Disruption of a topoisomerase-DNA cleavage complex by a DNA helicase.
نویسندگان
چکیده
منابع مشابه
Cleavage of DNA by Mammalian DNA Topoisomerase
Using the P4 unknotting assay, DNA topoisomerase I1 has been purified from several mammalian cells. Similar to prokaryotic DNA gyrase, mammalian DNA topoisomerase I1 can cleave double-stranded DNA and be trapped as a covalent protein-DNA complex. This cleavage reaction requires protein denaturant treatment of the topoisomerse 11-DNA complex and is reversible with respect to salt and temperature...
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Topoisomerase II, purified from chicken erythrocytes, was reacted with a large number of different DNA fragments and cleavages were catalogued in the presence and absence of drugs that stabilize the cleavage intermediate. Cleavages were sequenced to derive a consensus for topoisomerase II that predicts catalytic sites. The consensus is: (sequence; see text) where N is any base and cleavage occu...
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Bulgarein, a fungal metabolite, induced mammalian topoisomerase I-mediated DNA cleavage in vitro. The cleavage activity of bulgarein was comparable to that of camptothecin at a drug concentration range of 0.025-approximately 5 microM. The DNA cleavage induced by bulgarein was suppressed at concentrations above 12.5 microM. Treatment of a reaction mixture containing bulgarein and topoisomerase I...
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Thiopurines and topoisomerase II-targeted drugs (e.g., etoposide) are widely used anticancer drugs. However, topoisomerase II-targeted drugs can cause acute myeloid leukemia, with the risk of this secondary leukemia linked to a genetic defect in thiopurine catabolism. Chronic thiopurines result in thioguanine substitution in DNA. The effect of these substitutions on DNA topoisomerase II activit...
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In order to study the sequence specificity of double-strand DNA cleavage by Drosophila topoisomerase II, we have mapped and sequenced 16 strong and 47 weak cleavage sites in the recombinant plasmid p pi 25.1. Analysis of the nucleotide and dinucleotide frequencies in the region near the site of phosphodiester bond breakage revealed a nonrandom distribution. The nucleotide frequencies observed w...
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ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1994
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.91.25.12031