Structural Basis for Antiarrhythmic Drug Action

抗心律失常药物作用的结构基础

• 批准号: 8454453
• 负责人: WILLIAM A CATTERALL
• 金额: $ 36.77万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-06 至 2017-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8454453
• 关键词: Action Potentials; Adverse effects; Affinity; Amino Acids; Anti-Arrhythmia Agents; Arrhythmia; Binding; Cardiac; Cardiac Myocytes; Cells; Clinical; Complex; Crystallography; Dependence; Development; Disulfides; Drug Receptors; Drug effect disorder; Drug usage; Heart; Human; Integral Membrane Protein; Ion Channel; Ions; Lead; Lidocaine; Life; Lipid Bilayers; Membrane Potentials; Molecular Conformation; Molecular Target; Mutagenesis; Pathway interactions; Pharmaceutical Preparations; Pharmacology; Prevention; Resolution; Safety; Site; Sodium; Sodium Channel; Specificity; Structure; abstracting; base; crosslink; design; drug structure; drug structure function; heart rhythm; improved; insight; mutant; receptor; sensor; therapeutic target; voltage

DESCRIPTION (provided by applicant): Structural Basis for Antiarrhythmic Drug Action Abstract Voltage-gated sodium (Na) channels initiate action potentials in cardiac myocytes, and they are the molecular targets for Class I antiarrhythmic drugs (AADs) used in the control of life- threatening cardiac arrhythmias. The structural basis for antiarrhythmic drug action is unknown. Na channels are large integral membrane proteins with 24 transmembrane segments. We have recently determined the crystal structure of an ancestral bacterial Na channel (NavAb) at 2.7 A resolution in a pre-open state with voltage sensors activated but the pore closed. This remarkable structure defines the structural basis for voltage sensing, pore opening and closing, and ion selectivity. Moreover, this structure reveals an entirely unexpected feature- fenestrations that lead laterally from the lipid bilayer into the pore and potentially provide an access pathway for entry of hydrophobic pore-blocking AADs to their receptor site in closed Na channels. The receptor site for antiarrhythmic drugs is located within the lumen of the pore. AADs block Na channels in rapidly firing cells more effectively because they reach their receptor site more rapidly when the pore is open. These drugs also block Na channels more effectively in damaged, depolarized cardiac myocytes because they bind with highest affinity to the inactivated state of the channel that is preferred at depolarized membrane potentials. Three different groups of Class I AADs (Ia, Ib, and Ic) modify Na channel function differentially and are useful in treatment of distinct classes of arrhythmias. Availability of the first high-resolution N channel structure now allows us to determine the structural basis for the complex blocking mechanism, use-dependence, and subclass specificity of AADs, which are essential for their clinical use. We will determine the structure of NavAb in the inactivated state, which has highest affinity for AADs. We will determine the structure of the NavAb channel with an antiarrhythmic drug bound by x-ray crystallography and define the structural basis for state-dependent drug binding. In addition, we will construct a human AAD receptor site in NavAb, determine the structure of the drug-bound, humanized Na channel, and define the structural basis for subclass-selective actions of Class Ia, Ib, and Ic AADs. These results will open a new era of Na channel pharmacology by revealing the structural basis for the state-dependent drug binding and block of this ion channel. Our results will be crucial in illuminating the structural determinants of high-affinity binding, the underlying mechanism for the complex, state- dependent access pathway of drugs to the AAD receptor site, and the structural basis for the selective binding and action of the Class Ia, Ib, and Ic AADs. This information will provide the structural basis for discovery and development of safer and more effective AADs.

描述（由申请人提供）：抗心律失常药物作用的结构基础摘要电压门控钠（NA）通道启动心肌细胞中的作用电位，它们是用于控制生命的I级抗心律失常药物（AAD）的分子靶标 威胁心律不齐。抗心律失常药物作用的结构基础尚不清楚。 NA通道是具有24个跨膜段的大型整体膜蛋白。我们最近已经确定了祖先细菌Na通道（NAVAB）的晶体结构，在2.7的分辨率下，在开启状态下，电压传感器激活但孔闭合。这种出色的结构定义了电压传感，打开和关闭以及离子选择性的结构基础。此外，这种结构揭示了完全出乎意料的功能 - 从脂质双层横向导致孔进入孔隙，并有可能为疏水孔隙阻滞AADS进入其受体位点的访问途径。抗心律失常药物的受体位点位于孔的腔内。 AADS阻止Na通道在迅速发射细胞中更有效地发射，因为当孔打开时，它们会更快地到达受体位点。这些药物还可以在受损的，去极化的心肌细胞中更有效地阻断Na通道，因为它们与在去极化膜电位上首选的通道的灭活状态具有最高亲和力结合。 I类AADS（IA，IB和IC）的三个不同组都会修改Na通道的功能，并且是 用于治疗不同类别的心律失常。现在，第一个高分辨率N通道结构的可用性使我们能够确定AADS的复杂阻塞机制，使用依赖性和子类特异性的结构基础，这对于它们的临床使用至关重要。我们将在灭活状态下确定NAVAB的结构，该状态对AAD具有最高的亲和力。我们将用X射线晶体学结合的抗心律失常药物来确定Navab通道的结构，并定义依赖状态依赖性药物结合的结构基础。此外，我们将在Navab中构建一个人类AAD受体位点，确定与药物结合的NA通道的结构，并定义IA，IB和IC AAD的亚类选择性作用的结构基础。这些结果将通过揭示该离子通道的状态依赖性药物结合的结构基础来打开NA通道药理学的新时代。我们的结果对于阐明高亲和力结合的结构决定因素至关重要。这些信息将为发现和开发更安全，更有效的AAD提供结构性基础。