Energy Transduction in Myosin

肌球蛋白的能量转导

基本信息

批准号：
7751330
负责人：
CHRISTOPHER M YENGO
金额：
$ 18.5万
依托单位：
PENNSYLVANIA STATE UNIV HERSHEY MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-12-15 至 2011-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7751330
关键词：
ATP Hydrolysis ATP phosphohydrolase Actins Active Sites Actomyosin Actomyosin Adenosinetriphosphatase Adopted Affinity Algorithms Binding Biochemical Biological Process Biophysics Calmodulin Cell division Chemicals Cleaved cell Communication Computing Methodologies Coupled Coupling DNA Sequence Rearrangement Data Disease Dissociation Doctor of Philosophy Familial Hypertrophic Cardiomyopathy Fluorescence Fluorescence Resonance Energy Transfer Fluorescent Probes Future Generations Goals Hereditary Disease Intracellular Transport Kinetics Lead Measures Mechanics Mediating Methods Microfilaments Modeling Molecular Molecular Conformation Monitor Monte Carlo Method Motion Motor Movement Muscle Muscle Contraction Myosin ATPase Myosin Phosphatase Pathway Myosin Type II Myosin Type V Nucleotides Pathway interactions Point Mutation Process Production Property Proteins Role Side Simulate Staging Structure System Techniques Testing Tryptophan Work arm base design flexibility improved inorganic phosphate insight literature survey models and simulation molecular dynamics non-muscle myosin public health relevance research study simulation tool vacuolar H+-ATPase

项目摘要

DESCRIPTION (provided by applicant): The ability of myosin to generate force and motion through its interaction with actin filaments is essential to many biological processes including muscle contraction, cell division, and intracellular transport. The atomic level structures of myosin in various stages of its enzymatic cycle have provided a framework of the molecular mechanism of force generation utilized by myosin. These structures as well as other biochemical and structural data suggest that myosin generates force by coupling small conformational changes in the nucleotide-binding region to a large swing of the light-chain binding region while myosin is strongly bound to actin. However, there is a lack of information about the structural details of how myosin alters its affinity for actin throughout its ATPase cycle, and how actin-binding activates the dissociation of the products of ATP hydrolysis (ADP and phosphate), which triggers force production. The current proposal hypothesizes that the large cleft that separates the actin-binding domain changes conformation rapidly to allow binding to actin prior to phosphate release and force generation. Moreover, the switch II region in the nucleotide-binding domain is hypothesized to directly couple conformational changes to the lever arm. Myosin V, a non-muscle myosin that has unique structural and biochemical properties, will be used as a model to examine specific conformational changes in the actin- and nucleotide-binding regions of myosin. Intrinsic and extrinsic fluorescence probes will be strategically placed to measure conformational changes in the actin-, nucleotide-binding, and lever arm regions during the enzymatic cycle of myosin. In addition, transient kinetic experiments will be used to correlate the conformational changes with specific biochemical steps in the actomyosin ATPase cycle. We will use computational methods to propose a conformational pathway of the myosin ATPase cycle consistent with our experimental data. By integrating the computational and experimental data we will elucidate critical details about the structural mechanism of force generation in myosin and further our understanding of genetic diseases associated with point mutations in myosin, such as Familial Hypertrophic Cardiomyopathy. PUBLIC HEALTH RELEVANCE: The goal of this project is to determine how myosin converts chemical energy into force and motion to drive the process of muscle contraction. A combination of experimental and computational biophysical tools will be utilized to define the structural pathway of the actomyosin V ATPase cycle, which will fill in critical gaps in what is known about how myosin generates force in muscle contraction. Since point mutations in myosin are associated with genetic diseases such as Familial Hypertrophic Cardiomyopathy, elucidating the structural pathway for energy transduction in myosin may improve our understanding of and lead to future treatments for these diseases.

描述（由申请人提供）：肌球蛋白通过与肌动蛋白丝相互作用产生力和运动的能力对于许多生物过程（包括肌肉收缩、细胞分裂和细胞内运输）至关重要。肌球蛋白在其酶促循环的各个阶段的原子水平结构提供了肌球蛋白利用的力产生的分子机制的框架。这些结构以及其他生化和结构数据表明，肌球蛋白通过将核苷酸结合区域中的小构象变化与轻链结合区域的大摆动耦合来产生力，而肌球蛋白与肌动蛋白强烈结合。然而，关于肌球蛋白如何在整个 ATP 酶循环中改变其对肌动蛋白的亲和力，以及肌动蛋白结合如何激活 ATP 水解产物（ADP 和磷酸盐）的解离（从而触发力的产生）的结构细节，目前还缺乏信息。目前的提议假设，分隔肌动蛋白结合结构域的大裂缝会迅速改变构象，以允许在磷酸盐释放和力产生之前与肌动蛋白结合。此外，假设核苷酸结合结构域中的开关 II 区域直接将构象变化耦合到杠杆臂。肌球蛋白 V 是一种具有独特结构和生化特性的非肌肉肌球蛋白，将用作检查肌球蛋白肌动蛋白和核苷酸结合区域的特定构象变化的模型。将策略性地放置内在和外在荧光探针，以测量肌球蛋白酶循环期间肌动蛋白、核苷酸结合和杠杆臂区域的构象变化。此外，瞬态动力学实验将用于将构象变化与肌动球蛋白 ATP 酶循环中的特定生化步骤关联起来。我们将使用计算方法提出与我们的实验数据一致的肌球蛋白 ATP 酶循环的构象途径。通过整合计算和实验数据，我们将阐明肌球蛋白力产生结构机制的关键细节，并进一步了解与肌球蛋白点突变相关的遗传疾病，例如家族性肥厚性心肌病。公共健康相关性：该项目的目标是确定肌球蛋白如何将化学能转化为力和运动，以驱动肌肉收缩过程。将利用实验和计算生物物理工具的组合来定义肌动球蛋白 V ATP 酶循环的结构途径，这将填补关于肌球蛋白如何在肌肉收缩中产生力的已知关键空白。由于肌球蛋白的点突变与家族性肥厚性心肌病等遗传性疾病有关，阐明肌球蛋白能量转导的结构途径可能会提高我们对这些疾病的理解并导致未来的治疗方法。