Selection of peptides with surface affinity for alpha-chymotrypsin using a phage display library

Area of Science:

• Biochemistry
• Molecular Biology
• Enzymology

Background:

• Alpha-chymotrypsin is a serine protease involved in protein digestion.
• Understanding enzyme-surface interactions is crucial for drug development.
• Phage display is a powerful tool for identifying peptide ligands.

Purpose of the Study:

• To identify peptides that bind to the surface of alpha-chymotrypsin.
• To explore peptides interacting with non-active sites of the enzyme.
• To characterize the binding affinity and specificity of selected peptides.

Main Methods:

• Hexapeptide phage display library screening against alpha-chymotrypsin.
• DNA sequencing to identify peptide sequences.
• Chemical synthesis and competitive binding assays.
• Enzyme activity assays to assess substrate potential and inhibition.

Main Results:

• Five distinct hexapeptide sequences with affinity for alpha-chymotrypsin were identified.
• Selected peptides showed enhanced binding to alpha-chymotrypsin compared to the library.
• Synthesized peptides competitively inhibited phage binding, confirming affinity.
• Some peptides recognized common surface areas on alpha-chymotrypsin.
• Selected peptides were poor substrates and did not inhibit enzyme activity.

Conclusions:

• Peptide phage display can successfully identify ligands for enzyme surface structures.
• Selected peptides bind to non-catalytic sites of alpha-chymotrypsin.
• These findings offer insights into enzyme-surface recognition and potential therapeutic applications.