A Kirkwood-Buff force field for the aromatic amino acids

Area of Science:

• Computational chemistry
• Molecular modeling
• Biophysics

Background:

• Developing accurate protein force fields is crucial for molecular simulations.
• Existing models often struggle to capture complex intermolecular interactions in solution.
• The Kirkwood-Buff Force Field (KBFF) approach offers a promising avenue for improved force field development.

Purpose of the Study:

• To develop and present KBFF models for phenylalanine, tyrosine, tryptophan, and histidine side chains.
• To improve the description of intermolecular interactions in solution by reproducing thermodynamic properties.
• To provide accurate models for both neutral and protonated histidine tautomers.

Main Methods:

• Utilized the Kirkwood-Buff Force Field (KBFF) approach based on solution theory.
• Parameterized partial charges in the solution phase to match experimental Kirkwood-Buff integrals.
• Validated models by simulating thermodynamic and structural properties of eleven binary mixtures.

Main Results:

• Successfully developed KBFF models for aromatic amino acid side chains.
• The models accurately reproduce experimental Kirkwood-Buff integrals for various mixtures.
• Simulated thermodynamic and structural properties show a reasonable description of intermolecular interactions.

Conclusions:

• The developed KBFF models provide an improved description of solute-solute, solute-solvent, and solvent-solvent interactions.
• This approach offers a robust method for creating accurate non-polarizable protein force fields.
• The models are valuable for molecular simulations requiring precise thermodynamic and structural predictions.