GPCR Structural Diversity

Science Signaling  25 Nov 2008:
Vol. 1, Issue 47, pp. ec409
DOI: 10.1126/scisignal.147ec409

G protein–coupled receptors (GPCRs) respond to diverse extracellular signals to activate different signaling pathways. They are important pharmacological targets, but, so far, structural information that might aid drug design is limited to the rhodopsin and adrenergic receptors, and determinants of ligand binding specificity among different GPCRs are unclear. Now Jaakola et al. report the structure of the human A2A adenosine receptor, a receptor that is blocked by caffeine, in complex with an antagonist. The binding pocket is distinct from that in the rhodopsin and adrenergic receptors, suggesting that, rather than a conserved binding pocket with specific amino acid side chains determining specificity, the GPCR binding pocket itself can vary in position and orientation.

V.-P. Jaakola, M. T. Griffith, M. A. Hanson, V. Cherezov, E. Y. T. Chien, J. R. Lane, A. P. IJzerman, R. C. Stevens, The 2.6 angstrom crystal structure of a human A2A adenosine receptor bound to an antagonist. Science 322, 1211–1217 (2008). [Abstract] [Full Text]