Energy Transduction in Myosin

肌球蛋白的能量转导

基本信息

批准号：
7921781
负责人：
CHRISTOPHER M YENGO
金额：
$ 19.28万
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 2010-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7921781
关键词：
ATP Hydrolysis ATP phosphohydrolase Actins Active Sites Actomyosin Actomyosin Adenosinetriphosphatase Adopted Affinity Binding Biochemical Biological Process Biophysics Calmodulin Cell division Chemicals Cleaved cell Communication Computing Methodologies Coupled Coupling Data Disease Dissociation Familial Hypertrophic Cardiomyopathy Fluorescence Fluorescence Resonance Energy Transfer Fluorescent Probes Future Generations Goals Hereditary Disease Intracellular Transport Kinetics Lead Maps Measures Mechanics Mediating Methodology Methods Microfilaments Modeling Molecular Molecular Conformation Molecular Models Monitor 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 Risk Role Side Staging Structure System Techniques Testing Tryptophan Upper arm Work design high risk improved inorganic phosphate literature survey models and simulation molecular dynamics molecular modeling public health relevance research study simulation tool vacuolar H+-ATPase

ATP Hydrolysis ATP phosphohydrolase Actins Active Sites Actomyosin Actomyosin Adenosinetriphosphatase Adopted Affinity Binding Biochemical Biological Process Biophysics Calmodulin Cell division Chemicals Cleaved cell Communication Computing Methodologies Coupled Coupling Data Disease Dissociation Familial Hypertrophic Cardiomyopathy Fluorescence Fluorescence Resonance Energy Transfer Fluorescent Probes Future Generations Goals Hereditary Disease Intracellular Transport Kinetics Lead Maps Measures Mechanics Mediating Methodology Methods Microfilaments Modeling Molecular Molecular Conformation Molecular Models Monitor 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 Risk Role Side Staging Structure System Techniques Testing Tryptophan Upper arm Work design high risk improved inorganic phosphate literature survey models and simulation molecular dynamics molecular modeling public health relevance research study simulation tool vacuolar H+-ATPase

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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通过其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学过程至关重要，包括肌肉收缩，细胞分裂和细胞内转运。肌球蛋白在其酶促周期的各个阶段的原子水平结构提供了肌球蛋白使用的力产生的分子机理的框架。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的小构象变化与轻链结合区域的大挥动区偶联而产生力，而肌球蛋白与肌动蛋白密切相关。但是，缺乏有关肌球蛋白在其整个ATPase周期中如何改变其对肌动蛋白的亲和力的结构细节的信息，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，这会触发强迫产生。当前的建议假设，将肌动蛋白结合结构域分离的大裂口迅速变化，以允许在磷酸盐释放和产生力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到杠杆臂上。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，将用作检查肌动蛋白和肌动蛋白肌动蛋白和核苷酸结合区域的特定构象变化。将固有和外在的荧光探针从策略上放置，以测量肌球蛋白酶促循环期间肌动蛋白，核苷酸结合和杠杆臂区域的构象变化。另外，将使用瞬态动力学实验将构象变化与肌动蛋白ATPase周期中的特定生化步骤相关联。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ATPase循环的构象途径。通过整合计算和实验数据，我们将阐明有关肌球蛋白中力产生的结构机理的关键细节，并进一步了解与肌球蛋白中点突变有关的遗传疾病，例如家族性肥厚性心肌病。公共卫生相关性：该项目的目标是确定肌球蛋白如何将化学能量转化为有效和运动以推动肌肉收缩的过程。将利用实验性生物物理工具和计算生物物理工具的结合来定义肌动蛋白V ATPase周期的结构途径，这将填补有关肌球蛋白如何在肌肉收缩中产生力的临界空白。由于肌球蛋白中的点突变与遗传疾病（例如家族性肥厚性心肌病）有关，因此阐明了肌球蛋白能量转导的结构途径可能会改善我们对我们对这些疾病的理解，并导致对这些疾病的未来治疗。