Ligand modulation of sidechain dynamics in a wild-type human GPCR
- The University of Texas Southwestern Medical Center, United States
- CUNY Advanced Science Research Center, United States
- University of Copenhagen, Denmark
- Weill Cornell Medical College, United States
Abstract
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.
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Author details
George Khelashvili
Daniel M Rosenbaum
Funding
Welch Foundation (I-1770)
- Daniel M Rosenbaum
National Institutes of Health (R01GM113050)
- Daniel M Rosenbaum
National Institutes of Health (R01GM106239)
- Kevin H Gardner
National Science Foundation (1000136529)
- Lindsay D Clark
American Heart Association (16PRE27200004)
- Lindsay D Clark
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2017, Clark et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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