Zinc binding in proteins and solution: a simple but accurate nonbonded representation

Area of Science:

• Computational chemistry
• Biomolecular modeling

Background:

• Divalent zinc ions play crucial roles in biological systems.
• Accurate modeling of zinc ions in simulations is essential for understanding their function.
• Existing force fields often struggle to precisely represent zinc ion interactions.

Purpose of the Study:

• To develop and validate new force field parameters for divalent zinc.
• To assess the performance of these parameters in both solution and protein simulations.
• To improve the accuracy of molecular dynamics simulations involving zinc.

Main Methods:

• Development of force field parameters combining Lennard-Jones and electrostatic interactions for zinc.
• Testing parameters using free energy of solution calculations.
• Performing molecular dynamics simulations of carboxypeptidase A and carbonic anhydrase.
• Utilizing the CHARMM 22 beta all-atom parameter set and the Extended Electrostatics model.

Main Results:

• The developed zinc parameters yield free energies of solution that closely match experimental data.
• Simulations with the new parameters achieve structural accuracy comparable to specialized bonded models.
• The Extended Electrostatics model enhances the equilibrium conformation of active sites.
• The parameters effectively allow for varied coordination geometries and ligand exchange for zinc.

Conclusions:

• The new zinc force field parameters are effective for both solution and protein simulations.
• These parameters enable more accurate modeling of zinc-containing biological systems.
• The developed parameters offer a versatile tool for computational studies of zinc's role in chemistry and biology.