Substrate specificity of the Ogg1 protein of Saccharomyces cerevisiae: Excision of guanine lesions produced in DNA by ionizing radiation- or hydrogen peroxide/metal ion-generated free radicals
We have investigated the substrate specificity of the Ogg1 protein of Saccharomyces cerevisiae (yOgg1 protein) for excision of modified DNA bases from oxidatively damaged DNA substrates using gas chromatography/isotope dilution mass spectrometry. Four DNA substrates prepared by treatment with H2O2/F...
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Published in | Nucleic acids research Vol. 26; no. 5; pp. 1228 - 1232 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
England
Oxford University Press
01.03.1998
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Subjects | |
Online Access | Get full text |
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Summary: | We have investigated the substrate specificity of the Ogg1 protein of Saccharomyces cerevisiae (yOgg1 protein) for excision of modified DNA bases from oxidatively damaged DNA substrates using gas chromatography/isotope dilution mass spectrometry. Four DNA substrates prepared by treatment with H2O2/Fe(III)-EDTA/ascorbic acid, H2O2/Cu(II) and γ-irradiation under N2O or air were used. The results showed that 8-hydroxyguanine (8-OH-Gua) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) were efficiently excised from DNA exposed to ionizing radiation in the presence of N2O or air. On the other hand, 8-OH-Gua and FapyGua were not excised from H2O2/Fe(III)-EDTA/ascorbic acid-treated and H2O2/Cu(II)-treated DNA respectively. Fourteen other lesions, including the adenine lesions 8-hydroxyadenine and 4,6-diamino-5-formamidopyrimidine, were not excised from any of the DNA substrates. Kinetics of excision significantly depended on the nature of the damaged DNA substrates. The findings suggest that, in addition to 8-OH-Gua, FapyGua may also be a primary substrate of yOgg1 in cells. The results also show significant differences between the substrate specificities of yOgg1 protein and its functional analog Fpg protein in Escherichia coli. |
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Bibliography: | ark:/67375/HXZ-WNF3S1Z7-T istex:3336271F8E6F0432F29785224FFEBF243DE994AB ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0305-1048 1362-4962 1362-4962 |
DOI: | 10.1093/nar/26.5.1228 |