Engineered staphylococcal protein A's IgG-binding domain with cathepsin L inhibitory activity

Area of Science:

• Biochemistry
• Protein Engineering
• Molecular Biology

Background:

• Papain-like cysteine proteases are implicated in various physiological and pathological processes.
• Developing specific inhibitors for these proteases is crucial for therapeutic and research applications.

Purpose of the Study:

• To engineer a novel fusion protein for inhibiting papain-like cysteine proteases.
• To create a stable and functional display system for protease inhibitors.

Main Methods:

• Affinity selection of an inhibitory peptide from a phage-displayed library.
• Grafting the selected peptide onto a staphylococcal protein A scaffold.
• Modifying the scaffold for solvent-exposed peptide display.
• Confirmation of protein folding and function using CD-spectroscopy and Fc-binding assays.

Main Results:

• Successfully created fusion proteins displaying the inhibitory peptide.
• Confirmed correct folding and functionality of the recombinant constructs.
• Demonstrated low-micromolar inhibition of cathepsin L by the engineered proteins.

Conclusions:

• The engineered fusion protein is a potent inhibitor of cathepsin L.
• This approach provides a versatile platform for developing novel protease inhibitors.