Solution structure of two insect-specific spider toxins and their pharmacological interaction with the insect voltage-gated Na+ channel
Solution structure of two insect-specific spider toxins and their pharmacological interaction with the insect voltage-gated Na+ channel
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DOI：
10.1002/prot.20424
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发表时间：
2005-05-01
影响因子：
2.9
通讯作者：
Corzo, G
中科院分区：
文献类型：
--
作者：
Ferrat, G;Bosmans, F;Corzo, G
delta-PaluIT 1和delta-PaluIT 2是从蜘蛛Paracoelotes luctuosus的毒液中纯化的毒素。与来自Agelenopsis aperta的mu-agatoxins的序列相似，它们的药理学靶点是电压门控昆虫钠通道，它们以类似于α-蝎毒素的方式改变其失活特性，但它们以类似于β-蝎毒素的方式结合在位点4上。我们确定的解决方案结构的两个毒素使用二维核磁共振（NMR）技术，然后距离几何和分子动力学。delta-paluIT 1和delta-paluIT 2的结构属于抑制性胱氨酸结结构家族，即一个紧密的二硫键键结合的核心，从中出现四个环。δ-PaluIT 1和δ-PaluIT 2分别含有两链和三链反平行β-折叠作为独特的二级结构。我们比较这些肽的结构和静电各向异性的其他钠和钙通道毒素，分析拓扑并列的关键功能残基，并得出结论，这些毒素的昆虫电压门控钠通道的识别涉及β-片层，除了环I和IV。除了罪犯残基在分子表面上的位置之外，偶极矩取向的差异是受体结合和生物活性差异的另一个决定因素。我们还表明，通过电生理实验克隆昆虫电压门控钠通道，帕拉，异源共表达与非洲爪蟾卵母细胞中的tipE亚基，即delta-paluIT 1和delta-paluIT 2采购增加的Na+电流。当使用相同浓度时，δ-PaluIT 1-OH似乎具有较小的效果。(c)2005 Wiley-Liss，Inc.
delta-PaluIT1 and delta-paluIT2 are toxins purified from the venom of the spider Paracoelotes luctuosus. Similar in sequence to mu-agatoxins from Agelenopsis aperta, their pharmacological target is the voltage-gated insect sodium channel, of which they alter the inactivation properties in a way similar to a-scorpion toxins, but they bind on site 4 in a way similar to beta-scorpion toxins. We determined the solution structure of the two toxins by use of two-dimensional nuclear magnetic resonance (NMR) techniques followed by distance geometry and molecular dynamics. The structures of delta-paluIT1 and delta-paluIT2 belong to the inhibitory cystine knot structural family, i.e. a compact disulfide-bonded core from which four loops emerge. delta-PaluIT1 and delta-paluIT2 contain respectively two- and three-stranded anti-parallel beta-sheets as unique secondary structure. We compare the structure and the electrostatic anisotropy of those peptides to other sodium and calcium channel toxins, analyze the topological juxtaposition of key functional residues, and conclude that the recognition of insect voltage-gated sodium channels by these toxins involves the beta-sheet, in addition to loops I and IV. Besides the position of culprit residues on the molecular surface, difference in dipolar moment orientation is another determinant of receptor binding and biological activity differences. We also demonstrate by electrophysiological experiments on the cloned insect voltage-gated sodium channel, para, heterologuously coexpressed with the tipE subunit in Xenopus laevis oocytes, that delta-paluIT1 and delta-paluIT2 procure an increase of Na+ current. delta-PaluIT1-OH seems to have less effect when the same concentrations are used. (c) 2005 Wiley-Liss, Inc.