CHEMISTRY OF MUSCLE PROTEINS

目前关于肌肉收缩中力产生步骤的理论包括： 肌球蛋白头相对于肌动蛋白丝的重新定向， 收缩周期 在这个模型中隐含的是存在更多的 在肌球蛋白的头部区域的一个构象状态。 的一个主要目的 我们的研究仍然是阐明这种假定的结构， 肌球蛋白重链和轻链亚基的变化。 我们将奉行 推进这一问题的两个主要方向：（1）特定标记，如 荧光探针、单克隆抗体和抗小 肽将被引入到轻链和重链上明确定义的位点， 店 抗体在肌球蛋白头上的位置将被可视化 通过阴影投射制备的电子显微镜。 之间的距离 荧光团将通过福斯特能量转移来测量。 的任何变化 与ATP和/或肌动蛋白结合的能量转移可以指示 头部的结构变化。 (2)的比较研究 广泛不同肌球蛋白同工酶的结构和功能可以提供 从任何一种肌球蛋白都无法获得重要的见解。 在肌球蛋白中 我们将继续研究快肌球蛋白和慢肌球蛋白，胚胎和 新生肌球蛋白和来自鸟类和哺乳动物的平滑肌肌球蛋白 源 轻链去除或磷酸化对细胞凋亡的影响 肌球蛋白的构象将被探索。 技术将包括动能 分析、肽图谱、免疫学、电泳和 沉降分析 通过研究这些肌球蛋白多晶型体， 单体和丝状状态，我们最终可能会明白， 复杂的分子工作，为什么肌肉是由这样一个看似 无穷无尽的纤维镶嵌

Current theories of the force generating step in muscle contraction involve a reorientation of the myosin head relative to the actin filament during the contractile cycle. Implicit in this model is the existence of more than one conformational state of the head region in myosin. A major aim of our research continues to be the elucidation of such putative structural changes in the heavy and light chain subunits of myosin. We will pursue two main directions to advance this problem: (1) Specific markers, such as fluorescent probes, monoclonal antibodies, and antibodies against small peptides will be introduced into well-defined sites on the light and heavy chains. The position of the antibody on the myosin head will be visualized by electron microscopy of shadow-cast preparations. Distances between fluorophores will be measured by Forster energy transfer. Any change in energy transfer with ATP and/or actin binding may be indicative of structural changes within the head. (2) Comparative studies on the structure and function of widely different myosin isozymes can provide important insights not obtainable from any one myosin. Among the myosins we will continue to study are fast and slow adult myosins, embryonic and neonatal myosins, and smooth muscle myosin from avian and mammalian sources. The effect of light chain removal or phosphorylation on the conformation of myosin will be explored. Techniques will include kinetic analysis, peptide mapping, immunological, electrophoretic, and sedimentation analysis. By investigating these myosin polymorphs both in the monomeric and filamentous state, we may eventually understand how this complex molecule works, and why muscle is composed of such a seemingly endless mosaic of fiber types.