Allosteric coupling from G protein to the agonist-binding pocket in GPCRs

Here, pharmacological and biochemical evidence is provided that shows that G-protein coupling to the β2-adrenergic receptor stabilizes a ‘closed’ conformation of the G-protein-coupled receptor (GPCR) and that that the effects of the G protein on the ligand-binding site of the GPCR are observed even in the absence of a bound agonist.