Repair of O6-methylguanine in adapted Escherichia coli.
نویسندگان
چکیده
منابع مشابه
Increased spontaneous mutation and alkylation sensitivity of Escherichia coli strains lacking the ogt O6-methylguanine DNA repair methyltransferase.
Escherichia coli expresses two DNA repair methyltransferases (MTases) that repair the mutagenic O6-methylguanine (O6MeG) and O4-methylthymine (O4MeT) DNA lesions; one is the product of the inducible ada gene, and here we confirm that the other is the product of the constitutive ogt gene. We have generated various ogt disruption mutants. Double mutants (ada ogt) do not express any O6MeG/O4MeT DN...
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Normal and malignant cells of the oligodendrocyte lineage show increased sensitivity to alkylating agents compared to astrocytes. One of the most mutagenic DNA lesions formed following exposure to alkylating agents is O6-alkylguanine. To determine whether the increased sensitivity to nitrosoureas seen in oligodendrocytes is due to decreased repair capacity for O6-alkylguanine, removal of this l...
متن کاملPyridyloxobutyl DNA adducts inhibit the repair of O6-methylguanine.
The carcinogenic tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), both methylates and pyridyloxobutylates DNA. O6-Methylguanine (O6-mG) persistence has been correlated to NNK-induced lung tumor formation in A/J mice. The pyridyloxobutylation pathway enhances the tumorigenicity of the methylation pathway. In this paper we test the hypothesis that DNA pyridyloxo...
متن کاملInhibition of O6-methylguanine-DNA methyltransferase by an alkyltransferase-like protein from Escherichia coli
The alkyltransferase-like (ATL) proteins contain primary sequence motifs resembling those found in DNA repair O(6)-alkylguanine-DNA alkyltransferase proteins. However, in the putative active site of ATL proteins, a tryptophan (W(83)) residue replaces the cysteine at the known active site of alkyltransferases. The Escherichia coli atl gene was expressed as a fusion protein and purified. Neither ...
متن کاملRepair of O6-methylguanine adducts in human telomeric G-quadruplex DNA by O6-alkylguanine-DNA alkyltransferase
O(6)-alkylguanine-DNA alkyltransferase (AGT) is a single-cycle DNA repair enzyme that removes pro-mutagenic O(6)-alkylguanine adducts from DNA. Its functions with short single-stranded and duplex substrates have been characterized, but its ability to act on other DNA structures remains poorly understood. Here, we examine the functions of this enzyme on O(6)-methylguanine (6mG) adducts in the fo...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1978
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.75.12.6017