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Guanine Oxidation by Electron Transfer: One‐ versus Two‐Electron Oxidation Mechanism
Author(s) -
Kupan Adam,
Saulière Aude,
Broussy Sylvain,
Seguy Christel,
Pratviel Geneviève,
Meunier Bernard
Publication year - 2006
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200500284
Subject(s) - guanine , chemistry , electron transfer , photochemistry , hydroxymethyl , oligonucleotide , adduct , dna oxidation , radical ion , tris , dna , stereochemistry , organic chemistry , nucleotide , ion , dna damage , biochemistry , gene
The degeneracy of the guanine radical cation, which is formed in DNA by oxidation of guanine by electron transfer, was studied by a detailed analysis of the oxidation products of guanine on oligonucleotide duplexes and by labeling experiments. It was shown that imidazolone, the major product of guanine oxidation, is formed through a one‐electron oxidation process and incorporates one oxygen atom from O 2 . The formation of 8‐oxo‐7,8‐dihydroguanine by a two‐electron oxidation process was a minor pathway. The two‐electron oxidation mechanism was also evidenced by the formation of a tris(hydroxymethyl)aminomethane adduct.