DNA polymerases from a parasitic protozoa Leishmania donovani UR6: evidence of presence of a novel kind of DNA polymerase.

DNA polymerases of Leishmania donovani have been isolated and purified. The cell extract has been chromatographed on a phosphocellulose column that separated into three peaks. The activity peak 1 was further purified to homogeneity. The DNA polymerase is a 64 KDa polypeptide, resistant to N-ethylmaleimide and aphidicolin. It requires MnCl2 and a high concentration of KCl (0.5 M) for maximal activity. It has both 3' to 5' and 5' to 3' exonuclease activities that reside in the same polypeptide.