Journal of Biochemistry Advance Access published online on October 15, 2007
Journal of Biochemistry, doi:10.1093/jb/mvm184
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© 2007 The Japanese Biochemical Society
Molecular interaction of Ferredoxin and Ferredoxin-NADP+ Reductase from Human Malaria Parasite
Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan,
3 Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan.
1Address correspondence to: Dr. Yoko Kimata-Ariga, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan: Phone +81-6-6879-8611; Fax +81-6-6879-8613, E-mail: a-yoko{at}protein.osaka-u.ac.jp
Received July 2, 2007; Accepted September 15, 2007
| Abstract |
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SUMMARY: The malaria parasite possesses plant-type ferredoxin (Fd) and ferredoxin -NADP+ reductase (FNR) in a plastid-derived organelle called the apicoplast. This Fd/FNR redox system, which potentially provides reducing power for essential biosynthetic pathways in the apicoplast, has been proposed as a target for the development of specific new anti-malarial agents. We studied the molecular interaction of Fd and FNR of human malaria parasite (Plasmodium falciparum), which were produced as recombinant proteins in Escherichia coli. NMR chemical shift perturbation analysis mapped the location of the possible FNR interaction sites on the surface of P. falciparum Fd. Site-specific mutation of acidic Fd residues in these regions and the resulting analyses of electron transfer activity and affinity chromatography of those mutants revealed that two acidic regions (a region including Asp26, Glu29 and Glu34, and the other including Asp65 and Glu66) dominantly contribute to the electro-static interaction with P. falciparum FNR. The combination of Asp26/Glu29/Glu34 conferred a larger contribution than that of Asp65/Glu66, and among Asp26, Glu29 and Glu34, Glu29 was shown to be the most important residue for the interaction with P. falciparum FNR. These findings provide the basis for understanding molecular recognition between Fd and FNR of the malaria parasite.
Key Words: ferredoxin, ferredoxin-NADP+ reductase, human malaria parasite, NMR
2Present address: Digital Medicine Initiative, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan.