Direct wiring of the azurin redox center to gold electrodes investigated by protein film voltammetry

Abstract

We present two surface-immobilization schemes that connect an azurin variant with mutations in the redox cavity to two oligophenylvinyl (OPV) molecular wires, along with an electrochemical study of their electron transfer (ET) properties. OPV embedded within alkanethiol films tether selectively the azurin mutants from solution and further connect them onto electrodes, as does protein reconstitution with OPV in solution followed by complex adsorption. Stable cyclic voltammograms are measured in either scenario, with highest ET values (k0≈740s−1) comparable to those observed for the gold-adsorbed native azurin (k0≈400s−1). Furthermore, subtle structural differences between the structurally-analogous OPV allow for the investigation of the optimal electronic conduit between the redox center and supporting gold electrodes (1.6–1.7 fold difference).