in vivo detection and application to protein labeling of special bilins

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05701
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 37010:Bio-related chemistry
• Research Institution: Tohoku University
• Principal Investigator: Matsui Toshitaka 東北大学, 多元物質科学研究所, 准教授 (90323120)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: ヘム / ビリン / 蛍光タンパク質 / テトラピロール / タンパク質ラベル化

Outline of Final Research Achievements

In this study, we have elucidated unique reaction mechanisms of new-type heme-degrading enzymes, MhuD from Mycobacterium tuberculosis and IsdG from Staphylococcus aureus, both of which bind heme in highly distorted conformation. MhuD successively catalyzes mono- and di-oxygenation reactions in a single active site. This is the first discovery of the enzyme that fuses the two distinct reactions, leading to the produce the unique heme catabolites of MhuD. Contrary to previous reports, reaction analysis on IsdG reveals, that the MhuD-type reaction becomes dominant under normal reaction conditions. The HCHO release reported is enhanced by increasing reduction rates. This mechanism may be biologically relevant to regulate the HCHO biosynthesis in S. aureus. Furthermore, fluorogenic proteins that bind new heme catabolites as pigments have been developed mainly for their detection with high sensitivity.

Free Research Field

生物無機化学

Academic Significance and Societal Importance of the Research Achievements

S置換型ビリンの選択的検出が可能な蛍光タンパク質の開発により、今後、生体内での挙動を解明する基盤技術が得られた。基質の立体的な歪みを利用し新たな酵素反応の機構には興味が持たれており、電子状態を含む詳細な酵素構造の解明や反応様式の確定は、今後の該当分野の研究進展に重要な知見を与えた。また、病原性細菌の増殖に重要な酵素反応における複数様式の発見は、新たな薬剤の開発が期待されるだけでなく、代謝物の直接決定の重要性も明らかにした。