Activity-based probe for specific photoaffinity labeling gamma-aminobutyric acid B (GABAB) receptors on living cells: design, synthesis, and biological evaluation.

A trimodular activity-based probe was designed, synthesized, characterized, and applied to photoaffinity label the GABA(B) receptors transiently expressed in Chinese hamster ovary (CHO) cells. The probe exhibits specific binding activity at the ligand-binding pocket of GB1 subunits and high specificity of photoaffinity labeling, which makes the probe valuable for studying the localization and function of GABA(B) receptors on living cells.