Tomoko Ohnishi

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Professor of Biochemistry and Biophysics
Department: Biochemistry and Biophysics

Contact information
214A Anatomy-Chemistry Building
3620 Hamilton Walk
Philadelphia, PA 19104
Office: (215) 898-8024
Fax: (215) 573-3748
Ph.D. (Biochemistry)
National Nagoya Univesity, Japan, 1962.
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Description of Research Expertise

Complex I (NADH-quinone oxidoreductase) is the largest transmembrane multi-subunit enzyme in the mitochondrial and bacterial respiratory chain. It transports electrons from NADH to quinone, and simultaneously transfers protons across the membrane to build up electrochemical proton gradient. This subsequently drives ATP synthesis. Complex I is also considered to be a major site for generation of reactive oxygen species (ROS), which may be associated with neurodegenerative diseases, Parkinson’s disease, as well as aging and apoptosis.

The major interest of my research group is the unique coupling between the electron transfer and proton pumping mechanism of complex I which covers both bacterial and mitochondrial systems, utilizing a wide range of research strategies, from molecular biology, protein biochemistry, enzymology, in combination with various CW- and pulse electron paramagnetic resonance techniques. We also investigate ROS generation mechanism and its relevance to the above mentioned human diseases.

Selected Publications

Yano, T., S. Magnitsky and T. Ohnishi : Characterization of the complex I-associated ubisemiquinone species: toward the understanding of their functional roles in the electron/proton transfer reaction. Biochim. Biophys. Acta 1459: 299-304, 2000.

Ohnishi, T., C.C. Moser, C.P. Page, P.L. Dutton and T. Yano: Simple redox-linked proton-transfer design: new insights from structures of quinol-fumarate reductase. Structure with Folding and Design 8: R23-32, 2000.

Yano, T., S. Magnitsky, V.D. Sled', T. Ohnishi and T. Yagi: Characterization of the putative 2x[4Fe-4S] binding NQO9 subunit of the proton translocating NADH-quinone oxidoreductase (NDH-1) of Paracoccus denitrificans: Expression, reconstitution, and EPR characterization. J. Biol. Chem. 274: 28598-605, 1999.

Ohnishi, T.: Iron-sulfur clusters/semiquinones in Complex I. Biochim. Biophys. Acta. 1364: 196-206, 1998.

Dutton, P.L., C.C. Moser, V.D. Sled, F. Daldal and T. Ohnishi: A reductant-induced oxidation mechanism for complex I. Biochim. Biophys. Acta. 1364: 245-57, 1998.

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Last updated: 08/31/2006
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