TKSA-MC: A web server for rational mutation through the optimization of protein charge interactions

Area of Science:

• Biochemistry
• Computational Biology
• Protein Engineering

Background:

• Protein stability is crucial for function and applications.
• Optimizing charge-charge interactions through mutations can enhance thermal stability.
• Understanding residue contributions to stability is key for protein engineering.

Purpose of the Study:

• To introduce the TKSAMC web server for calculating protein charge-charge interactions.
• To identify specific residues for mutation to improve protein thermal stability.
• To provide insights into residue electrostatic free energy contributions across pH conditions.

Main Methods:

• Utilizes the Tanford-Kirkwood Surface Accessibility model.
• Employs Monte Carlo methods for sampling protein protonation states.
• Calculates electrostatic free energy contributions of polar-charged residues.

Main Results:

• The server quantifies the electrostatic free energy contribution of each polar-charged residue to native state stability.
• Identifies residues with positive free energy contributions and high solvent exposure as targets for mutation.
• Visualizes residue energy contributions as a function of pH.

Conclusions:

• TKSAMC is a valuable tool for protein engineering and stability enhancement.
• Directed mutations based on electrostatic analysis can improve protein thermal stability.
• The server facilitates the rational design of proteins with improved stability profiles.