Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Lab for Marine Drugs of Haikou, Hainan University, Haikou 570228, Hainan, China.
Mar Drugs. 2018 Dec 13;16(12):507. doi: 10.3390/md16120507.
Recently, the muscle-type nicotinic acetylcholine receptors (nAChRs) have been pursued as a potential target of several diseases, including myogenic disorders, muscle dystrophies and myasthenia gravis, etc. α-conotoxin GI isolated from selectively and potently inhibited the muscle-type nAChRs which can be developed as a tool to study them. Herein, alanine scanning mutagenesis was used to reveal the structure⁻activity relationship (SAR) between GI and mouse α1β1δε nAChRs. The Pro⁵, Gly⁸, Arg⁸, and Tyr were proved to be the critical residues for receptor inhibiting as the alanine (Ala) replacement led to a significant potency loss on mouse α1β1δε nAChR. On the contrary, substituting Asn⁴, His and Ser with Ala respectively did not affect its activity. Interestingly, the [E1A] GI analogue exhibited a three-fold potency for mouse α1β1δε nAChR, whereas it obviously decreased potency at rat α9α10 nAChR compared to wildtype GI. Molecular dynamic simulations also suggest that loop2 of GI significantly affects the interaction with α1β1δε nAChR, and Tyr of GI is a critical residue binding with three hydrophobic amino acids of the δ subunit, including Leu, Tyr and Leu. Our research elucidates the interaction of GI and mouse α1β1δε nAChR in detail that will help to develop the novel analogues of GI.
最近，肌肉型烟碱型乙酰胆碱受体（nAChRs）已被作为多种疾病的潜在靶点进行研究，包括肌肉疾病、肌肉萎缩症和重症肌无力等。从 中分离出的 α-芋螺毒素 GI 选择性和有效地抑制了肌肉型 nAChRs，可将其开发为研究这些受体的工具。在此，通过丙氨酸扫描突变来揭示 GI 与小鼠 α1β1δε nAChRs 之间的结构-活性关系（SAR）。脯氨酸（Pro）⁵、甘氨酸（Gly）⁸、精氨酸（Arg）⁸ 和酪氨酸（Tyr）被证明是抑制受体的关键残基，因为丙氨酸（Ala）取代会导致对小鼠 α1β1δε nAChR 的显著效力损失。相反，分别用丙氨酸（Ala）取代 Asn⁴、His 和 Ser 不会影响其活性。有趣的是，[E1A]GI 类似物对小鼠 α1β1δε nAChR 的效力提高了三倍，而与野生型 GI 相比，其对大鼠 α9α10 nAChR 的效力明显降低。分子动力学模拟也表明，GI 的环 2 显著影响与 α1β1δε nAChR 的相互作用，并且 GI 的 Tyr 是与 δ 亚基的三个疏水性氨基酸（包括 Leu、Tyr 和 Leu）结合的关键残基。我们的研究详细阐明了 GI 和小鼠 α1β1δε nAChR 的相互作用，这将有助于开发 GI 的新型类似物。
