Oxidative DNA damage following photoexcitation of daunomycin: Direct role of oxygen

Radhika Kainthla, Maha Zewail-Foote

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

The chemistry of the photoactivation of daunomycin-DNA complexes is reported and the mechanism is elucidated. We quantitatively assessed the type of DNA damage, such as strand breaks, oxidized bases, and abasic sites, that arise using a plasmid relaxation assay coupled with DNA repair endonucleases. Photoexcitation of daunomycin leads to oxidative DNA damage in a dose- and irradiation time-dependent manner and guanine-specific oxidized purines are substantially produced under these conditions. Oxidative DNA base damage was also inhibited by argon degassing, indicating that guanine-specific damage arises from an oxygen-dependent mechanism. In addition, photoexcitation of daunomycin-DNA complexes leads to superoxide anion radical formation. From these studies of the actual product formed, we conclude that a charge transfer is a main driving force of the mechanism.

Original languageEnglish (US)
Pages (from-to)200-204
Number of pages5
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume198
Issue number2-3
DOIs
StatePublished - Aug 15 2008

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Keywords

  • Charge transfer reactions
  • DNA damage
  • Daunomycin
  • Photochemistry

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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