Domains of β1 and β2 adrenergic receptors to bind subtype selective agonists

Abstract

We studied the binding region of several β 1 and β 2 selective agonists by using chimeric β 1 and β 2 ARs, and point-mutated β 2 adrenergic receptors (ARs). By replacing a single transmembrane domain (TMD) of β 1AR (or β 2 AR) with the corresponding region of β 2AR (or β 1AR), we found that β 2 or β 1 selectivities were determined by TMD2 and TMD7 of β 2AR or by TMD2 of β 1AR, respectively. Alanine-substituted β 2AR mutants showed that tyrosine at position 308 in TMD7 played an important role in binding of β 2 selective agonists with high affinity. These data also suggested that the substituent on the amine portion was important for subtype selective agonist binding.