Selective peptide antagonist of the class E calcium channel from the venom of the tarantula Hysterocrates gigas
Selective peptide antagonist of the class E calcium channel from the venom of the tarantula Hysterocrates gigas
复制标题
DOI：
10.1021/bi981255g
复制
发表时间：
1998-11-03
期刊：
影响因子：
2.9
通讯作者：
Miljanich, G
中科院分区：
文献类型：
--
作者：
Newcomb, R;Szoke, B;Miljanich, G
我们描述了第一个有效的和选择性的E类钙通道阻滞剂。SNX-482是一种存在于非洲狼蛛（Hysterocrates gigas）毒液中的新型41个氨基酸的肽，通过其抑制在哺乳动物细胞系中稳定表达的人E类Ca 2+通道的能力而被鉴定。使用膜片钳电生理学或K+诱发的Ca 2+通量，获得了15-30 nM的阻断E类Ca 2+通道的IC 50。在低纳摩尔浓度下，SNX-482也阻断了大鼠神经垂体神经末梢中的天然电阻或R型Ca 2+电流，但200-500 nM浓度对几种类型的大鼠中枢神经元中的R型Ca 2+电流没有影响。该肽的序列为GVDKAGRIGMFGGCSVNDDCCPRLGCHSLFSYCAWDLTFSD-OH，与蜘蛛肽grammatoxin S1 A和hanatoxin同源，这两种肽具有非常不同的离子通道阻断选择性。未观察到SNX-482对以下离子通道活性的影响：几种培养细胞类型中的Na+或K+电流（高达500 nM）;通过非洲爪蟾卵母细胞中表达的克隆钾通道Kv1.1和Kv1.4的K+电流（高达140 nM）;垂体前叶细胞系中通过L型和T型Ca 2+通道的Ca 2+通量（GH 3，高达500 nM）;和通过非洲爪蟾卵母细胞中表达的A类Ca 2+通道的Ba 2+电流（高达280 nM）。通过克隆和稳定表达的B类Ca 2+通道，观察到对Ca 2+电流的良好影响（IC 50> 500 nM）。SNX-482的独特选择性表明其在研究E类和/或R型Ca 2+通道的多样性、功能和药理学方面的有用性。
We describe the first potent and selective blocker of the class E Ca2+-channel. SNX-482, a novel 41 amino acid peptide present in the venom of the African tarantula, Hysterocrates gigas, was identified through its ability to inhibit human class E Ca2+ channels stably expressed in a mammalian cell line. An IC50 of 15-30 nM was obtained for block of the class E Ca2+ channel, using either patch clamp electrophysiology or K+-evoked Ca2+ flux. At low nanomolar concentrations, SNX-482 also blocked a native resistant or R-type Ca2+ current in rat neurohypophyseal nerve terminals, but concentrations of 200-500 nM had no effect on R-type Ca2+ cut-rents in several types of rat central neurons. The peptide has the sequence GVDKAGCRYMFGGCSVNDDCCPRLGCHSLFSYCAWDLTFSD-OH and is homologous to the spider peptides grammatoxin S1A and hanatoxin, both peptides with very different ion channel blocking selectivities. No effect of SNX-482 was observed on the following ion channel activities: Na+ or K+ currents in several cultured cell types (up to 500 nM); K+ current through cloned potassium channels Kv1.1 and Kv1.4 expressed in Xenopus oocytes (up to 140 nM); Ca2+ flux through L- and T-type Ca2+ channels in an anterior pituitary cell line (GH3, up to 500 nM); and Ba2+ current through class A Ca2+ channels expressed in Xenopus oocytes (up to 280 nM). A weal; effect was noted on Ca2+ current through cloned and stably expressed class B Ca2+ channels (IC50 > 500 nM). The unique selectivity of SNX-482 suggests its usefulness in studying the diversity, function, and pharmacology of class E and/or R-type Ca2+ channels.