Reductive damage in directly ionized DNA : saturation of the C5-C6 bond of cytosine in d(CGCG)2 crystals

M.G. Debije, D.M. Close, W.A. Bernhard

Research output: Contribution to journalArticleAcademicpeer-review

14 Citations (Scopus)

Abstract

Electron paramagnetic resonance (EPR) was used to study an oligodeoxynucleotide duplex of d(CGCG)2 that is known to crystallize in Z-form. After X irradiation at 4 K, EPR data were collected on single crystals and polycrystalline samples as a function of annealing temperature and dose. A radical produced by the net gain of a hydrogen atom at C6 and a proton at N3, Cyt(C6+H, N3+H+)+¿·, is identified. This radical had not been positively identified in polymeric DNA previously. The Cyt(C6+H, N3+H+)+¿· makes up about 4¿% of the total radical population at 4 K, increasing to about 10¿–¿15¿% after the DNA is annealed to 240 K. There appears to be neither an increase nor a decrease in the absolute concentration of Cyt(C6+H, N3+H+)+¿· upon annealing from 4 K to 240 K. Additionally, the presence of another radical, one due to the net gain of hydrogen at C5 of cytosine, the Cyt(C5+H)·, is implicated. Together, these two radicals appear to account for 60¿–¿80¿% of the reduced species in DNA that has been irradiated at 4 K and annealed to 240 K.
LanguageEnglish
Pages235-242
Number of pages8
JournalRadiation Research
Volume157
Issue number3
DOIs
StatePublished - 2002

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Cytosine
deoxyribonucleic acid
Electron Spin Resonance Spectroscopy
damage
saturation
Hydrogen
DNA
crystals
Oligodeoxyribonucleotides
electron paramagnetic resonance
Protons
annealing
Temperature
hydrogen atoms
Population
d(CGCG)
dosage
irradiation
protons
single crystals

Cite this

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title = "Reductive damage in directly ionized DNA : saturation of the C5-C6 bond of cytosine in d(CGCG)2 crystals",
abstract = "Electron paramagnetic resonance (EPR) was used to study an oligodeoxynucleotide duplex of d(CGCG)2 that is known to crystallize in Z-form. After X irradiation at 4 K, EPR data were collected on single crystals and polycrystalline samples as a function of annealing temperature and dose. A radical produced by the net gain of a hydrogen atom at C6 and a proton at N3, Cyt(C6+H, N3+H+)+¿·, is identified. This radical had not been positively identified in polymeric DNA previously. The Cyt(C6+H, N3+H+)+¿· makes up about 4¿{\%} of the total radical population at 4 K, increasing to about 10¿–¿15¿{\%} after the DNA is annealed to 240 K. There appears to be neither an increase nor a decrease in the absolute concentration of Cyt(C6+H, N3+H+)+¿· upon annealing from 4 K to 240 K. Additionally, the presence of another radical, one due to the net gain of hydrogen at C5 of cytosine, the Cyt(C5+H)·, is implicated. Together, these two radicals appear to account for 60¿–¿80¿{\%} of the reduced species in DNA that has been irradiated at 4 K and annealed to 240 K.",
author = "M.G. Debije and D.M. Close and W.A. Bernhard",
year = "2002",
doi = "10.1667/0033-7587(2002)157[0235:RDIDID]2.0.CO;2",
language = "English",
volume = "157",
pages = "235--242",
journal = "Radiation Research",
issn = "1938-5404",
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}

Reductive damage in directly ionized DNA : saturation of the C5-C6 bond of cytosine in d(CGCG)2 crystals. / Debije, M.G.; Close, D.M.; Bernhard, W.A.

In: Radiation Research, Vol. 157, No. 3, 2002, p. 235-242.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Reductive damage in directly ionized DNA : saturation of the C5-C6 bond of cytosine in d(CGCG)2 crystals

AU - Debije,M.G.

AU - Close,D.M.

AU - Bernhard,W.A.

PY - 2002

Y1 - 2002

N2 - Electron paramagnetic resonance (EPR) was used to study an oligodeoxynucleotide duplex of d(CGCG)2 that is known to crystallize in Z-form. After X irradiation at 4 K, EPR data were collected on single crystals and polycrystalline samples as a function of annealing temperature and dose. A radical produced by the net gain of a hydrogen atom at C6 and a proton at N3, Cyt(C6+H, N3+H+)+¿·, is identified. This radical had not been positively identified in polymeric DNA previously. The Cyt(C6+H, N3+H+)+¿· makes up about 4¿% of the total radical population at 4 K, increasing to about 10¿–¿15¿% after the DNA is annealed to 240 K. There appears to be neither an increase nor a decrease in the absolute concentration of Cyt(C6+H, N3+H+)+¿· upon annealing from 4 K to 240 K. Additionally, the presence of another radical, one due to the net gain of hydrogen at C5 of cytosine, the Cyt(C5+H)·, is implicated. Together, these two radicals appear to account for 60¿–¿80¿% of the reduced species in DNA that has been irradiated at 4 K and annealed to 240 K.

AB - Electron paramagnetic resonance (EPR) was used to study an oligodeoxynucleotide duplex of d(CGCG)2 that is known to crystallize in Z-form. After X irradiation at 4 K, EPR data were collected on single crystals and polycrystalline samples as a function of annealing temperature and dose. A radical produced by the net gain of a hydrogen atom at C6 and a proton at N3, Cyt(C6+H, N3+H+)+¿·, is identified. This radical had not been positively identified in polymeric DNA previously. The Cyt(C6+H, N3+H+)+¿· makes up about 4¿% of the total radical population at 4 K, increasing to about 10¿–¿15¿% after the DNA is annealed to 240 K. There appears to be neither an increase nor a decrease in the absolute concentration of Cyt(C6+H, N3+H+)+¿· upon annealing from 4 K to 240 K. Additionally, the presence of another radical, one due to the net gain of hydrogen at C5 of cytosine, the Cyt(C5+H)·, is implicated. Together, these two radicals appear to account for 60¿–¿80¿% of the reduced species in DNA that has been irradiated at 4 K and annealed to 240 K.

U2 - 10.1667/0033-7587(2002)157[0235:RDIDID]2.0.CO;2

DO - 10.1667/0033-7587(2002)157[0235:RDIDID]2.0.CO;2

M3 - Article

VL - 157

SP - 235

EP - 242

JO - Radiation Research

T2 - Radiation Research

JF - Radiation Research

SN - 1938-5404

IS - 3

ER -