Coupling Constant pH Molecular Dynamics with Accelerated Molecular Dynamics.

Area of Science:

• Computational Chemistry
• Biomolecular Modeling
• Molecular Dynamics

Background:

• Standard constant pH molecular dynamics methods face sampling challenges, leading to slow convergence for certain residues.
• Previous work by Mongan et al. showed promise but noted inconsistencies in predicted pK(a) values for systems like hen egg-white lysozyme (HEWL) due to slow convergence of strongly interacting residues.

Purpose of the Study:

• To propose an extension of the constant pH method by integrating it with accelerated molecular dynamics.
• To overcome sampling limitations inherent in standard constant pH molecular dynamics approaches.
• To improve the accuracy and speed of pK(a) predictions for complex biomolecular systems.

Main Methods:

• Coupling the constant pH methodology with the enhanced sampling technique of accelerated molecular dynamics.
• Applying the adapted method to the hen egg-white lysozyme (HEWL) system for pK(a) value prediction.

Main Results:

• The coupled method demonstrates improved sampling efficiency compared to the standard constant pH method.
• Faster convergence was observed for residues that previously converged slowly.
• Predicted pK(a) values for HEWL showed closer agreement with experimental data, particularly for challenging residues.

Conclusions:

• The integration of accelerated molecular dynamics with the constant pH method effectively addresses sampling issues in molecular simulations.
• This enhanced approach provides more reliable and experimentally consistent pK(a) predictions for biomolecules.
• The method offers a valuable advancement for computational studies of protein protonation states.