Mitochondrial localization of functional ferrochelatase from Plasmodium falciparum.

In the malarial parasite, enzymes of heme-biosynthetic pathway are distributed in different cellular compartments. The site of localization of ferrochelatase in the malarial parasite is crucial, since it will decide the ultimate site of heme synthesis. Earlier results have differed in terms of localization, being the mitochondrion or apicoplast and the functional enzyme has not been cloned, expressed and characterized. The present study reveals that Plasmodium falciparum ferrochelatase (PfFC) gene encodes multiple transcripts of which the one encoding the full length functional protein (PfFC) has been cloned and the recombinant protein over-expressed and purified from E. coli cells. The enzyme shows maximum activity with iron, while zinc is a poor substrate. Immunofluorescence studies with antibodies to functional ferrochelatase reveal that the native enzyme is localized to the mitochondrion of the parasite indicating that this organelle is the ultimate site of heme synthesis.