虎纹捕鸟蛛毒素-I单残基突变体R20A-HWTX-I的化学合成与性质分析

虎纹捕鸟蛛毒素－１（Ｈｕｗｅｔｏｘｉｎ－１，ＨＷＴＸ－１）是从虎纹捕乌蛛（Ｓｅｌｅｎｏｃｏｓｍｉａ ｈｕｗｅｎａ）的粗只同的一种多肽类神经毒素。为了探明该毒素分子中统一的Ａｒｇ残基与其生物学活性的关系，运用固相多肽合成技术和Ｆｍｏｃ化学直接构建了Ａｌａ取代ＨＷＴＸ－１第２０位Ａｒｇ（Ｒ２０）的突变体Ｒ２０Ａ－ＨＷＴＸ－１；将合成的突一置于含谷胱甘肽的缓冲体系中氧化复性后用反相和特殊设计的离子交换Ｈ

Chemical Synthesis and Characterization of R20A-HWTX-I, a Mutant of Huwentoxin-I with Single Residue Replacement

Huwentoxin-I (HWTX-I ) is a polypeptide neurotoxin purified from the venom of the spider Selenocosmia huwena.R20A-HWTX-I ,a mutant of HWTX-I in which the Arg was replaced by Ala,was synthesized on solid support by using Fmoc chemistry. The synthetic mutant was oxdatively renatured in glutathione-containing buffer,and then isolated by reversed phase and specially designed ion-exchange HPLC. The chemical structure of R20A-HWTX-I was confirmed by amino acid analysis, Edman degradation and MALDI-TOF mass analysis. Physiological experiment showed that the replacement of R20 by a decreased the bioactivity of the HWTX-I by 92%,indicating that R20 is a key residue closely related to the bioactivity of the HWTX-I.