Electrochemistry, AFM, and PM‐IRRA Spectroscopy of Immobilized Hydrogenase: Role of a Hydrophobic Helix in Enzyme Orientation for Efficient H2 Oxidation

A transmembrane helix surrounded by detergent molecules close to the surface electron relay is shown, by electrochemical, AFM, and PM-IRRAS studies, to control the orientation of a membrane-bound [NiFe] hydrogenase on electrochemical interfaces. Hence, H2 oxidation proceeds as a mixture of direct (DET) and mediated electron transfer (MET) on hydrophilic interfaces, but by a MET process on hydrophobic interfaces (see picture).