McEnery M W, Snowman A M, Sharp A H, Adams M E, Snyder S H
Department of Neuroscience, Johns Hopkins Medical Institutions, Baltimore, MD 21205.
Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11095-9. doi: 10.1073/pnas.88.24.11095.
The omega-conotoxin GVIA (CTX) receptor has been purified 1900-fold to apparent homogeneity by monitoring both reversible binding of 125I-labeled CTX (125I-CTX) and photoincorporation of N-hydroxysuccinimidyl-4-azidobenzoate-125I-CTX (HSA-125I-CTX). Photoincorporation of HSA-125I-CTX into a 230-kDa protein exhibits a pharmacologic and chromatographic profile indicating that the 230-kDa protein is the CTX-binding subunit of the receptor. The pharmacologic specificity of 125I-CTX binding to the purified CTX receptor closely resembles that of the native membrane-bound form with respect to sensitivity towards CTX (Kd = 32 pM) and other peptide toxin antagonists. The purified CTX receptor comprises the 230-kDa protein (alpha 1) and four additional proteins with apparent molecular masses of 140 (alpha 2), 110, 70 (beta 2), and 60 (beta 1) kDa. This subunit structure closely resembles that of the 1,4-dihydropyridine-sensitive L-type calcium channel.
通过监测¹²⁵I标记的ω-芋螺毒素GVIA（CTX）的可逆结合以及N-羟基琥珀酰亚胺-4-叠氮苯甲酸酯-¹²⁵I-CTX（HSA-¹²⁵I-CTX）的光掺入，已将CTX受体纯化了1900倍，达到明显的均一性。HSA-¹²⁵I-CTX掺入到一个230 kDa的蛋白质中，其药理学和色谱特征表明该230 kDa的蛋白质是受体的CTX结合亚基。¹²⁵I-CTX与纯化的CTX受体结合的药理学特异性在对CTX（Kd = 32 pM）和其他肽类毒素拮抗剂的敏感性方面与天然膜结合形式非常相似。纯化的CTX受体由230 kDa的蛋白质（α1）和另外四种表观分子量分别为140（α2）、110、70（β2）和60（β1）kDa的蛋白质组成。这种亚基结构与1,4-二氢吡啶敏感的L型钙通道的结构非常相似。
