1996 Fiscal Year Final Research Report Summary
Dynamics of supramolecular biological systems by synchrotron radiation
| Project/Area Number |
06302086
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 総合 |
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| Research Field |
Biophysics
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| Research Institution | Osaka University |
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Principal Investigator |
WAKABAYASHI Katsuzo Osaka Univ., Fac.Engn.Sci., Dpet.Biophys.Engn, Assoc.Prof., 基礎工学部, 助教授 (00029521)
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| Co-Investigator(Kenkyū-buntansha) |
TAWADA Katsuhisa Kyushu Univ., Fac.Sci., Dept.Biol., Assoc.Prof., 理学部, 助教授 (20029507)
TOKUNAGA Fumio Osaka Univ., Fac.Sci., Dept.Earth and Space Sci., Prof., 教授 (80025452)
WAKABAYASHI Takeyuki Tokyo Univ., Fac.Sci., Dept., Phys., Prof., 理学部, 教授 (90011717)
AMEMIYA Yoshiyuki Tokyo Univ., Fac.Engn., Engn.Res.Inst., Assoc.Prof., 工学部, 助教授 (70151131)
YAGI Naoto Tohoku Univ., Fac.Med., Dept., Pharma., Assoc.Prof., 医学部, 助教授 (80133940)
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| Project Period (FY) |
1994 – 1996
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| Keywords | biophysics / synchroton radiation / x-ray diffraction / electron microscope / muscle contraction / halobacterial purple membrane / bacterial flagellar / cephalopod visual cell |
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| Research Abstract |
Wakabayshi et al.constructed the model of F-actin bound with tropomyosin which showed the good fitness between the calculated and observed x-ray intensities from the thin filament in relaxing state, based on the crystallographic data of actin monomers. From this result, it was suggested that the structural change of the actin molecule playd important role in the contraction of muscle. Wakabayashi et al.observed successfuly the interacting actinmyosin head complex at 2 nm resolution by electron cryo-microscopy. The micrographs indicated that the relative orientation between actin and myosin molecules was not constant and the various interaction sites existed in the sliding movement. Also, Katayama et al.could obtain images of the actin-heavy meromyosin complexes on mica surfaces after the addition of ATP using a quick-freeze, freeze-fracture, deep-etch technique. The result showed that the myosin head bound to the actin filament with a broad orientational distribution and could move over the range of several actin monomers. Namba et al.studied the molecular mechanism of polymorphism of flagellar filaments by electron cryo-microscopy and x-ray fiber diffraction method. It appeared that the double tublar structure of the filament core was essential for the polymorphic ability of flagellar filaments, which is required for the swimming-tunbling of bacterial taxies. Tokunaga et al.studied the structure of the D96N mutant of bacteriorhodopsin, the intermediates of which had longer life times than the native ones, by x-ray diffraction and detected significant changes of the structure at M and N intermediates of the photocycle. Tawada et al.showed the force production by chemically crosslinked myosin-actin cross-brideges in response to MgATP depletion. They also studied the fluctuation in the translational sliding movement of microtubles by kinesin and showed that the protein friction places significant constraint on the possible mechanisms of the sliding movement.
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