Replacement of the human topoisomerase linker domain with the plasmodial counterpart renders the enzyme camptothecin resistant

PLoS One. 2013 Jul 2;8(7):e68404. doi: 10.1371/journal.pone.0068404. Print 2013.


A human/plasmodial hybrid enzyme, generated by swapping the human topoisomerase IB linker domain with the corresponding domain of the Plasmodium falciparum enzyme, has been produced and characterized. The hybrid enzyme displays a relaxation activity comparable to the human enzyme, but it is characterized by a much faster religation rate. The hybrid enzyme is also camptothecin resistant. A 3D structure of the hybrid enzyme has been built and its structural-dynamical properties have been analyzed by molecular dynamics simulation. The analysis indicates that the swapped plasmodial linker samples a conformational space much larger than the corresponding domain in the human enzyme. The large linker conformational variability is then linked to important functional properties such as an increased religation rate and a low drug reactivity, demonstrating that the linker domain has a crucial role in the modulation of the topoisomerase IB activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites / genetics
  • Biocatalysis / drug effects
  • Camptothecin / pharmacology*
  • DNA Topoisomerases, Type I / chemistry
  • DNA Topoisomerases, Type I / genetics*
  • DNA Topoisomerases, Type I / metabolism
  • DNA, Superhelical / chemistry
  • DNA, Superhelical / metabolism
  • Humans
  • Models, Molecular
  • Molecular Dynamics Simulation
  • Plasmodium falciparum / enzymology
  • Plasmodium falciparum / genetics
  • Principal Component Analysis
  • Protein Engineering / methods
  • Protein Structure, Tertiary
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics*
  • Protozoan Proteins / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics*
  • Recombinant Fusion Proteins / metabolism
  • Substrate Specificity
  • Topoisomerase I Inhibitors / pharmacology


  • DNA, Superhelical
  • Protozoan Proteins
  • Recombinant Fusion Proteins
  • Topoisomerase I Inhibitors
  • DNA Topoisomerases, Type I
  • TOP1 protein, human
  • Camptothecin

Grant support

This work has been supported by the AIRC project 10121 to A.D. and the Minister Erna Hamiltons Grant for Science and Art to B.K. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.