DYNAMIC EVENTS IN MYOSIN DURING CONTRACTION OF MUSCLE

拟议研究的长期目标是阐明 肌肉收缩的结构和化学基础。这一目标将 通过开展三个相关的研究项目来进行，目的是 澄清：(1)肌肉收缩的调节；(2) 肌动蛋白、肌球蛋白和肌动球蛋白的功能结构关系 (3)肌原纤维结构的组装。 (一)整治工程的具体目标是：(一)检验 假设肌动蛋白的N-末端片段参与了 调节不同肌肉的收缩；(Ii)澄清 Caldesmon与肌动蛋白的相互作用；以及(Iii)在 空间位阻的生理条件及催化机理 肌肉收缩的调节。 (2)肌动蛋白、肌球蛋白和肌动球蛋白的研究目标 界面是：(I)澄清选定的位点对肌动蛋白和 肌球蛋白在强(-ATP)和弱(+ATP)肌球蛋白结合中；以及(Ii) 为了确定SHI肽的作用，选择肌动蛋白上的位点和 肌球蛋白和肌动蛋白在收缩过程中的动态运动。 前两个项目将涉及免疫化学、酶学、 化学修饰、体外运动、荧光和沉淀 用多肽抗体、修饰和未修饰的蛋白质进行实验， 肌动蛋白突变体，肌球蛋白和肌动蛋白细丝，肌原纤维和肌肉纤维。 (三)装配式项目的具体目标是：(一)明确 调控因子在成核、生长和稳定中的作用 肌球蛋白细丝；(Ii)表征肌球蛋白的溶液性质；以及 (Iii)研究肌原纤维中肌球蛋白细丝的形成 骨骼肌肌球蛋白与Smooth轻链-2杂交 肌肉肌球蛋白。这些研究将使用流体动力学、光散射、 电子显微镜和光谱技术。 在本申请中提出的研究将导致改进 了解肌肉和非肌肉细胞的收缩过程。

The long term objective of the proposed research is to elucidate the structural and chemical basis of muscle contraction. This objective will be pursued by working on three related research projects aimed at the clarification of: (1) the regulation of muscle contraction; (2) function-structure relationships on actin, myosin, and actomyosin interface; and (3) the assembly of myofibrilar structures. (1)The specific aims of the regulation project are: (i) to test the hypothesis that the N-terminal segment of actin is involved in the regulation of contraction in different muscles; (ii) to clarify the interaction of caldesmon with actin; and (iii) to test under physiological conditions the steric block and catalytic mechanisms for regulation of muscle contraction. (2)The goals of the studies on actin, myosin, and actomyosin interface are: (i) to clarify the role of selected sites on actin and myosin in the strong (-ATP) and weak (+ATP) actomyosin binding; and (ii) to determine the role of the SHI peptide, selected sites on actin and myosin, and dynamic motions in actin in the contractile process. The first two projects will involve immunochemical, enzymological, chemical modification, in vitro motility, fluorescence and sedimentation experiments with peptide antibodies, modified and unmodified proteins, actin mutants, myosin and actin filaments, myofibrils, and muscle fibers. (3)The specific aims of the assembly project are: (i) to clarify the role of regulatory factors in the nucleation, growth, and stability of myosin filaments; (ii) to characterize solution properties of titin; and (iii) to examine the formation of myosin filaments in myofibrils by using myosin from skeletal muscle hybridized with light chain-2 from smooth muscle myosin. These studies will employ hydrodynamic, light scattering, electron microscopy, and spectroscopic techniques. The research proposed in this application will result in an improved understanding of contractile processes in muscle and non-muscle cells.