Infrared Spectroscopy During Electrocatalytic Turnover Reveals the Ni-L Active Site State During H2Oxidation by a NiFe Hydrogenase

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