Caught in the Hinact : Crystal Structure and Spectroscopy Reveal a Sulfur Bound to the Active Site of an O2 -stable State of FeFe Hydrogenase

• Published in: Angewandte Chemie International Edition Vol. 59; no. 38; p. 16786
• Main Authors: Rodríguez-Maciá, Patricia, Galle, Lisa M, Bjornsson, Ragnar, Lorent, Christian, Zebger, Ingo, Yoda, Yoshitaka, Cramer, Stephen P, DeBeer, Serena, Span, Ingrid, Birrell, James A
• Format: Journal Article
• Language: English
• Published: 14.09.2020
• ISSN: 1521-3773; 1521-3773
• DOI: 10.1002/anie.202005208

[FeFe] hydrogenases are the most active H2 converting catalysts in nature, but their extreme oxygen sensitivity limits their use in technological applications. The [FeFe] hydrogenases from sulfate reducing bacteria can be purified in an O2 -stable state called Hinact . To date, the structure and mechanism of formation of Hinact remain unknown. Our 1.65 Å crystal structure of this state reveals a sulfur ligand bound to the open coordination site. Furthermore, in-depth spectroscopic characterization by X-ray absorption spectroscopy (XAS), nuclear resonance vibrational spectroscopy (NRVS), resonance Raman (RR) spectroscopy and infrared (IR) spectroscopy, together with hybrid quantum mechanical and molecular mechanical (QM/MM) calculations, provide detailed chemical insight into the Hinact state and its mechanism of formation. This may facilitate the design of O2 -stable hydrogenases and molecular catalysts.[FeFe] hydrogenases are the most active H2 converting catalysts in nature, but their extreme oxygen sensitivity limits their use in technological applications. The [FeFe] hydrogenases from sulfate reducing bacteria can be purified in an O2 -stable state called Hinact . To date, the structure and mechanism of formation of Hinact remain unknown. Our 1.65 Å crystal structure of this state reveals a sulfur ligand bound to the open coordination site. Furthermore, in-depth spectroscopic characterization by X-ray absorption spectroscopy (XAS), nuclear resonance vibrational spectroscopy (NRVS), resonance Raman (RR) spectroscopy and infrared (IR) spectroscopy, together with hybrid quantum mechanical and molecular mechanical (QM/MM) calculations, provide detailed chemical insight into the Hinact state and its mechanism of formation. This may facilitate the design of O2 -stable hydrogenases and molecular catalysts.