School of Medicine, Guangxi University, Nanning 530004, China.
Key Laboratory of Tropical Biological Resources, Ministry of Education, Key Laboratory for Marine Drugs of Haikou, Hainan University, Haikou 570228, China.
Mar Drugs. 2023 May 1;21(5):286. doi: 10.3390/md21050286.
α4/6-conotoxin TxID, which was identified from , simultaneously blocks rat (r) α3β4 and rα6/α3β4 nicotinic acetylcholine receptors (nAChRs) with IC values of 3.6 nM and 33.9 nM, respectively. In order to identify the effects of loop2 size on the potency of TxID, alanine (Ala) insertion and truncation mutants were designed and synthesized in this study. An electrophysiological assay was used to evaluate the activity of TxID and its loop2-modified mutants. The results showed that the inhibition of 4/7-subfamily mutants [+9A]TxID, [+10A]TxID, [+14A]TxID, and all the 4/5-subfamily mutants against rα3β4 and rα6/α3β4 nAChRs decreased. Overall, ala-insertion or truncation of the 9th, 10th, and 11th amino acid results in a loss of inhibition and the truncation of loop2 has more obvious impacts on its functions. Our findings have strengthened the understanding of α-conotoxin, provided guidance for further modifications, and offered a perspective for future studies on the molecular mechanism of the interaction between α-conotoxins and nAChRs.
从 中鉴定出的 α4/6-芋螺毒素 TxID，分别以 3.6 nM 和 33.9 nM 的 IC 值同时阻断大鼠 (r)α3β4 和 rα6/α3β4 烟碱型乙酰胆碱受体 (nAChRs)。为了确定环 2 大小对 TxID 效力的影响，本研究设计并合成了丙氨酸 (Ala) 插入和截断突变体。采用电生理测定法评估 TxID 及其环 2 修饰突变体的活性。结果表明，抑制 4/7 亚家族突变体 [+9A]TxID、[+10A]TxID、[+14A]TxID 和所有 4/5 亚家族突变体对 rα3β4 和 rα6/α3β4 nAChRs 的抑制作用降低。总的来说，第 9、10 和 11 个氨基酸的 Ala 插入或截断导致抑制作用丧失，并且环 2 的截断对其功能有更明显的影响。我们的发现加强了对 α-芋螺毒素的理解，为进一步修饰提供了指导，并为未来关于 α-芋螺毒素与 nAChRs 相互作用的分子机制的研究提供了一个视角。
