一种东亚钳蝎碱性神经毒素的纯化和初步晶体学研究

Purification and Preliminary Crystallographic Studies of A New Basic Neurotoxin From Scorpion Buthus martensii Karsch

经ＳｅｐｈａｄｅｘＧ－５０和ＳＰ－ＳｅｐｈａｄｅｘＣ－２５两次柱层析，从河南淅川马氏钳蝎毒素中分得一种碱性神经毒素ＢｍＫＭＩ８．等电聚焦和ＳＤＳ电泳显示单一组分，其ｐＩ为９．１，Ｍｒ为７１００．毒性测试结果表明，该组分对小白鼠有较强的毒性，对昆虫也有一定的毒性，已获得该毒素的两种晶型的大单晶，并测定其空间群为Ｐ２＿１２＿１２＿１，晶胞参数为：ＢｍＫＭＩ８－Ａ：ａ＝３６．７，ｂ＝２６．６，ｃ＝５２．０，ＢｍＫＭＩ８－Ｂ：ａ＝３６．６４Ａ，ｂ＝３７．３１，ｃ＝３７．９５，已收集了ＢｍＫＭＩ８－Ｂ分辨率为１．７４的Ｘ射线单晶衍射数据。

A new basic neurotoxin with toxicity towards both mice and insect,named BmK MI8 has been purified from venom of scorpion Buthus martensii Karsch (BmK) by chromatography ,on Sephadex G-50 and SP-Sephadex C-25. Its homogeneity was demonstrated by SDS-PAGE and IEF-PAGE. The molecular weight and isoelectric point of BmK MIS are 7 100 and 9. 1 respectively. Biological tests showed that BmK MIS displayed strong toxic activity toward mice(LD_50)=1. 0μg/g mouse)and simultaneously exhibited a weak but definite toxicity toward insect (lethal dose= 12 μg/g cockroach) . Two forms of BmK MIS crystals have been grown up in a recipe containing Tris-MPD solutions, which belong to the same space group P2_12_12_1, but possess the different cell constants. The cell parameters for BmK MI8-A are:a= 36. 7,b= 26. 6,c= 52. 0;and for BmK MISB are: a= 36. 64,b= 37. 31,c= 37. 95 . A set of diffraction data to the resolution 1. 74 for BmK MI8-B has been collected on SIEMENS B-200 Area Detector.