Infrared characterization of the guanine radical cation: Finger printing DNA damage

Anthony W. Parker, Ching Yeh Lin, Michael W. George, Michael Towrie, Marina K. Kuimova

Research output: Journal PublicationArticlepeer-review

46 Citations (Scopus)

Abstract

Oxidation of DNA represents a major pathway of genetic mutation. We have applied infrared spectroscopy in 77 K glass with supporting density functional theory (DFT) calculations (EDF1/6-31+G*) to provide an IR signature of the guanine radical cation G, formed as a result of 193 nm photoionization of DNA. Deprotonation of this species to produce the neutral radical G(-H)̇ does not occur in 77 K glass. DFT calculations indicate that the formation of G within the double helix does not significantly perturb the geometry of the G/C pair, even though there is a significant movement of the N1 proton away from G toward C. However, this is in stark contrast to drastic changes that are expected if full deprotonation of G/C occurs, producing the G(-H)̇/C pair. These results are discussed in light of solution-phase time-resolved IR spectroscopic studies and demonstrate the power of IR to follow dynamics of DNA damage in natural environments.

Original languageEnglish
Pages (from-to)3660-3667
Number of pages8
JournalJournal of Physical Chemistry B
Volume114
Issue number10
DOIs
Publication statusPublished - 18 Mar 2010
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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