，将 由激光脉冲光解制成的耐光“笼”前驱体。一个 将使用新开发的固定光纤末端的方法来改进 宫缩的一致性和重复性。方向感 共价结合到肌球蛋白头部的荧光分子将是 以高时间分辨率进行监测，以确定 蛋白质分子的特殊结构变化。这种方法 结合激光光解、新的发色探针和其他 通过重组技术提供的标签站点将提供 肌球蛋白多个区域的取向和运动信息 头。实验将在猪的单个肌肉纤维上进行。 兔腰肌和青蛙半腱肌。本项目的成果 应该大大提高对收缩过程的了解，并 从而对正常和病理都有更好的理解 横纹肌和其他类型的细胞运动的状态。

The overall aims of this research are to understand the molecular mechanism by which muscle proteins convert chemical energy into mechanical work, and to obtain a precise correlation between the physiological, biochemical and structural events of muscular contraction. Novel methods will be applied to striated muscle fibers to probe the relations between biochemical reactions of the contractile proteins, the elementary mechanical steps of the cross-bridge cycle and the corresponding structural motions. Rapid changes in the chemical concentrations of pertinent biochemical species, such as ATP, will be made by laser pulse photolysis of photolabile "caged" precursors. A newly developed method to secure the fiber ends will be used to improve the uniformity and reproducibility of the contractions. The orientation of fluorescent molecules covalently bound to the myosin heads will be monitored at high time resolution to determine the rates and identity of specific structural changes of the protein molecules. This method combined with laser photolysis, new chromophoric probes, and additional labelling sites made available by recombinant technology will provide orientation and mobility information from several regions of the myosin head. The experiments will be carried out on single muscle fibers of rabbit psoas and frog semitendinosus muscles. Results from this project should significantly advance knowledge of the contractile process and thus bring a greater understanding of both normal and pathological states of striated muscle and other types of cell motility.