Guangxi Key Laboratory of Special Biomedicine, School of Medicine, Guangxi University, Nanning 530004, China.
Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China.
Mar Drugs. 2024 Aug 29;22(9):390. doi: 10.3390/md22090390.
α-Conotoxins are disulfide-rich peptides obtained from the venom of cone snails, which are considered potential molecular probes and drug leads for nAChR-related disorders. However, low specificity towards different nAChR subtypes restricts the further application of many α-conotoxins. In this work, a series of loop1 amino acid-substituted mutants of α-conotoxin RegIIA were synthesized, whose potency and selectivity were evaluated by an electrophysiological approach. The results showed that loop1 alanine scanning mutants [H5A]RegIIA and [P6A]RegIIA blocked rα7 nAChR with ICs of 446 nM and 459 nM, respectively, while their inhibition against rα3β2 and rα3β4 subtypes was negligible, indicating the importance of the fifth and sixth amino acid residues for RegIIA's potency and selectivity. Then, second-generation mutants were designed and synthesized, among which the analogues [H5V]RegIIA and [H5S]RegIIA showed significantly improved selectivity and comparable potency towards rα7 nAChR compared with the native RegIIA. Overall, these findings provide deep insights into the structure-activity relationship of RegIIA, as well as revealing a unique perspective for the further modification and optimization of α-conotoxins and other active peptides.
α- 芋螺毒素是从芋螺毒液中获得的富含二硫键的肽，被认为是潜在的分子探针和与烟碱型乙酰胆碱受体（nAChR）相关疾病的药物先导。然而，许多 α- 芋螺毒素对不同 nAChR 亚型的特异性低限制了它们的进一步应用。在这项工作中，合成了一系列环 1 氨基酸取代的 α-芋螺毒素 RegIIA 突变体，通过电生理学方法评估了它们的效力和选择性。结果表明，环 1 丙氨酸扫描突变体 [H5A]RegIIA 和 [P6A]RegIIA 对 rα7 nAChR 的抑制作用分别为 446 nM 和 459 nM，而对 rα3β2 和 rα3β4 亚型的抑制作用可以忽略不计，这表明第五和第六个氨基酸残基对 RegIIA 的效力和选择性很重要。然后设计并合成了第二代突变体，其中类似物 [H5V]RegIIA 和 [H5S]RegIIA 对 rα7 nAChR 的选择性和效力与天然 RegIIA 相比有显著提高。总的来说，这些发现深入了解了 RegIIA 的结构-活性关系，并为进一步修饰和优化 α-芋螺毒素和其他活性肽提供了独特的视角。
