Infrared Spectroscopy During Electrocatalytic Turnover Reveals the Ni‐L Active Site State During H2 Oxidation by a NiFe Hydrogenase1. (29th April 2015)

• Record Type: Journal Article
• Authors: Hidalgo, Ricardo; Ash, Philip A.; Healy, Adam J.; Vincent, Kylie A.
• Is Part Of: Angewandte Chemie. Volume 127:Number 24(2015)
• Page Start: 7216
• Page End: 7219
• Publication Date: 2015-04-29
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201502338
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A novel in situ IR spectroscopic approach is demonstrated for the characterization of hydrogenase during catalytic turnover. <italic>E. coli</italic> hydrogenase 1 (Hyd‐1) is adsorbed on a high surface‐area carbon electrode and subjected to the same electrochemical control and efficient supply of substrate as in protein film electrochemistry during spectral acquisition. The spectra reveal that the active site state known as Ni‐L, observed in other NiFe hydrogenases only under illumination or at cryogenic temperatures, can be generated reversibly in the dark at ambient temperature under both turnover and non‐turnover conditions. The observation that Ni‐L is present at all potentials during turnover under H₂ suggests that the final steps in the catalytic cycle of H₂ oxidation by Hyd‐1 involve sequential proton and electron transfer via Ni‐L. A broadly applicable IR spectroscopic technique is presented for addressing electrode‐adsorbed redox enzymes under fast catalytic turnover.</p> </abstract>