Spectroscopic and Computational Evidence that [FeFe] Hydrogenases Operate Exclusively with CO-Bridged Intermediates.

ABSTRACT: [FeFe] hydrogenases are extremely active H₂-converting enzymes. Their mechanism remains highly controversial, in particular, the nature of the one-electron and two-electron reduced intermediates called H_redH⁺ and H_sredH⁺. In one model, the H_redH⁺ and H_sredH⁺ states contain a semibridging CO, while in the other model, the bridging CO is replaced by a bridging hydride. Using low-temperature IR spectroscopy and nuclear resonance vibrational spectroscopy, together with density functional theory calculations, we show that the bridging CO is retained in the H_sredH⁺ and H_redH⁺ states in the [FeFe] hydrogenases from Chlamydomonas reinhardtii and D

SUBMITTER: Birrell JA 

PROVIDER: S-EPMC6956316 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature