Discovery of human cardiac myosin regulatory sites, modulating cross-bridge kinetics in heart muscle

发现人类心肌肌球蛋白调节位点，调节心肌的跨桥动力学

基本信息

批准号：
9098891
负责人：
YURI NESMELOV
金额：
$ 44万
依托单位：
UNIVERSITY OF NORTH CAROLINA CHARLOTTE
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-04-05 至 2020-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9098891
关键词：
Active Sites Address Affect Animal Model Binding Binding Sites Cardiac Cardiac Myosins Charge Computer Simulation Data Development Electrostatics Exhibits Failure Genes Goals Head Heart Heart failure Human Kinetics Knowledge Lead Learning Left ventricular structure Molecular Molecular Conformation Molecular Motors Muscle Muscle function Mutagenesis Mutation Myocardium Myosin ATPase Myosin Heavy Chains N-terminal Nucleotides Oryctolagus cuniculus Output Performance Positioning Attribute Production Property Protein Isoforms Rattus Recombinants Research Site Site-Directed Mutagenesis Structure System Testing Therapeutic Transgenic Organisms Work abstracting adenoviral-mediated base beta-Myosin crosslink drug development experimental analysis improved insight melting molecular dynamics mutant novel therapeutics public health relevance research study skeletal

项目摘要

DESCRIPTION (provided by applicant): Abstract Healthy human cardiac muscle is composed of two myosin isoforms, alpha and beta, which are significantly different in kinetics of the cross-bridge cycle. The specific myosin isoform composition tunes muscle for maximum performance, force production, power output, and economy. The mechanisms behind this fine muscle's performance tune-up are not known, thus limiting our understanding of a fundamental muscle property. Our long-term goal is to apply insights gained from learning the origin of kinetic differences of cardiac myosin isoforms to help devise ways to restore impaired muscle function. We envision tune-up of failed heart muscle by mimicking the healthy muscle isoform composition. The immediate objective of this proposal is to elucidate the molecular mechanism of kinetic difference of cardiac myosin isoforms. Our central hypothesis is that isoform kinetics i determined by the electrostatic interactions at the regulatory site within myosin head. Our hypothesis is based on a significant body of experimental data, confirming possibility of myosin kinetics modulation. Three specific aims are to validate our hypothesis. The specific aims are focused on potential regulatory sites within different parts of myosin head, Loop1 (Aim 1), upper 50 kDa domain (Aim 2), and the force generating region (Aim 3). According to our working hypothesis, these regulatory sites modulate myosin-nucleotide interaction, including the rate of ADP release from the cross-bridge, which is the rate limiting step of the slow beta myosin isoform. We plan to use site specific mutagenesis, altering electrostatic interactions within proposed regulatory sites. We will prepare mutants of recombinant human cardiac beta myosin and will characterize kinetics of prepared myosin mutants. We will examine our hypothesis on importance of electrostatic interactions within proposed regulatory sites on myosin kinetics modulation. The proposed research is significant because it will provide a detailed understanding of the mechanism by which human cardiac muscle is fine tuned for maximum performance. We will gain new insights into fundamental mechanisms by which produced force and power, and muscle energetics are modulated by muscle isoform composition. Elucidating kinetic tune-up mechanisms may lead to therapeutic ways of restoring or improving muscle function.

描述（由适用提供）：抽象健康的人类心脏肌肉由两个肌球蛋白同工型，α和β组成，它们在跨桥循环的动力学中有显着差异。特定的肌球蛋白同工型成分会调节肌肉，以最大程度地表现，力量产生，功率输出和经济。这种精细的肌肉性能调节背后的机制尚不清楚，从而限制了我们对基本肌肉特性的理解。我们的长期目标是利用学习心脏肌球蛋白同工型动力学差异的起源而获得的见解，以帮助设计方法来恢复肌肉功能受损。我们通过模仿健康的肌肉同工型组成来设想心脏肌肉失败的调整。该建议的直接目的是阐明心脏肌球蛋白同工型动力学差异的分子机制。我们的中心假设是，同工型动力学I由肌球蛋白头内的调节部位的静电相互作用确定。我们的假设基于大量实验数据，确认了肌球蛋白动力学调节的可能性。三个具体的目的是验证我们的假设。具体目的集中在肌球蛋白头部不同部位，Loop1（AIM 1），上50 kDa域（AIM 2）和力产生区域（AIM 3）内的潜在调节位置。根据我们的工作假设，这些调节部位调节肌球蛋白 - 核苷酸相互作用，包括从跨桥上释放的ADP速率，这是慢速β肌球蛋白同工型的速率限制步骤。我们计划使用特定位点的诱变，以改变拟议的调节位点内的静电相互作用。我们将准备重组人心脏β肌球蛋白的突变体，并将表征准备好的肌球蛋白突变体的动力学。我们将研究我们对肌球蛋白动力学调节的拟议调节位点中静电相互作用的重要性的假设。拟议的研究很重要，因为它将对人类心肌进行微调的机制提供详细的理解，以提高性能。我们将获得对产生力和力量的基本机制的新见解，肌肉能量受肌肉同工型组成调节。阐明动力学调节机制可能会导致恢复或改善肌肉功能的治疗方法。