Hydroxy-bridged resting states of a [NiFe]-hydrogenase unraveled by cryogenic vibrational spectroscopy and DFT computations
Giorgio Caserta, Vladimir Pelmenschikov, Christian Lorent, Armel F. Tadjoung Waffo, Sagie Katz, Lars Lauterbach, Janna Schoknecht, Hongxin Wang, Yoshitaka Yoda, Kenji Tamasaku, Martin Kaupp, Peter Hildebrandt, Oliver Lenz, Stephen P. Cramer, Ingo Zebger
Abstract
Fe-labeled HoxC provided an unprecedented insight into the [NiFe] site modes, revealing their contributions in a spectral range otherwise superimposed by FeS cluster-derived bands. Rationalized by density functional theory (DFT) calculations, our data provide structural descriptions of the previously uncharacterized hydroxy- and water-containing resting states. Our work highlights the relevance of cryogenic vibrational spectroscopy and DFT to elucidate the structure of barely defined redox states of the [NiFe]-hydrogenase active site.