Long-Time-Step Molecular Dynamics through Hydrogen Mass Repartitioning.

Area of Science:

• Computational Chemistry
• Biophysics
• Molecular Dynamics Simulations

Background:

• Molecular dynamics (MD) simulations are crucial for studying molecular behavior.
• Increasing simulation time steps can significantly accelerate MD, but often leads to instability or errors.
• Hydrogen mass repartitioning (HMR) is a technique that redistributes mass to hydrogen atoms to slow high-frequency motions.

Purpose of the Study:

• To investigate the stability and accuracy of MD simulations using hydrogen mass repartitioning (HMR) with increased time steps.
• To determine if HMR enables larger time steps without introducing significant discretization errors.
• To validate the effectiveness of HMR on both small peptides and larger proteins.

Main Methods:

• Simulations were performed on a three-residue peptide and a 129-residue hen egg white lysozyme (HEWL) protein.
• Varying time steps and mass distributions were tested to assess HMR's impact.
• Structural comparisons, pKa calculations, and potential of mean force (PMF) calculations were conducted.

Main Results:

• HMR allows for stable increases in simulation time steps, up to a factor of 2, without significant discretization error.
• Simulations on HEWL showed that HMR is effective for larger, more realistic systems.
• Kinetic and thermodynamic properties calculated using HMR trajectories showed no significant differences compared to standard MD.

Conclusions:

• Hydrogen mass repartitioning (HMR) is a viable method for accelerating molecular dynamics (MD) simulations.
• HMR enables longer time steps, leading to faster simulations of molecules with biochemical interest.
• The technique maintains simulation accuracy and stability, making it a valuable tool for computational studies.