A Doorway mechanism for Electron Attachment Induced DNA Strand Break

TL;DR

This paper introduces a new doorway mechanism involving dipole-bound states that explains how electrons attach and induce bond cleavage in DNA, with implications for understanding radiation damage.

Contribution

It proposes a novel electron attachment pathway via dipole-bound states that accounts for the rates of DNA strand breaks.

Findings

Dipole-bound states facilitate electron capture in DNA.

The sugar-phosphate bond cleavage rate exceeds that of the nucleobase.

Both bond cleavages are slower than stable anion formation.

Abstract

We report a new doorway mechanism for the dissociative electron attachment to genetic materials. The dipole-bound state of the nucleotide anion acts as the doorway for electron capture in the genetic material. The electron gets subsequently transferred to a dissociative {\sigma}* type anionic state localized on a sugar-phosphate or a sugar-nucleobase bond, leading to their cleavage. The electron transfer is mediated by the mixing of electronic and nuclear degrees of freedom. The cleavage rate of the sugar-phosphate bond predicted by this new mechanism is higher than that of the sugar-nucleobase bond breaking, and both processes are considerably slower than the formation of a stable valence-bound anion. The new mechanism explains the relative rates of electron attachment induced bond cleavages in genetic materials.