FCCC LOGO Faculty Publications
Buguliskis JS , Casta LJ , Butz CE , Matsumoto Y , Taraschi TF
Expression and biochemical characterization of Plasmodium falciparum DNA ligase I
Molecular and Biochemical Parasitology. 2007 Oct;155(2) :128-137
Back to previous list
We report that Plasmodium falciparum (Pf) encodes a 912 amino acid ATP-dependent DNA ligase. Protein sequence analysis of Pf DNA ligase I indicates a strong sequence similarity, particularly in the C-terminal region, to DNA ligase I homologues. The activity of recombinant Pf DNA ligase I (PfLigI) was investigated using protein expressed in HEK293 cells. The PfLigI gene product is similar to 94 kDa and catalyzes phosphodiester bond formation on a singly nicked DNA substrate. The enzyme is most active at alkaline pH (8.5) and with Mg2+ or Mn2+ and ATP as cofactors. Kinetic studies of PfLigI revealed that the enzyme has similar substrate affinity (K-m 2.6 nM) as compared to human DNA ligase I and k(cat) (2.3 x 10(-3) s(-1)) and k(cat)/K-m (8.8 x 105 M-1 s(-1)) which are similar to other ATP-dependent DNA ligases. PfLigI was able to join RNA-DNA substrates only when the RNA sequence was upstream of the nick, confirming that it is DNA ligase I and has no associated DNA ligase !
ISI Document Delivery No.: 211UJ