Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, United States; Molecular Biophysics Graduate Program, The University of Texas Southwestern Medical Center, Dallas, United States
Structural Biology Initiative, CUNY Advanced Science Research Center, New York, United States
Karen Chapman
Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, United States
Karin EJ Rödström
Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
James Aramini
Structural Biology Initiative, CUNY Advanced Science Research Center, New York, United States
Michael V LeVine
Department of Physiology and Biophysics, Weill Cornell Medical College, New York, United States; Institute for Computational Bioscience, Weill Cornell Medical College, New York, United States
Department of Physiology and Biophysics, Weill Cornell Medical College, New York, United States; Institute for Computational Bioscience, Weill Cornell Medical College, New York, United States
Søren GF Rasmussen
Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
Structural Biology Initiative, CUNY Advanced Science Research Center, New York, United States; Department of Chemistry and Biochemistry, City College of New York, New York, United States; Biochemistry, Chemistry and Biology PhD Programs, Graduate Center, City University of New York, New York, United States
Department of Biophysics, The University of Texas Southwestern Medical Center, Dallas, United States; Molecular Biophysics Graduate Program, The University of Texas Southwestern Medical Center, Dallas, United States
GPCRs regulate all aspects of human physiology, and biophysical studies have deepened our understanding of GPCR conformational regulation by different ligands. Yet there is no experimental evidence for how sidechain dynamics control allosteric transitions between GPCR conformations. To address this deficit, we generated samples of a wild-type GPCR (A2AR) that are deuterated apart from 1H/13C NMR probes at isoleucine δ1 methyl groups, which facilitated 1H/13C methyl TROSY NMR measurements with opposing ligands. Our data indicate that low [Na+] is required to allow large agonist-induced structural changes in A2AR, and that patterns of sidechain dynamics substantially differ between agonist (NECA) and inverse agonist (ZM241385) bound receptors, with the inverse agonist suppressing fast ps-ns timescale motions at the G protein binding site. Our approach to GPCR NMR creates a framework for exploring how different regions of a receptor respond to different ligands or signaling proteins through modulation of fast ps-ns sidechain dynamics.
