Aarhus University Seal / Aarhus Universitets segl

Minimal DNA duplex requirements for topoisomerase I-mediated cleavage in vitro

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

  • J Q Svejstrup, Department of Molecular Biology and Plant Physiology, University of Aarhus, Denmark., Denmark
  • K Christiansen
  • ,
  • A H Andersen
  • K Lund, Department of Molecular Biology and Plant Physiology, University of Aarhus, Denmark., Denmark
  • O Westergaard

The minimal DNA duplex requirements for topoisomerase I-mediated cleavage at a specific binding sequence were determined by analyzing the interaction of the enzyme with sets of DNA substrates varying successively by single nucleotides at the 5'- or 3' end of either strand. Topoisomerase I cleavage experiments showed a minimal region of nine nucleotides on the scissile strand and five nucleotides on the noncleaved strand. On the scissile strand, seven of the nine nucleotides were situated upstream to the cleavage site, while all five nucleotides required on the non-cleaved strand were located to this side. The results suggested that topoisomerase I bound tightly to this region, stabilizing the DNA duplex extensively. On minimal substrates which were partially single-stranded downstream to the cleavage site, cleavage was suicidal, that is, the enzyme was able to cleave the substrates, but unable to perform the final religation.

Original languageEnglish
JournalJournal of Biological Chemistry
Volume265
Issue21
Pages (from-to)12529-35
Number of pages7
ISSN0021-9258
Publication statusPublished - 25 Jul 1990

    Research areas

  • Base Sequence, DNA, DNA Topoisomerases, Type I, Humans, Molecular Sequence Data, Species Specificity, Substrate Specificity, Journal Article, Research Support, Non-U.S. Gov't

See relations at Aarhus University Citationformats

ID: 116462619