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

doi:10.1021/jp9106958

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

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51 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 language	English
Pages (from-to)	3660-3667
Number of pages	8
Journal	Journal of Physical Chemistry B
Volume	114
Issue number	10
DOIs	https://doi.org/10.1021/jp9106958
Publication status	Published - 18 Mar 2010

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title = "Infrared characterization of the guanine radical cation: Finger printing DNA damage",

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.",

author = "Parker, {Anthony W.} and Lin, {Ching Yeh} and George, {Michael W.} and Michael Towrie and Kuimova, {Marina K.}",

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TY - JOUR

T1 - Infrared characterization of the guanine radical cation

T2 - Finger printing DNA damage

AU - Parker, Anthony W.

AU - Lin, Ching Yeh

AU - George, Michael W.

AU - Towrie, Michael

AU - Kuimova, Marina K.

PY - 2010/3/18

Y1 - 2010/3/18

N2 - 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.

AB - 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.

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JF - Journal of Physical Chemistry B

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ER -

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

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