Protein Cold Denaturation in Implicit Solvent Simulations: A Transfer Free Energy Approach

Area of Science:

• Computational chemistry
• Biophysics
• Protein dynamics

Background:

• Proteins exhibit optimal function within a narrow temperature range.
• Extreme temperatures (hot and cold) induce denaturation, impairing protein function.
• Cold denaturation is driven by favorable water-protein interactions, posing challenges for implicit solvent models.

Purpose of the Study:

• To develop a novel computational implicit solvent model.
• To accurately simulate both hot and cold protein denaturation.
• To capture the parabolic temperature dependence of protein stability.

Main Methods:

• Mining nuclear magnetic resonance (NMR) structures to derive transfer free energy contributions.
• Developing an implicit solvent model incorporating temperature-dependent free energies.
• Simulating the Trp-cage protein as a model system.

Main Results:

• The developed implicit solvent model successfully recovers the parabolic temperature dependence of protein stability.
• The model captures both hot and cold denaturation phenomena.
• Cold-denatured states exhibit reduced secondary structure but retain hydrogen bonds, unlike heat-denatured states.

Conclusions:

• A novel implicit solvent model can accurately simulate protein stability across a wide temperature range.
• The model provides insights into the distinct structural characteristics of cold-denatured versus heat-denatured proteins.
• This approach advances computational modeling of protein behavior under thermal stress.