A universal method for surface-based binding assays by preparing immobilized β₂-adrenergic receptor stationary phase...

Area of Science:

• Biochemistry
• Molecular Biology
• Drug Discovery

Background:

• G protein-coupled receptors (GPCRs) are crucial drug targets, but their purification and immobilization for assays remain challenging.
• Developing universal methods for handling these complex membrane proteins is essential for advancing pharmaceutical research.

Purpose of the Study:

• To establish a general, rapid, and efficient method for purifying and immobilizing functional GPCRs, specifically the beta-2 adrenergic receptor (β2AR).
• To evaluate the impact of a novel immobilization strategy on ligand-binding assays.

Main Methods:

• Screened six silica-binding peptides to identify CotB1p for its affinity to macroporous silica gel.
• Investigated adsorption and desorption of CotB1p-tagged β2AR (β2AR-CotB1p) under various conditions.
• Optimized a protocol for direct immobilization from E. coli lysates and elution using L-arginine/L-lysine.

Main Results:

• Achieved 95% purity of β2AR from E. coli lysates using the CotB1p-silica gel system.
• Immobilized β2AR-CotB1p demonstrated significantly higher ligand-binding affinities (KAs) compared to a traditional covalent method.
• The entire immobilization process was completed within 30 minutes, simplifying assay development.

Conclusions:

• The CotB1p-mediated strategy offers a simple, rapid, and universal approach for purifying and immobilizing unstable biomolecules like GPCRs.
• This method enhances the accuracy of receptor-ligand binding parameter determination, benefiting analytical and biological applications.
• The developed technique holds potential for creating novel assays for drug-like properties and GPCR partner discovery.