High-resolution crystallographic and functional studies of K+ channel gating

K 通道门控的高分辨率晶体学和功能研究

• 批准号: 8642193
• 负责人: Luis Gonzalo Cuello
• 金额: $ 28.12万
• 依托单位: TEXAS TECH UNIVERSITY HEALTH SCIS CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8642193
• 关键词: Address; Affect; Alkali Metals; Amino Acids; Aromatic Amino Acids; Biological Process; Cell membrane; Cells; Cellular Membrane; Cessation of life; Characteristics; Chemicals; Communication; Complex; Coupled; Coupling; Cysteine; Data; Disease; Drug Design; Elements; Engineering; Functional disorder; Goals; Human body; Immune system; Ions; Kinetics; Knowledge; Lead; Life; Mechanics; Mediating; Membrane; Metabolic; Methods; Molecular; Molecular Conformation; NK Cell Activation; Nature; Pancreas; Pharmaceutical Preparations; Phenylalanine; Physiological Processes; Potassium Channel; Property; Proteins; Resolution; Role; Series; Side; Structure; Therapeutic; X-Ray Crystallography; base; blood glucose regulation; design; disulfide bond; driving force; electrical potential; extracellular; improved; information model; mutant; solute; voltage

DESCRIPTION (provided by applicant): The long-term goal of this project is to determine the structural changes that underlie K+ channel function. These membrane-spanning proteins are critical in controlling the electrical potential difference across the membrane, which, in turn, forms the basis for solute exchange and cellular excitability. It follows that a full understanding of the relation between structure and function in K+ channels is a high priority. Achieving this goal will require knowledge of the conformational changes that mediate two key properties, ion permeation and gating. In this proposal, we will characterize at the atomic level these two properties by trapping the channel complex in different kinetic states. Subsequent structural analysis will address the following fundamental but unanswered questions: 1) what is the high-resolution structure of KcsA trapped in the open and C-type inactivated state? 2) what is the amino-acid network underlying allosteric communication between the activation gate and the selectivity filter of KcsA? and 3) which are the structural changes of the KcsA selectivity filter that lead to C-type inactivation? The answers to these questions will provide us with the structural background needed to understand ion selectivity, permeation, and gating of K+ channels in a dynamic context and eventually will assist in the rational design of drugs for the treatment of K+ channel- related diseases. We will focus our study on an archetypal prokaryotic channel, KcsA, that contains all the structural elements characteristic of K+ channel function (i.e., ion permeation, activation, and C-type inactivation gating) but possesses a structure simple enough to facilitate analysis. A dual approach combining crystallographic and electrophysiological methods will provide high-resolution functional and structural information for this model channel in various kinetic states.

描述(由申请人提供)：该项目的长期目标是确定K+通道功能的结构变化。这些跨膜蛋白在控制跨膜电势差方面起着关键作用，而电势差反过来又构成了溶质交换和细胞兴奋性的基础。由此得出的结论是，完全理解 K+通道的结构和功能之间的关系是一个高度优先考虑的问题。要实现这一目标，需要了解与离子渗透和门控这两个关键性质有关的构象变化。在这个提议中，我们将通过捕获处于不同动力学状态的通道络合物来在原子水平上表征这两个性质。随后的结构分析将解决以下基本但尚未回答的问题：1)处于开放和C型失活状态的KCSA的高分辨结构是什么？2)KCSA的活化门和选择性过滤器之间的变构通讯背后的氨基酸网络是什么？以及3)导致C型失活的KCSA选择性过滤器的结构变化是什么？对这些问题的回答将为我们提供在动态背景下理解K+通道离子选择性、渗透和门控所需的结构背景，并最终有助于合理设计治疗K+通道相关疾病的药物。我们将集中研究一个原型原核生物通道KCSA，它包含K+通道功能的所有结构元素(即离子渗透、激活和C型失活门控)，但具有简单的结构 足以方便分析。结合结晶学和电生理方法的双重方法将提供高分辨率的功能和结构信息 该模型通道处于各种运动状态。