title: Current-voltage characteristics and transition voltage spectroscopy of individual redox proteins.
abstract: Understanding how molecular conductance depends on voltage is essential for characterizing molecular electronics devices. We reproducibly measured current-voltage characteristics of individual redox-active proteins by scanning tunneling microscopy under potentiostatic control in both tunneling and wired configurations. From these results, transition voltage spectroscopy (TVS) data for individual redox molecules can be calculated and analyzed statistically, adding a new dimension to conductance measurements. The transition voltage (TV) is discussed in terms of the two-step electron transfer (ET) mechanism. Azurin displays the lowest TV measured to date (0.4 V), consistent with the previously reported distance decay factor. This low TV may be advantageous for fabricating and operating molecular electronic devices for different applications. Our measurements show that TVS is a helpful tool for single-molecule ET measurements and suggest a mechanism for gating of ET between partner redox proteins.
authors.affiliation: Institute for Bioengineering of Catalonia  (IBEC), Baldiri Reixac 15-21, 08028 Barcelona, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Artés
authors.forename: Montserrat
authors.initials: M
authors.lastname: López-Martínez
authors.forename: Arnaud
authors.initials: A
authors.lastname: Giraudet
authors.forename: Ismael
authors.initials: I
authors.lastname: Díez-Pérez
authors.forename: Fausto
authors.initials: F
authors.lastname: Sanz
authors.forename: Pau
authors.initials: P
authors.lastname: Gorostiza
mesh_terms: D016252:Microscopy, Scanning Tunneling; D010084:Oxidation-Reduction; D011506:Proteins / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D011506:Proteins