PMID: 28235198
Authors:
Glukhova A, Thal DM, Nguyen AT, Vecchio EA, Jorg M, Scammells PJ, May LT, Sexton PM, Christopoulos A
Title:
Structure of the Adenosine A1 Receptor Reveals the Basis for Subtype Selectivity.
Journal:
Cell. 2017 Feb 23;168(5):867-877.e13. doi: 10.1016/j.cell.2017.01.042.
Abstract:
The adenosine A1 receptor (A1-AR) is a G-protein-coupled receptor that plays a vital role in cardiac, renal, and neuronal processes but remains poorly targeted by current drugs. We determined a 3.2 A crystal structure of the A1-AR bound to the selective covalent antagonist, DU172, and identified striking differences to the previously solved adenosine A2A receptor (A2A-AR) structure. Mutational and computational analysis of A1-AR revealed a distinct conformation of the second extracellular loop and a wider extracellular cavity with a secondary binding pocket that can accommodate orthosteric and allosteric ligands. We propose that conformational differences in these regions, rather than amino-acid divergence, underlie drug selectivity between these adenosine receptor subtypes. Our findings provide a molecular basis for AR subtype selectivity with implications for understanding the mechanisms governing allosteric modulation of these receptors, allowing the design of more selective agents for the treatment of ischemia-reperfusion injury, renal pathologies, and neuropathic pain.