1] CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Pudong, Shanghai 201203, China [2].
Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
Nature. 2014 May 1;509(7498):115-8. doi: 10.1038/nature13083. Epub 2014 Mar 23.
P2Y receptors (P2YRs), a family of purinergic G-protein-coupled receptors (GPCRs), are activated by extracellular nucleotides. There are a total of eight distinct functional P2YRs expressed in human, which are subdivided into P2Y1-like receptors and P2Y12-like receptors. Their ligands are generally charged molecules with relatively low bioavailability and stability in vivo, which limits our understanding of this receptor family. P2Y12R regulates platelet activation and thrombus formation, and several antithrombotic drugs targeting P2Y12R--including the prodrugs clopidogrel (Plavix) and prasugrel (Effient) that are metabolized and bind covalently, and the nucleoside analogue ticagrelor (Brilinta) that acts directly on the receptor--have been approved for the prevention of stroke and myocardial infarction. However, limitations of these drugs (for example, a very long half-life of clopidogrel action and a characteristic adverse effect profile of ticagrelor) suggest that there is an unfulfilled medical need for developing a new generation of P2Y12R inhibitors. Here we report the 2.6 Å resolution crystal structure of human P2Y12R in complex with a non-nucleotide reversible antagonist, AZD1283. The structure reveals a distinct straight conformation of helix V, which sets P2Y12R apart from all other known class A GPCR structures. With AZD1283 bound, the highly conserved disulphide bridge in GPCRs between helix III and extracellular loop 2 is not observed and appears to be dynamic. Along with the details of the AZD1283-binding site, analysis of the extracellular interface reveals an adjacent ligand-binding region and suggests that both pockets could be required for dinucleotide binding. The structure provides essential insights for the development of improved P2Y12R ligands and allosteric modulators as drug candidates.
P2Y 受体（P2YRs）是一类嘌呤能 G 蛋白偶联受体（GPCRs），可被细胞外核苷酸激活。人类共有 8 种不同功能的 P2YRs，可分为 P2Y1 样受体和 P2Y12 样受体。它们的配体通常是带电荷的分子，在体内的生物利用度和稳定性相对较低，这限制了我们对该受体家族的了解。P2Y12R 调节血小板激活和血栓形成，几种针对 P2Y12R 的抗血栓药物——包括前药氯吡格雷（Plavix）和普拉格雷（Effient），它们被代谢并发生共价结合，以及核苷类似物替卡格雷（Brilinta），它直接作用于受体——已被批准用于预防中风和心肌梗死。然而，这些药物存在局限性（例如，氯吡格雷作用的半衰期非常长，替卡格雷的特征不良作用谱），这表明开发新一代 P2Y12R 抑制剂存在未满足的医疗需求。在这里，我们报告了人 P2Y12R 与非核苷酸可逆拮抗剂 AZD1283 复合物的 2.6Å 分辨率晶体结构。该结构揭示了独特的直构象的第五螺旋，这使得 P2Y12R 与所有其他已知的 A 类 GPCR 结构区分开来。与 AZD1283 结合时，GPCR 中高度保守的第三螺旋和细胞外环 2 之间的二硫键未被观察到，并且似乎是动态的。与 AZD1283 结合位点的详细信息一起，对外界界面的分析揭示了相邻的配体结合区域，并表明两个口袋都可能需要二核苷酸结合。该结构为开发改进的 P2Y12R 配体和变构调节剂作为候选药物提供了重要的见解。
