title: Cloning and characterization of ferredoxin and ferredoxin-NADP+ reductase from human malaria parasite.
abstract: The human malaria parasite (Plasmodium falciparum) possesses a plastid-derived organelle called the apicoplast, which is believed to employ metabolisms crucial for the parasite's survival. We cloned and studied the biochemical properties of plant-type ferredoxin (Fd) and Fd-NADP+ reductase (FNR), a redox system that potentially supplies reducing power to Fd-dependent metabolic pathways in malaria parasite apicoplasts. The recombinant P. falciparum Fd and FNR proteins were produced by synthetic genes with altered codon usages preferred in Escherichia coli. The redox potential of the Fd was shown to be considerably more positive than those of leaf-type and root-type Fds from plants, which is favourable for a presumed direction of electron flow from catabolically generated NADPH to Fd in the apicoplast. The backbone structure of P. falciparum Fd, as solved by X-ray crystallography, closely resembles those of Fds from plants, and the surface-charge distribution shows several acidic regions in common with plant Fds and some basic regions unique to this Fd. P. falciparum FNR was able to transfer electrons selectively to P. falciparum Fd in a reconstituted system of NADPH-dependent cytochrome c reduction. These results indicate that an NADPH-FNR-Fd cascade is operative in the apicoplast of human malaria parasites.
authors.affiliation: Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Japan. a-yoko@protein.osaka-u.ac.jp
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kimata-Ariga
authors.forename: Genji
authors.initials: G
authors.lastname: Kurisu
authors.forename: Masami
authors.initials: M
authors.lastname: Kusunoki
authors.forename: Sayaka
authors.initials: S
authors.lastname: Aoki
authors.forename: Dan
authors.initials: D
authors.lastname: Sato
authors.forename: Tamaki
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Kita
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Horii
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Hase
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D004579:Electron Transport; D005287:Ferredoxin-NADP Reductase / Q000096:biosynthesis / Q000737:chemistry*; D005288:Ferredoxins / Q000096:biosynthesis / Q000737:chemistry*; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010963:Plasmodium falciparum / Q000201:enzymology*; D011994:Recombinant Proteins / Q000302:isolation & purification; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D005288:Ferredoxins; D011994:Recombinant Proteins; D005287:Ferredoxin-NADP Reductase