Laboratory of Interdisciplinary Biology (Plant Science)


Associate Professor
Hirozo OH-OKA
mail ohka @
Assistant Professor
Tetsuhiro ASADA
mail tasada @

Interdisciplinary Biology


Graduate School of Science


Toyonaka Campus

Research Theme

Three important problems of biology are energy transduction, signal transduction and morphogenesis. First, we are studying on molecular mechanisms of motor, pump and switch proteins. Secondly, we are studying on molecular mechanism of photosynthesis that supplies energy for functioning of proteins. Thirdly, we are studying on pattern formation in plant growth.

Dynamic Structural Physiology on Molecular Motor, Pump, Switch and Clock Proteins (Dr. T. Arata)

Studies on energy transduction of muscle at molecular level were started by Prof. Yuji Tonomura on 1952 (*01). Based on a view that protein undergoes biological functions by a use of its dynamic structure on a nanometer scale, we are studying on a supramolecular protein complex or interacting proteins during activity in solution or in a cell. As a member of advanced measurement and analysis project, we are developing site-directed mutagenesis-based spin labeling ESR techniques to map intersite distance, side-chain mobility and domain flexibility. We also use electron microscopy1a and small angle x-ray scattering to see molecular shape. Our interest is now focused on myosin-actin1a and kinesin-tubulin2c complexes, mycoplasma motor protein1a and calcium-switch troponin3a-tropomyosin3b-actin complex, and also on clock ATPases2b, and calcium1b or copper pump and photo-switch rhodopsin1b in membrane (*02). A variety of protein complexes are studied in collaboration.

Molecular Mechanism of Photosynthetic Light Energy Conversion (Dr. K. Oh-oka)

Photosynthetic energy conversion system is a key process carried out by pigment-associated protein complexes embedded in membranes. Our interest lies in understanding of molecular mechanisms how light energy is converted into chemical energy in phototrophs. We have two major research projects; (a) molecular structure and electron transfer mechanism in type 1 reaction center, (b) biosynthetic pathways of chlorophyll pigments.

Mechanism of Pattern Formation in Plant (Dr. T. Asada)

Under Construction.

0Biological Molecular Energy Transduction since 1952

1ESR Studies on Molecular Motion of Motor, Switch, Pump, and Clock Proteins.

2Analyses of energy and electron transfer mechanisms in photosynthetic reaction centers


1a. Adan-Kubo et al. J Bacteriol.188,2821-2828 (2006); Kamada et al. Nat. Struct. Mol. Biol. 14, 388-96 ('07); 1b. Yasuda et al. BBRC 425, 134-7 ('12); Narumi et al. FEBS Lett. 586 , 3172 - 8 ('12)

2a. Arata, T. J Struct Biol 123, 8-16 (1998); Sagara et al. PLoS ONE, e4247, 1-11 (2009);2b.Ishii et al. Genes Cells 19, 297-324 (2014); 2c. Sugata et al. BBRC 314, 447-451(2004); Yamada et al. BBRC 364, 620-624 (2007) ;Yasuda et al. BBRC 443, 911-916 (2014) ; Sugata, K. et al. J Mol Biol 386 626-36 ('09); Yasuda et al. BBRC 443 , 911 - 916 ('14)

3a.Ueki, S. et al. Biochemistry, 44, 411-416 (’05); Nakamura et al. J Mol Biol 348,127-137 (’05); Aihara et al. BBRC 340, 462-468 (’06); Aihara et al. J Biol Chem 285 10671-7 (’10); 3b.Ueda, K. et al. Biophys. J.100, 2432-9 (’11); Ueda, K. et al. Biophys J 103 , 2366 - 73 ('13)

C. Azai, K. Kim, T. Kondo, J. Harada, S. Itoh and H. Oh-oka A heterogeneous tag-attachment to the homodimeric type 1 photosynthetic reaction center core protein in the green sulfur bacterium Chlorobaculum tepidum Biochim. Biophys. Acta 1807 , 803 - 812 (2011)

R. Miyamoto, H. Mino, T. Kondo, S. Itoh, and H. Oh-oka An electron spin-polarized signal of the P800+A1(Q)- state in the homodimeric reaction center core complex of Heliobacterium modesticaldum Biochemistry 47 , 4386 - 4393 (2008)

H. Oh-oka Type 1 reaction center of photosynthetic heliobacteria Photochem. Photobiol. 83 , 177 - 186 (2007)

Goto Y., Asada T Excessive expression of the plant kinesin TBK5 converts cortical and perinuclear microtubules into a radial array emanating from a single focus. Plant and Cell Physiology 48 , 753 - 761 (2007)

Asada T Division of shape-standardized tobacco cells reveals a limit to the occurrence of single-criterion-based selection of the plane of symmetric division. Plant Cell Physiol 54 , 827 - 837 (2013)


TEL:06-6850-5427 FAX:06-6850-5441 (Dr. T. Arata)

TEL:06-6850-5423 FAX:06-6850-5425 (Dr. K. Oh-oka)

TEL:06-6850-5818,6776 FAX:06-6850-6765 T. Asada)