Native contacts determine protein folding mechanisms in atomistic simulations

Area of Science:

• Biophysics
• Computational Biology
• Protein Dynamics

Background:

• Understanding protein folding is crucial for molecular biology and disease research.
• Atomistic simulations provide detailed insights into complex biological processes.
• Identifying key interactions driving protein folding remains a significant challenge.

Purpose of the Study:

• To identify the critical interactions governing protein folding mechanisms.
• To evaluate the role of native versus nonnative contacts in folding pathways.
• To develop quantitative measures for assessing contact importance in folding.

Main Methods:

• Analysis of long equilibrium simulations for over 10 proteins in atomistic detail.
• Quantification of the collective fraction of native amino acid contacts (Q) to capture transition states.
• Development of two novel measures: log-ratio of contact lifetimes and a Bayesian predictive measure.

Main Results:

• The collective fraction of native contacts (Q) accurately describes transition states for proteins with folding barriers.
• Both developed measures confirm the importance of native or near-native contacts in determining folding mechanisms.
• Nonnative contacts were found to play a negligible role in the folding mechanisms of most studied proteins.

Conclusions:

• Protein folding mechanisms are predominantly dictated by native contacts.
• Nonnative contacts generally do not significantly influence the folding pathways of proteins.
• The developed quantitative measures are effective tools for dissecting folding mechanisms.