title: A novel dual Dbp5/DDX19 homologue from Plasmodium falciparum requires Q motif for activity.
abstract: Helicases are ubiquitous essential enzymes which have significant role in the nucleic acid metabolism. Using in silico approaches in the recent past we have identified a number of helicases in the Plasmodium falciparum genome. In the present study we report purification and detailed characterization of a novel helicase from P. falciparum. Our results indicate that this helicase is a homologue of Dbp5 and DDX19 from yeast and human, respectively. The biochemical characterization shows that it contains DNA and RNA unwinding, nucleic acid dependent ATPase and RNA binding activities. It is interesting to note that this enzyme can unwind DNA duplexes in both 5' to 3' and 3' to 5' directions. Using truncated derivatives we further show that Q motif is essentially required for all of its activities. These studies should make an important contribution in understanding the enzymes involved in nucleic acid metabolism in the parasite.
authors.affiliation: Malaria Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Jatin
authors.initials: J
authors.lastname: Mehta
authors.forename: Renu
authors.initials: R
authors.lastname: Tuteja
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000235:genetics*; D017434:Protein Structure, Tertiary; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D016601:RNA-Binding Proteins; D053487:DEAD-box RNA Helicases