The primary structure of Plasmodium falciparum DNA polymerase delta is similar to drug sensitive delta-like viral DNA polymerases

Abstract

We report the isolation and sequencing of genomic DNA clones that encode the 1094-amino acid catalytic subunit of DNA polymerase delta from the human malaria parasite Plasmodium falciparum. Protein sequence comparison to other DNA polymerases revealed the presence of six highly conserved regions found in alpha-like DNA polymerases from different prokaryotic, viral, and eukaryotic sources. Five additional regions of amino acid sequence similarity that are only conserved in delta and delta-like DNA polymerases, so far, were present in P. falciparum DNA polymerase delta. P. falciparum DNA polymerase delta was highly similar to both Saccharomyces cerevisiae DNA polymerase delta (DNA polymerase III; CDC2) and Epstein-Barr virus DNA polymerase at the amino acid sequence, and the predicted protein secondary structure levels. The gene that encodes DNA polymerase delta resides as a single copy on chromosome 10, and is expressed as a 4.5-kb mRNA during the trophozoite and schizont stages when parasite chromosomal DNA synthesis is active.