Abstract
8-Oxo-7,8-dihydroguanine is one the most abundant base lesions in pro- and eukaryotic DNA. In mammalian cells, it is excised by the 8-oxoguanine DNA glycosylase (OGG1) during DNA base-excision repair, and the generated free 8-oxoG base is one of the DNA-derived biomarkers of oxidative stress in biological samples. The modification of 8-oxoG in the context of nucleoside and DNA has been the subject of many studies; however, the oxidative transformation of the free 8-oxoG base has not been described. By using biochemical and cell biological assays, we show that in the presence of molecular oxygen, the free 8-oxoG base transforms to a highly reactive hydroperoxide (8-oxoG*). Specifically, 8-oxoG* oxidizes Amplex red to resorufin, H 2DCF to DCF, Fe 2+ to Fe 3+, and GSH to GSSG. This property of 8-oxoG* was diminished by treatment with catalase and glutathione peroxidase, but not superoxide dismutase. 8-OxoG* formation was prevented by reducing agents or nitrogen atmosphere. Its addition to CM-H 2DCF-DA-loaded cells rapidly increased intracellular DCF fluorescence. There were no such properties observed for 8-oxodeoxyguanosine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 2′-deoxyguanosine, guanine, adenine, guanosine, and 8-hydroxyadenine. These data imply that a free 8-oxoG base is more susceptible to oxidation than is its nucleoside form and, consequently, it stands as unique among intact and oxidatively modified purines.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 749-756 |
| Number of pages | 8 |
| Journal | Free Radical Biology and Medicine |
| Volume | 52 |
| Issue number | 4 |
| DOIs | |
| State | Published - Feb 15 2012 |
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Keywords
- Free 8-oxoguanine base
- Free radicals
- Oxidative stress
ASJC Scopus subject areas
- Biochemistry
- Physiology (medical)
Cite this
Biochemical identification of a hydroperoxide derivative of the free 8-oxo-7,8-dihydroguanine base. / Hajas, Gyorgy; Bacsi, Attila; Aguilerra-Aguirre, Leopoldo; German, Peter; Radak, Zsolt; Sur, Sanjiv; Hazra, Tapas; Boldogh, Istvan.
In: Free Radical Biology and Medicine, Vol. 52, No. 4, 15.02.2012, p. 749-756.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Biochemical identification of a hydroperoxide derivative of the free 8-oxo-7,8-dihydroguanine base
AU - Hajas, Gyorgy
AU - Bacsi, Attila
AU - Aguilerra-Aguirre, Leopoldo
AU - German, Peter
AU - Radak, Zsolt
AU - Sur, Sanjiv
AU - Hazra, Tapas
AU - Boldogh, Istvan
PY - 2012/2/15
Y1 - 2012/2/15
N2 - 8-Oxo-7,8-dihydroguanine is one the most abundant base lesions in pro- and eukaryotic DNA. In mammalian cells, it is excised by the 8-oxoguanine DNA glycosylase (OGG1) during DNA base-excision repair, and the generated free 8-oxoG base is one of the DNA-derived biomarkers of oxidative stress in biological samples. The modification of 8-oxoG in the context of nucleoside and DNA has been the subject of many studies; however, the oxidative transformation of the free 8-oxoG base has not been described. By using biochemical and cell biological assays, we show that in the presence of molecular oxygen, the free 8-oxoG base transforms to a highly reactive hydroperoxide (8-oxoG*). Specifically, 8-oxoG* oxidizes Amplex red to resorufin, H 2DCF to DCF, Fe 2+ to Fe 3+, and GSH to GSSG. This property of 8-oxoG* was diminished by treatment with catalase and glutathione peroxidase, but not superoxide dismutase. 8-OxoG* formation was prevented by reducing agents or nitrogen atmosphere. Its addition to CM-H 2DCF-DA-loaded cells rapidly increased intracellular DCF fluorescence. There were no such properties observed for 8-oxodeoxyguanosine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 2′-deoxyguanosine, guanine, adenine, guanosine, and 8-hydroxyadenine. These data imply that a free 8-oxoG base is more susceptible to oxidation than is its nucleoside form and, consequently, it stands as unique among intact and oxidatively modified purines.
AB - 8-Oxo-7,8-dihydroguanine is one the most abundant base lesions in pro- and eukaryotic DNA. In mammalian cells, it is excised by the 8-oxoguanine DNA glycosylase (OGG1) during DNA base-excision repair, and the generated free 8-oxoG base is one of the DNA-derived biomarkers of oxidative stress in biological samples. The modification of 8-oxoG in the context of nucleoside and DNA has been the subject of many studies; however, the oxidative transformation of the free 8-oxoG base has not been described. By using biochemical and cell biological assays, we show that in the presence of molecular oxygen, the free 8-oxoG base transforms to a highly reactive hydroperoxide (8-oxoG*). Specifically, 8-oxoG* oxidizes Amplex red to resorufin, H 2DCF to DCF, Fe 2+ to Fe 3+, and GSH to GSSG. This property of 8-oxoG* was diminished by treatment with catalase and glutathione peroxidase, but not superoxide dismutase. 8-OxoG* formation was prevented by reducing agents or nitrogen atmosphere. Its addition to CM-H 2DCF-DA-loaded cells rapidly increased intracellular DCF fluorescence. There were no such properties observed for 8-oxodeoxyguanosine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 2′-deoxyguanosine, guanine, adenine, guanosine, and 8-hydroxyadenine. These data imply that a free 8-oxoG base is more susceptible to oxidation than is its nucleoside form and, consequently, it stands as unique among intact and oxidatively modified purines.
KW - Free 8-oxoguanine base
KW - Free radicals
KW - Oxidative stress
UR - http://www.scopus.com/inward/record.url?scp=84856224029&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84856224029&partnerID=8YFLogxK
U2 - 10.1016/j.freeradbiomed.2011.11.015
DO - 10.1016/j.freeradbiomed.2011.11.015
M3 - Article
VL - 52
SP - 749
EP - 756
JO - Free Radical Biology and Medicine
JF - Free Radical Biology and Medicine
SN - 0891-5849
IS - 4
ER -