Creation of solid catalyst for cascade reaction by immobilization of metal complexes in the protein crystals

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05140
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34010:Inorganic/coordination chemistry-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Abe Satoshi 東京工業大学, 生命理工学院, 助教 (40508595)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: タンパク質結晶 / 多角体 / 人工酵素 / 固体触媒

Outline of Final Research Achievements

In this study, we constructed artificial enzymes that catalyze cascade reactions by immobilizing multiple metal complexes and enzymes in the internal space of protein crystals formed in living cells. We have prepared the polyhedra crystals immobilizing Pd and Ir complexes. The ICP-MS result indicated that Pd and Ir complexes were immobilized in the crystals. Molecular design for catalytic reaction activity will be carried out in the future.
We have constructed the 38-amino acid deletion mutants, which forms interlinked hollow nanocages with a diameter of 5 nm in the crystals. The mutant crystal can encapsulate lipase and alcohol dehydrogenase. The composite crystal enhances the reactivity of the cascade reaction. The higher reactivity is because of the substrate and intermediate efficiently diffusing through the extended channels designed within the nanoporous crystal.

Free Research Field

タンパク質工学

Academic Significance and Societal Importance of the Research Achievements

本研究は、極めて高い安定性をもつ多角体結晶を利用し、アミノ酸置換や欠損による触媒活性中心の最適化や基質の取り込み、拡散制御を試み、様々な反応条件下での活性制御が可能な反応場を構築した。また、細胞内で形成されるタンパク質結晶を利用するため、将来的には、細胞内での触媒反応も可能となり、触媒科学だけでなく、生体機能を制御する人工酵素の創製も可能となる。さらに、本研究で使用した多角体結晶は、細胞内で酵素の内包を完結し、乾燥や熱に対して高い安定性をもつため、タンパク質精製の高速化やタンパク質の長期保存と放出活性化など、生体機能材料の合成に止まらず、医薬品開発などへも応用可能な分子技術である。