Direct observation of ultrafast-electron-transfer reactions unravels high effectiveness of reductive DNA damage

Jenny Nguyen, Yuhan Ma, Ting Luo, Robert G Bristow, David A Jaffray, Qing-Bin Lu

Research output: Contribution to journalArticlepeer-review

Abstract

Both water and electron-transfer reactions play important roles in chemistry, physics, biology, and the environment. Oxidative DNA damage is a well-known mechanism, whereas the relative role of reductive DNA damage is unknown. The prehydrated electron (e(pre)-), a novel species of electrons in water, is a fascinating species due to its fundamental importance in chemistry, biology, and the environment. e(pre)- is an ideal agent to observe reductive DNA damage. Here, we report both the first in situ femtosecond time-resolved laser spectroscopy measurements of ultrafast-electron-transfer (UET) reactions of e(pre)- with various scavengers (KNO(3), isopropanol, and dimethyl sulfoxide) and the first gel electrophoresis measurements of DNA strand breaks induced by e(pre)- and OH(•) radicals co-produced by two-UV-photon photolysis of water. We strikingly found that the yield of reductive DNA strand breaks induced by each e(pre)- is twice the yield of oxidative DNA strand breaks induced by each OH(•) radical. Our results not only unravel the long-standing mystery about the relative role of radicals in inducing DNA damage under ionizing radiation, but also challenge the conventional notion that oxidative damage is the main pathway for DNA damage. The results also show the potential of femtomedicine as a new transdisciplinary frontier and the broad significance of UET reactions of e(pre)- in many processes in chemistry, physics, biology, and the environment.

Original languageEnglish
Pages (from-to)11778-11783
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number29
DOIs
Publication statusPublished - 19 Jul 2011

Keywords

  • Biophysics
  • DNA Damage/physiology
  • Electron Transport/physiology
  • Electrophoresis, Agar Gel
  • Free Radical Scavengers/metabolism
  • Hydroxides/chemistry
  • Oxidation-Reduction
  • Spectrum Analysis
  • Water/chemistry

Research Beacons, Institutes and Platforms

  • Manchester Cancer Research Centre

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