Novel Tetrafunctional Probes Identify Target Receptors and Binding Sites of Small-Molecule Drugs from Living Systems

ACS Chem Biol. 2020 Sep 18;15(9):2364-2373. doi: 10.1021/acschembio.0c00335. Epub 2020 Aug 20.

Abstract

Significant advancement of chemoproteomics has contributed to uncovering the mechanism of action (MoA) of small-molecule drugs by characterizing drug-protein interactions in living systems. However, cell-membrane proteins such as G protein-coupled receptors (GPCRs) and ion channels, due to their low abundance and unique biophysical properties associated with multiple transmembrane domains, can present challenges for proteome-wide mapping of drug-receptor interactions. Herein, we describe the development of novel tetrafunctional probes, consisting of (1) a ligand of interest, (2) 2-aryl-5-carboxytetrazole (ACT) as a photoreactive group, (3) a hydrazine-labile cleavable linker, and (4) biotin for enrichment. In live cell labeling studies, we demonstrated that the ACT-based probe showed superior reactivity and selectivity for labeling on-target GPCR by mass spectrometry analysis compared with control probes including diazirine-based probes. By leveraging ACT-based cleavable probes, we further identified a set of representative ionotropic receptors, targeted by CNS drugs, with remarkable selectivity and precise binding site information from mouse brain slices. We anticipate that the robust chemoproteomic platform using the ACT-based cleavable probe coupled with phenotypic screening should promote identification of pharmacologically relevant target receptors of drug candidates and ultimately development of first-in-class drugs with novel MoA.

MeSH terms

  • Animals
  • Binding Sites
  • Brain / metabolism
  • CHO Cells
  • Central Nervous System Agents / chemical synthesis
  • Central Nervous System Agents / chemistry
  • Cricetulus
  • Cyclohexanones / chemical synthesis
  • Cyclohexanones / chemistry
  • Hydrazines / chemistry
  • Mass Spectrometry
  • Mice
  • Molecular Probes / chemical synthesis
  • Molecular Probes / chemistry*
  • Molecular Probes / radiation effects
  • Proteomics / methods
  • Receptors, AMPA / analysis*
  • Receptors, AMPA / chemistry
  • Receptors, AMPA / metabolism
  • Receptors, Dopamine D2 / analysis*
  • Receptors, Dopamine D2 / chemistry
  • Receptors, Dopamine D2 / metabolism
  • Receptors, GABA / analysis*
  • Receptors, GABA / chemistry
  • Receptors, GABA / metabolism
  • Tetrazoles / chemical synthesis
  • Tetrazoles / chemistry*
  • Tetrazoles / radiation effects
  • Ultraviolet Rays

Substances

  • Central Nervous System Agents
  • Cyclohexanones
  • Hydrazines
  • Molecular Probes
  • Receptors, AMPA
  • Receptors, Dopamine D2
  • Receptors, GABA
  • Tetrazoles
  • hydrazine