Atomic level rendering of DNA-drug encounter.

Area of Science:

• Computational chemistry
• Molecular modeling
• Biophysics

Background:

• Computer simulations are vital for understanding biological atomic mechanisms.
• Metal-based drugs, like cisplatin, are used in cancer therapy.
• Understanding drug-DNA interactions is crucial for drug development.

Purpose of the Study:

• To investigate the noncovalent interactions between metal-based drugs and DNA using molecular dynamics simulations.
• To compare the DNA binding affinity of cisplatin and its derivatives.
• To establish a simulation framework for future DNA-ligand interaction studies.

Main Methods:

• Extensive all-atom molecular dynamics simulations (3.7 μs total length).
• Analysis of drug-DNA noncovalent adduct formation.
• Estimation of binding free energies using Markov state models, Molecular Mechanics Poisson-Boltzmann Surface Area (MMPB-SA), and steered molecular dynamics with the Jarzynski estimator.

Main Results:

• Cisplatin exhibits lower affinity for noncovalent adducts in the DNA major groove compared to its aquo complexes.
• The entry position of drugs into the major groove is influenced by their net charge.
• Charged hydrolysis products demonstrate slightly more favorable binding free energies with DNA than cisplatin.
• Interaction energies for all complexes with DNA are below 3 kcal/mol.

Conclusions:

• Unbiased molecular dynamics simulations effectively describe metal-based drug interactions with DNA.
• Drug charge significantly impacts binding affinity and location within the DNA major groove.
• Computational methods provide reliable estimations of binding free energies, complementing experimental data.
• This study provides a foundation for simulating more complex DNA-ligand interactions.