一种强毒性中华马氏钳蝎哺乳动物神经毒素新晶型的初步晶体学研究

CRYSTALLZATION AND PRELIMINARY CRYSTALLOGRAHIC ANALYSIS OF A NEW CRYSTAL FROM OF A MAMMAL NEUROTOXIN WITH GIGH TOXICITY FROM CHINESE SCORPION

经ＳｅｐｈａｄｅｘＧ－５０和Ｓｐ－ＳｅｐｈａｄｅｘＣ－２５两次柱层析，从常德马氏钳蝎毒素中分离得到一种强毒性的哺乳动物神经毒（Ｂｍｋｌ），等电聚焦及ＳＤＳ－电泳显示它为单一组份，其ｐＩ为９．４４，ＭＷ为７．１ＫＤ．毒性试验结果表明，该组份对小白鼠的最小致死刘量为０．５μｇ／ｇ小白鼠，对昆虫及甲壳动物也有毒性．已获得该毒素的一种新晶型的大晶体。其空间群为Ｐ２１２１２，晶胞参数为：α＝８３．４６Ａ，ｂ＝４０．３６Ａ，ｃ＝２４．００Ａ，单位晶胞体积为８０８４２．６９Ａ，一个不对称单位含１个分子，已收集了分辨率为１．７５Ａ的数据．

A kind of mammal neurotoxin (BmK1) with high toxicity is obtained from Buthus martensii Karsch by the mean of Sephadex G-50 followed by Sp-Sephadex C-25 liquid chromatography.The results of IEF-PAGE and SDS-PAGE indicate its high homogenity and its pI (9.44) and MW (7100 D)are obtained. The lethal dose of BmK1 for mouse is 0.5μg/g mouse. It is also toxic for insectS and crustaceans.A new crystal form of BmK1 has been obtained with cell palameters:α=83.46A, b=40.36A,c=24.00 A,V=80842.69A,Vm =2. 85A3/Da.Its space group belongs to P21212. Each asymmetric unit contains a singel molecule.The data at 1.75A resolution have been collected.