The evolutional origin of metabolon formed within the TCA cycle

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06608
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 43060:System genome science-related
• Research Institution: The University of Tokyo
• Principal Investigator: Kameya Masafumi 東京大学, 大学院農学生命科学研究科(農学部), 助教 (80748517)
• Co-Investigator(Kenkyū-buntansha): 石井 正治 東京大学, 大学院農学生命科学研究科(農学部), 教授 (30193262)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: TCA回路 / rTCA回路 / 代謝複合体 / 炭酸固定

Outline of Final Research Achievements

We conducted an investigation into the formation of metabolons within the reductive tricarboxylic acid (rTCA) cycle of Hydrogenobacter thermophilus, a member of the Aquificota phylum, which represents an ancient lineage of bacteria. Our study involved the utilization of various techniques, including gel filtration, affinity tagging, cross-linking of associated proteins, BN-PAGE, and specific antibody detection of target enzymes. Despite previous reports of robust binding between specific enzymes in the tricarboxylic acid (TCA) cycle, we did not detect such interactions, suggesting that they may have evolved independently subsequent to the divergence from the rTCA cycle. However, certain enzymes exhibited weak associations in our in vitro analysis, implying the possibility of protein-protein interactions under specific conditions.

Free Research Field

代謝進化

Academic Significance and Societal Importance of the Research Achievements

代謝酵素複合体とは、ある代謝系を構成する酵素群が細胞内で形成する複合体である。TCA回路においても代謝酵素複合体が形成されることが知られているが、その進化的起源は明らかでない。 TCA回路を逆回転させた二酸化炭素固定経路、reductive TCA (rTCA)回路はTCA回路の祖先型代謝と推定され、TCA回路という生物普遍的な代謝系の進化を理解する上で不可欠な存在である。本研究を通じて、rTCA回路における複合体形成を検証し、液液相分離など微弱なタンパク質間相互作用についての概念・研究手法を適用することでさらなる解明につながる結果が得られた。