Bimodal modulation of the botulinum neurotoxin protein-conducting channel
Bimodal modulation of the botulinum neurotoxin protein-conducting channel
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DOI：
10.1073/pnas.0812839106
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发表时间：
2009-02-03
影响因子：
11.1
通讯作者：
Montal, Mauricio
中科院分区：
文献类型：
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作者：
Fischer, Audrey;Nakai, Yuya;Montal, Mauricio
肉毒梭菌神经毒素（BoNT）是肉毒中毒的病原体，肉毒中毒是一种神经麻痹性疾病。我们在这里描述了一种半合成的策略，以确定抑制剂的基础上川楝素，传统的中药报告，以防止BoNT中毒。使用BoNT血清型A和E轻链（LC）易位通过神经元中的重链（HC）通道的单分子测定，我们发现川楝素及其四氢呋喃类似物以亚纳摩尔效力选择性地阻止中毒的LC易位步骤，并以微摩尔效力增加未封闭的HC通道开放的倾向。在2种不同的BoNT中毒测定中，即小鼠保护和原代大鼠脊髓细胞测定中准确地概括了对LC易位的抑制概况。川楝素对蛋白质传导通道具有前所未有的双重作用模式，作为转运的货物依赖性抑制剂和作为无货物通道激活剂。这些结果意味着川楝素的双峰调制依赖于通道和货物之间的动态相互作用，突出了它们在LC转运通过内体的进展过程中的紧密相互作用。
Clostridium botulinum neurotoxin (BoNT) is the causative agent of botulism, a neuroparalytic disease. We describe here a semisynthetic strategy to identify inhibitors based on toosendanin, a traditional Chinese medicine reported to protect from BoNT intoxication. Using a single molecule assay of BoNT serotypes A and E light chain (LC) translocation through the heavy chain (HC) channel in neurons, we discovered that toosendanin and its tetrahydrofuran analog selectively arrest the LC translocation step of intoxication with subnanomolar potency, and increase the unoccluded HC channel propensity to open with micromolar efficacy. The inhibitory profile on LC translocation is accurately recapitulated in 2 different BoNT intoxication assays, namely the mouse protection and the primary rat spinal cord cell assays. Toosendanin has an unprecedented dual mode of action on the protein-conducting channel acting as a cargo-dependent inhibitor of translocation and as cargo-free channel activator. These results imply that the bimodal modulation by toosendanin depends on the dynamic interactions between channel and cargo, highlighting their tight interplay during the progression of LC transit across endosomes.