Method for screening and MALDI-TOF MS sequencing of encoded combinatorial libraries.

Area of Science:

• Biochemistry
• Organic Chemistry
• Molecular Biology

Background:

• Combinatorial peptide libraries are crucial for drug discovery and biochemical research.
• Efficient synthesis, screening, and sequencing methods are needed to accelerate the analysis of these libraries.

Purpose of the Study:

• To develop a novel method for encoded synthesis, on-resin screening, and sequencing of combinatorial peptide libraries.
• To apply this method to study transglutaminase (TGase) enzyme substrates and identify novel peptide sequences.

Main Methods:

• An improved binary tag system was used for encoded synthesis of peptide libraries.
• A versatile on-resin screening strategy involving magnetic separation and flow-cytometry-based sorting was developed.
• Sequencing was performed using MALDI-TOF MS analysis.

Main Results:

• The method was demonstrated on two libraries, identifying TGase-reactive peptides.
• A peptide sequence (PQQQYV) with 68-fold greater substrate specificity than known substrates was discovered.
• New details on the effect of amino acid composition on TGase substrates were revealed.

Conclusions:

• The developed method provides efficient and unambiguous analysis of combinatorial peptide libraries.
• This approach is broadly applicable for future peptide library synthesis and screening.
• The findings advance the understanding of enzyme-substrate interactions and peptide design.