Repair of Secondary Lesions Arising in DNA after Treatment with Alkylating Agents
Treatment of cells with alkylating agents results in DNA modification. The reaction products are alkylpurines, phosphotriesters and some minor products such as alkylpyrimidines. Some of them are repaired by alkyl DNA transferase while others are repaired by DNA glycosylases which generate as products the free alkylated base and an apurinic site (AP-site). This is a secondary lesion which is harmful to the cell and is actively repaired. Alkylation of the N7 of guanine labilizes i) the glycosidic bond yielding an AP-site and ii) the imidazole ring leading to the corresponding formamidopyrimidine, another secondary lesion. We review the biological implications of AP-sites and the formamidopyrimidine lesion which may form following alkylation of DNA.
KeywordsAlkylating Agent Imidazole Ring Micrococcus Luteus Secondary Lesion Cruciform Structure
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