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Shedding Light on Proton and Electron Dynamics in [FeFe] Hydrogenases

Lorent, Christian; Katz, Sagie; Duan, Jifu; Kulka, Catharina Julia; Caserta, Giorgio; Teutloff, Christian; Yadav, Shanika; Apfel, Ulf-Peter; Winkler, Martin; Happe, Thomas; Horch, Marius; Zebger, Ingo

FG Physikalische Chemie / Biophysikalische Chemie

[FeFe] hydrogenases are highly efficient catalysts for reversible dihydrogen evolution. H2 turnover involves different catalytic intermediates including a recently characterized hydride state of the active site (H-cluster). Applying cryogenic infrared and electron paramagnetic resonance spectroscopy to an [FeFe] model hydrogenase from Chlamydomonas reinhardtii (CrHydA1), we have discovered two new hydride intermediates and spectroscopic evidence for a bridging CO ligand in two reduced H-cluster states. Our study provides novel insights into these key intermediates, their relevance for the catalytic cycle of [FeFe] hydrogenase, and novel strategies for exploring these aspects in detail.