Structure of the GABA-A Receptor Binding Sites

GABA-A 受体结合位点的结构

• 批准号: 8640210
• 负责人: CYNTHIA M CZAJKOWSKI
• 金额: $ 49.84万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-12-01 至 2017-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8640210
• 关键词: Agonist; Alzheimer' s Disease; Anesthetics; Anti-Anxiety Agents; Antiemetics; Barbiturates; Benzodiazepines; Binding; Binding Sites; Biochemical; Brain; Butyric Acids; Chemicals; Convulsants; Coupling; Crosslinker; Cysteine; Data; Defect; Disulfides; Drug Design; Drug effect disorder; Drug usage; Electron Spin Resonance Spectroscopy; Emetics; Ethanol; Etiology; GABA A Receptor Binding; Gated Ion Channel; Genes; Glycine Receptors; Goals; HTR3A gene; Homologous Gene; Intravenous; Ion Channel; Ion Channel Gating; Ion Channel Protein; Knowledge; Lead; Length; Ligand Binding Domain; Ligands; Lighting; Maps; Measures; Mediating; Membrane; Mental disorders; Metals; Molecular; Molecular Conformation; Molecular Structure; Motion; Movement; Muscle relaxants; Neurons; Neurotransmitters; Nicotine Dependence; Nicotinic Receptors; Outcome; Pectobacterium chrysanthemi; Pharmaceutical Preparations; Process; Proteins; Protons; Radial; Receptor Activation; Relative (related person); Serotonin; Signal Transduction; Site; Spin Labels; Structural Models; Structure; Synapses; Testing; Therapeutic; Thermodynamics; Transmembrane Domain; Vestibule; Work; barbituric acid salt; crosslink; design; disease-causing mutation; extracellular; flexibility; gamma-Aminobutyric Acid; hypnotic; improved; insight; member; mutant; nervous system disorder; neurosteroids; novel strategies; prevent; public health relevance; receptor; receptor binding; research study; sedative; simulation; voltage clamp

DESCRIPTION (provided by applicant): Chemical signaling in the brain relies on rapid opening and closing of ligand-gated ion channels (LGICs) in the membranes of nerve cells. Members of the pentameric LGIC superfamily include nicotinic acetylcholine receptors (nAChR), serotonin-type-3 receptors (5HT3R), gamma-amino butyric acid type A receptors (GABAAR) and glycine receptors. Defects in these channels lead to a variety of neurological diseases and psychiatric disorders and a number of therapeutic drugs, including muscle relaxants, sedative-hypnotics, anti- convulsants, anxiolytics, intravenous and volatile anesthetics, anti-emetics, drugs for nicotine addiction and drugs to treat Alzheimer's disease target these channels. For these receptors, binding of neurotransmitter in the extracellular ligand-binding domain triggers opening of an intrinsic ion channel more than 50¿ away in the transmembrane domain of the receptor. Although we know a fair amount about the structure of these receptors, the mechanisms by which the binding of neurotransmitter triggers channel opening are still under debate and our understanding of the protein motions underlying this process limited. The general plan of this proposal is to investigate the binding-to-gating motions in the prokaryotic pLGIC homologs from Gloeobacter violaceus (GLIC) using site-directed spin labels and electron paramagnetic resonance spectroscopy (SDSL- EPR) and to test these motions in the GABAAR using an array of biochemical and electrophysiological approaches including voltage clamping, mutant cycle analysis, cysteine cross-linking, disulfide trapping and structural modeling. We will focus on three key regions: the extracellular binding domain (EBD), the gating interface and the transmembrane channel domain (TCD). These studies will build on our previous work and will provide new insights into how neurotransmitters activate pLGICs and how allosteric drugs modulate their activity. A deeper understanding of how these channels work at a molecular level will improve our ability to predict the actions of drugs and ligands that act on these channels, design safer and more effective drugs, develop better therapeutic strategies, and understand the etiology of disease-causing mutations.

描述（由申请人提供）：大脑中的化学信号传导依赖于神经细胞膜中配体门控离子通道（LGIC）的快速打开和关闭。五聚体 LGIC 超家族的成员包括烟碱乙酰胆碱受体 (nAChR)、3 型血清素受体 (5HT3R)、γ-氨基丁酸 A 型受体 (GABAAR) 和甘氨酸受体。这些通道的缺陷会导致多种神经系统疾病和精神疾病，许多治疗药物，包括肌肉松弛剂、镇静催眠药、抗惊厥药、抗焦虑药、静脉麻醉剂和挥发性麻醉剂、止吐剂、治疗尼古丁成瘾的药物和治疗阿尔茨海默病的药物都针对这些通道。对于这些受体，神经递质在细胞外配体结合域中的结合触发了受体跨膜域中超过50°的内在离子通道的打开。尽管我们对这些受体的结构有相当多的了解，但神经递质的结合触发通道开放的机制仍然存在争议，并且我们对该过程背后的蛋白质运动的理解有限。该提案的总体计划是使用定点自旋标签和电子顺磁共振波谱（SDSL-EPR）研究来自紫色格莱杆菌（GLIC）的原核pLGIC同源物中的结合门控运动，并使用一系列生化和电生理学方法（包括电压钳、突变周期分析、 半胱氨酸交联、二硫键捕获和结构建模。我们将重点关注三个关键区域：细胞外结合域（EBD）、门控界面和跨膜通道域（TCD）。这些研究将建立在我们之前的工作的基础上，并将为神经递质如何激活 pLGIC 以及变构药物如何调节其活性提供新的见解。更深入地了解这些通道如何在分子水平上发挥作用，将提高我们预测作用于这些通道的药物和配体的作用、设计更安全、更有效的药物、开发更好的治疗策略以及了解致病突变的病因学的能力。