Structural Studies on Prokaryotic Potassium Channels

原核生物钾通道的结构研究

• 批准号: 6967305
• 负责人: Adrian Gross
• 金额: $ 27.83万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6967305
• 关键词: Streptomyces; X ray crystallography; electron spin resonance spectroscopy; electrophysiology; lipid bilayer membrane; membrane model; membrane potentials; molecular cloning; potassium channel; prokaryote; protein folding; protein structure function; voltage gated channel

DESCRIPTION (provided by applicant): Ion channels are instrumental in the generation of membrane potential, receptor potential, and action potential. They are the molecular building blocks for what is an essential characteristic of many cells in neuroscience: excitability. These proteins are implicated in the physiology and pathophysiology of all excitable tissues, underlie many disease processes including epilepsies and arrhythmias, and are major targets of essential drugs used in clinical medicine. Potassium channels are the phylogenetic founders of a large superfamily of structurally related ion channels that includes nucleotide gated channels, sodium channels, and calcium channels. Potassium channels are typically assembled from four identical subunits in a four-fold symmetrical fashion. This rather simple structural blueprint and the substantial practical advantage of only one subunit type have made potassium channels a much studied model system. Potassium channels exhibit two important properties: they selectively admit potassium over sodium and they change their structure during function in a process called gating. This proposal explores the gating transition in potassium channels. We will use a combination of cysteine scanning mutagenesis, site-directed spin labeling, site-directed mass tagging, X-ray crystallography, and electrophysiology to study the gating transition in three prokaryotic potassium channels: KcsA, MthK, and KvAP. The long term goal of this proposal is to understand functional properties of ion channels at a structural level.

描述(由申请人提供)：离子通道在膜电位、受体电位和动作电位的产生中起重要作用。它们是神经科学中许多细胞的一个基本特征：兴奋性的分子构建块。这些蛋白与所有可兴奋组织的生理学和病理生理学有关，是包括癫痫和心律失常在内的许多疾病过程的基础，也是临床药物使用的主要靶点。钾通道是一个结构相关的离子通道超家族的系统发育创始人，包括核苷酸门控通道、钠通道和钙通道。钾通道通常由四个相同的亚基以四重对称的方式组装而成。这种相当简单的结构蓝图和只有一种亚基类型的实质性实用优势使钾通道成为一个被广泛研究的模型系统。钾通道表现出两个重要的性质：它们选择性地接纳钾而不是钠；它们在功能过程中改变自己的结构，这一过程被称为门控。这一建议探索了钾通道的门控转换。我们将使用半胱氨酸扫描突变、定点自旋标记、定点质量标记、X射线结晶学和电生理学相结合的方法来研究三种原核钾通道：KCSA、MthK和KvAP的门控转换。这项提议的长期目标是在结构水平上了解离子通道的功能属性。