| Autor: |
Futera Z; Faculty of Science, University of South Bohemia, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic.; Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, U.K., Ide I; Graduate School of Science and Engineering, Chiba University, Chiba, Japan., Kayser B; Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel., Garg K; Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel., Jiang X; Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, U.K., van Wonderen JH; School of Chemistry, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K., Butt JN; School of Chemistry, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K., Ishii H; Graduate School of Science and Engineering, Chiba University, Chiba, Japan., Pecht I; Department of Immunology, Weizmann Institute of Science, Rehovot, Israel., Sheves M; Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel., Cahen D; Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel., Blumberger J; Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, U.K. |
| Abstrakt: |
Multi-heme cytochromes (MHCs) are fascinating proteins used by bacterial organisms to shuttle electrons within, between, and out of their cells. When placed in solid-state electronic junctions, MHCs support temperature-independent currents over several nanometers that are 3 orders of magnitude higher compared to other redox proteins of similar size. To gain molecular-level insight into their astonishingly high conductivities, we combine experimental photoemission spectroscopy with DFT+Σ current-voltage calculations on a representative Gold-MHC-Gold junction. We find that conduction across the dry, 3 nm long protein occurs via off-resonant coherent tunneling, mediated by a large number of protein valence-band orbitals that are strongly delocalized over heme and protein residues. This picture is profoundly different from the electron hopping mechanism induced electrochemically or photochemically under aqueous conditions. Our results imply that the current output in solid-state junctions can be even further increased in resonance, for example, by applying a gate voltage, thus allowing a quantum jump for next-generation bionanoelectronic devices. |
