蝎子
毒液
毒素
蝎子毒素
蝎子毒
分子生物学
生物
化学
生物化学
作者
Hélène Vacher,Mériem Alami,Marcel Crest,Lourival D. Possani,Pierre E. Bougis,Marie‐France Martin‐Eauclaire
出处
期刊:European journal of biochemistry
[Wiley]
日期:2002-12-01
卷期号:269 (24): 6037-6041
被引量:55
标识
DOI:10.1046/j.1432-1033.2002.03294.x
摘要
A novel toxin, AmmTX3 (3823.5 Da), was isolated from the venom of the scorpion Androctonus mauretanicus . It showed 94% sequence homology with Aa1 from Androctonus australis and 91% with BmTX3 from Buthus martensi which, respectively, block A‐type K + current in cerebellum granular cells and striatum cultured neurons. Binding and displacement experiments using rat brain synaptosomes showed that AmmTX3 and Aa1 competed effectively with 125 I‐labelled sBmTX3 binding. They fully inhibited the 125 I‐labelled sBmTX3 binding ( K i values of 19.5 p m and 44.2 p m , respectively), demonstrating unambiguously that the three molecules shared the same target in rat brain. The specific binding parameters of 125 I‐labelled AmmTX3 for its site were determined at equilibrium ( K d = 66 p m , B max = 22 fmol per mg of protein). Finally, patch‐clamp experiments on striatal neurons in culture demonstrated that AmmTX3 was able to inhibit the A‐type K + current ( K i = 131 n m ).
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