XFEL crystal structure of human melatonin receptor MT2 (H208A) in complex with 2-phenylmelatonin
XFEL crystal structure of human melatonin receptor MT2 (H208A) in complex with 2-phenylmelatonin
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DOI：
10.2210/pdb6me6/pdb
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发表时间：
2019-04
期刊：
影响因子：
64.8
通讯作者：
L. Johansson;B. Stauch;J. McCorvy;G. Han;N. Patel;Xi Ping Huang;A. Batyuk;C. Gati;Samuel T. Slocum;Chufeng Li;J. Grandner;S. Hao;Reid H. J. Olsen;A. Tribo;S. Zaare;Lan Zhu;N. Zatsepin;U. Weierstall;S. Yous;R. Stevens;Wei Liu;B. Roth;V. Katritch;V. Cherezov
中科院分区：
文献类型：
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作者：
L. Johansson;B. Stauch;J. McCorvy;G. Han;N. Patel;Xi Ping Huang;A. Batyuk;C. Gati;Samuel T. Slocum;Chufeng Li;J. Grandner;S. Hao;Reid H. J. Olsen;A. Tribo;S. Zaare;Lan Zhu;N. Zatsepin;U. Weierstall;S. Yous;R. Stevens;Wei Liu;B. Roth;V. Katritch;V. Cherezov
人类MT 1和MT 2褪黑激素受体1，2是G蛋白偶联受体（GPCR），有助于调节昼夜节律和睡眠模式3。药物开发工作已经针对两种受体用于治疗失眠、昼夜节律和情绪障碍以及癌症3，并且MT 2也与2型糖尿病有关4，5。在这里，我们报告了人MT 2受体与激动剂2-苯基褪黑激素（2-PMT）和雷美汀6复合物的X射线自由电子激光（XFEL）结构，分辨率分别为2.8 A和3.3 A，沿着两种功能相关突变体的结构：H2085.46A（上标表示Ballesteros-Weinstein残基编号命名法7）和N862.50D，在与2-PMT的复合物中获得。MT 2的结构与MT 1已发表的结构8的比较表明，尽管正构配体结合位点残基保守，但[3 H]褪黑激素解离动力学存在显着的构象变化以及差异，这提供了对褪黑激素之间选择性的见解受体亚型。在MT 1和MT 2中观察到膜埋的侧向配体进入通道，但此外MT 2结构揭示了受体的细胞外部分中朝向溶剂的狭窄开口。我们提供的功能和动力学数据，支持一个突出的作用膜内配体进入这两种受体，并建议也可能有一个细胞外进入途径MT 2。我们的研究结果有助于褪黑激素受体亚型的选择性和配体的访问模式，这是必不可少的高度选择性褪黑激素工具化合物和治疗剂的设计的分子理解。结构和功能的研究表明，MT 2褪黑激素受体，不像MT 1受体，含有一个细胞外的配体进入开口，揭示受体亚型特异性。
The human MT1 and MT2 melatonin receptors1,2 are G-protein-coupled receptors (GPCRs) that help to regulate circadian rhythm and sleep patterns3. Drug development efforts have targeted both receptors for the treatment of insomnia, circadian rhythm and mood disorders, and cancer3, and MT2 has also been implicated in type 2 diabetes4,5. Here we report X-ray free electron laser (XFEL) structures of the human MT2 receptor in complex with the agonists 2-phenylmelatonin (2-PMT) and ramelteon6 at resolutions of 2.8 A and 3.3 A, respectively, along with two structures of function-related mutants: H2085.46A (superscripts represent the Ballesteros–Weinstein residue numbering nomenclature7) and N862.50D, obtained in complex with 2-PMT. Comparison of the structures of MT2 with a published structure8 of MT1 reveals that, despite conservation of the orthosteric ligand-binding site residues, there are notable conformational variations as well as differences in [3H]melatonin dissociation kinetics that provide insights into the selectivity between melatonin receptor subtypes. A membrane-buried lateral ligand entry channel is observed in both MT1 and MT2, but in addition the MT2 structures reveal a narrow opening towards the solvent in the extracellular part of the receptor. We provide functional and kinetic data that support a prominent role for intramembrane ligand entry in both receptors, and suggest that there might also be an extracellular entry path in MT2. Our findings contribute to a molecular understanding of melatonin receptor subtype selectivity and ligand access modes, which are essential for the design of highly selective melatonin tool compounds and therapeutic agents. Structural and functional studies show that the MT2 melatonin receptor, unlike the MT1 receptor, contains an extracellular opening for ligand entry, shedding light on receptor subtype specificity.