STRUCTURE AND FUNCTION OF NICOTINIC RECEPTORS

描述（改编自应用）：本研究的长期目标 建议联合收割机电生理学、生物化学、生物物理学和 分子生物学技术来深入了解 烟碱乙酰胆碱受体（AChR），特别注意 蛋白质-脂质相互作用该项目的重点是组织在三个 独立的方法：（1）第一种方法是扩展正在进行的网站 针对鱼雷AChR的脂质暴露残基的定向诱变， 显示影响通道选通机制。研究人员建议， 在新的疏水性变构位点引入额外的氨基酸置换， 位置α-V425位置。这些研究将进一步验证这一假设 在脂质蛋白质界面处的许多变构位点具有 在AChR通道门控中起关键作用。识别和功能 这些脂质暴露的变构位点的表征将提供进一步的 深入了解AChR的结构-功能关系。(2)第二 一种方法提出引入周期性色氨酸取代以覆盖所有 沿着M4跨膜结构域的β、γ和δ的位置沿着 亚单位。对一系列色氨酸取代的系统分析将 提供螺旋-螺旋或亚基-亚基的物理位置信息 这些接触对于AChR的功能性寡聚化至关重要。的 可能的约束位点的位置定位可以识别另外的约束位点。 M4跨膜结构域的空间组织方面 Ml和M3结构域以及Ml和M3结构域的结构-功能关系。 乙酰胆碱受体(3)第三种方法是使用新的Torpedo M4 AChR突变， 检查脂质-蛋白质界面对各种 全身麻醉药的种类本项目的目标是确定 这些变构位点的生物化学和生物物理相互作用， 确定M4跨膜空间组织的其他方面 AChR的结构域。

Description (Adapted from Application): The long-range goal of this research proposal is to combine electrophysiological, biochemical, biophysical and molecular biological techniques to gain insight into the structure and function of the nicotinic acetylcholine receptor (AChR) with special attention on protein-lipid interactions. The emphasis of this project is organized on three independent approaches: (1) The first approach is to extend ongoing site directed mutagenesis at lipid-exposed residues of the Torpedo AChR that have shown to affect the channel gating mechanism. The investigators propose to introduce additional amino acid replacements at the new hydrophobic allosteric position alpha-V425 position. These studies will further test the hypothesis that a number of allosteric sites at the lipid protein interface have a critical role on the AChR channel gating. The identification and functional characterization of these lipid-exposed allosteric sites will provide further insights into the structure-function relationships of the AChR. (2) The second approach proposes to introduce periodic tryptophan substitutions to cover all the positions along the M4 transmembrane domains for beta, gamma and delta subunits. A systematic analysis of a series of tryptophan substitutions will provide information of the physical location of helix-helix or subunit-subunit contacts that are critical for the functional oligomerization of the AChR. The positional location of possible constraint sites may identify additional aspects of the spatial organization of the M4 transmembrane domains in respect to the Ml and M3 domains as well as to structure-function relationships of the AChR. (3) The third approach is to use novel Torpedo M4 AChR mutations to examine the sensitivity of the lipid-protein interface to the action of various types of general anesthetics. The objectives of this project are to define the biochemical and biophysical interactions of these allosteric sites and to identify additional aspects of the spatial organization of the M4 transmembrane domains of the AChR.