Electronic Excitation Response of DNA to High-energy Proton Radiation in Water

Abstract

The lack of molecular-level understanding for the electronic excitation response of DNA to charged particle radiation, such as high-energy protons, remains a fundamental scientific bottleneck in advancing proton and other ion beam cancer therapies. In particular, the dependence of different types of DNA damage on high-energy protons represents a significant knowledge void. Here we employ first-principles real-time time-dependent density functional theory simulation, using a massively-parallel supercomputer, to unravel the quantum-mechanical details of the energy transfer from high-energy protons to DNA in water. The calculations reveal that protons deposit significantly more energy onto the DNA sugar-phosphate side chains than onto the nucleobases, and greater energy transfer is expected onto the DNA side chains than onto water. As a result of this electronic stopping process, highly energetic holes are generated on the DNA side chains as a source of oxidative damage.

Main text (9 pages) with 4 figures and Supplemental Information

References in corpus (2)

• Canonical sampling through velocity-rescaling
• Propagation of maximally localized Wannier functions in real-time TDDFT

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• Theory of Moment Propagation for Quantum Dynamics in Single-Particle Description
• In Situ Observation of Proton-Induced DNA Fragmentation in the Bragg Peak: Evidence for a Protective Role of Water