STRUCTURAL STUDIES ON PROKARYOTIC POTASSIUM CHANNELS

电压依赖的离子通道在产生 膜电位、受体电位和动作电位。他们是 牵涉到所有可兴奋的生理学和病理生理学 纸巾。这些蛋白质构成了许多疾病过程的基础，包括 心律失常和癫痫，是基本药物的主要使用对象 在临床医学上。尽管明显的生物学和临床 这些蛋白质的重要性，人们对它们的了解很少 结构。获得这种结构信息至关重要。 从机械上理解它们的功能是非常重要的。 这项提议提出了一种解决结构问题的新方法 以及这些蛋白质的功能。将研究细菌模型系统 通过两种免费的技术：定点自旋标记和 电生理学。这项研究将解决两个关键特性 钾通道：通透性和门控性。据认为， 渗透的基础结构元素，在某种程度上，浇注 已经被确认了。全阳离子选择性电压依赖离子 通道共享一个足以满足离子交换的公共核心域 渗透。此外，一种非常不寻常的跨膜片段被称为S4 已被牵连为结构元素的一部分 电压依赖门控。这两个结构元素将被研究 使用这两种技术。 预计自旋标记研究的结果将 提供足够的约束来确定这两者的结构 将元素折叠到主干级别。生成的折叠模型 将为机械启发的功能研究提供基础 使用电生理学。这项提议的长期目标是 在结构层面上理解离子通道的功能特性。

Voltage-dependent ion channels are instrumental in the generation of membrane potential, receptor potential, and action potential. They are implicated in the physiology and pathophysiology of all excitable tissues. These proteins underlie many disease processes including arrhythmias and epilepsies and are major targets of essential drugs used in clinical medicine. Despite the obvious biological and clinical importance of these proteins, very little is known about their structure. Obtaining this structural information is of paramount importance to a mechanistic understanding of their function. This proposal presents a new approach toward addressing the structure and function of these proteins. Bacterial model systems will be studied by two complimentary techniques: site-directed spin labeling and electrophysiology. The study will address two key properties of potassium channels: permeation and gating. It is thought that the structural elements underlying permeation and, to some extent, gating have been identified. All cation selective voltage-dependent ion channels share a common core domain that is sufficient for ion permeation. Also, a highly unusual transmembrane segment known as S4 has been implicated as part of the structural element responsible for voltage-dependent gating. These two structural elements will be studied with the two techniques. It is anticipated that the results of the spin labeling study will provide sufficient constraints to determine the structure of these two elements to the level of the backbone fold. The resulting folding model will provide the basis for a mechanistically inspired functional study using electrophysiology. The long-term goal of this proposal is to understand functional properties of ion channels at a structural level.