Identification of the novel lesion 8,5'-cyclo-2'-deoxyguanosine in DNA isolated from. gamma. -irradiated human cells

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5120482

Dizdaroglu, M; Dirksen, M L; Simic, M G; Robbins, J H

The authors used capillary gas chromatography (GC)-mass spectrometry (MS) to detect damage in DNA from ..gamma..-irradiated viable cells. Epstein-Barr virus-transformed peripheral blood B-lymphocytes (lines GM 130 and RB 4580) were ..gamma..-irradiated at 0/sup 0/C at 1 to 10 krad (8.2 krad/min). The cells were immediately lysed with sodium dodecyl sulfate and incubated with proteinase K. The DNA was isolated by phenol-chloroform extractions, ethanol precipitations, and RNase A digestion. The DNA was hydrolyzed to 2'-deoxyribonucleosides with a mixture of DNase I, venom and spleen exonucleases, and alkaline phosphatase. The hydrolysate was dried, trimethylsilylated, and analyzed by GC-MS with selected-ion monitoring. Chromatographic retention time and mass spectrum were determined for a trimethylsilylated sample of authentic 8,5'-cyclo-2'-deoxyguanosine (8,5'-cyclo-dGuo). DNA from ..gamma..-irradiated cells gave the characteristic ions of this compound with proper relative intensities. Formation of 8,5'-cyclo-dGuo was dose-dependent. It was detectable in ca. 0.05 mg of DNA from cells irradiated at doses as low as 1 krad. The (5'R)- and the (5'S)-epimer of 8,5'-cyclo-dGuo were observed in a ratio of 1 to 3. The formation of 8,5'-cyclo-dGuo is believed to involve hydrogen atom abstraction from the carbon-5' of 2'-deoxyribose by radiation-generated OH radicals followed by intramolecular cyclization between carbon-5' and carbon-8 and subsequent oxidation of the resulting nitrogen-7 radical.

• Research Organization: NIH, Bethesda, MD
• OSTI ID: 5120482
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALINE PHOSPHATASE
ANIMAL CELLS
ANIMALS
BIOLOGICAL EFFECTS
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GENETIC RADIATION EFFECTS
HYDROLASES
LEUKOCYTES
LYMPHOCYTES
LYSIS
MAMMALS
MAN
MASS SPECTROSCOPY
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NUCLEASES
NUCLEIC ACIDS
ORGANIC COMPOUNDS
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