COOPERATIVE ACTIVATION OF ACTION POTENTIAL NA+ IONOPHORE BY NEUROTOXINS
COOPERATIVE ACTIVATION OF ACTION POTENTIAL NA+ IONOPHORE BY NEUROTOXINS
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DOI：
10.1073/pnas.72.5.1782
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发表时间：
1975-01-01
影响因子：
11.1
通讯作者：
CATTERALL, WA
中科院分区：
文献类型：
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作者：
CATTERALL, WA
激活电兴奋神经母细胞瘤细胞的动作电位Na+离子载体的四种神经毒素与两类不同的位点相互作用，一类专用于藜芦碱、巴曲毒素和乌头碱，另一类专用于蝎子毒素。在这两类位点结合的毒素之间观察到正的各向异性的协同作用。河豚毒素是这些毒素(Ki=4-8 nM)激活的非竞争性抑制物。这些结果表明，动作电位Na+离子载体存在三个功能上可分离的成分：两个规则成分，它们结合激活的神经毒素，并变构相互作用，控制第三个离子转运成分的活性，第三个离子转运成分结合河豚毒素。
Four neurotoxins that activate the action potential Na+ ionophore of electrically excitable neuroblastoma cells interact with two distinct classes of sites, one specific for the alkaloids veratridine, batrachotoxin, and aconitine, and the second specific for scorpion toxin. Positive heterotropic cooperativity is observed between toxins bound at these two classes of sites. Tetrodotoxin is a noncompetitive inhibitor of activation by each of these toxins (KI = 4-8 nM). These results suggest the existence of three functionally separable components of the action potential Na+ ionophore: two regulatroy components, which bind activating neurotoxins and interact allosterically in controlling the activity of a third ion-transport component, which binds tetrodotoxin.