HETEROBIFUNCTIONAL CROSSLINKERS: EFFECT ON THIN FILAMENT

异双功能交联剂：对细丝的影响

• 批准号: 3437071
• 负责人: THOMAS W HOUK
• 金额: $ 4.46万
• 依托单位: MIAMI UNIVERSITY OXFORD
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-07-01 至 1990-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3437071
• 关键词: X ray crystallography; calcium metabolism; chemical structure function; conformation; crosslink; electron microscopy; enzyme induction /repression; hormone regulation /control mechanism; muscle contraction; phosphorylation; striated muscles

The regulation of vertebrate striated muscle contraction by Ca++ has been a topic of considerable interest in recent years. The initial structural biochemical and structural information concerning the thin filament led to the development of the steric blocking theory for the physical mode of action of tropomyosin. The evidence for the movement of tropomyosin relative to actin on Ca++ activation of muscle is well grounded in x-ray diffraction, electron microscopic reconstructions, and in some biochemical and biophysical probe studies. However beginning with Bremel and Weber's discovery of potentiation of the regulated thin filament, a number of other studies indicate that the actual effects of Ca++ involve the kinetics of the activated ATPase reaction as well as the properties of myosin, probably through the phosporylatable light chain of the enzymatically active regions of the molecule. This increasing complexity of the regulation mechanism mandates that the role of tropomyosin in the regulatory process be more intensively studied. It is proposed to investigate the use of a number of relatively newly developed heterobifunctional crosslinking reagents to study their effects on the regulatory ability of reconstituted thin filaments. Attempts will be made to crosslink tropomyosin and actin using these reagents to try to immobilize actin in a less stringent way than has been accomplished before with general crosslinking reagents such as gluteraldehyde. The results of intramolecular crosslinking of tropomyosin and actin before reconstitution of the thin filament will also be studied, both as a control and for its own interest. In this preliminary study the alterations in the activated myosin ATPase and superpercipitation will be examined. The results of one set of preliminary investigations is presented.

钙离子对脊椎动物横纹肌收缩的调节 近年来，这是一个相当令人感兴趣的话题。 的 初始结构生化和结构信息 关于细丝导致了空间位阻的发展， 原肌球蛋白物理作用模式的阻断理论。 原肌球蛋白相对于肌动蛋白运动的证据 对肌肉Ca++激活的影响在X射线中有很好的基础 衍射，电子显微镜重建，并在一些 生物化学和生物物理探针研究。 然而，开始 布雷梅尔和韦伯发现了 调节细丝，一些其他研究表明， Ca++的实际作用涉及活化的 ATP酶反应以及肌球蛋白的性质，可能 通过酶促磷酸化的轻链 分子的活性区域。 这种日益复杂的 调节机制要求原肌球蛋白在 对监管程序进行更深入的研究。 建议调查使用一些相对 新开发的异双功能交联试剂可供研究 它们对重组蛋白的调节能力的影响 细丝。 将尝试交联原肌球蛋白和 肌动蛋白使用这些试剂，试图在一个较小的 严格的方式比已经完成之前与一般 交联剂如戊二醛。 的结果 原肌球蛋白和肌动蛋白分子内交联 也将研究细丝的重构，作为 控制和自己的利益。 在这项初步研究中， 激活的肌球蛋白ATP酶和超沉淀的改变 将被审查。 一组初步的结果 调查提出。