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）通道启动心肌细胞的动作电位，并且它们是用于控制生命的I类抗心律失常药物（AAD）的分子靶点。 有心律失常的危险抗疟疾药物作用的结构基础尚不清楚。Na通道是具有24个跨膜区段的大的膜整合蛋白。我们最近确定了一个祖先的细菌钠通道（NavAb）的晶体结构，在2.7 A的分辨率在一个预开放状态下，电压传感器激活，但孔关闭。这种非凡的结构定义了电压传感、孔打开和关闭以及离子选择性的结构基础。此外，这种结构揭示了一个完全出乎意料的特征-开窗 其从脂质双层侧向通向孔中，并潜在地为疏水性孔阻断AAD进入封闭的Na通道中的其受体位点提供进入途径。抗肿瘤药物的受体位点位于孔的内腔内。AAD更有效地阻断快速放电细胞中的Na通道，因为当孔打开时，它们更快速地到达其受体位点。这些药物还在受损的去极化心肌细胞中更有效地阻断Na通道，因为它们以最高的亲和力与去极化膜电位下优选的通道失活状态结合。三组不同的I类AAD（Ia、Ib和Ic）对Na通道功能的修饰不同， 可用于治疗不同类型的心律失常。第一个高分辨率N通道结构的可用性现在使我们能够确定AAD的复杂阻断机制、使用依赖性和亚类特异性的结构基础，这些对于AAD的临床应用至关重要。我们将确定失活状态下NavAb的结构，其对AAD具有最高亲和力。我们将通过X射线晶体学确定具有抗肿瘤药物结合的NavAb通道的结构，并定义状态依赖性药物结合的结构基础。此外，我们将在NavAb中构建人AAD受体位点，确定药物结合的人源化Na通道的结构，并确定Ia类、Ib类和Ic类AAD的亚类选择性作用的结构基础。这些结果将打开一个新时代的钠通道药理学揭示的结构基础，为国家依赖的药物结合和封锁这一离子通道。我们的研究结果对于阐明高亲和力结合的结构决定因素、药物进入AAD受体位点的复杂、状态依赖性通路的潜在机制以及Ia、Ib和Ic类AAD选择性结合和作用的结构基础至关重要。这些信息将为发现和开发更安全、更有效的AAD提供结构基础。