Both rhodopsin and β2-AR are GPCRs, allowing the transduction of extracellular signals to intracellular signalling cascades. They both consist of 7 transmembrane alpha helices, arranged in a twisted bundle, with the ligand binding site located within the bundle. As both receptors are GPCRs, they have a G protein bound to the connecting loop from transmembrane helices 5 to 6.
The β2-AR has a blocker binding site, which locks the receptor in a single conformation.
There are many conserved residues between the two proteins, suggesting they came from common evolutionary lineages.