Learning by building: constructing voltage gated ion channels from individual modular components

电压依赖性K+通道（Kv）是模块化蛋白；它们由通道孔、电压传感器通道和连接后两部分的连接器组成。尽管有关于这些重要蛋白质的详细结构信息，但关于电压传感器运动导致孔打开的机制仍有许多悬而未决的问题。本文提出了一种新的方法来解决千伏通道中孔与电压传感器之间机电耦合的基本机理。它的基础是成功构建了一个由不相关元素合成的Kv通道，一个电压无关的微型K+通道孔和来自被囊动物的磷酸酶电压传感器。在一个循序渐进的过程中，我们将分别通过系统地改变孔、电压传感器和连接器的结构和/或功能特征来构建和表征新的合成通道。这些已定义元素在合成通道中的天然组合将结合基于理论的粗粒计算提供以下方面的机械信息：1)连接器在机电耦合中的影响2)传感器域对整流的重要性3)电压传感器对门控机制的影响，这是孔中固有的。

Voltage dependent K+ channels (Kv) are modular proteins; they are composed of a channel pore, a voltage sensor dornain and a linker, which connects the latter two parts. ln spite of detailed structui:al information on these important proteins there are still rnany open questions on the mechanism by which the voltage sensor movement results in an opening of the pore. Here we propose a new approach for tackling the basic mechanism of etectromechanical coupling between pore and voltage sensor in Kv channels. lt is based on the successful constructlon of a synthetic Kv channel from unrelated elements, a voltage indepenclent miniature K+ channel pore and the voltage sensor of the phosphatase from the tunicate Ciona intestinalis. ln a learning-by-building procedure we will construct and characterize new synthetic channels by systematically varying lhe structural and/or functional character of the pore, the voltage sensor and the linker respectively. The native combination of these defined elements in synthetic channels will provide in combination with theoreticaly based coarsed grain calculations mechanistic information on i) the impact of the linker in electromechanical coupling ii) the importance of the sensor domain for rectification iii) the impact of the voltage sensor on gating mechanisms, which are inherent in the pore.