RADACK, a stochastic simulation of hydroxyl radical attack to DNA

Area of Science:

• Computational chemistry
• Molecular modeling
• Radiation chemistry

Background:

• DNA is susceptible to radiation-induced damage.
• Understanding DNA damage is crucial for fields like radiobiology and cancer therapy.
• Existing models may not fully capture sequence- and structure-dependent damage.

Purpose of the Study:

• To introduce RADACK, a computational tool for simulating radiation-induced DNA attack.
• To assess how DNA sequence, structure, and ligand binding influence damage.
• To predict the formation of frank strand breaks (FSB) and alkali-revealed breaks (ARB).

Main Methods:

• RADACK simulates OH* radical attack probabilities on reactive DNA atoms.
• Incorporates sequence-dependent DNA structures from experimental or modeled data.
• Calculates damage conversion efficiencies for different DNA forms and ligand complexes.

Main Results:

• RADACK successfully models damage distribution in various DNA forms (B, Z, quadruplex).
• Calculated radical attack probabilities correlate with experimental FSB and ARB data.
• Demonstrated accuracy in DNA-protein systems like lac repressor-operator and nucleosome core.

Conclusions:

• RADACK provides a robust framework for simulating radiation-DNA interactions.
• The model accurately predicts sequence-, structure-, and ligand-dependent DNA damage.
• This tool can advance our understanding of DNA repair and radiosensitivity.