Free-energy calculations along a high-dimensional fragmented path with constrained dynamics

Area of Science:

• Computational chemistry
• Biophysics
• Molecular dynamics

Background:

• Free-energy calculations are crucial for understanding biomolecular processes.
• High-dimensional systems like proteins present significant sampling challenges in conformational space.
• Existing path-based methods (thermodynamic integration, free-energy perturbation) require extensive sampling along predefined paths.

Purpose of the Study:

• To address the sampling problem in free-energy calculations for high-dimensional biomolecular systems.
• To develop a practical method for free-energy calculations along complex transition paths.
• To overcome the difficulty of defining explicit reaction coordinates in constrained dynamics.

Main Methods:

• Utilized restrained dynamics to define and optimize a transition path.
• Divided the optimized path into smaller fragments.
• Introduced a virtual reaction coordinate for positional reference within fragments.
• Employed constrained dynamics for formal free-energy calculations on each fragment.
• Integrated fragment-based calculations to obtain the complete free-energy profile.

Main Results:

• Successfully performed free-energy calculations without explicit Cartesian reaction coordinates.
• Demonstrated a novel strategy for calculating free-energy profiles of biomolecules.
• The proposed method avoids the need for complex, atom-specific coordinate definitions.

Conclusions:

• The developed method offers a practical solution for free-energy calculations in complex biomolecular systems.
• This approach enhances the feasibility of studying transitions in peptides and proteins.
• Provides a novel computational strategy for biophysical and computational chemistry research.