Laboratories & Administration Office

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Laboratories & Administration Office
Division of Protein Structural Biology

Laboratory of Molecular Biophysics

member

Director	Toshimichi FUJIWARA
Associate Professor	Chojiro KOJIMA
Instructor	Yoh MATSUKI

Correspondence

Tel	81-6-6879-8598
Fax	81-6-6879-8599
E-mail
URL	http://www.protein.osaka-u.ac.jp/biophys/index.html

Research

We are studying the structures of the biological macromolecules mainly by using nuclear magnetic resonance (NMR). NMR provides information on the protein structure at work with atomic resolution. Taking this advantage, we can understand the biological activities for energy conversion and signal transduction from structures. Structures for the rotational catalysis of F1 ATPase are investigated by solution NMR. Structures of Fo c-ring, light-harvesting Bchl c complex, β₂-microglobulin amyloid, and membrane-bound mastoparan-X are determined by solid-state NMR. Since supramolecular systems such as biomembranes play important roles in biological systems, we are also developing new methodologies in solid-state and solution NMR to analyze the structure of those systems. One of our programs for solid-state NMR features high-field dynamic nuclear polarization (DNP) for a 1000-fold signal enhancement by using high-intensity terahertz light source, gyrotron.

<Fig.1>
The solution structures of C-terminal domain of TF1 ε subunit. Left side:
superposition of 20 structures with the lowest target function values in the
presence of ATP for residues 90-131. Right side: those in the absence of ATP.
The backbone heavy atoms are superimposed for the regions
comprising residues 90-102.

<Fig.2>
Structure of the light-harvesting bacteriochlorophyll c assembly in chlorosomes
determined by solid-state NMR. This cylinder with a diameter of 10 nm
contributes to photon absorption and excitation transfer to reaction centers.

<Fig.3>
Two-dimensional ¹³Cα_i+1-¹³Cαi solid-state NMR spectrum and the determined
structure of membrane-bound mastoparan-X. The distance correlation with
phospholipid indicated that MPX is located at the interface between the
water layer and the hydrophobic domain in the bilayer membrane.

Current Research Programs

1) New methodologies in solid-state and solution NMR
2) Structure and function of H⁺-ATP synthase
3) Structural analysis of membrane proteins by NMR

References

1. Structure of the light-harvesting bacteriochlorophyll c assembly in chlorosomes from Chlorobium limicola determined by solid-state NMR. Egawa et al. (2007) Proc. Natl. Acad. Sci. USA 104, 790−795.
2. Detection of peptide−phospholipid interaction sites in bilayer membranes by ¹³C-NMR Spectroscopy: Observation of ²H/³¹P-selective ¹H-depolarization under magic-angle spinning. Harada et al. (2006) J. Am. Chem. Soc. 128, 10654-10655.
3. Conformational change of H⁺-ATPase β monomer revealed on segmental isotope labeling NMR spectroscopy. Yagi et al. (2004) J. Am. Chem. Soc. 126, 16632-16638.

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