| Project/Area Number |
17370056
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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 | 一般 |
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| Research Field |
Biophysics
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| Research Institution | Nagoya University |
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Principal Investigator |
KOUYAMA Tsutomu Nagoya University, Graduate School of Science, Professor, 大学院理学研究科, 教授 (30170210)
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| Co-Investigator(Kenkyū-buntansha) |
IHARA Kunio Nagoya University, Center for Gene Research, Assistant Prefessor, 遺伝子実験施設, 助手 (90223297)
MURAKAMI Midori Nagoya University, Graduate school of Science, Assis tant Professor, 大学院理学研究科, 助手 (20324387)
YAMATO Takahisa Nagoya University, Graduate school of Science, Assistant Professor, 大学院理学研究科, 助教授 (90251587)
OKUMURA Hideo Nagoya University, Graduate school of Science, Assistant Professor, 7・1より理化学研究所の協力研究員), 産学官連携研究員 (90377903)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥10,700,000 (Direct Cost: ¥10,700,000)
Fiscal Year 2006: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥7,200,000 (Direct Cost: ¥7,200,000)
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| Keywords | bacteriorhodopsin / halorhodopsin / squid rhodopsin / proton pump / chloride pump / membrane protein / retinal protein / X-ray crystallography / レチナール蛋白質 / 生物物理 / 蛋白質 / ナノバイオ / 計算物理 / 分子機械 |
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| Research Abstract |
Bacteriorhodopsin, a light-driven proton pump found in the cell membrane of halobacteria, is one of well characterized biological ion pumps. Based on the results of four-dimensional X-ray crystallographic analyses, the principal investigator and colleague have proposed a new hypothesis that bacteriorhodopsin actually functions as an antiporter of water and proton. To get supports for this hypothesis, we investigated time-resolved spectroscopy as well as X-ray crystallographic analysis of bacteriorhodopin exposed to pressurized noble gases. It was then found that when Xe or Kr atom binds specificically to a hydrophobic cavity in the cytoplasmic side of bacteriorhodopsin, the decay of the M intermediate is accelerated significantly. We also performed X-ray crystallographic analysis of archaearhodopsin-2, a light-driven proton pump found in Halorubrum, and determined its three-dimensional structure at 2.1 angstrom resolution. It was shown that the crystal of archaerhodopsin-2 is made up of stacked membranes, in each of which the trimeric complexes are arranged on a honeycomb lattice and that the second chromophore, bacterioruberin, mediates interactions between neighboring proteins within the trimer. We succeeded in getting a three-dimensional crystal of proteorhodopsin, a light-driven proton pump from a proteobacterioum. We have established to prepare a large amount of halorhodopsin, a light-driven chloride pump, after a repeated cycle of UV mutagenesis. We obtained a well-ordered three-dimensional crystal of squid rhodopsin and determined its structure at 2.8 angstrom resolution.
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