The case for trypsin release of affinity-selected phages

Area of Science:

• Biotechnology
• Molecular Biology
• Biochemistry

Background:

• Phage display libraries are crucial tools for identifying peptides that bind to specific targets.
• Current affinity selection methods often involve immobilized biomolecules as selectors.
• A significant challenge in phage display is recovery bias, where high-affinity binders are underrepresented due to inefficient release.

Purpose of the Study:

• To introduce and validate trypsin digestion as a superior release method in phage display affinity selection.
• To address and mitigate the issue of recovery bias inherent in traditional release methods.
• To demonstrate the effectiveness of trypsin digestion in recovering high-affinity phage clones.

Main Methods:

• Phage display libraries were constructed with peptides linked via trypsin-sensitive tethers.
• Affinity selection was performed using immobilized biomolecule selectors.
• Bound phages were released using trypsin digestion, exploiting phage resistance to the protease.
• Phage recovery rates were compared between trypsin digestion and conventional release methods.

Main Results:

• Trypsin digestion demonstrated a nearly complete release of bound phages, even from multiple irreversible bonds.
• This method significantly reduced or eliminated recovery bias associated with high-affinity binders.
• Phage infectivity was preserved during the trypsin-mediated release process.

Conclusions:

• Trypsin digestion is a highly effective and unbiased method for releasing phages from affinity selection.
• This technique enhances the recovery of high-affinity peptide binders from phage display libraries.
• The use of trypsin-sensitive tethers and phage protease resistance offers a robust solution to recovery bias.