Biosynthetic pathway of long-chain polyamines and their role in silica formation

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02886
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38030:Applied biochemistry-related
• Research Institution: Hiroshima University
• Principal Investigator: Ikeda Takeshi 広島大学, 統合生命科学研究科(先), 准教授 (10505754)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 細菌 / ケイ素 / ポリアミン

Outline of Final Research Achievements

Biosilicifying organisms form inorganic silica intracellularly. Long-chain polyamines (LCPAs) have been isolated from biosilica of phylogenetically distant biosilicifying organisms and are thought to be involved in biological silica formation. However, the biosynthetic pathway of LCPAs has not been clarified yet, which makes it difficult to investigate their physiological functions.
We previously found the genes that are essential for LCPA production in a mesophilic biosilicifying bacterium. In this study, we investigated the functions of the proteins encoded by these genes and found that one of them serves as the LCPA-synthesizing enzyme. We also developed a method to produce and isolate LCPAs from recombinant Escherichia coli cells. In vitro experiments showed that the purified LCPAs promotes silica formation from silicic acid.

Free Research Field

生物工学

Academic Significance and Societal Importance of the Research Achievements

本研究課題の成果によって、シリカ形成生物における長鎖ポリアミン合成酵素を初めて同定し、長鎖ポリアミン生合成経路を解明することに成功した。本菌のシリカ形成における長鎖ポリアミンの機能は未だ不明な点が多いが、遺伝子破壊株や変異体を用いた機能解析が可能となったことで、今後一層研究が進展することが期待される。生物による洗練された鉱物形成メカニズムを明らかにすることで、ナノテクノロジー分野への応用につながることが期待される。