Evolution of active center metals used in antioxidant enzymes and its relationship to the redox history of the atmosphere and oceans

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K22359
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0204:Astronomy, earth and planetary science, and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: Harada Mariko 筑波大学, 生命環境系, 助教 (80833631)
• Project Period (FY): 2020-09-11 – 2023-03-31
• Keywords: 抗酸化酵素 / シアノバクテリア / 酸化還元環境

Outline of Final Research Achievements

Molecular phylogenetic analysis and biological experiments were conducted to elucidate the origin and evolution of the active metal center of the antioxidant enzyme, superoxide dismutase (SOD). Molecular phylogenetic analysis of four cyanobacterial SODs: iron (Fe)-, manganese (Mn)-, copper/zinc (Cu/Zn)-, and nickel (Ni)-SOD, suggested that the active metal centers of cyanobacterial SODs were selected consistently with the history of variation in dissolved metal concentrations in the ocean. Among these, for FeSOD and MnSOD, the ancestral gene sequence has been deduced and gene synthesis has been completed, thus it will be possible to regenerate the ancestral protein in the future.

Free Research Field

地球生命科学

Academic Significance and Societal Importance of the Research Achievements

抗酸化酵素は現代の生物に広く分布し、活性酸素の毒性から生体分子を防御するために重要な役割を果たしている。しかしながら、その進化の過程は明らかでなく、種々の抗酸化酵素が選択されてきた背景も不明であった。本研究は、さまざまなSODが生息する化学的な環境に応じて選択される可能性を、シアノバクテリアと大気海洋の環境変動史との比較を例に明らかにした。同様の事象が他の生物や抗酸化酵素について検証されれば、抗酸化酵素の分布や役割の整理につながり、地球生命科学のみならず生物学等の他分野にも波及する重要性をもつと考えられる。