The Enzymatic Release of O6-methylguanine and 3-methyladenine from DNA Reacted with the Carcinogen N-methyl-N-nitrosourea
نویسندگان
چکیده
منابع مشابه
The enzymatic release of O6-methylguanine and 3-methyladenine from DNA reacted with the carcinogen N-methyl-N-nitrosourea.
Endonuclease II (deoxyribonucleate oligonucleotidohydrolase, EC 3.1.4.30) of Escherichia coli has been shown to break phosphodiester bonds in alkylated DNA and depurinated DNA. The hypothesis that depurination is a step in the mechanism of the reaction with alkylated DNA is supported by in vitro experiments with DNA reacted with N-methyl-N-nitrosourea. Endonuclease II releases O(6)-methylguanin...
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Alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) are known to covalently link alkyl groups at the position 6 of guanines (O6MG) in DNA. O6-alkylguanine-DNA alkyltransferase (AGT) specifically removes the methyl group of the O6MG. Using purified human topoisomerase I (Top1), we found an 8-10-fold enhancement of Top1 cleavage complexes when O6MG is incorporated in oligonucleo...
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Lymphocytes from patients with various diseases associated with autoimmunity showed both impaired capacity to repair O6-methylguanine (a powerful, promutagenic, directly miscoding base lesion) and increased sensitivity to the cytocidal effects of cellular methylation by N-methyl-N-nitrosourea (MNU) compared with normal controls and patients with other disorders. Defective repair of O6-methylgua...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1974
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.71.5.2022