Repair of alkylated DNA in Escherichia coli. Methyl group transfer from O6-methylguanine to a protein cysteine residue.
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چکیده
منابع مشابه
Inhibition 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 ...
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Cell extracts from Micrococcus luteus release both free 3-methyladenine and free 7-methylguanine from alkylated DNA. The glycosylase activity responsible for the liberation of 7-methylguanine is not 3-methyladenine-DNA glycosylase, which, when purified, does not liberate it. Furthermore, the heat inactivation rates of the two enzymatic activities are different. The release of 7-methylguanine by...
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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...
متن کاملCloning of the E. coli O6-methylguanine and methylphosphotriester methyltransferase gene using a functional DNA repair assay.
Alkylating agents react with various nitrogen and oxygen atoms in DNA and many of the products are substrates for repair processes. Oxygen atom derivatives such as O6-methylguanine (O6-meG) O4-methylthymine and methylphosphotriesters (MP) have been shown to undergo repair by methyl group removal. The proteins involved in the latter reaction can be considered to be methyltransferases (MT) becaus...
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...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1980
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)70341-x