Development of an indole-based chemically cleavable linker concept for immobilizing bait compounds for protein...

Area of Science:

• Biochemistry
• Chemical Biology
• Proteomics

Background:

• Protein pull-down assays are crucial for identifying protein interactions.
• Existing methods often rely on affinity-based purification, which can introduce biases.
• A need exists for affinity-independent methods enabling cleaner elution of target proteins.

Purpose of the Study:

• To develop a novel, chemically cleavable linker system for affinity-independent protein pull-downs.
• To demonstrate the utility of this linker in identifying drug-target interactions.

Main Methods:

• A novel linker chemistry based on malondialdehyde-indole condensation was developed.
• The linker was used to immobilize bosutinib (a tyrosine kinase inhibitor) onto solid supports.
• Protein pull-down experiments were performed using K562 whole cell lysate.
• Eluted proteins were identified using liquid chromatography-tandem mass spectrometry.

Main Results:

• The novel linker chemistry proved compatible with protein pull-down experiments.
• The linker cleavage step, using pyrrolidine, did not cause protein hydrolysis or amino acid degradation.
• Key bosutinib targets, including Bruton's tyrosine kinase (Btk), were successfully identified.

Conclusions:

• The developed malondialdehyde-indole based linker system provides an effective method for affinity-independent protein pull-downs.
• This system facilitates the identification of drug targets and protein interaction partners.
• The chemical cleavage strategy ensures sample integrity for downstream analysis.