SAR STUDIES OF A TOXIC PEPTIDE

最近，一组来自Trimeresurus wagleri毒液的多肽，或 瓦格勒毒蛇，已被提纯并鉴定为 它们对老鼠的杀伤力。人们对这种分子知之甚少。 这类多肽的作用机制称为 小推车。然而，初步数据表明，以下行动 一种更有效的Waglerin，多肽I：1.对 大鼠骨骼肌烟碱型乙酰胆碱受体； 抑制自发的但不是刺激诱发的量子释放 大鼠神经肌肉接头的递质；3.增强的 重复神经刺激时的终板电流；4.抑制 小鼠神经元电压激活型钠、钾电流 大脑。本研究提案旨在证实这些 初步发现并验证了长期存在的假设 瓦格雷毛滴虫的毒液具有神经毒性。此外，这项工作将使 对单一多肽的结构可以是 对几个功能过程都是等毒的。最后，实验是 建议探索涉及的结构-活性关系(SAR) 提纯的瓦格林蛋白、合成类似物或片段的作用 其中之一。为了达到这些目标，传统的电生理学 录音将被用来探索浓度依赖的效应 7种纯Waglerin多肽对大鼠突触前、后功能的影响 小鼠胸骨三角肌的神经肌肉连接。在……里面 此外，膜片电压钳技术将被用来探索 这些多肽与电压门控相互作用的分子基础 小鼠脑细胞中的离子通道。预计这类研究 会产生新的毒素，用来探索兴奋性的功能 细胞以及控制神经功能的新的治疗剂。

Recently, a group of peptides from the venom of Trimeresurus wagleri, or Wagler's pit viper, have been purified and characterized in terms of their lethality to mice. Little is known concerning the molecular mechanism underlying the action of this class of peptides known as the waglerins. However, preliminary data indicate the following actions of one of the more potent waglerins, peptide I: 1. a "curare-like" action on the nicotinic acetylcholine receptor of rat skeletal muscle; 2. suppression of spontaneous, but not stimulus-evoked, quantal release of transmitter at the rat neuromuscular junction; 3. enhanced "rundown" of end-plate currents during repetitive nerve stimulation; 4. suppression of voltage-activated sodium and potassium currents in neurons from mouse brain. The present research proposal is designed to confirm these preliminary findings and validate the longstanding hypothesis that the venom of T. wagleri is neurotoxic. In addition, this work will enable a test of the hypothesis that the structure of a single polypeptide can be equi-toxic to several functional processes. Finally, experiments are proposed to explore the structure-activity relations (SAR) involved in the action of the purified waglerins, synthetic analogues, or fragments thereof. To meet these objectives, conventional electrophysiological recording will be used to explore the concentration-dependent effects of 7 pure waglerin peptides on pre- and postsynaptic functions of the neuromuscular junction of the mouse Triangularis sterni muscle. In addition, patch voltage-clamp techniques will be employed to explore the molecular basis of the interaction of these peptides with voltage-gated ion channels in murine brain cells. It is anticipated that such studies will lead to new toxins with which to explore the function of excitable cells as well as to new therapeutic agents to control neuronal function.