Abstract
Previously, we demonstrated the involvement of Asn293 in helix VI of the human β2-adrenergic receptor in stereoselective agonist recognition and activation. In the present study, we have further explored the role of this residue by synthesizing derivatives of isoproterenol and clenbuterol, two β-adrenergic receptor agonists. We analyzed their efficacy and affinity on the wild-type and a mutant receptor (Asn293Leu). Each compound had similar efficacy (τ values) on both the wild-type and mutant receptor, although τ values varied considerably among the eight compounds studied. It appeared that one derivative of isoproterenol, but not of clenbuterol, showed a gain in affinity from the wild type to the mutant receptor. This derivative had a methyl substituent instead of the usual β-OH group in the aliphatic side chain of isoproterenol, compatible with the more lipophilic nature of the leucine side chain. Such a “gain of function” approach through a combination of synthetic chemistry with molecular biology, may be useful to enhance our insight into the precise atomic events that govern ligand-receptor interactions.
Footnotes
- Received February 23, 1999.
- Accepted July 22, 1999.
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Send reprint requests to: Adriann P. IJzerman, Ph.D., Receptor Medical Chemistry, Leiden/Amsterdam Center for Drug Research, P.O. Box 9502, 2300RA Leiden, the Netherlands. E-mail:ijzerman{at}lacdr.leidenuniv.nl
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This study was supported by grants from the European Community (programs EUROCEPTOR and InverseA).
- The American Society for Pharmacology and Experimental Therapeutics