Research Results

How Viologen Cation Radicals Improve the Carbon Dioxide Reduction Catalytic Activity of Formate Dehydrogenase

Key Points of This Research

• In the process of converting carbon dioxide into formate, an organic molecule, within artificial photosynthesis systems, this study clarified the precise mechanism of how the cation radical (*1) of methyl viologen—a coenzyme effective in activating formate dehydrogenase—is involved in enhancing enzyme activity. This was achieved through an analysis based on theoretical chemical calculations in addition to enzyme kinetics to evaluate the mechanism based on experimental data.
• This discovery will serve as an important guideline for the design and development of coenzymes that efficiently convert carbon dioxide into organic molecules toward the realization of artificial photosynthesis systems.

*1 Cation radical: A chemical species that possesses both a positive charge and an unpaired electron.

Summary

Yutaka Amao (Professor, Research Center for Artificial Photosynthesis, Osaka City University) and Terumitsu Miyaji (Assistant Professor, Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology) have clarified the electron-supply mechanism of the methyl viologen cation radical during the process of carbon dioxide reduction to formate catalyzed by formate dehydrogenase within artificial photosynthesis systems.

In the development of catalysts, which is being pursued as a key component technology for creating artificial photosynthesis systems that utilize solar energy to convert carbon dioxide into organic molecules, the essential interactions regarding how the coenzyme methyl viologen cation radical (MV.+) reduces carbon dioxide to formate within formate dehydrogenase (FDH) had not yet been fully understood.

In addition to several reaction models based on enzyme kinetics, this study clarified the electron-supply mechanism of MV.+ from both experimental and theoretical perspectives by determining the binding mode of MV.+ within FDH based on theoretical chemical calculations and the electronic state of MV.+ using density functional theory (DFT).

These research results were published in Physical Chemistry Chemical Physics (PCCP), a specialized physical chemistry journal published by the Royal Society of Chemistry (RSC).

Funding Information

These research results were obtained through the Joint Usage/Research Project of the Core of Excellence at Research Center for Artificial Photosynthesis, Osaka City University Media Center; the Fund for the Promotion of Joint International Research (Fostering Joint International Research (B)) from the Grants-in-Aid for Scientific Research; and a Grant-in-Aid for Scientific Research on Innovative Areas.

Publication Information

⇒All Press Release (PDF:404.9KB)

Article source: Osaka City University website