TOPOGRAPHICAL STUDIES OF SMOOTH AND NONMUSCLE MYOSINS

描述：(改编自应用)平滑肌的磷酸化 肌球蛋白(SMM)和非肌肉肌球蛋白II是激活细胞所必需的 功能。调控轻链(RLC)中的单个丝氨酸 肌球蛋白的两个“头”结构域被一种钙激活的激酶磷酸化。 目前的知识表明，这种调节效应是通过 肌球蛋白结构的大的构象变化。克雷莫博士的长期目标是 确定磷酸化依赖的调控的结构基础 机制。 克雷莫博士假设，两个头部之间的特定互动是 处于非磷酸化的“关闭”或下调状态。对…的预测 假设头部附近的杆状结构域被改变 磷酸化，从而帮助打破头部之间的相互作用。 克雷莫博士现在将这一假说扩展到这样的观点，即 根据她最近的发现，这两个头并不对称 实验室。她提出了一个详细的“结构假说”，说明 RLC的磷酸化控制着头部-头部的相互作用。她还会 验证其他人提出的假设，即两者之间的相互作用 催化结构域，受调控结构域相互作用控制，解释了 下调非磷酸化状态的动力学。这些实验应该 回答“头-尾的两个残基如何磷酸化？ 结点改变了15 nm以外的两个ATP结合位点的结构？ 具体目标是： (1)获得肌球蛋白RLC的二级和三级结构数据 构建一个三维模型来研究糖尿病的分子机制 依赖于磷酸化的调节。 (2)获取关于磁头间的初始四元结构数据 两个ELC(必需轻链)之间的相互作用，ELC和 重链，以及两条重链之间。 (3)确定一个头部的哪些部分必须存在才能下调 合伙人主管。 (4)获得关于棒状区的二级和三级结构数据 头部附近的肌球蛋白并构建三维模型来解决 磷酸化依赖调控的分子机制。

Description:(Adapted from the application) Phosphorylation of smooth muscle myosin (SMM) and nonmuscle myosin II is required to activate cellular functions. A single serine in the regulatory light chain (RLC) of each of the two "head" domains of myosin is phosphorylated by a calcium-activated kinase. Current knowledge suggests that this regulatory effect is mediated through large conformational changes in myosin structure. Dr. Cremo's long-term goal is to determine the structural basis of the phosphorylation-dependent regulatory mechanism. Dr. Cremo hypothesizes that a specific interaction between the two heads is favored in the unphosphorylated "off" or down-regulated state. A prediction of the hypothesis is that the rod domain near the heads is altered by phosphorylation, thus assisting in breaking the interaction between the heads. Dr. Cremo now extends this hypothesis to the idea that the interaction between the two heads is not symmetrical, based upon recent findings from her laboratory. She presents a detailed "structural hypothesis" for how phosphorylation of the RLC controls the head-head interactions. She will also test the hypothesis proposed by others that interactions between the two catalytic domains, controlled by regulatory domain interactions, explain the down-regulated kinetics of the unphosphorylated state. These experiments should answer the question "How does phosphorylation of two residues at the head-tail junction alter the structure of two ATP binding sites 15 nm away?" The Specific Aims are: (1) Obtain secondary and tertiary structural data about the RLC of myosin and construct a 3-dimensional model to address the molecular mechanism of phosphorylation-dependent regulation. (2) Obtain initial quaternary structural data concerning the inter-head interactions between the two ELC (essential light chain), between the ELC and the heavy chain, and between the two heavy chains. (3) Determine which portions of one head must be present to down-regulate the partner head. (4) Obtain secondary and tertiary structural data about the rod region of myosin near the heads and construct a three-dimensional model to address the molecular mechanism of phosphorylation-dependent regulation.