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Probing the Active Site of an Azurin Mutant Hot-Wired to Gold Electrodes

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journal contribution
posted on 21.03.2016, 00:00 by Razvan C. Stan, Alexander Kros, Jeroen Appel, Nusrat J. M. Sanghamitra
The adsorption of azurin H117G reconstituted with π-conjugated molecular wires, capable of interfacing its redox site to an underlying gold surface, has been studied with conductive-atomic force microscopy. The protein complexes display improved electrical conductivity to electrodes through the molecular wires compared to the native proteins and its mediation of electron transfer via the protein framework alone. Furthermore, both the wild-type azurin and thus-reconstituted azurin variants show the electronic signature of the redox-active metal at different voltage ranges. These results bring new insights into the origin of negative differential resistance features observed in metalloproteins and illustrate the feasibility of assembling engineered proteins with appropriate molecular linkers in solution, followed by adsorption in a controlled orientation and distance with respect to an electrode.