| Project/Area Number |
23510251
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Living organism molecular science
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| Research Institution | Hokkaido University |
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Principal Investigator |
KIKUKAWA Takashi 北海道大学, 先端生命科学研究科(研究院), 講師 (20281842)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAUCHI Seiji 東邦大学, 薬学部, 教授 (30202352)
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| Co-Investigator(Renkei-kenkyūsha) |
TAMOGAMI Jun 松山大学, 薬学部, 助教 (30580089)
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| Project Period (FY) |
2011 – 2013
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| Project Status |
Completed (Fiscal Year 2013)
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| Budget Amount *help |
¥5,460,000 (Direct Cost: ¥4,200,000、Indirect Cost: ¥1,260,000)
Fiscal Year 2013: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2012: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2011: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | ハロロドプシン / フォトサイクル / アニオンポンプ / 膜蛋白質 / レチナール / イオンポンプ |
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| Research Abstract |
Halorhodopsin (HR) is an inward light-driven Cl- pump in the membrane of halophilic archaea. Illumination triggers the photoreaction of HR called photocycle where the intermediates of K, L1, L2, N, O, NpHR' form and decay sequentially. During this cyclic reaction, HR releases Cl- to the cytoplasmic (CP) medium and captures another Cl- from the extracellular medium. To examine the elementary processes for Cl- translocation, we analyzed the photocycle using the flash-photolysis technique and obtained the following results: 1) Cl- release and uptake occur during N to O and O to NpHR' transitions, respectively. The subsequent NpHR' to original NpHR transition involves Cl- displacement inside the protein. 2) The Cl- binding affinity decreases at the Cl- releasing step. This decreased binding affinity contributes to maintain the Cl- pumping activity even in the presence of the interior negative membrane potential.
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