Construction of Cell Membrane Chromatography Screening Materials Based on Avi-Tag Fused G Protein-Coupled Receptors

Mas-related G protein-coupled receptor X2 (MrgprX2) plays a crucial role in anaphylactoid reactions and allergic diseases. Some antagonists with reasonable potency and selectivity have been reported. Cell membrane chromatography (CMC) is effective for discovering ligands. Protein-tag-based CMC models (e.g., SNAP tags and HALO tags) have enhanced performance but also increased nonspecific adsorption of small molecules. The Avi tag, a short peptide sequence, binds biotin specifically via BirA catalysis. Our study showed that 2-iminobiotin (IB) can be a BirA substrate, enabling the development of a new cell membrane stationary phase (CMSP) based on the chemical properties (modifying carboxyl silica gel and specifically labeling the Avi tag) of IB. First, we constructed the MrgprX2-Avi-tag HEK293T cell line. Next, we synthesized IB-modified silica gel (SiO