Site-directed mutagenesis and continuous expression of human beta-adrenergic receptors. Identification of a conserved aspartate residue involved in agonist binding and receptor activation.

摘要: Using a new expression vector that allows stable and steroid inducible of the human beta 2-adrenergic receptor in mouse L cells, we have examined functional significance highly conserved aspartate residue putative second transmembrane region receptor. Substitution 79 with asparagine produced mutant displays expected affinity stereoselectivity for antagonists but 40-, 140-, 240-fold reduction its isoproterenol, epinephrine, norepinephrine, respectively. This does not display guanine nucleotide-sensitive high binding agonists. Addition saturating concentrations isoproterenol to cell cultures expressing produces slight, albeit significant, increase intracellular levels cyclic AMP as compared cells wild type These observations demonstrate substitution at beta-adrenergic differentially affects catecholamines uncoupling receptors stimulatory nucleotide regulatory proteins (Gs). data are consistent role counterion amine agonist-induced activation associated ligand binding, Gs coupling, adenylate cyclase stimulation.