Ligand modulation of sidechain dynamics in a wild-type human GPCR

Authors

Lindsay D. Clark, University of Texas
Igor Dikiy, CUNY Advanced Science Research Center
Karen Chapman, University of Texas
Karin EJ Rodstrom, University of Copenhagen
James Aramini, CUNY Advanced Science Research Center
Michael V. LeVine, Weill Cornell Medical College
George Khelashvili, Weill Cornell Medical College
Soren GF Rasmussen, University of Copenhagen
Kevin H. Gardner, CUNY Graduate CenterFollow
Daniel M. Rosenbaum, University of Texas

Document Type

Article

Publication Date

10-6-2017

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 d1 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.

Comments

This article was originally published in eLife, available at DOI: https://doi.org/10.7554/eLife.28505.

This article is distributed under the terms of the Creative Commons Attribution License (CC BY 4.0).