Simplified proteomics approach to discover protein-ligand interactions

Area of Science:

• Biochemistry
• Proteomics
• Chemical Biology

Background:

• Identifying small molecule targets is crucial for drug discovery and chemical genetics.
• Traditional methods often require molecule labeling or immobilization, limiting their scope.
• Energetics-based approaches leverage changes in protein stability upon ligand binding.

Purpose of the Study:

• To develop a simplified, energetics-based method for identifying protein targets of small molecules.
• To demonstrate the method's utility in discovering ATP-binding proteins within a complex proteome.
• To validate novel protein-ATP interactions identified by the method.

Main Methods:

• Proteome fractionation using ion exchange chromatography.
• Monitoring urea-induced protein unfolding via changes in proteolytic susceptibility in the presence and absence of a ligand.
• Protein identification using SDS PAGE and mass spectrometry.

Main Results:

• Successfully identified ATP-binding proteins in the Escherichia coli proteome.
• Discovered novel ATP-interacting proteins beyond previously known binders.
• Validated a new ATP interaction with phosphoglyceromutase, confirming its stabilization by ATP.

Conclusions:

• The developed method offers a simple, label-free approach for proteomic-scale target identification.
• This technique requires minimal instrumentation and protein/ligand modification.
• It provides a valuable tool for investigating protein-drug and protein-metabolite interactions.