Structural Comparison of Strongly-Bound Actomyosin States

强结合肌动球蛋白状态的结构比较

• 批准号: 7932528
• 负责人: DORIT HANEIN
• 金额: $ 21.49万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7932528
• 关键词: ATP Hydrolysis; Actins; Actomyosin; Adhesions; Affect; Algorithms; Amino Acids; Anatomy; Animals; Arts; Binding; Biochemical; Bioinformatics; Biological Models; Cardiac; Cardiac Myosins; Cardiovascular system; Cell physiology; Cells; Characteristics; Cleaved cell; Communities; Complex; Computational Technique; Cryoelectron Microscopy; Data; Data Collection; Defect; Deoxyribonucleases; Development; Diagnostic; Disease; Docking; Electron Microscopy; Elements; Event; F-Actin; Familial Hypertrophic Cardiomyopathy; Funding; Gel; Glutamine; Goals; Grant; Hand; Head; Heart Diseases; Heart failure; Hemoglobin; Histology; Histopathology; Hydrolysis; Image; Image Analysis; Imaging Techniques; Imaging technology; Individual; Inherited; Intervention; Intracellular Transport; Kinetics; Knowledge; Laboratories; Light; Link; Mammals; Maps; Mechanics; Medical; MgADP; Modeling; Molecular; Molecular Conformation; Molecular Machines; Molecular Motors; Motor; Movement; Mus; Muscle; Mutation; Myofibrils; Myosin ATPase; Myosin Type II; Myosin Type V; NMR Spectroscopy; Neurons; Nucleotides; Organ; Organelles; Output; Pathology; Patients; Performance; Phase; Phenotype; Physiological; Point Mutation; Positioning Attribute; Preparation; Property; Protein Isoforms; Public Health; Rattus; Research; Research Personnel; Resolution; Role; Sampling; Science; Sequence Homology; Sickle Cell Anemia; Signal Transduction; Skeletal Muscle; Skeletal Muscle Myosins; Slide; Smooth Muscle; Smooth Muscle Myosins; Specificity; Structure; Sudden Death; Surface; System; Technology; Testing; Time; Transgenic Mice; Tumor Suppression; United States; Upper arm; Ventricular Cardiac alpha-Myosin; Vertebral column; Work; X ray diffraction analysis; X-Ray Crystallography; X-Ray Diffraction; base; beta pleated sheet; beta-Myosin; cell motility; design; disease-causing mutation; gain of function; heart function; human disease; image reconstruction; improved; macromolecule; molecular assembly/self assembly; monomer; mutant; protein expression; reconstruction; response; skeletal; therapeutic target; three dimensional structure; tool

DESCRIPTION (provided by applicant): Myosins are a superfamily of actin-based molecular motors, ubiquitous in animal cells. The cyclic, ATP-hydrolysis-driven interaction of myosin with filamentous actin (F-actin) has been implicated in a variety of intracellular functions, including cell migration and adhesion; intracellular transport and localization of organelles and macromolecules; signal transduction; and tumor suppression. The importance of these interactions is illustrated by the identification of disease-causing myosin mutations, manifested in development defects as well as cardiovascular and neuronal diseases. The basic mechanism by which all myosins interact with actin is generally conserved, but different myosins have tuned their structural, kinetic, and mechanical properties to optimize performance for their particular cellular role. We hypothesize that the modes in which myosins adapted, correspond to specific "structural signatures", which we aim in determining here using electron cryo-microscopy and advanced computational imaging techniques, focusing on class II myosins, in the context of the cardiac system. Since the inception of the grant, our studies showed that myosin loops at the actin interface (loop 2), at the nucleotide-binding pocket (loop 1), and a large cleft that divides the actin-binding region of myosin are key structural elements that determine the mode in which myosin binds actin during the hydrolysis cycle. Our studies provided detailed residue-based actomyosin interface information for the strong-binding states. We showed the existence of a structural correlate to the postulated strain-dependent ADP release mechanism in smooth muscle myosin that does not exist for skeletal myosin. Such a release mechanism would benefit a myosin designed for high forces and slow contractions. Finally, we provided a detailed structural mechanism for myosin V processivity which included the determination of two structures of previously inaccessible weakly-bound actomyosin states one of which shows the lever-arm in an 'up' position for the first time. In this proposal, we will continue developing and using state-of-the-art EM image reconstruction approaches and use an array of specifically selected myosins and actins to provide (a) high-resolution structure of F-actin, (b) a detailed, residue-level actomyosin interface information (c) provide "structural signatures" directly associated with the two cardiac myosin isoforms, alpha- and beta-cardiac, in the context of the actomyosin assembly and disease-causing mutations associated with familial hypertrophic cardiomyopathy. PUBLIC HEALTH REVELANCE: Heart failure is a world wide public health problem that affects several million patients in the United States alone. One prime cause of heart disease is familial hypertrophic cardiomyopathy (FHC), which is an inherited cardiac disease that frequently results in sudden death of young and otherwise healthy individuals. Here, we propose using a combination of advanced imaging and computational techniques to provide an in-depth characterization of the molecular motors intimately involved in normal and aberrant (FHC) heart function. Our studies will provide new perspectives to consider for targeted therapeutic diagnostics or intervention.

描述（由申请人提供）：肌凝蛋白是一种基于肌动蛋白的分子马达超家族，普遍存在于动物细胞中。肌球蛋白与丝状肌动蛋白（F-actin）的环状、atp水解驱动的相互作用涉及多种细胞内功能，包括细胞迁移和粘附；细胞器和大分子的胞内转运和定位；信号转导;还有肿瘤抑制。这些相互作用的重要性是通过鉴定致病肌球蛋白突变来说明的，这种突变表现在发育缺陷以及心血管和神经元疾病中。所有肌凝蛋白与肌动蛋白相互作用的基本机制通常是保守的，但不同的肌凝蛋白已经调整了它们的结构、动力学和机械特性，以优化其特定细胞作用的性能。我们假设肌凝蛋白适应的模式对应于特定的“结构特征”，我们的目标是在这里使用电子冷冻显微镜和先进的计算成像技术来确定，重点关注心脏系统背景下的II类肌凝蛋白。