O 2 reactions at the six-iron active site (H-cluster) in [FeFe]-hydrogenase
Irreversible inhibition by molecular oxygen (O 2) complicates the use of [FeFe]-hydrogenases (HydA) for biotechnological hydrogen (H 2) production. Modification by O 2 of the active site six-iron complex denoted as the H-cluster ([4Fe4S]-2Fe H) of HydA1 from the green alga Chlamydomonas reinhardtii was characterized by x-ray absorption spectroscopy at the iron K-edge. In a time-resolved approach,