Infrared Characterization of the Bidirectional Oxygen-Sensitive [NiFe]-Hydrogenase from E. coli

Catalysts

SvenT. Stripp¹  Konstantin Laun¹  Moritz Senger¹  Basem Soboh² 

[1] Department of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany;Department of Physics, Genetic Biophysics, Freie Universität Berlin, 14195 Berlin, Germany;

关键词: redox enzymes;    FTIR spectroscopy;    small molecules;   

DOI  :  10.3390/catal8110530

来源: DOAJ

【 摘 要 】

[NiFe]-hydrogenases are gas-processing metalloenzymes that catalyze the conversion of dihydrogen (H₂) to protons and electrons in a broad range of microorganisms. Within the framework of green chemistry, the molecular proceedings of biological hydrogen turnover inspired the design of novel catalytic compounds for H₂ generation. The bidirectional “O₂-sensitive„ [NiFe]-hydrogenase from Escherichia coli HYD-2 has recently been crystallized; however, a systematic infrared characterization in the presence of natural reactants is not available yet. In this study, we analyze HYD-2 from E. coli by in situ attenuated total reflection Fourier-transform infrared spectroscopy (ATR FTIR) under quantitative gas control. We provide an experimental assignment of all catalytically relevant redox intermediates alongside the O₂- and CO-inhibited cofactor species. Furthermore, the reactivity and mutual competition between H₂, O₂, and CO was probed in real time, which lays the foundation for a comparison with other enzymes, e.g., “O₂-tolerant„ [NiFe]-hydrogenases. Surprisingly, only Ni-B was observed in the presence of O₂ with no indications for the “unready„ Ni-A state. The presented work proves the capabilities of in situ ATR FTIR spectroscopy as an efficient and powerful technique for the analysis of biological macromolecules and enzymatic small molecule catalysis.

【 授权许可】

Unknown