MOLECULAR CHARACTERIZATION OF THE GLUTATHIONE-PEROXIDASE GENE OF THE HUMAN MALARIA PARASITE PLASMODIUM-FALCIPARUM

In this paper we report the isolation and the characterization of a ge ne encoding the antioxidant enzyme glutathione peroxidase from the hum an malaria parasite Plasmodium falciparum. This gene contains two intr ons of 208 and 168 bp and is present in a single copy on chromosome 13 . The open reading frame encodes a protein with a predicted length of 205 amino acids, which possesses a potential cleavage site between res idues 21 and 22 after a hydrophobic region with the characteristics of a signal sequence. Therefore, the mature protein is predicted to be 1 84 residues long with a molecular mass of 21 404 Da. In comparison wit h other known glutathione peroxidases many amino acid residues implica ted in catalysis are conserved in the malarial enzyme. Phylogenetic an alysis indicates that the deduced protein sequence is more closely rel ated to plant glutathione peroxidase and phospholipid hydroperoxide gl utathione peroxidase. A 1.5-kb transcript was identified in asynchrono us erythrocytic stages.