2005 Fiscal Year Final Research Report Summary
Molecular organization and physiological functions of the respiratory chain specific for mitochondria from Plasmodium
| Project/Area Number |
14021014
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Biological Sciences
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KITA Kiyoshi The University of Tokyo, Graduate School of Medicine, Professor, 大学院医学系研究科, 教授 (90134444)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Malaria / Mitochondria / apicoplast / cell fractionation / percoll / Trypanosome / cyanide-resistant oxidase / asucofuranone |
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| Research Abstract |
1. Studies on the respiratory chain specific for mitochondria from Plasmodium
The mitochondrion and the apicoplast of the malaria parasite, Plasmodium spp is microscopically observed in a close proximity to each other. In this study, we tested the suitability of two different separation techniques-Percoll density gradient centrifugation and fluorescence-activated organelle sorting for improving the purity of mitochondria isolated from the crude organelle preparation of P falciparum. To our surprise, the apicoplast was inseparable from the plasmodial mitochondrion by each method. This implies these two plasmodial organelles are bound each other. This is the first experimental evidence of a physical binding between the two organelles in Plasmodium.
2. Studies on cyanide-resistant alternative oxidases from parasitic protozoa and its spescific inhibitor, ascofuranone
Based on amino acid sequence similarity and the ability to catalyze the four-electron reduction of oxygen to water using a quin
… More
ol substrate, mitochondrial alternative oxidase (AOX) and plastid terminal oxidase (PTOX) appear to be two closely related members of the membrane-bound diiron carboxylate group of proteins. In the current studies, we took advantage of the high activity of Trypanosoma vivax AOX (TvAOX) to examine the importance of the conserved Glu and the Tyr residues around the predicted third helix region of AOXs and PTOXs. We first compared the amino acid sequences of TvAOX with AOXs and PTOXs from various taxa and then performed alanine-scanning mutagenesis of TvAOX between amino acids Y199 and Y247. We found that the ubiquinol oxidase activity of TvAOX is completely lost in the E214A mutant, whereas mutants E215A and E216A retained more than 30% of the wild-type activity. Among the Tyr mutants, a complete loss of activity was also observed for the Y221A mutant, whereas the activities were equivalent to wild-type for the Y199A, Y212A, and Y247A mutants. Finally, residues G1u214 and Tyr221 were found to be strictly conserved among AOXs and PTOXs. Based on these findings, it appears that AOXs and PTOXs are a novel subclass of diiron carboxylate proteins that require the conserved motif E(X)eY for enzyme activity. Less
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Research Products
(12 results)
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[Journal Article] Mitochondria and apicoplast of Plasmodium fakiparum : behaviour on subcellular fractionation and the implication2007
Author(s)
Kobayashi T., Sato, S., Takamiya, S., Komaki-Yasuda, K., Yano, K., Hirata, A., Onitsuka, I., Hata, M., Mi-ichi, F., Tanaka, T., Hase, T., Miyajima, A., Kawazu, S., Watanabe, Y., Kita, K.
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Journal Title
Mitochondrion 7
Pages: 125-132
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Genetic diversity and kinetic properties of Trypanosoma cruzi dihydroorotate dehydrogenase2006
Author(s)
Sariego, I., Annoura, T., Nara, T., Hashimoto, M., Tsubouchi, A., Iizumi, K., Makiuchi, T., Murata, E., Kita, K., Aoki, T.
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Journal Title
Parasitol. Int. 55
Pages: 1116
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] PfPDE1, a novel cGMP-specific phosphodiesterase, from the human malaria parasite Plasmodium fakiparum2005
Author(s)
Yuasa, K., Mi-ichi, F., Kobayashi, T., Yamanouchi, M., Kotera, J., Kita, K., Omori, K.
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Journal Title
Biochem. J. 392
Pages: 221-229
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Mutational analysis of the Trypanosoma vivax alternative oxidase : the E(X)eY motif is conserved in both mitochondrial alternative oxidase and plastid terminal oxidase and is indispensable for enzyme activity2005
Author(s)
Nakamura, K., Sakamoto, K.Kido, Y., Fujimoto, Y., Suzuki, T., Suzuki, M., Yabu, Y, Ohta, N., Tsuda, A., Onuma, M., Kita, K.
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Journal Title
Biochem. Biophys. Res. Commun. 334
Pages: 593-600
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Parasite mitochondria as a target of chemotherapy : The inhibitory effect of licochalcone A on the Plasmodium fakiparum respiratory chain
Author(s)
Mi-ichi, F., Miyadera, H., Kobayashi, T., Takamiya, S., Waki, S., Iwata, S.(2005) Shibata, S., Kita, K.
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Journal Title
Ann.New York Acad. Sci. 1056
Pages: 46-54
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Expression, purification, and crystallization of Trypanosoma cruzi dihydroorotate dehydrogenase complexed with orotate
Author(s)
Inaok, D.K., Takashima, E., Osanai, A., Shimizu, H., Nara, T., Aoki, T., (2005) Harada, S., Kita, K.
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Journal Title
Acta Crystallographica F61
Pages: 875-878
Description
「研究成果報告書概要(欧文)」より
