STRUCTURE/FUNCTION STUDY OF A VOLTAGE GATED K CHANNEL

描述：离子通道密切参与了细胞的产生和 神经和肌肉等兴奋性组织中电事件的调制。 不同的离子通道活动是静息电位的基础， 动作电位的产生和传播，神经递质的释放， 兴奋-收缩耦合等。最近，人们已经清楚地看到 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，发作性共济失调，以及某些形式的心律失常，如Long QT间期综合征。这些发现使离子通道不仅成为 学术兴趣也突显了它们的巨大重要性和潜力 治疗药物干预的靶点。尽管这一核心作用在 组织兴奋性和丰富的功能信息，相对 人们对离子通道的结构知之甚少。如果我们想要 从分子细节上理解通道功能的机制，例如， 离子选择性，电压或配体依赖的门控，与 治疗药物，我们需要知道渠道之间的关系 结构和功能。有关渠道拓扑和次要信息的知识 结构母题与三维的最终确定 结构将代表着我们对电压理解的重大进步 传感和选择性离子渗透。这一知识将是极其重要的 对理解离子传导途径之间的相互作用有价值 以及电压感测和/或通道选通中涉及的机制。它 也将为分子建模研究奠定基础，这有助于我们 要了解通道与药物的相互作用，这是一个极具治疗意义的话题 潜力。拟议的研究完全针对结构 K+通道的各个方面。调查员提议使用 半胱氨酸取代的K+通道突变体用于测量 前庭与应用Homo-and的通道离子传导通路 具有已知尺寸的间隔基的异双官能团交联剂。这个 调查人员还建议进行系统研究，以导致 功能性K+和通道模块在大肠杆菌中的高效表达 纯化、功能表征和重构，以及结构 研究包括X射线结晶学和核磁共振波谱。

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.