Identification of a mitochondrial superoxide dismutase with an unusual targeting sequence in Plasmodium falciparum.
The intraerythrocytic stages of Plasmodium falciparum are exposed to oxidative stress and require functional anti-oxidant systems to survive. In addition to the parasite's known iron-dependent superoxide dismutase PfSOD1, a second SOD gene (PfSOD2) interrupted by 8 introns was identified on chromosome 6. Molecular modelling shows that the structure of PfSOD2 is similar to other iron-dependent SODs and phylogenetic analysis suggests PfSOD1 and PfSOD2 are the result of an ancestral gene duplication. The deduced amino acid sequence of PfSOD2 is similar to PfSOD1 but has a long N-terminal extension. Immunofluorescence studies show that PfSOD1 is cytosolic, whereas the N-terminal extension of PfSOD2 targets a green fluorescent protein fusion into the parasite's mitochondrion. Both SOD genes are transcribed during the erythrocytic cycle with PfSOD1 mRNA levels up to 35-fold higher than those of PfSOD2. Northern blots demonstrated that the mRNA levels of both SOD genes are up-regulated upon exposure to oxidative stress.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe
Biologie, Adaptation, Psychological, Amino Acid Sequence, Animals, Cytoplasm -- enzymology, DNA, Complementary, DNA, Protozoan -- chemistry, Erythrocytes -- parasitology, Fluorescent Antibody Technique, Indirect, Gene Duplication, Gene Expression Regulation, Introns -- genetics, Mitochondria -- enzymology, Models, Molecular, Molecular Sequence Data, Oxidative Stress, Phylogeny, Plasmodium falciparum -- enzymology -- genetics -- growth & development, Protein Sorting Signals, Protein Transport, RNA, Messenger -- analysis, RNA, Protozoan -- analysis, Recombinant Fusion Proteins -- metabolism, Sequence Analysis, DNA, Sequence Homology, Superoxide Dismutase -- chemistry -- genetics -- metabolism, Biologie structurale
Publisher: 'Elsevier BV'
DOI identifier: 10.1016/j.molbiopara.2004.05.005
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