STRUCTURE/FUNCTION STUDY OF A VOLTAGE GATED K CHANNEL

描述：离子通道密切参与生成和 调节神经和肌肉等可兴奋组织中的电事件。 不同的离子通道活性是静息电位的基础， 动作电位的产生和传播，神经递质的释放， 兴奋-收缩偶联等。最近，已经很清楚， 几种人类神经肌肉疾病是离子通道疾病： 高钾性周期性麻痹，先天性副肌强直，肌强直， 先天性，间歇性共济失调，和一些形式的心律失常，如长 QT综合征。 这些发现使离子通道不仅成为 学术兴趣，但也强调其巨大的重要性， 治疗药物干预的目标。 尽管这一核心作用， 组织兴奋性和丰富的功能信息，相对 对离子通道的结构知之甚少。 如果我们想 了解分子细节中通道功能的机制，例如， 离子选择性，电压或配体依赖性门控，与 治疗药物，我们需要知道通道之间的关系 结构和功能。 了解通道拓扑结构和辅助 结构图案和最终确定的三维 结构将代表我们对电压的理解的重大进展 传感和选择性离子渗透。 这些知识将是非常 对理解离子传导途径之间的相互作用很有价值 以及涉及电压感测和/或沟道选通的机制。 它 也将为分子建模研究奠定基础， 了解通道药物相互作用，一个伟大的治疗主题， 潜力 本研究主要针对结构 K+通道。 研究者建议使用 半胱氨酸取代的K+通道突变体，以测量 前庭和离子传导通路的通道应用同源和 具有已知尺寸间隔区的异双功能交联剂。 的 研究人员还建议进行系统研究， 在E.大肠杆菌， 纯化、功能表征和重构，以及结构 包括X射线晶体学和NMR光谱学的研究。

DESCRIPTION: Ion channels are intimately involved in the generation and modulation of electrical events in excitable tissues like nerve and muscle. Differential ion channel activity underlies the resting potential, the generation and propagation of action potentials, neurotransmitter release, excitation-contraction coupling, etc. Recently, it has become clear that several human neuromuscular disorders are ion channel diseases: Hyperkalemic periodic paralysis, paramyotonia congenita, myotonia, congenita, episodic ataxia, and some forms of cardiac arrhythmias, like long QT syndromes. These findings make ion channels not only a subject of academic interest but also underline their great importance a potential targets for intervention by therapeutic drugs. Despite this central role in tissue excitability and an abundance of functional information, relatively little is known about the structure of ion channels. If we ever want to understand the mechanisms of channel function in molecular details, e.g., ion selectivity, voltage- or ligand-dependent gating, interaction with therapeutic drugs, we need to know the relationship between channel structure and function. Knowledge of the channel topology and secondary structural motifs and the eventual determination of the three dimensional structure will represent major advances in our understanding of voltage sensing and selective ion permeation. This knowledge will be extremely valuable in understanding interactions between the ion-conduction pathway and the mechanisms involved in voltage sensing and/or channel gating. It will also lay the foundation for molecular modelling studies which help us to understand channel-drug interactions, a topic of great therapeutic potential. The proposed research is entirely directed towards structural aspects of the K+ channels. The investigator proposes to use cysteine-substituted K+ channel mutants to measure distances in the vestibule and the ion conduction pathway of the channel applying homo- and heterobifunctional crosslinkers with spacers of known dimensions. The investigator also proposes to conduct systematic studies leading to overexpression of functional K+ and channel modules in E. coli suitable for purification, functional characterization and reconstitution, and structural studies including X-ray crystallography and NMR spectroscopy.