Guanine oxidation by electron transfer: one- versus two-electron oxidation mechanism.
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 O2. 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.
Kupan
Adam
A
Laboratoire de Chimie de Coordination du CNRS, 205 route de Narbonne, 31077 Toulouse Cedex4, France.
Saulière
Aude
A
Broussy
Sylvain
S
Seguy
Christel
C
Pratviel
Geneviève
G
Meunier
Bernard
B
D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000737:chemistry; D004563:Electrochemistry; D004583:Electrons; D005609:Free Radicals / Q000737:chemistry; D006147:Guanine / Q000138:chemical synthesis / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D011166:Porphyrins / Q000737:chemistry; D012256:Riboflavin / Q000737:chemistry; D013997:Time Factors
D005609:Free Radicals; D009942:Organometallic Compounds; D011166:Porphyrins; D008345:Manganese; D006147:Guanine; D004247:DNA; D012256:Riboflavin