title: Solid-state electron transport across azurin: from a temperature-independent to a temperature-activated mechanism.
abstract: The temperature dependence of current-voltage values of electron transport through proteins integrated into a solid-state junction has been investigated. These measurements were performed from 80 up to 400 K [above the denaturation temperature of azurin (Az)] using Si/Az/Au junctions that we have described previously. The current across the ∼3.5 nm thick Az junction was temperature-independent over the complete range. In marked contrast, for both Zn-substituted and apo-Az (i.e., Cu-depleted Az), thermally activated behavior was observed. These striking temperature-dependence differences are ascribed to the pivotal function of the Cu ion as a redox center in the solid-state electron transport process. Thus, while Cu enabled temperature-independent electron transport, upon its removal the polypeptide was capable only of supporting thermally activated transport.
authors.affiliation: Departments of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Lior
authors.initials: L
authors.lastname: Sepunaru
authors.forename: Israel
authors.initials: I
authors.lastname: Pecht
authors.forename: Mordechai
authors.initials: M
authors.lastname: Sheves
authors.forename: David
authors.initials: D
authors.lastname: Cahen
mesh_terms: D001400:Azurin / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D004579:Electron Transport; D013696:Temperature; D015032:Zinc / Q000737:chemistry
chemical_list: D001400:Azurin; D003300:Copper; D015032:Zinc