α-Conotoxin EI

α-Conotoxin EI（CAS 170663-33-9）是一种源自大西洋鱼猎芋螺（Conus ermineus）毒液的肽类毒素，能够特异性作用于烟碱型乙酰胆碱受体（nAChRs）。nAChRs 是一类由多个亚基组成的配体门控离子通道，广泛分布于肌肉和神经系统中，介导突触传递和细胞信号传导。α-Conotoxin EI 通过与 nAChRs 的亚基界面结合，在极低浓度（0.2-10 nM）和短暂处理（2-15 s）时增强α₁β₁γδ和α₄β₂等受体亚型对乙酰胆碱的响应，而在高浓度（1-10 μM）和长时间处理（>30 s）时竞争性阻断受体功能，尤其对α₁β₁γδ和α₃β₄受体亚型作用显著。这种双重作用源于其对受体构象的调控：低浓度稳定激活态构象，高浓度占据配体结合位点。α-Conotoxin EI 通过靶向α₁β₁γδ、α₄β₂、α₃β₄等特定 nAChR 亚型，在神经受体亚型区分、突触传递机制研究以及神经疾病治疗药物开发（如肌肉松弛剂、神经退行性疾病药物）等方面展现出重要的研究价值。

Reference:

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[3] López-Vera E, Aguilar MB, Schiavon E, Marinzi C, Ortiz E, Restano Cassulini R, Batista CV, Possani LD, Heimer de la Cotera EP, Peri F, Becerril B, Wanke E. Novel alpha-conotoxins from Conus spurius and the alpha-conotoxin EI share high-affinity potentiation and low-affinity inhibition of nicotinic acetylcholine receptors. FEBS J. 2007 Aug;274(15):3972-85.

[4] Ning J, Ren J, Xiong Y, Wu Y, Zhangsun M, Zhangsun D, Zhu X, Luo S. Identification of Crucial Residues in α-Conotoxin EI Inhibiting Muscle Nicotinic Acetylcholine Receptor. Toxins (Basel). 2019 Oct 16;11(10):603.

[5] Rybin MJ, O'Brien H, Ramiro IBL, Azam L, McIntosh JM, Olivera BM, Safavi-Hemami H, Yoshikami D. αM-Conotoxin MIIIJ Blocks Nicotinic Acetylcholine Receptors at Neuromuscular Junctions of Frog and Fish. Toxins (Basel). 2020 Mar 21;12(3):197.