The dynamic process of β(2)-adrenergic receptor activation

• Published in: Cell 2013-01, Vol.152 (3), p.532-542
• Main Authors: Nygaard, Rie, Zou, Yaozhong, Dror, Ron O, Mildorf, Thomas J, Arlow, Daniel H, Manglik, Aashish, Pan, Albert C, Liu, Corey W, Fung, Juan José, Bokoch, Michael P, Thian, Foon Sun, Kobilka, Tong Sun, Shaw, David E, Mueller, Luciano, Prosser, R Scott, Kobilka, Brian K
• Format: Article
• Language: English
• Subjects: Adrenergic beta-2 Receptor Agonists - metabolism; Amino Acid Sequence; Humans; Molecular Dynamics Simulation; Molecular Sequence Data; Nuclear Magnetic Resonance, Biomolecular; Protein Conformation; Receptors, Adrenergic, beta-2 - chemistry; Receptors, Adrenergic, beta-2 - metabolism; Signal Transduction; Thermodynamics
• ISSN: 1097-4172
• DOI: 10.1016/j.cell.2013.01.008

G-protein-coupled receptors (GPCRs) can modulate diverse signaling pathways, often in a ligand-specific manner. The full range of functionally relevant GPCR conformations is poorly understood. Here, we use NMR spectroscopy to characterize the conformational dynamics of the transmembrane core of the β(2)-adrenergic receptor (β(2)AR), a prototypical GPCR. We labeled β(2)AR with (13)CH(3)ε-methionine and obtained HSQC spectra of unliganded receptor as well as receptor bound to an inverse agonist, an agonist, and a G-protein-mimetic nanobody. These studies provide evidence for conformational states not observed in crystal structures, as well as substantial conformational heterogeneity in agonist- and inverse-agonist-bound preparations. They also show that for β(2)AR, unlike rhodopsin, an agonist alone does not stabilize a fully active conformation, suggesting that the conformational link between the agonist-binding pocket and the G-protein-coupling surface is not rigid. The observed heterogeneity may be important for β(2)AR's ability to engage multiple signaling and regulatory proteins.