title: Alpha 1-adrenergic receptor subtype determinants for 4-piperidyl oxazole antagonists.
abstract: Mutational studies in conjunction with ligand binding assays were used to examine the basis of alpha1-adrenergic receptor subtype selectivity for a series of 4-piperidyloxazole antagonists. A set of chimeric alpha 1A receptors were created by systematically substituting individual transmembrane domains from alpha 1D adrenergic receptors. The oxazole antagonists exhibited significant reductions in affinity against the receptor construct alpha 1A/D(TM2), and moderate reductions in affinity versus constructs alpha 1A/D(TM5), alpha 1A/B(TM5), and alpha 1A/D(TM6). Antagonist affinities for these chimeras exceeded those found for wild type alpha 1D and alpha 1B. Site-directed mutagenesis methods were then used to explore the role that individual residues in TM2 and TM5 play in ligand binding affinity and selectivity. These studies revealed that mutations at position 86 in the second transmembrane domain and position 185 in the fifth transmembrane domain of the alpha 1A receptor have a major impact on receptor subtype selectivity.
authors.affiliation: Department of Structural Chemistry, Glaxo Wellcome Research Institute, Research Triangle Park, North Carolina 27709, USA.
authors.forename: N
authors.initials: N
authors.lastname: Hamaguchi
authors.forename: T A
authors.initials: TA
authors.lastname: True
authors.forename: A S
authors.initials: AS
authors.lastname: Goetz
authors.forename: M J
authors.initials: MJ
authors.lastname: Stouffer
authors.forename: T P
authors.initials: TP
authors.lastname: Lybrand
authors.forename: P W
authors.initials: PW
authors.lastname: Jeffs
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000737:chemistry / Q000494:pharmacology*; D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D008024:Ligands; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D010080:Oxazoles / Q000737:chemistry / Q000494:pharmacology*; D010880:Piperidines / Q000737:chemistry / Q000494:pharmacology*; D018340:Receptors, Adrenergic, alpha-1 / Q000737:chemistry / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D008024:Ligands; D010080:Oxazoles; D010880:Piperidines; D018340:Receptors, Adrenergic, alpha-1; D011993:Recombinant Fusion Proteins