| 李浩楠,毛楷林,熊洋,等.α-芋螺毒素LvIA特定氨基酸的突变对其活性的影响[J].中国海洋药物,2020,39(6):45-51. |
| α-芋螺毒素LvIA特定氨基酸的突变对其活性的影响 |
| Effect of the mutation of specific amino acid on α-Conotoxin LvIA potency |
| 投稿时间：2020-05-22 修订日期：2020-06-15 |
| DOI： |
| 中文关键词: α-芋螺毒素LvIA 烟碱型乙酰胆碱受体 突变体 电生理 活性 |
| English Keywords:α-CTx LvIA Acetylcholine receptor Mutant Electrophysiology Activity |
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| 中文摘要: |
| α-芋螺毒素(α-Conotoxin, α-CTx)作为烟碱型乙酰胆碱受体(nicotinic acetylcholine receptor, nAChR)的专一性拮抗剂,是研究nAChRs相关药理和生理功能的重要工具。目的 对特异区分α6/α3β2β3和α3β2两种nAChRs亚型的α-CTx LvIA进行研究,确定影响其活性的关键氨基酸位点。 方法 通过序列比对,两步法氧化折叠、双电极电压钳和圆二色谱等技术确定LvIA中影响其活性的关键氨基酸位点,并探索该位点对LvIA影响的机制。结果 确定了LvIA中第五位组氨酸(His,H)的关键作用,当第五位的His分别被丙氨酸(Ala,A)、天冬氨酸(Asp,D)和色氨酸(Trp,W)分别取代后,都会导致LvIA对所有受体亚型的活性丧失。圆二色结果表明该位点的变化对LvIA的二级结构没有显著的影响。结论 第5位His是维持LvIA活性的关键氨基酸残基,该氨基酸极性和侧链的变化均会导致LvIA活性的丧失,但是对其二级结构影响较小。LvIA中第5位氨基酸与nAChR的相互作用力是保证其活性的关键。该结论为基于LvIA设计新型专一作用于乙酰胆碱受体的工具探针改造提供了重要信息。 |
| English Summary: |
| α-Conotoxin (CTx) as a specific antagonist of nicotinic acetylcholine receptor (nAChR), is an important tool to study the pharmacological and physiological functions of nAChR. Objective Identify the key amino acid residue that affects the activity of the α-CTx LvIA, which is specific to distinguish the related two nAChRs subtypes α6/α3β2β3, and α3β2. Methods By sequence alignment, two-step oxidative folding, two-electrode voltage clamp, and circular dichroism, the key amino acid residue affecting the activity of LvIA was identified and the relationship of the key site with the potency of LvIA was explored. Results The vital role of the fifth histidine (His5, H5) in LvIA was identified. When the His5 was substituted with alanine (Ala, A), aspartic acid (Asp, D) and tryptophan (Trp, W), respectively, the activities of LvIA mutants for all nAChR subtypes were lost. The circular dichroism results showed that the change of this site had no significant effect on the secondary structure of LvIA. Conclusion The His5 is the key amino acid residue to maintain the activity of LvIA. Changes in the polarity and side chains of His5 can lead to the loss of potency but have little effect on its secondary structure. The interaction between the 5th amino acid and nAChR in LvIA is the key to its activity. This conclusion provides key information for further design novel probe tools based on LvIA which specifically target different nAChR subtypes. |
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