OPEN STATE STRUCTURE OF THE GATED MECHANOSENSOR MSCL

这项研究的目的是描述机械传感通道MSCL的开放(传导)形式。我们将使用几种方法，包括定点自旋标记，二硫键扫描和X射线结晶学来阐明该离子通道的开放状态结构和激活机制。在系统发育树的所有基本分支中都发现了机械敏感通道，并在人类的多种组织类型中观察到了机械敏感通道。目前有很大比例的药物是针对离子通道的，然而这些通道是如何打开和关闭(门控)的机制仍然未知。最近对闭合构象中机械敏感通道MSCL的结构测定提供了这类无处不在的蛋白质的第一张高分辨率图像。MSCL蛋白是目前唯一可用的系统，用来研究高结构分辨率的离子通道是如何门控的。为了帮助结晶，还将进行现场定向自旋标记和二硫化物扫描研究，以提供适合结晶的材料，即处于开放状态，以及确定关于通道门控的更一般信息。

The goal of the proposed research is to characterize an open (conducting) form of the mechanosensitve channel MscL. We will employ a several approaches including site-directed spin labeling, disulfide scanning and X-ray crystallography to elucidate the open state structure and mechanism of activation of this ion channel. Mechanosensitive channels have been found in all basic branches of the phylogenetic tree, and have been observerved in multiple tissue types in humans. A large percentage of current pharmaceuticals are targeted to ion channels, yet the mechanism of how these channels are opened and closed (gated) remains unknown. The recent structural determination of the mechanosensitive channel MscL in a closed conformation provided the first high resolution picture of this ubiquitous class of protein. The MscL protein is currently the only available system with which to study, at a high level of structural resolution, how ion channels are gated. To aid in crystallization, site-directed spin labeling and disulfide scanning studies will also be performed to both provide materail suitable for crystallization, i.e. in an open state, as well as determine more general information on channel gating.