Structural Characterization of Agonist Binding to an A3 Adenosine Receptor through Biomolecular Simulations and Mutagenesis Experiments.
Journal of Medicinal Chemistry
American Chemical Society
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Stamatis, D., Lagarias, P., Barkan, K., Vrontaki, E., Ladds, G., & Kolocouris, A. (2019). Structural Characterization of Agonist Binding to an A3 Adenosine Receptor through Biomolecular Simulations and Mutagenesis Experiments.. Journal of Medicinal Chemistry https://doi.org/10.1021/acs.jmedchem.9b01164
The adenosine A3 receptor (A3R) binds adenosine and is a drug target against cancer cell proliferation. Currently, there is no experimental structure of A3R. Here, we have generated a molecular model of A3R in complex with two agonists, the nonselective 1-(6-amino-9H-purin-9-yl)-1-deoxy-N-ethyl-β-d-ribofuranuronamide (NECA) and the selective 1-deoxy-1-[6-[[(3-iodophenyl)methyl]amino]-9H-purin-9-yl]-N-methyl-β-d-ribofuranuronamide (IB-MECA). Molecular dynamics simulations of the wild-type A3R in complex with both agonists, combined with in vitro mutagenic studies revealed important residues for binding. Further, molecular mechanics-generalized Born surface area calculations were able to distinguish mutations that reduce or negate agonistic activity from those that maintained or increased the activity. Our studies reveal that selectivity of IB-MECA toward A3R requires not only direct interactions with residues within the orthosteric binding area but also with remote residues. Although V1695.30 is considered to be a selectivity filter for A3R binders, when it was mutated to glutamic acid or alanine, the activity of IB-MECA increased by making new van der Waals contacts with TM5. This result may have implications in the design of new A3R agonists.
This research represents part of the Master thesis of D.S. and post-doctoral work E.V. We also thank Chiesi Hellas which supported this research (SARG no. 10354) and the State Scholarships Foundation (IKY) for providing a Ph.D fellowship to P.L. (MIS 5000432, NSRF 2014-2020) and a post-doctoral fellowship to E.V. (MIS 5001552, NSRF 2014-2020). We gratefully acknowledge the support of the Leverhulme Trust (K.B. and G.L.) and the BBSRC (G.L.). This work was supported by computational time granted from the Greek Research & Technology Network (GRNET) in the National HPC facility—ARIS—under project IDs pr002021 and pr001004.
Leverhulme Trust (via University of Essex) (DBG3000)
External DOI: https://doi.org/10.1021/acs.jmedchem.9b01164
This record's URL: https://www.repository.cam.ac.uk/handle/1810/297468
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