Metal complex-DNA binding: Insights from molecular dynamics and DFT/MM calculations

Area of Science:

• Computational Chemistry
• Biophysical Chemistry
• Molecular Modeling

Background:

• Cationic metallointercalators are crucial in DNA-based therapeutics.
• Understanding their binding mechanisms at a molecular level is essential for drug design.

Purpose of the Study:

• To elucidate the detailed binding interactions between [Cu(gly)(dppz)](+) and dodecanucleotide duplexes.
• To computationally determine the binding modes and energetics of the metallointercalator-DNA complex.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model the system.
• Density functional theory/molecular mechanics (DFT/MM) calculations were performed for detailed structural and energetic analysis.
• Thermodynamic parameters (enthalpy, Gibbs free energy) were calculated in vacuo and in solution.

Main Results:

• Three distinct DNA binding modes were identified: metal coordination, dppz chromophore intercalation, and hydrogen bonding by the glycinato ligand.
• The calculated formation energies of the complexes showed excellent agreement with experimental DNA-binding constants.
• The study provides a physical interpretation of enthalpy, entropy, and solvent contributions to the binding mechanism.

Conclusions:

• The combined MD and DFT/MM approach successfully models complex DNA-metallointercalator interactions.
• The findings offer a detailed molecular understanding of the binding mechanism, aiding in the development of novel DNA-targeting agents.