Structure-based discovery of beta2-adrenergic receptor ligands

Area of Science:

• Pharmacology
• Structural Biology
• Medicinal Chemistry

Background:

• Aminergic G protein-coupled receptors (GPCRs) are crucial drug targets.
• Traditional drug discovery for GPCRs has been ligand-based due to limited structural data.
• The beta(2)-adrenergic receptor X-ray structure provides a new opportunity for structure-based design.

Purpose of the Study:

• To evaluate the efficacy and limitations of a structure-based approach for GPCR ligand discovery.
• To identify novel small molecules targeting the beta(2)-adrenergic receptor using its X-ray structure.
• To explore the potential of structure-based methods for discovering inverse agonists.

Main Methods:

• Docking of approximately 1 million commercially available, lead-like molecules against the beta(2)-adrenergic receptor structure.
• In vitro testing of 25 high-ranking docked molecules for binding affinity.
• Characterization of active molecules, including affinity determination and agonist/inverse agonist activity profiling.

Main Results:

• Six out of 25 tested molecules showed activity with binding affinities below 4 microM.
• The most potent molecule exhibited a K(i) of 9 nM.
• Five of the active molecules were identified as inverse agonists, revealing novel chemotypes.

Conclusions:

• Structure-based drug discovery is a viable and effective strategy for targeting aminergic GPCRs.
• This approach can identify potent inverse agonists and novel chemical scaffolds.
• The findings have significant implications for future GPCR-targeted drug discovery efforts.