A role for Leu118 of loop E in agonist binding to the α7 nicotinic acetylcholine receptor
A role for Leu118 of loop E in agonist binding to the α7 nicotinic acetylcholine receptor
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DOI：
10.1124/mol.107.041590
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发表时间：
2008-06-01
影响因子：
3.6
通讯作者：
Sattelle, David B.
中科院分区：
文献类型：
--
作者：
Amiri, Shiva;Shimomura, Masaru;Sattelle, David B.
烟碱型乙酰胆碱受体(NAChRs)是一种配体门控离子通道，在大脑和神经肌肉接头处介导快速的胆碱能突触传递。我们使用Lymneea stagnalis的乙酰胆碱结合蛋白的结构来模拟鸡α7激动剂结合结构域。最初的模型和初步的对接研究表明，Leu118位置可能在决定α7的激动剂作用中发挥重要作用。在电子研究中的预测，L118E和L118D将保留与乙酰胆碱的结合，而L118K和L118R不会，在非洲爪哇卵母细胞表达的功能性重组突变受体的电生理学研究中得到证实。功能研究还表明，第118位残基对吡虫啉(一种野生型α7受体的部分激动剂)及其去硝基衍生物的作用有显著影响。分子动力学模拟证实，Leu118可以强烈地影响激动剂的结合，并且该模型对乙酰胆碱结合的预测是稳健的。综上所述，结果表明Leu118在影响α7nAChRs激动剂作用中起作用。
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels mediating fast cholinergic synaptic transmission in the brain and at neuromuscular junctions. We used the structure of the acetylcholine binding protein from Lymnaea stagnalis to model the chicken alpha 7 agonist-binding domain. The initial models and a preliminary docking study suggested that position Leu118 may play an important role in determining agonist actions on alpha 7. A prediction from these in silico studies, that L118E and L118D would retain binding to acetylcholine but L118K and L118R would not, was confirmed in electrophysiological studies on functional recombinant mutant receptors expressed in Xenopus laevis oocytes. The functional studies also demonstrated that residues at position 118 have a dramatic effect on the actions of imidacloprid (a partial agonist of wild-type alpha 7 receptors) and its des-nitro derivative. Molecular dynamics simulations confirmed that Leu118 can strongly influence agonist binding and that the model was robust in terms of its prediction for acetylcholine binding. Together, the results indicate a role for Leu118 in influencing agonist actions on alpha 7 nAChRs.