2004 Fiscal Year Final Research Report Summary
Mechanisms of oxygen evolution in cyanobacteria and its acquisition process(es)
| Project/Area Number |
15370021
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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 |
植物生理・分子
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| Research Institution | Kyoto University |
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Principal Investigator |
MIMURO Mamoru Kyoto University, Graduate School of Global Environmental Studies, Professor, 大学院・地球環境学堂, 教授 (40142004)
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| Co-Investigator(Kenkyū-buntansha) |
TSUCHIYA Tohru Kyoto University, Graduate School of Global Environmental Studies, Assistant Professor, 大学院・地球環境学堂, 助手 (20362569)
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| Project Period (FY) |
2003 – 2004
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| Keywords | cyanobacteria / oxygen evolving system / complete genome information / Gloeobacter violaceus |
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| Research Abstract |
In order to understand the molecular mechanism of oxygen evolution in cyanobacteria and its acquisition process(es) during the evolution from anoxygenic photosynthetic bacteria to cyanobacteria, we selected one unique species of cyanobacteria, i.e., Gloeobacter violaceus PCC 7421 that lacks thylakoid membranes, a representative example of its primitive characteristics.
1.First of all, we determined the complete genome sequence of G.violcaeus by the co-operative research with the Kazusa DNA Research Institute (DNA Res. 10,137,2003). The genome information revealed that this species lacks many genes relating to photosynthesis and other metabolic pathways ; for example, kai A/B/C for circadian rhythm.
2.We tried to construct the transformation system of this species, however at the moment, we have not yet succeeded the development of the system. A rigid cell wall may be the cause for incorporation of exogenous gene.
3.We directly evaluated the oxygen evolution properties of this species. The steady-state oxygen evolution activity was approximately 250 μmoleO2/mg Chl/hr, a little lower than that estimated on Synechocystis sp.PCC 6803. A typical feature was a very high activity in respiration, approximately 10 times higher than that in Synechocystis sp.PCC 6803. This clearly indicates difference in the electron transfer system in G.violaceus where respiratory and photosynthetic flows are coupled to each other.
4.Thermoluminescence, an index of oxygen evolution, was measured on G.violaceus. Its oscillation pattern showed the four-periodic change, as seen in other cyanobacteria, indicating the conserved reaction mechanism of water oxidation, four-step electron transfer.
5.As revealed from genome sequence, G.vioalceus is unique in its properties of photosystem II, it seems convincing that transformation of this species will bring about many possible experiments for our understanding on the oxygen evolving system.
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Research Products
(35 results)
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[Journal Article] Minor but key chlorophylls in Photosystem II.2005
Author(s)
Masami Kobayashi, Satoru Watanabe, Takanori Gotoh, Hajime Koizumi, Yuka Itoh, Machiko Akiyama, Yoshihiro Shiraiwa, Tohru Tsuchiya, Hideaki Miyashita, Mamoru Mimuro, Takashi Yamashita, Tadashi Watanabe
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Journal Title
Photosynth.Res. (in press)
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Complete genome structure of Gloeobacter violaceus sp.PCC 7421, a cyanobacterium that lacks thylakoids.2003
Author(s)
Nakamura, Y., T.Kaneko, S.Sato, M.Mimuro, H.Miyashita, T.Tsuchiya, S.Sasamoto, A.Watanabe, K.Idesawa, M.Iriguchi, K.Kawashima, M.Kohara, M.Matsumoto, S.Shimpo, H.Tsuruoka, T.Wada, M.Yamada, S.Tabata
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Journal Title
DNA Res. 10
Pages: 137-145
Description
「研究成果報告書概要(欧文)」より
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