Electrochemical characterization of synthetic metalloenzymes

Aim of this project is focused on establishing the relationship between electron transfer properties and catalytic activities of selected artificial metalloenzymes. These hybrid biomacromolecules were designed by French partners by covalent anchoring of new catalytically-active metal complexes within the active site of a selected protein host to achieve asymmetric catalysis in aqueous media. Catalytic cycle involves transfer of two electrons and thus electrochemical methods can provide new insights into the mechanism of the catalytic process. Namely, catalytic hydrogen evolution is the targeted electrochemical process at the electrode-electrolyte interface in the aqueous solution. This process will be explored using the protein host before and after covalent linking of the organometallic fragments. Cyclic voltammetry, spectroelectrochemistry, chronopotentiometric stripping analysis (H-peak) and phase sensitive electrochemical methods including electrochemical impedance spectroscopy will be used. Ultimately, we aim at addressing the electron transfer mechanism issues. Two types of approaches will be used. First one is the classical transfer of electrons from electrode to redox active site of the biomolecule and second one involves transport of charge in the electrode-metalloenzyme-electrode junctions. In both cases current as a function of applied voltage is obtained. In the second case Czech partners will use their unique instrumentation that allows measurements of very low currents and the current voltage characteristics in the statistically significant number of two electrode junctions. From such experiments one can obtain conductance value corresponding to a single metalloenzyme molecule. Single molecule conductance studies will aim at evaluation of these artificial biopolymers as possible building blocks of molecular bioelectronic devices. Results will be published in international journals and participation of students is expected for further strengthening of the cooperation.