Polarizable Force Field for Protein with Charge Response Kernel.

Area of Science:

• Computational Chemistry
• Biomolecular Modeling
• Molecular Dynamics

Background:

• Accurate molecular mechanical force fields are crucial for simulating protein behavior.
• Existing force fields often neglect electronic polarization, limiting simulation accuracy.
• Developing polarizable force fields is essential for understanding protein dynamics.

Purpose of the Study:

• To introduce a novel molecular mechanical force field for polypeptides and proteins that incorporates electronic polarization.
• To refine electrostatic and torsional parameters using ab initio calculations for enhanced accuracy.
• To validate the new force field through molecular dynamics simulations and spectral analysis.

Main Methods:

• Developed a force field incorporating the charge response kernel for electronic polarization.
• Derived electrostatic parameters for 20 amino acids from ab initio electronic structure calculations.
• Refitted dihedral angle parameters to match ab initio optimized geometries and energies of dipeptide conformers.
• Performed molecular dynamics simulations of peptides in aqueous solution.
• Calculated infrared spectra to analyze polarization effects.

Main Results:

• The new force field successfully models polypeptides and proteins with electronic polarization.
• Ab initio calculations provided accurate electrostatic and torsional parameters.
• Simulations of alanine tetrapeptides and cyclic pentapeptides demonstrated the force field's applicability.
• Analysis of infrared spectra revealed the impact of charge polarization on spectral profiles.

Conclusions:

• The developed polarizable force field enhances the accuracy of biomolecular simulations.
• This approach provides a more realistic representation of protein behavior in solution.
• The method offers improved tools for analyzing protein dynamics and spectral properties.