title: Nuclear gyrB encodes a functional subunit of the Plasmodium falciparum gyrase that is involved in apicoplast DNA replication.
abstract: 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.
authors.affiliation: Division of Molecular and Structural Biology, Central Drug Research Institute, Post Box 173, Chattar Manzil, Mahatma Gandhi Marg, Lucknow 226001, India.
authors.forename: E V S
authors.initials: EV
authors.lastname: Raghu Ram
authors.forename: Ambrish
authors.initials: A
authors.lastname: Kumar
authors.forename: Subir
authors.initials: S
authors.lastname: Biswas
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Kumar
authors.forename: Sushma
authors.initials: S
authors.lastname: Chaubey
authors.forename: Mohammad Imran
authors.initials: MI
authors.lastname: Siddiqi
authors.forename: Saman
authors.initials: S
authors.lastname: Habib
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000962:Antimalarials / Q000494:pharmacology; D027081:DNA Gyrase / Q000032:analysis / Q000235:genetics* / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009675:Novobiocin / Q000494:pharmacology; D015388:Organelles / Q000235:genetics / Q000502:physiology*; D010963:Plasmodium falciparum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D020836:Protein Structure, Quaternary
chemical_list: D000962:Antimalarials; D004791:Enzyme Inhibitors; D009675:Novobiocin; D027081:DNA Gyrase