2020 Fiscal Year Final Research Report
Determining sulfur isotope fractionation values of individual enzymes and how they evolve through time.
| Project/Area Number |
18H01325
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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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| Review Section |
Basic Section 17050:Biogeosciences-related
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
McGlynn Shawn 東京工業大学, 地球生命研究所, 准教授 (10751084)
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| Co-Investigator(Kenkyū-buntansha) |
上野 雄一郎 東京工業大学, 理学院, 教授 (90422542)
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | enzyme mechanism / enzyme evolution / kinetic isotope effect / sulfate reduction / geobiology / microbial evolution / Earth-Life Science / geochemistry |
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| Outline of Final Research Achievements |
The oldest record of life on Earth is in the form of non-equilibrium isotope ratios, because biology uses isotopes in unique compared to equilibrium (abiotic) chemistry. One element which shows biological like isotope ratios deep in time is sulfur. In this research, we focused on which type of organisms may have been on the ancient Earth and left signals in sulfur isotope ratios. We found that the enzyme APS reductase (a biological catalyst which allows chemistry to occur more quickly than non-biological reactions) may be responsible for a substantial portion of the ancient sulfur ratios. Furthermore, we found that we could understand the nutritional state of ancient organisms, because the forward and reverse rates of the enzymatic reaction depends on the amount of energy available. Our work integrates biochemistry and life with knowledge of the ancient Earth.
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| Free Research Field |
Geobiology
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| Academic Significance and Societal Importance of the Research Achievements |
We found that the evolutionary history of sulfate respiration is complex, but probably not among the most ancient metabolisms on Earth. We determined that a single enzyme in the respiratory pathway appears to control the whole cell rate under certain conditions.
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