Local structure formation in simulations of two small proteins

Area of Science:

• Computational biology
• Biophysics
• Protein dynamics

Background:

• Understanding protein folding is crucial for molecular biology.
• Local structures like alpha-helices are fundamental to protein architecture.
• The formation of these structures in small proteins is not fully understood.

Purpose of the Study:

• To investigate the formation and persistence of local structures in small alpha-helical proteins.
• To determine the sequence of helix formation during protein folding.
• To identify residue-residue interactions that predict local structure formation.

Main Methods:

• Utilized massively parallel all-atom, explicit solvent molecular dynamics simulations.
• Simulated two small alpha-helical proteins: villin headpiece and helical fragment B of protein A.
• Analyzed simulation trajectories to observe transient helices and residue-residue contacts.

Main Results:

• Observed the existence of transient helices and helix combinations within the unfolded ensemble.
• Determined the order of helix formation, aligning with previous experimental findings.
• Found transient local structure formation independent of overall native structure.
• Identified statistically predictive residue-residue pairs for specific local structure formation.

Conclusions:

• Transient local structures, including alpha-helices, are present in the unfolded state of small proteins.
• The sequence of helix formation is consistent with experimental data.
• Specific residue interactions can predict the emergence of local structural elements during folding.