Shon K J, Hasson A, Spira M E, Cruz L J, Gray W R, Olivera B M
Department of Biology, University of Utah, Salt Lake City 84112.
Biochemistry. 1994 Sep 27;33(38):11420-5. doi: 10.1021/bi00204a003.
A novel peptide toxin, delta-conotoxin GmVIA, was purified from the venom of Conus gloriamaris, a mollusc-hunting snail. It consists of 29 amino acids, including six Cys residues: [sequence: see text] The pattern of disulfide connectivity (4-19, 12-24, and 18-29) is the same as for the omega-conotoxins, which are Ca2+ channel ligands. However, the peptide does not compete with omega-conotoxin for binding to membrane preparations from frog, rat, and chick brain. Instead, initial electrophysiological results suggest that the peptide induces action potential broadening in molluscan neurons by slowing down Na+ current inactivation. Synthetic delta-conotoxin GmVIA was prepared by solid-phase methods and appeared identical in all respects to the natural material. The chromatographic behavior of native and reduced delta-conotoxins is quite remarkable, suggesting that the disulfides form a core which forces hydrophobic residues to point out toward the solvent.
一种新型肽毒素，δ-芋螺毒素GmVIA，是从以软体动物为食的蜗牛——荣耀芋螺的毒液中纯化得到的。它由29个氨基酸组成，包括6个半胱氨酸残基：[序列：见正文]其二硫键连接模式（4-19、12-24和18-29）与作为Ca2+通道配体的ω-芋螺毒素相同。然而，该肽在与来自青蛙、大鼠和鸡脑的膜制剂结合时并不与ω-芋螺毒素竞争。相反，初步的电生理结果表明，该肽通过减缓Na+电流失活来诱导软体动物神经元的动作电位展宽。合成的δ-芋螺毒素GmVIA通过固相方法制备，在所有方面都与天然物质相同。天然和还原型δ-芋螺毒素的色谱行为非常显著，表明二硫键形成了一个核心，迫使疏水残基指向溶剂。
