| Project/Area Number |
10680640
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biophysics
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| Research Institution | Himeji Institute of Technology |
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Principal Investigator |
MORIMOTO Yukio Himeji Inst.Tech., Science, Ass.Prof., 理学部, 助教授 (80200450)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2000: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1999: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1998: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | proteasome / supramolecule / crystal structure / immuno-response / プロテアソーム活性化因子 |
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| Research Abstract |
Proteasome is a most important protease particle composed of 28 heterosubunits. It functions a proteolysis in the cell to maintain stable it, and has the molecular weight of 750kDa, a large multifunctional enzyme. Proteasomes are also having an immuno-response by generating antigenic peptides presented by class l molecules of major histocompatibility complex when the proteasome activator (PA28) binds proteasomes. In this work, a structural investigation for an interaction of proteasomes with PA28 in solution by the X-ray scattering and the crystal structure of the proteasome are discussed.
Proteasomes are isolated and purified from bovine liver, and crystallized by MPD precipitant (Y.Morimoto, et.al., J.B.(1995). Diffraction experiments are carried out at the BL41 XU , SPring-8. Resolution of the diffraction is up to 2.5 Å and intensities have good quality for a structure analysis (Tomisugi, et.al., J.B.(2000). A structural refinement with non-crystallographic symmetry operations goes down the crystallographic R-factor to 28.8% ( FreeR=33.7%). The refinement are now still in progress. One of features for a crystal structure of proteasomes is a location of acidic amino acids of the central cavity in proteasomes. It seems likely to present the mechanism of strict proteolysis against unneeded protein or antigen-presenting. The X-ray scattering analysis of the proteasome and its complex with the proteasome activator (PA28) shows that the PA28 binds one-side of the proteasome, but both ends. It shows one end of the proteasome with PA28 catches endogenous antigen with highly specificity and releases antigen-presenting peptides through the other end. These results should be established by the crystal structure analysis of the complex of proteasome with its activator (PA28).
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