Barhanin J, Schmid A, Lazdunski M
Centre de Biochimie, Centre National de la Recherche Scientifique, Nice, France.
Biochem Biophys Res Commun. 1988 Feb 15;150(3):1051-62. doi: 10.1016/0006-291x(88)90736-x.
Binding properties of omega-conotoxin (GVIA) to avian and mammalian neuronal Ca2+ channels were investigated using a radioiodinated toxin derivative. An exceptionally high affinity of 0.6 to 2 pM was found both from equilibrium and kinetics measurements. Only one class of non-interacting binding sites was detected. In chick brain, dissucinimidyl suberate specifically cross-linked the toxin to 170 kDa component that comprises a 140 kDa peptide disulfide linked to a 30 kDa peptide, very similar to the heavily glycosylated component of the L-type DHP-sensitive Ca2+ channel. A large peptide of 210-220 kDa was labelled using the azidonitrobenzoyloxy derivative of omega-conotoxin as cross-linking reagent but not the 170/140+30 kDa component. The results suggest that the neuronal Ca2+ channel could be composed by the association of two distinct high molecular weight peptides of 220 kDa and 170/140+30 kDa.
使用放射性碘化毒素衍生物研究了ω-芋螺毒素（GVIA）与禽类和哺乳动物神经元Ca2+通道的结合特性。通过平衡和动力学测量发现其具有0.6至2 pM的极高亲和力。仅检测到一类非相互作用的结合位点。在鸡脑中，辛二酸二琥珀酰亚胺酯将毒素特异性交联至170 kDa的组分，该组分由与30 kDa肽通过二硫键连接的140 kDa肽组成，与L型二氢吡啶敏感Ca2+通道的高度糖基化组分非常相似。使用ω-芋螺毒素的叠氮硝基苯氧基衍生物作为交联试剂标记了210 - 220 kDa的大肽，但未标记170/140 + 30 kDa的组分。结果表明，神经元Ca2+通道可能由220 kDa和170/140 + 30 kDa这两种不同的高分子量肽缔合而成。
