Structural and functional characterization of ryanodine receptor-natrin toxin interaction.
Structural and functional characterization of ryanodine receptor-natrin toxin interaction.
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DOI：
10.1529/biophysj.108.137224
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发表时间：
2008-11
影响因子：
3.4
通讯作者：
Qiang Zhou;Qiong-ling Wang;Xing Meng;Y. Shu;T. Jiang;T. Wagenknecht;C. Yin;Sen‐fang Sui;Zheng Liu
中科院分区：
文献类型：
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作者：
Qiang Zhou;Qiong-ling Wang;Xing Meng;Y. Shu;T. Jiang;T. Wagenknecht;C. Yin;Sen‐fang Sui;Zheng Liu
富含半胱氨酸的分泌蛋白广泛分布于哺乳动物的生殖道和有毒爬行动物的唾液腺中。大多数薯片可以抑制离子通道，如环核苷酸门控离子通道、钾通道和钙通道。Natrin是一种从蛇毒中提纯出来的脆片。其作用靶点包括钙激活钾通道、电压门控钾通道和钙释放通道/兰尼定受体(RyR)。免疫沉淀实验表明，Natrin能与骨骼肌中I型RyR(RyR1)特异性结合。研究发现，Natrin既能抑制ryanodine与RyR1的结合，又能抑制RyR1的钙通道活性。冷冻电子显微镜和单粒子图像重建分析表明，Natrin结合在RyR1的钳制结构域上。将Natrin的晶体结构对接到我们的RyR1+Natrin复合体的冷冻电子显微镜密度图中，表明Natrin通过稳定结构域-结构域相互作用来抑制RyR1，而Natrin的富含半胱氨酸的结构域是结合的关键。这些发现有助于揭示Natrin毒素如何抑制RyR钙释放通道，并使我们能够提出一种普遍的机制，管理脆片和离子通道之间的相互作用。
Cysteine-rich secretory proteins (CRISPs) are widely distributed, and notably occur in the mammalian reproductive tract and in the salivary glands of venomous reptiles. Most CRISPs can inhibit ion channels, such as the cyclic nucleotide-gated ion channel, potassium channel, and calcium channel. Natrin is a CRISP that has been purified from snake venom. Its targets include the calcium-activated potassium channel, the voltage-gated potassium channel, and the calcium release channel/ryanodine receptor (RyR). Immunoprecipitation experiments showed that natrin binds specifically to type 1 RyR (RyR1) from skeletal muscle. Natrin was found to inhibit both the binding of ryanodine to RyR1, and the calcium-channel activity of RyR1. Cryo-electron microscopy and single-particle image reconstruction analysis revealed that natrin binds to the clamp domains of RyR1. Docking of the crystal structure of natrin into our cryo-electron microscopy density map of the RyR1 + natrin complex suggests that natrin inhibits RyR1 by stabilizing a domain-domain interaction, and that the cysteine-rich domain of natrin is crucial for binding. These findings help reveal how natrin toxin inhibits the RyR calcium release channel, and they allow us to posit a generalized mechanism that governs the interaction between CRISPs and ion channels.