title: Plasmodium falciparum UvrD helicase translocates in 3' to 5' direction, colocalizes with MLH and modulates its activity through physical interaction.
abstract: Malaria is a global disease and a major health problem. The control of malaria is a daunting task due to the increasing drug resistance. Therefore, there is an urgent need to identify and characterize novel parasite specific drug targets. In the present study we report the biochemical characterization of parasite specific UvrD helicase from Plasmodium falciparum. The N-terminal fragment (PfUDN) containing UvrD helicase domain, which consists of helicase motifs Q, Ia-Id, II, III and most of motif IV, and the C-terminal fragment (PfUDC1) containing UvrD helicase C terminal domain, consisting of remaining part of motif IV and motifs IVa-IVc and 161 amino acids of intervening sequence between motif IV and V, possess ssDNA-dependent ATPase and DNA helicase activities in vitro. Using immunodepletion assays we show that the ATPase and helicase activities are attributable to PfUDN and PfUDC1 proteins. The helicase activity can utilize the hydrolysis of all the nucleotide and deoxynucleotide triphosphates and the direction of unwinding is 3' to 5'. The endogenous P. falciparum UvrD contains the characteristic DNA helicase activity. PfUDN interacts with PfMLH (P. falciparum MutL homologue) and modulates the endonuclease activity of PfMLH and PfMLH positively regulates the unwinding activity of PfUDN. We show that PfUvrD is expressed in the nucleus distinctly in the schizont stages of the intraerythrocytic development of the parasite and it colocalizes with PfMLH. These studies will make an important contribution in understanding the nucleic acid transaction in the malaria parasite.
authors.affiliation: Malaria Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, India.
authors.forename: Moaz
authors.initials: M
authors.lastname: Ahmad
authors.forename: Abulaish
authors.initials: A
authors.lastname: Ansari
authors.forename: Mohammed
authors.initials: M
authors.lastname: Tarique
authors.forename: Akash Tripathi
authors.initials: AT
authors.lastname: Satsangi
authors.forename: Renu
authors.initials: R
authors.lastname: Tuteja
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000595:Amino Acid Sequence; D015153:Blotting, Western; D004265:DNA Helicases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004720:Endonucleases / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology; D005455:Fluorescent Antibody Technique; D006801:Humans; D047468:Immunoprecipitation; D007700:Kinetics; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification; D010963:Plasmodium falciparum / Q000201:enzymology*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D015800:Protozoan Proteins / Q000378:metabolism*; D020539:Sequence Analysis, Protein
chemical_list: D010446:Peptide Fragments; D015800:Protozoan Proteins; D004720:Endonucleases; D000251:Adenosine Triphosphatases; D004265:DNA Helicases