MOLECULAR BASIS OF LIGAND-NA+ CHANNEL INTERACTIONS

这个项目的目标是更好地理解分子 电压门控钠离子之间的动态相互作用机制 通道和特定结合的配体。在这些配体中有 局麻药(L.A.)抑制钠电流的药物和 甲型和乙型蝎子毒素，主要改变 通道失活和激活门控过程分别进行。 钠通道是一种极具活力的蛋白质，它表现出 与时间和电压相关的快速构象变化 去极化。通道特异性配体干扰这些 结构重组，因此是潜在的探索者 配基结合部位及其相应的功能。在这 建议，我们计划研究离子通道和门控特性 肌细胞和心肌细胞的配基结合钠通道的研究 平面脂质双层和/或膜片钳技术。…的行为 洛杉矶的药物似乎受到电压的强烈调节，钠 离子和pH值，如希尔的调节受体假说中所概述的。 在他的模型中，受体的构象在 去极化，因此，受体与配体的结合是 被更改了。目前，L.A.的物理化学性质。 受体及其调控的分子基础在很大程度上仍然存在 未知。为了达成这一理解，我们将确定 钠通道中LA受体的数量及其作用机制 受体的调节以及结构-活性 洛杉矶毒品的关系。除了洛杉矶的药物，我们还计划使用 α-蝎子毒素和β-蝎子毒素分别检测其 “外部”结合部位。这些多肽毒素是治疗 描述激活和失活过程 受外源性钠通道结构的影响。反过来，蝎子 毒素稍后可能会被应用于与灭活或 洛杉矶行动的激活门控流程。加在一起，这些 研究应该为我们提供一个关于配体-钠通道的综合观点 互动。

The goal of this project is to understand better the molecular mechanism of dynamic interactions between the voltage-gated Na channel and specifically bound ligands. Among these ligands are local anesthetic (L.A.) drugs which inhibit the Na currents and alpha- and beta- scorpion toxins which modify primarily the channel inactivation and activation gating process respectively. The Na channel is an extremely dynamic protein which exhibits rapid time- and voltage- dependent conformational changes upon depolarization. Channel-specific ligands interfere with these structural rearrangements and thus are potential probes for the ligand binding sites and their corresponding functions. In this proposal, we plan to examine the ion pathway and gating property of the ligand-bound Na channel in muscle and heart cells using planar lipid bilayer and/or patch-clamp techniques. The action of the L.A. drug appears to be strongly modulated by voltage, Na+ ions, and pH as outlined in Hille's modulated receptor hypothesis. In his model, the receptor conformation is changed upon depolarization and accordingly, the receptor-ligand binding is altered. At present, the physico-chemical properties of the L.A. receptor and the molecular basis of its modulation remain largely unknown. Toward this understanding, we will determine the number of L.A. receptors within the Na channel, the mechanism of receptor modulation, as well as the structure-activity relationship of L.A. drugs. Beside L.A. drugs, we also plan to use alpha- and beta-scorpion toxins to examine their separate "external" binding sites. These peptide toxins are ideal tools for characterizing the activation and inactivation processes influenced by external Na channel structure. In turn, scorpion toxins may later be applied to relate the inactivation or activation gating process to the L.A. action. Together, these studies should provide us an integrated view of ligand-Na channel interactions.