Abstract
How drugs dissociate from their targets is largely unknown. We investigated the molecular basis of this process in the adenosine A2A receptor (A2AR), a prototypical G protein–coupled receptor (GPCR). Through kinetic radioligand binding experiments, we characterized mutant receptors selected based on molecular dynamic simulations of the antagonist ZM241385 dissociating from the A2AR. We discovered mutations that dramatically altered the ligand’s dissociation rate despite only marginally influencing its binding affinity, demonstrating that even receptor features with little contribution to affinity may prove critical to the dissociation process. Our results also suggest that ZM241385 follows a multistep dissociation pathway, consecutively interacting with distinct receptor regions, a mechanism that may also be common to many other GPCRs.
Footnotes
- Received November 26, 2015.
- Accepted February 11, 2016.
↵1 Current affiliation: Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical College, Xuzhou, Jiangsu, China.
↵2 Current affiliation: Departments of Computer Science and of Molecular and Cellular Physiology, and Institute for Computational and Mathematical Engineering, Stanford University, Palo Alto, California.
↵3 Current affiliation: Amsterdam Institute for Molecules, Medicines and Systems, VU University Amsterdam, Amsterdam.
This work was supported by the Innovational Research Incentive Scheme of The Netherlands Research Organization [Grant 11188].
- Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics
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