Flexible Boundaries for Multiresolution Solvation: An Algorithm for Spatial Multiscaling in Molecular Dynamics...

Area of Science:

• Computational Chemistry
• Biophysics
• Molecular Dynamics Simulations

Background:

• Molecular dynamics (MD) simulations are crucial for understanding biomolecular behavior.
• Accurately modeling solvent effects at different resolutions presents a computational challenge.
• Existing methods often struggle to balance accuracy and efficiency in solvation studies.

Purpose of the Study:

• To introduce a novel algorithm, flexible boundaries for multiresolution solvation (FBMS), for MD simulations.
• To enable efficient simulations by combining atomistic fine-grained (FG) and coarse-grained (CG) solvent representations.
• To develop a method that adapts to solute shape and conformational changes.

Main Methods:

• The FBMS method employs a three-region solvent layering: FG, mixed FG-CG buffer, and bulk CG.
• Layer boundaries are defined by an effective solute surface distance, adapting to solute geometry.
• Half-harmonic distance restraints enforce layering, with a restraint-free buffer zone for FG-CG mixing.

Main Results:

• Validation using GROMOS force field with SPC (FG) and CGW (CG) water models.
• Simulations of pure water, deca-alanine peptide (unfolding), and four proteins showed good agreement with pure FG simulations.
• The method successfully simulated dynamic changes in solvation layers during peptide unfolding.

Conclusions:

• The FBMS algorithm provides an efficient and accurate approach for multiresolution molecular dynamics simulations.
• It effectively captures structural, energetic, and solvation properties comparable to all-atom simulations.
• FBMS is a promising method for studying large biomolecules and their interactions with solvent.