Crystal structure of a human neuronal nAChR extracellular domain in pentameric assembly: Ligand-bound α2 homopentamer
Crystal structure of a human neuronal nAChR extracellular domain in pentameric assembly: Ligand-bound α2 homopentamer
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DOI：
10.1073/pnas.1602619113
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发表时间：
2016-08-23
影响因子：
11.1
通讯作者：
Tzartos, Socrates J.
中科院分区：
文献类型：
--
作者：
Kouvatsos, Nikolaos;Giastas, Petros;Tzartos, Socrates J.
在这项研究中，我们报告的X-射线晶体结构的细胞外结构域（ECD）的人神经元α 2烟碱乙酰胆碱受体（nAChR）亚基在复杂的激动剂地棘蛙素在3.2埃。有趣的是，α 2结晶为五聚体，揭示了野生型神经元nAChR ECD中的亚基间相互作用和两个相邻α亚基赋予的完整配体结合口袋。五聚体组装呈现在同源蛋白质中观察到的保守结构支架，以及独特的特征，提供了主面和互补面之间的结合位点的独特结构信息。结构导向突变和电生理数据证实了在异聚体低敏感性α 2 β 2 nAChR上存在α 2（+）/α 2（-）结合位点，并验证了α 2和β 2 nAChR亚基中特定残基的功能重要性。鉴于α 2 nAChR亚基的病理重要性以及与α 4（78%）和其他神经元nAChR亚基的高度序列同一性，我们的研究结果为模拟几种nAChR并最终为针对nAChR相关疾病的亚型特异性药物的基于结构的设计提供了有价值的信息。
In this study we report the X-ray crystal structure of the extracellular domain (ECD) of the human neuronal alpha 2 nicotinic acetylcholine receptor (nAChR) subunit in complex with the agonist epibatidine at 3.2 angstrom. Interestingly, alpha 2 was crystallized as a pentamer, revealing the intersubunit interactions in a wild type neuronal nAChR ECD and the full ligand binding pocket conferred by two adjacent a subunits. The pentameric assembly presents the conserved structural scaffold observed in homologous proteins, as well as distinctive features, providing unique structural information of the binding site between principal and complementary faces. Structure-guided mutagenesis and electrophysiological data confirmed the presence of the alpha 2(+)/alpha 2(-) binding site on the heteromeric low sensitivity alpha 2 beta 2 nAChR and validated the functional importance of specific residues in alpha 2 and beta 2 nAChR subunits. Given the pathological importance of the alpha 2 nAChR subunit and the high sequence identity with alpha 4 (78%) and other neuronal nAChR subunits, our findings offer valuable information formodeling several nAChRs and ultimately for structure-based design of subtype specific drugs against the nAChR associated diseases.