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 language | English |
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Pages (from-to) | 3660-3667 |
Number of pages | 8 |
Journal | Journal of Physical Chemistry B |
Volume | 114 |
Issue number | 10 |
DOIs | |
Publication status | Published - 18 Mar 2010 |
Externally published | Yes |
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films
- Materials Chemistry