Lorent, ChristianKatz, SagieDuan, JifuKulka, Catharina JuliaCaserta, GiorgioTeutloff, ChristianYadav, ShanikaApfel, Ulf-PeterWinkler, MartinHappe, ThomasHorch, MariusZebger, Ingo2023-01-192023-01-192020-03-030002-7863https://depositonce.tu-berlin.de/handle/11303/18013https://doi.org/10.14279/depositonce-16805[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.en541 Physikalische Chemieanionselectron paramagnetic resonance spectroscopyinfrared lightligandsreaction mechanismsArticle1520-5126