Deglycosylated mammalian β2-adrenergic receptors: Effect on radioligand binding and peptide mapping

Abstract

Mammalian β-adrenergic receptors are glycoproteins containing both high-mannose and complex-type carbohydrate chains [G. L. Stiles, J. L. Benovic, M. G. Caron, and R. J. Lefkowitz (1984) J. Biol. Chem., 259, 8655–8663] . Endoglycosidase F treatment of β 2-adrenergic receptors results in the removal of at least two N-linked oligosaccharides, resulting in an increased mobility of the receptor peptide on sodium dodecyl sulfate-polyacrylamide gel electrophoresis ( M r 62,000 to 49,000). In the present study the properties of the deglycosylated β 2-adrenergic receptor were assessed. Following deglycosylation, the β 2-adrenergic receptor recognized both agonists and antagonists with the same potency order and affinities as the glycosylated form. In addition, two-dimensional gel electrophoresis peptide mapping techniques applied to control and deglycosylated β 2-adrenergic receptors (both within and between species) demonstrated that there was a marked homology of the β 2-adrenergic receptor between species which are closely related phylogenetically. In addition, the glycan component of the receptor did not appear to interfere with the ability of proteinases to generate accurate peptide maps.