title: Characterization of kinetics of DNA strand-exchange and ATP hydrolysis activities of recombinant PfRad51, a Plasmodium falciparum recombinase.
abstract: Although homologous recombination-mediated DNA rearrangements are quite widespread in Plasmodium falciparum, the molecular mechanisms involved are essentially unknown. Recent identification of PfRad51 in P. falciparum has suggested that it may play central role during homologous recombination and DNA rearrangements. Full-length recombinant PfRad51 was over expressed in Escherichia coli and purified to near homogeneity. Using optimized enzymatic activity conditions recombinant PfRad51 protein was shown to catalyze DNA strand-exchange reaction, a central step during homologous recombination. Unlike bacterial RecA protein, PfRad51 promoted strand-exchange reaction does not require ATP hydrolysis. The PfRad51 protein also catalyzed ssDNA-dependent ATP hydrolysis and the k(cat) values were similar to those reported for human Rad51. The demonstration of strand-exchange activity of PfRad51 protein, first such report in any protozoan parasite, suggests importance of similar recombination mechanism during DNA rearrangements associated with antigenic variation in P. falciparum.
authors.affiliation: Johns Hopkins Malaria Research Institute, The W. Harry Feinstone Department of Molecular Microbiology and Immunology, 615 N. Wolfe Street, Baltimore, MD 21205, USA. mbhattac@jhsph.edu
authors.forename: Mrinal Kanti
authors.initials: MK
authors.lastname: Bhattacharyya
authors.forename: Sunanda
authors.initials: S
authors.lastname: Bhattacharyya nee Deb
authors.forename: Bamini
authors.initials: B
authors.lastname: Jayabalasingham
authors.forename: Nirbhay
authors.initials: N
authors.lastname: Kumar
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000940:Antigenic Variation; D003001:Cloning, Molecular; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D016054:DNA, Protozoan / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D010963:Plasmodium falciparum / Q000201:enzymology*; D015800:Protozoan Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D051135:Rad51 Recombinase; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D045522:Recombinases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D003598:Cytoskeletal Proteins; D016054:DNA, Protozoan; C446619:EscF protein, E coli; D029968:Escherichia coli Proteins; D015800:Protozoan Proteins; C483018:Rad51 protein, Plasmodium falciparum; D011994:Recombinant Proteins; D045522:Recombinases; D000255:Adenosine Triphosphate; D051135:Rad51 Recombinase; D000251:Adenosine Triphosphatases; C037693:single stranded DNA dependent ATPase