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Updated: May 10, 2026

Quantification of three DNA Lesions by Mass Spectrometry and Assessment of Their Levels in Tissues of Mice Exposed to Ambient Fine Particulate Matter
Published on: May 29, 2019
Generation of guanine-thymine cross-links in human cells by one-electron oxidation mechanisms
Guru S Madugundu1, J Richard Wagner, Jean Cadet
1Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine, 3001 12e Avenue Nord, Université de Sherbrooke , Québec J1H 5N4, Canada.
Abstract:
The one-electron oxidation of cellular DNA in cultured human HeLa cells initiated by intense nanosecond 266 nm laser pulse irradiation produces cross-links between guanine and thymine bases (G*-T*), characterized by a covalent bond between C8 guanine (G*) and N3 thymine (T*) atoms. The DNA lesions were quantified by isotope dilution LC-MS/MS methods in the multiple reaction-monitoring mode using isotopically labeled [(15)N, (13)C]-nucleotides as internal standards. Among several known pyrimidine and 8-oxo-7,8-dihydroguanine lesions, the G*-T* cross-linked lesions were detected at levels of ~0.21 and 1.19 d(G*-T*) lesions per 10(6) DNA bases at laser intensities of 50 and 280 mJ/cm(2)/pulse, respectively.
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