Oxidative damage to DNA constituents by iron-mediated Fenton reactions - The deoxyguanosine family

被引:120
作者
Henle, ES [1 ]
Luo, YZ [1 ]
Gassmann, W [1 ]
Linn, S [1 ]
机构
[1] UNIV CALIF BERKELEY,DIV BIOCHEM & MOL BIOL,BERKELEY,CA 94720
关键词
D O I
10.1074/jbc.271.35.21177
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
2'-Deoxyguanosine, 3'-dGMP, 5'-dGMP, d-GpG, or double-stranded DNA were exposed to H2O2 in the presence of Fe2+ under anaerobic conditions or under aerobic conditions in the presence of Fe3+, Fe2+, Fe2+/NADH, or Fe3+/NADH with and without ethanol. The products were enzymatically digested to nucleosides, separated by high performance liquid chromatography (HPLC), quantified, and characterized by HPLC retention time, radiolabeling, UV absorbance spectrometry, NMR, and mass spectrometry. 20 products, constituting 78-81% of the damage, were distinguished from aerobic reactions of Fe2+/H2O2 with dG and dGMP, 16 of which were identified. The product spectra from dG, 3'-dGMP, and 5'-dGMP differ from one another, and the spectrum of the 5' nucleoside of d-GpG differs from that of the 3' nucleoside, 7,8-Dihydro-8-oxo-2'-deoxyguanosine is the most abundant DNA-bound product aside from abasic sites, and its formation was more closely analyzed. Both NADH, which can reduce Fe3+, and ethanol, which can scavenge some free radicals, change the product profiles, Damage enhancement by NADH follows the sequence dG < d-GpG < 3'-dGMP < 5'-dGMP < DNA; the reverse sequence is observed for ethanol quenching, This sequence of susceptibility and the product differences seen for the 3' and 5' phosphate may reflect localization of iron and the damaging radicals upon the substrate.
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页码:21177 / 21186
页数:10
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