Structurally altered substrates for DNA topoisomerase I. Effects of inclusion of a single 3'-deoxynucleotide within the scissile strand.
A partial DNA duplex containing a high efficiency topoisomerase I cleavage site was substituted singly at each of three sites with 3'-deoxyadenosine. Depending on the site of substitution, the facility of the topoisomerase I-mediated cleavage or ligation reactions was altered. Inclusion of the modified nucleoside at the 5'-end of the acceptor oligonucleotide diminished the rate of religation following substrate cleavage by the enzyme.
Department of Chemistry, University of Virginia, Charlottesville 22901, USA.
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Arslan
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Abraham
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Hecht
D001665:Binding Sites / Q000235:genetics; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D003839:Deoxyadenosines / Q000737:chemistry*; D004591:Electrophoresis, Polyacrylamide Gel; D015394:Molecular Structure; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013379:Substrate Specificity
D003839:Deoxyadenosines; D009838:Oligodeoxyribonucleotides; D004247:DNA; D004264:DNA Topoisomerases, Type I; C058120:cordycepin