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PubMed · 2542321

Interactions between eukaryotic DNA topoisomerase I and a specific binding sequence.

T Stevnsner·U H Mortensen·O Westergaard·B J Bonven
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Abstract

The interaction between eukaryotic DNA topoisomerase I and a high affinity binding sequence was investigated. Quantitative footprint analysis demonstrated that the substrate preference results from strong specific binding of topoisomerase I to the sequence. The specificity was conferred by a tight noncovalent association between the enzyme and its target DNA, whereas the transient formation of a covalently bound enzyme.nicked DNA intermediate contributed insignificantly to the overall affinity. Topoisomerase I protected both strands over a 20-base pair region in which the cleavage site was centrally located. DNA modification interference analysis revealed a 16-base pair interference region on the scissile strand. Essential bases were confined to the 5' side of the cleavage site. The 6-base pair interference region observed on the complementary strand did not contain essential bases.

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AnimalsBase SequenceDNADNA Topoisomerases, Type IKineticsMethylationRestriction MappingSubstrate SpecificityTetrahymenaJournal ArticleResearch Support, Non-U.S. Gov't

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T Stevnsner, U H Mortensen, O Westergaard, B J Bonven. 1989-06-15. Interactions between eukaryotic DNA topoisomerase I and a specific binding sequence.. https://pubmed.ncbi.nlm.nih.gov/2542321/

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