A Tandem-Affinity Purification Method for Identification of Primary Intracellular Drug-Binding Proteins

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• Understanding small molecule drug interactions with cellular components is vital for drug discovery.
• Identifying primary drug targets is essential for elucidating drug mechanisms of action and selectivity.

Purpose of the Study:

• To introduce a novel methodology, Tandem Affinity Purification for Drug-Binding Proteins (TAP-DBP), for unbiased identification of primary drug targets.
• To enable precise identification of drug-protein interactions within cells.

Main Methods:

• Generation of a FLAG-hemagglutinin (HA)-tagged chimeric protein with FKBP12(F36V) adaptor and TurboID enzyme.
• Conjugation of drugs to the FKBP12(F36V) ligand for recruitment of binding partners.
• In-cell TurboID-mediated biotinylation followed by tandem affinity purification (FLAG-immunoprecipitation and streptavidin pulldown) and mass spectrometry.

Main Results:

• Successful development and implementation of the TAP-DBP methodology.
• Precise identification of primary drug-binding proteins.
• Demonstration of the method's utility in understanding drug-target engagement and selectivity.

Conclusions:

• TAP-DBP provides a systematic and unbiased approach for identifying drug-protein interactions.
• This method significantly contributes to understanding the mode of action of drugs at the cellular level.
• The study advances drug discovery by offering a tool to clarify target engagement and drug selectivity.