Succinate dehydrogenase in Plasmodium falciparum mitochondria: molecular characterization of the SDHA and SDHB genes for the catalytic subunits, the flavoprotein (Fp) and iron-sulfur (Ip) subunits.

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Takeo S, Kokaze A, Ng CS, Mizuchi D, Watanabe JI, Tanabe K, Kojima S, Kita K

Succinate dehydrogenase in Plasmodium falciparum mitochondria: molecular characterization of the SDHA and SDHB genes for the catalytic subunits, the flavoprotein (Fp) and iron-sulfur (Ip) subunits.

Mol Biochem Parasitol. 2000 Apr 15;107(2):191-205.

PubMed ID

10779596 [ View in PubMed

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Abstract

Mitochondria of malaria parasites generate a membrane potential through an electron transport system that is a possible target of primaquine and a new anti-malarial drug, atovaquone. However, little information is available for conclusive understanding of the respiratory chain in Plasmodium mitochondria. In the present study, we cloned and characterized from Plasmodium falciparum the genes for the catalytic subunits, SDHA for the flavoprotein (Fp) and SDHB for iron-sulfur protein (Ip), of succinate-ubiquinone oxidoreductase (complex II), which is a marker enzyme for mitochondria and links the TCA cycle and respiratory chain directly. Each of the two genes contains a single open reading frame (ORF), which are located on different chromosomes, 1860 nucleotides on chromosome 10 for SDHA and 963 nucleotides on chromosome 12 for SDHB. The expression of these genes in asynchronous erythrocytic stage cells was confirmed by observation of 3.3 and 2.4 kb transcripts from the SDHA and SDHB genes, respectively. The SDHA and SDHB genes encode proteins of 620 (Fp) and 321 (Ip) amino acids with molecular masses of 69.2 and 37.8 kDa, respectively. A mitochondrial presequence essential for the import of mitochondrial proteins encoded by nuclear DNA, as well as almost all the conserved amino acids indispensable for substrate binding and the catalytic reaction were found in these peptides, indicating the functional importance of this enzyme in the parasite. Interestingly, a P. falciparum-specific insertion and a unicellular organism-specific deletion were found in the amino acid sequence of Fp. This is the first report of the primary structure of the protozoan succinate dehydrogenase.

DrugBank Data that Cites this Article

Drug Enzymes

Drug	Enzyme	Kind	Organism	Pharmacological Action	Actions
Succinic acid	Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial	Protein	Humans	Unknown	Substrate	Details