作者:Tian Hua、Kiran Vemuri、Spyros P. Nikas、Robert B. Laprairie、Yiran Wu、Lu Qu、Mengchen Pu、Anisha Korde、Shan Jiang、Jo-Hao Ho、Gye Won Han、Kang Ding、Xuanxuan Li、Haiguang Liu、Michael A. Hanson、Suwen Zhao、Laura M. Bohn、Alexandros Makriyannis、Raymond C. Stevens、Zhi-Jie Liu
DOI:10.1038/nature23272
日期:2017.7
Crystal structures of the human cannabinoid receptor 1 (CB1) bound to the agonists AM11542 and AM841 reveal notable structural rearrangements upon receptor activation, and this flexibility may be a common feature among other G-protein-coupled receptors. The human cannabinoid receptor 1 (CB1) is the main target of the plant cannabinoid Î9-tetrahydrocannbinol (Î9-THC), the key psychoactive compound in Cannabis sativa. CB1 is activated by endocannabinoids and is a therapeutic target for pain management, epilepsy and obesity, among others, although an active receptor structure is still lacking. Here, Zhi-Jie Liu and colleagues report the crystal structure of CB1 activated by two potent Î9-THC derivatives, AM11542 and AM841. Both of these agonists have a gem-dimethyl group on their alkyl chain which leads to significant enhancement in their potency and efficacy. Receptor activation involves large-scale structural rearrangements on both extracellular and cytoplasmic sides and a significant reduction in the size of the binding pocket. These conformational changes involve a novel molecular 'twin toggle switch', the synergistic movement of two key residues during activation, which the authors suggest may be common to other G-protein-coupled receptors. The cannabinoid receptor 1 (CB1) is the principal target of the psychoactive constituent of marijuana, the partial agonist Î9-tetrahydrocannabinol (Î9-THC)1. Here we report two agonist-bound crystal structures of human CB1 in complex with a tetrahydrocannabinol (AM11542) and a hexahydrocannabinol (AM841) at 2.80âÃ
and 2.95âÃ
resolution, respectively. The two CB1âagonist complexes reveal important conformational changes in the overall structure, relative to the antagonist-bound state2, including a 53% reduction in the volume of the ligand-binding pocket and an increase in the surface area of the G-protein-binding region. In addition, a âtwin toggle switchâ of Phe2003.36 and Trp3566.48 (superscripts denote BallesterosâWeinstein numbering3) is experimentally observed and appears to be essential for receptor activation. The structures reveal important insights into the activation mechanism of CB1 and provide a molecular basis for predicting the binding modes of Î9-THC, and endogenous and synthetic cannabinoids. The plasticity of the binding pocket of CB1 seems to be a common feature among certain class A G-protein-coupled receptors. These findings should inspire the design of chemically diverse ligands with distinct pharmacological properties.
人类大麻素受体1(CB1)与激动剂AM11542和AM841结合的晶体结构揭示了受体激活时显著的结构重排,这种灵活性可能是其他G蛋白偶联受体的一个共同特征。人类大麻素受体1(CB1)是植物大麻素Δ9-四氢大麻酚(Δ9-THC)的主要靶点,后者是大麻(Cannabis sativa)中的关键精神活性成分。CB1通过内源性大麻素激活,是疼痛管理、癫痫和肥胖等疾病的治疗靶点,尽管仍缺乏活性受体的结构信息。在这里,Zhi-Jie Liu及其同事报告了CB1与两种强效Δ9-THC衍生物AM11542和AM841激活后的晶体结构。这两种激动剂的烷基链上都有一个双甲基基团,这使得它们的效能和有效性显著增强。受体激活涉及细胞外和细胞内侧的大规模结构重排,并显著减少了结合口袋的大小。这些构象变化涉及一个新颖的分子“孪生切换开关”,即激活过程中两个关键残基的协同运动,作者认为这可能是其他G蛋白偶联受体的共性特征。大麻素受体1(CB1)是大麻中精神活性成分部分激动剂Δ9-四氢大麻酚(Δ9-THC)的主要靶点。在此,我们报告了人类CB1与四氢大麻酚(AM11542)和六氢大麻酚(AM841)结合的两种激动剂结合的晶体结构,分辨率分别为2.80Å和2.95Å。这两个CB1-激动剂复合物相较于拮抗剂结合状态揭示了整体结构的重要构象变化,包括配体结合口袋体积减少53%以及G蛋白结合区域表面积增大。此外,实验观察到的Phe2003.36和Trp3566.48的“孪生切换开关”(上标表示Ballesteros-Weinstein编号)似乎对受体激活至关重要。这些结构提供了关于CB1激活机制的重要见解,并为预测Δ9-THC及内源性和合成大麻素的结合模式提供了分子基础。CB1结合口袋的可塑性似乎是某些A级G蛋白偶联受体的共同特征。这些发现应激励设计具有不同药理特性的化学多样性配体。