Ligands selectively tune the local and global motions of neurotensin receptor 1 (NTS1)
Fabian Bumbak,
Miquel Pons,
Asuka Inoue,
Juan Carlos Paniagua,
Fei Yan,
Hongwei Wu,
Scott A. Robson,
Ross A.D. Bathgate,
Daniel J. Scott,
Paul R. Gooley,
Joshua J. Ziarek
Affiliations
Fabian Bumbak
Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA; Corresponding author
Miquel Pons
Department of Inorganic and Organic Chemistry, Universitat de Barcelona, 08028 Barcelona, Spain
Asuka Inoue
Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
Juan Carlos Paniagua
Department of Materials Science and Physical Chemistry & Institute of Theoretical and Computational Chemistry, Universitat de Barcelona, 08028 Barcelona, Spain
Fei Yan
Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
Hongwei Wu
Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
Scott A. Robson
Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA
Ross A.D. Bathgate
The Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3010, Australia
Daniel J. Scott
The Florey Institute of Neuroscience and Mental Health and Department of Biochemistry and Pharmacology, The University of Melbourne, Parkville, VIC 3010, Australia
Paul R. Gooley
Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, VIC 3010, Australia
Joshua J. Ziarek
Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA; Corresponding author
Summary: Nuclear magnetic resonance (NMR) studies have revealed that fast methyl sidechain dynamics can report on entropically-driven allostery. Yet, NMR applications have been largely limited to the super-microsecond motional regimes of G protein-coupled receptors (GPCRs). We use 13Cε-methionine chemical shift-based global order parameters to test if ligands affect the fast dynamics of a thermostabilized GPCR, neurotensin receptor 1 (NTS1). We establish that the NTS1 solution ensemble includes substates with lifetimes on several, discrete timescales. The longest-lived states reflect those captured in agonist- and inverse agonist-bound crystal structures, separated by large energy barriers. We observe that the rapid fluctuations of individual methionine residues, superimposed on these long-lived states, respond collectively with the degree of fast, global dynamics correlating with ligand pharmacology. This approach lends confidence to interpreting spectra in terms of local structure and methyl dihedral angle geometry. The results suggest a role for sub-microsecond dynamics and conformational entropy in GPCR ligand discrimination.
