We leveraged variable-temperature F-NMR spectroscopy to compare the conformational equilibria of the human A adenosine receptor (AAR), a class A G protein-coupled receptor (GPCR), across a range of temperatures ranging from lower temperatures typically employed in F-NMR experiments to physiological temperature. AAR complexes with partial agonists and full agonists showed large increases in the population of a fully active conformation with increasing temperature. NMR data measured at physiological temperature were more in line with functional data. This was pronounced for complexes with partial agonists, where the population of active AAR was nearly undetectable at lower temperature but became evident at physiological temperature. Temperature-dependent behavior of complexes with either full or partial agonists exhibited a pronounced sensitivity to the specific membrane mimetic employed. Cellular signaling experiments correlated with the temperature-dependent conformational equilibria of AAR in lipid nanodiscs but not in some detergents, underscoring the importance of the membrane environment in studies of GPCR function.

中文翻译：

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GPCR 能量景观的膜模拟依赖性

我们利用变温 F-NMR 光谱来比较人类 A 腺苷受体 (AAR)（一种 AG 类蛋白偶联受体 (GPCR)）在一系列温度下的构象平衡，从 F-NMR 中通常使用的较低温度开始实验到生理温度。具有部分激动剂和完全激动剂的 AAR 复合物显示，随着温度的升高，完全活性构象的数量大幅增加。在生理温度下测量的核磁共振数据更符合功能数据。这对于含有部分激动剂的复合物来说尤为明显，其中活性 AAR 的数量在较低温度下几乎检测不到，但在生理温度下变得明显。具有完全或部分激动剂的复合物的温度依赖性行为对所使用的特定膜模拟物表现出明显的敏感性。细胞信号传导实验与脂质纳米盘中 AAR 的温度依赖性构象平衡相关，但在某些去污剂中则不然，这强调了膜环境在 GPCR 功能研究中的重要性。