Laboratory of Protein Crystallography


Associate Professor
Hideaki TANAKA

Functional Biomolecular Biology


Institute for Protein Research, Osaka University


3-2 Yamadaoka, Suita, Osaka, Japan

Research Theme

Three-dimensional protein structure brings us the beautiful structural biology. X-ray crystallography is the best method to determine atomic coordinates of protein molecules. The main aim of us is the X-ray structure determination of the biological macromolecular assemblies including membrane protein complexes in order to elucidate the molecular mechanism of the highly organized biological processes at atomic level.

Structural studies of the photosynthetic membrane protein complex and related redox enzymes

Photosynthetic light reaction establish electron flow in the chloroplast thylakoid membranes, leading to the production of ATP and NADPH, and also providing the reducing power to many redox enzymes. We want to understand the blanching mechanism of this electron flow based on the crystal structures. Ferredoxin (Fd) is a key protein that is reduced from photosystem I and serve as an electron carrier protein for many Fd-dependent enzymes, including Ferredoxin-NADP+ reductase, Sulfite reductase, Nitrite reductase, Glutamate synthase (Fd-GOGAT), Protochlorophyllide reductase and Hydrogenase. These Fd-dependent enzymes do not have any consensus sequence and common structural motif. We are trying to crystallize these Fd-dependent enzymes complexed with Fd in order to provide the structural basis for Fd-dependency.

Crystal structure analysis of the dynein motor domain

Dynein is a microtuble-based motor protein, consisting of the identical heavy-chains with assorted light-, light intermediate- and intermediate chains. The motor activity is located in the heavy chain, whose molecular mass is more than 500kDa. Sequence analysis and electron microscopy reconstuctions indicate that the microtuble-binding domain of dynein heavy chain is separated from the AAA core of the motor which contains the ATP hydrolysis sites, by an elongated stalk domain consisting of an anti-parallel coiled-coil structure. It was hypothesized that the dynein utilized small amounts of sliding displacement between the AAA core and the microtuble-binding head. However, the structural basis of how to slide the two long colied-coil helices in the opposite directions and couple the microtuble binding is still unkown. In order to address these questions, we are trying to crystallize the several recombinant proteins of the dynein stalk.

0X-ray crystal structure of the light-independent protochlorophyllide reductase (N.Muraki et al., 2010 Nature)

1Crystal structure of the dynein motor domain (T.Kon et al., 2012 Nature)


Kon T. et al. The 2.8 A structure of the dynein motor domain Nature 484 , 345 - 350 (2012)

Muraki, N. et al., X-ray crystal structure of the light-independent protochlorophyllide reductase Nature 465 , 110 - 114 (2010)

Tanaka, N. et al., The Structure of Rat Liver Vault at 3.5 Angstrom Resolution Science 323 , 384 - 388 (2009)

Kurisu, G. et al., Structural Basis of Equisetum arvense Ferredoxin Isoform II Producing an Alternative Electron Transfer with Ferredoxin-NADP+ Reductase. J. Biol. Chem. 280 , 2275 - 2281 (2005)

Kurisu, G. et al., Structure of the Cytochrome b6f complex of Oxygenic Photosynthesis: Tuning the cavity Science 302 , 1009 - 1014 (2003)

Kurisu G. et al. Structure of the electron transfer complex between ferredoxin and ferredoxin-NADP(+) reductase. Nature Struct. Biol. 8 , 117 - 121 (2001)


Laboratory of Protein Crystallography,
Institute for Protein Research, Osaka University 
3-2 Yamadaoka, Suita-shi, Osaka 565-0871, Japan
Tel: 06-6879-8604 Fax: 06-6879-8606