G protein–coupled receptors (GPCRs) are transmembrane proteins that act as key gatekeepers between external signals and cellular responses. GPCRs that are activated by diffusible ligands are dynamic, but in structural studies GPCRs have generally been cocrystallized with antagonists to stabilize them in their inactive state. Xu et al. now report a high-resolution crystal structure of human A2A adenosine receptor bound to a potent agonist, which provides insight into the structural basis of activation.
F. Xu, H. Wu, V. Katritch, G. W. Han, K. A. Jacobson, Z.-G. Gao, V. Cherezov, R. C. Stevens, Structure of an agonist-bound human A2A adenosine receptor. Science 332, 322–327 (2011). [Abstract] [Full Text]