| Project/Area Number |
15370067
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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 |
ITOH Shigeru Nagoya University, Graduate School of Science, Professor, 大学院・理学研究科, 教授 (40108634)
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| Co-Investigator(Kenkyū-buntansha) |
MINO Hiroyuki Nagoya University, Graduate School of Science, Assistant Professor, 大学院・理学研究科, 助手 (70300902)
SHIBATA Yutaka Nagoya University, Graduate School of Science, Assistant Professor, 大学院・理学研究科, 助手 (20300832)
NAKAMURA Yoko Nagoya University, Graduate School of Science, Assistant Professor, 大学院・理学研究科, 助手 (20217912)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥15,600,000 (Direct Cost: ¥15,600,000)
Fiscal Year 2004: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2003: ¥11,600,000 (Direct Cost: ¥11,600,000)
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| Keywords | Photosynthesis / cyanobacteria / silica mesoscopic compounds / World Exposition '06 / arctic plants / photosynthetic bacteria / Zn-chlorophyll / artificial photosynthesis / アカリオクロリス / chl d / アシドフィリウム / Zn-Chl / 光化学系I / 光化学系II / 新型光合成 / エネルギー移動 / 電子移動 / 励起エネルギー移動 / 光合成反応中心 / 進化 / クロロフィル / 色素タンパク質 |
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| Research Abstract |
Structure and function of a wide variety of the photosynthetic reaction center pigment protein complexes, including those of newly discovered ones, are studied by ultra last laser spectroscopy up to 0.1 ps, fluorescence life time measurements at cryogenic temperature, electron spin resonance and by the single molecular confocal microscope spectroscopy. The biomaterials used were (1)Acaryochloris marina that can evolve oxygen even with near far-red light, (2)Zn-bacteriochlorophyll containing Acidiphillium rubrum, (3)Zooxanthellae that lives in corals, (4)photosynthetic green sulfur bacterium Chlorobium tepidum ant its site-directed mutants, (5)Chloroflexus aurantiacus, (6)cyanobacteria that are modified to be depleted of a phospholipid phosphatydil glycerol. Acaryochloris marina is shown to have a special photosystems I and II reaction centers in which chlorophyll d but not chlorophyll a functions as the special pair primary electron donor chlorophylls. This organism, thus, is an only one exceptional case in the oxygen evolving photosynthesis that can use 700-750 nm near far-red light. This makes a clear contrast to all the other oxygenic organisms that absorb only 650-690 nm red ight with chlorophyll a. A bacterium Acidiphilium rubrum uses Zn-bacteriochlorophyll a and was shown to undergo highly efficient photo-energy conversion even in the pico-to femto-second time ranges. These new photosynthesis indicated that pigment can be replaced rather easily in photosynthesis although now it is rather rare. On the other hand, the modifications of reaction center proteins yielded drastic decrease of efficiency indicating that the structure of the reaction center is highly optimized for the reaction. Reacion centers are shown to be functional even inside silica mesoscopic nanopores. A part of research to hunt for new organisms was exhibited with arctic plants from Alaska in Aichi World Exposition '06.
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