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Analysis of β2AR-Gs and β2AR-Gi complex formation by NMR spectroscopy.
Proceedings of the National Academy of Sciences of the United States of America ( IF 9.4 ) Pub Date : 2020-09-15 , DOI: 10.1073/pnas.2009786117
Xiuyan Ma 1 , Yunfei Hu 2, 3 , Hossein Batebi 4 , Jie Heng 1 , Jun Xu 1 , Xiangyu Liu 1, 5 , Xiaogang Niu 2 , Hongwei Li 2 , Peter W Hildebrand 4, 6, 7 , Changwen Jin 8 , Brian K Kobilka 9, 10
Affiliation  

The β2-adrenergic receptor (β2AR) is a prototypical G protein-coupled receptor (GPCR) that preferentially couples to the stimulatory G protein Gs and stimulates cAMP formation. Functional studies have shown that the β2AR also couples to inhibitory G protein Gi, activation of which inhibits cAMP formation [R. P. Xiao, Sci. STKE 2001, re15 (2001)]. A crystal structure of the β2AR-Gs complex revealed the interaction interface of β2AR-Gs and structural changes upon complex formation [S. G. Rasmussen et al., Nature 477, 549–555 (2011)], yet, the dynamic process of the β2AR signaling through Gs and its preferential coupling to Gs over Gi is still not fully understood. Here, we utilize solution nuclear magnetic resonance (NMR) spectroscopy and supporting molecular dynamics (MD) simulations to monitor the conformational changes in the G protein coupling interface of the β2AR in response to the full agonist BI-167107 and Gs and Gi1. These results show that BI-167107 stabilizes conformational changes in four transmembrane segments (TM4, TM5, TM6, and TM7) prior to coupling to a G protein, and that the agonist-bound receptor conformation is different from the G protein coupled state. While most of the conformational changes observed in the β2AR are qualitatively the same for Gs and Gi1, we detected distinct differences between the β2AR-Gs and the β2AR-Gi1 complex in intracellular loop 2 (ICL2). Interactions with ICL2 are essential for activation of Gs. These differences between the β2AR-Gs and β2AR-Gi1 complexes in ICL2 may be key determinants for G protein coupling selectivity.



中文翻译:


通过 NMR 光谱分析 β2AR-Gs 和 β2AR-Gi 复合物的形成。



β 2 -肾上腺素能受体 (β 2 AR) 是一种典型的 G 蛋白偶联受体 (GPCR),它优先与刺激性 G 蛋白 G s偶联并刺激 cAMP 形成。功能研究表明,β 2 AR 还与抑制性 G 蛋白 G 偶联,其激活会抑制 cAMP 形成 [RP Xiao,Sci. STKE 2001 ,re15 (2001)]。 β 2 AR- G复合物的晶体结构揭示了 β 2 AR- G的相互作用界面以及复合物形成时的结构变化 [SG Rasmussen 等人, Nature 477, 549–555 (2011)],然而, β 2 AR 信号传导通过 G s的动态过程及其相对于 G 与 G s 的优先耦合尚未完全了解。在这里,我们利用溶液核磁共振 (NMR) 光谱和支持分子动力学 (MD) 模拟来监测 β 2 AR 的 G 蛋白偶联界面响应完全激动剂 BI-167107 和 G s和 G 的构象变化i1 。这些结果表明,BI-167107 在与 G 蛋白偶联之前稳定了四个跨膜片段(TM4、TM5、TM6 和 TM7)的构象变化,并且激动剂结合的受体构象与 G 蛋白偶联状态不同。虽然在 β 2 AR 中观察到的大多数构象变化对于 G s和 G i1来说在质量上是相同的,但我们在细胞内环 2 中检测到 β 2 AR-G s和 β 2 AR-G i1复合物之间存在明显差异(ICL2 )。 与 ICL2 的相互作用对于G的激活至关重要。 ICL2 中 β 2 AR-G s和 β 2 AR-G i1复合物之间的这些差异可能是 G 蛋白偶联选择性的关键决定因素。

更新日期:2020-09-16
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