Nuclear gyrB encodes a functional subunit of the Plasmodium falciparum gyrase that is involved in apicoplast DNA replication

Mol Biochem Parasitol. 2007 Jul;154(1):30-9. doi: 10.1016/j.molbiopara.2007.04.001. Epub 2007 Apr 7.


The DNA replication machinery of the Plasmodium falciparum apicoplast is a validated drug target. Nuclear-encoded gyrase subunits are predicted to play a critical role in maintaining DNA topology during the D-loop/bi-directional ori replication process of the parasite. We show the presence of P. falciparum gyrase subunits in parasite lysates by using antibodies generated against recombinant gyrase A and B. The ATPase activity of PfGyrB was inhibited by novobiocin that also caused parasite death in culture. Reduction of apicoplast/nuclear DNA ratio in the presence of novobiocin indicated that the drug targets apicoplast DNA replication. Molecular modeling of gyrase A and B subunits revealed extensive fold conservation with the Escherichia coli counterparts as well as the presence of a long disordered loop adjacent to the ATPase domain of PfGyrB. Our results have implications for development of PfGyrB as a drug target against malaria.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antimalarials / pharmacology
  • DNA Gyrase / analysis
  • DNA Gyrase / genetics*
  • DNA Gyrase / physiology*
  • DNA Replication / physiology*
  • Enzyme Inhibitors / pharmacology
  • Escherichia coli / enzymology
  • Models, Molecular
  • Molecular Sequence Data
  • Novobiocin / pharmacology
  • Organelles / genetics
  • Organelles / physiology*
  • Plasmodium falciparum / chemistry
  • Plasmodium falciparum / enzymology*
  • Plasmodium falciparum / genetics
  • Plasmodium falciparum / physiology
  • Protein Structure, Quaternary


  • Antimalarials
  • Enzyme Inhibitors
  • Novobiocin
  • DNA Gyrase