两种抑制性昆虫神经毒素的纯化及其从东亚钳蝎中克隆基因

Purification of two depressant insect neurotoxins and their gene cloning from the scorpion Buthus martensi Karsch.

作者信息

Wang C-G, Ling M-H, Chi C-W, Wang D-C, Pelhate M

机构信息

Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, China.

出版信息

J Pept Res. 2003 Jan;61(1):7-16. doi: 10.1034/j.1399-3011.2003.21020.x.

DOI:10.1034/j.1399-3011.2003.21020.x

PMID:12472844

Abstract

Insect-specific neurotoxins are important components of scorpion venoms. In this study, two toxins from the scorpion Buthus martensi Karsch (BmK) were purified. They shared high sequence homology with other depressant insect toxins and were designated BmK ITa and BmK ITb, respectively. They were able to suppress the action potential of cockroach isolated axon, which is due to a decrease in the peak sodium current. Furthermore, the effect of BmK ITb was lower than that of BmK ITa, and some of the electrophysiological characteristics of BmK ITb even resemble that of excitatory insect toxins. Their primary structures were determined by N-terminal partial sequence determination and cDNA cloning. The differences in their structures, especially the 31st residues, may result in the unique activity of BmK ITb.

摘要

昆虫特异性神经毒素是蝎毒的重要组成部分。在本研究中，从东亚钳蝎（Buthus martensi Karsch，BmK）中纯化出两种毒素。它们与其他抑制性昆虫毒素具有高度的序列同源性，分别被命名为BmK ITa和BmK ITb。它们能够抑制蟑螂离体轴突的动作电位，这是由于峰值钠电流的降低所致。此外，BmK ITb的作用效果低于BmK ITa，并且BmK ITb的一些电生理特性甚至类似于兴奋性昆虫毒素。通过N端部分序列测定和cDNA克隆确定了它们的一级结构。它们结构上的差异，尤其是第31位残基，可能导致BmK ITb具有独特的活性。