Electronic Structure of Two Catalytic States of the [FeFe] Hydrogenase H-Cluster As Probed by Pulse Electron Paramagnetic Resonance Spectroscopy.

ABSTRACT: The active site of the [FeFe] hydrogenase (HydA1), the H-cluster, is a 6-Fe cofactor that contains CO and CN^- ligands. It undergoes several different oxidation and protonation state changes in its catalytic cycle to metabolize H₂. Among them, the well-known H_ox state and the recently identified H_hyd state are thought to be directly involved in H₂ activation and evolution, and they are both EPR active with net spin S = 1/2. Herein, we report the pulse electronic paramagnetic spectroscopic investigation of these two catalytic states in Chlamydomonas reinhardtii HydA1 ( CrHydA1). Using an in vitro biosynthetic maturation approach, we site-specifically installed ¹³C into the CO or CN^- ligands and ⁵⁷Fe into

SUBMITTER: Rao G 

PROVIDER: S-EPMC6366938 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature