Topoisomerase V relaxes supercoiled DNA by a constrained swiveling mechanism

Bhupesh Taneja, Bernhard Schnurr, Alexei Slesarev, John F. Marko, Alfonso Mondragón*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Topoisomerase V is a type I topoisomerase without structural or sequence similarities to other topoisomerases. Although it belongs to the type I subfamily of topoisomerases, it is unrelated to either type IA or IB enzymes. We used real-time single-molecule micromechanical experiments to show that topoisomerase V relaxes DNA via events that release multiple DNA turns, employing a constrained swiveling mechanism similar to that for type IB enzymes. Relaxation is powered by the torque in the supercoiled DNA and is constrained by friction between the protein and the DNA. Although all type IB enzymes share a common structure and mechanism and type IA and type II enzymes show marked structural and functional similarities, topoisomerase V represents a different type of topoisomerase that relaxes DNA in a similar overall manner as type IB molecules but by using a completely different structural and mechanistic framework.

Original languageEnglish (US)
Pages (from-to)14670-14675
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number37
StatePublished - Sep 11 2007


  • Archaeon
  • DNA topology
  • Magnetic tweezers
  • Single molecule
  • Type IC

ASJC Scopus subject areas

  • General


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