Folding thermodynamics of peptides.

Area of Science:

• Computational biology
• Biophysics
• Protein dynamics

Background:

• Protein folding is crucial for biological function.
• Accurate atomic-level modeling of protein folding remains a challenge.
• Existing models often require extensive parameterization for different proteins.

Purpose of the Study:

• To introduce and validate a simplified, sequence-based interaction potential for atomic-level protein folding simulations.
• To assess the model's ability to fold diverse peptide structures, including alpha-helical and beta-sheet conformations.
• To compare the model's predicted peptide melting behavior with experimental observations.

Main Methods:

• Development of a novel, sequence-dependent simplified interaction potential.
• Application of the potential to a test set of peptides (approx. 20 residues) with known structures (e.g., Trp cage, GB1 variants, Betanova, LLM).
• Simulation of peptide folding and melting behavior using the developed model.

Main Results:

• The sequence-based model successfully folded diverse peptides (alpha-helical and beta-sheet) using a single set of parameters.
• Predicted peptide melting behavior showed good quantitative agreement with experimental data.
• Comparison of folding populations from different observables revealed peptide-specific behaviors, with some peptides exhibiting two-state-like melting.

Conclusions:

• The simplified, sequence-based potential is effective for modeling atomic-level protein folding across different peptide types.
• The model's ability to reproduce experimental melting curves highlights its quantitative accuracy.
• The findings suggest the potential's utility for studying protein folding mechanisms and dynamics.