Vibrational Perturbation of the [FeFe] Hydrogenase H-Cluster Revealed by 13C2H-ADT Labeling.

摘要: [FeFe] hydrogenases are highly active catalysts for the interconversion of molecular hydrogen with protons and electrons. Here, we use a combination isotopic labeling, 57Fe nuclear resonance vibrational spectroscopy (NRVS), density functional theory (DFT) calculations to observe characterize modes involving motion 2-azapropane-1,3-dithiolate (ADT) ligand bridging two iron sites in [2Fe]H subcluster. A -13C2H2- ADT labeling synthetic diiron precursor produced isotope effects observed throughout NRVS spectrum. The isotopologues were then used reconstitute H-cluster hydrogenase from Chlamydomonas reinhardtii (CrHydA1), was measured on samples poised catalytically crucial Hhyd state containing terminal hydride at distal Fe site. 13C2H also DFT simulations spectra allowed identification normal coupled motions. Particularly, variety involve shortening distance between Fe-H N-H bridgehead hydrogen, which may be relevant formation transition way H2 formation.