Coherent Electron Transport across a 3 nm Bioelelectronic Junction made of Multi-heme Proteins

Zdenek, Futera, Ide, Ichiro, Kayser, Ben, Garg, Kavita, Jiang, Xiuyun, van Wonderen, Jessica H., Butt, Julea N., Ishii, Hisao, Pecht, Israel, Sheves, Mordechai, Cahen, David and Blumberger, Jochen (2020) Coherent Electron Transport across a 3 nm Bioelelectronic Junction made of Multi-heme Proteins. The Journal of Physical Chemistry Letters, 11 (22). 9766–9774. ISSN 1948-7185

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Multi-heme cytochromes (MHCs) are fascinating proteins used by bacterial organisms to shuttle electrons within and between their cells. When placed in solid state electronic junctions, MHCs support temperature-independent currents over several nanometers that are three orders of magnitude higher compared to other redox proteins. To gain molecular-level insight into their astonishingly high conductivities, we combine experimental photoemission spectroscopy with DFT+Σ current-voltage calculations on a representative 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, e.g. by applying a gate voltage, thus allowing a quantum jump for next-generation bionanoelectronic devices.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
Depositing User: LivePure Connector
Date Deposited: 20 Oct 2020 23:58
Last Modified: 03 Aug 2021 00:01

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