Biochemical identification of a hydroperoxide derivative of the free 8-oxo-7,8-dihydroguanine base

Gyorgy Hajas, Attila Bacsi, Leopoldo Aguilerra-Aguirre, Peter German, Zsolt Radak, Sanjiv Sur, Tapas Hazra, Istvan Boldogh

Research output: Contribution to journalArticle

12 Citations (Scopus)

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 languageEnglish (US)
Pages (from-to)749-756
Number of pages8
JournalFree Radical Biology and Medicine
Volume52
Issue number4
DOIs
StatePublished - Feb 15 2012

Fingerprint

Hydrogen Peroxide
Derivatives
DNA
Nucleosides
DNA Glycosylases
Purines
Deoxyguanosine
Oxidative stress
Glutathione Disulfide
Molecular oxygen
Guanosine
Reducing Agents
Guanine
Biomarkers
Adenine
Glutathione Peroxidase
Atmosphere
DNA Repair
Biological Assay
Catalase

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 journalArticle

Hajas, Gyorgy ; Bacsi, Attila ; Aguilerra-Aguirre, Leopoldo ; German, Peter ; Radak, Zsolt ; Sur, Sanjiv ; Hazra, Tapas ; Boldogh, Istvan. / Biochemical identification of a hydroperoxide derivative of the free 8-oxo-7,8-dihydroguanine base. In: Free Radical Biology and Medicine. 2012 ; Vol. 52, No. 4. pp. 749-756.
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AU - Hajas, Gyorgy

AU - Bacsi, Attila

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AU - German, Peter

AU - Radak, Zsolt

AU - Sur, Sanjiv

AU - Hazra, Tapas

AU - Boldogh, Istvan

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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.

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