Open AccessCoherent Electron Transport across a 3 nm Bioelectronic Junction Made of Multi-Heme Proteins
Author(s) -
Zdeněk Futera,
Ichiro Ide,
Ben Kayser,
Kavita D. Garg,
Xiuyun Jiang,
Jessica H. van Wonderen,
Julea N. Butt,
Hisao Ishii,
İsrael Pecht,
Mordechai Sheves,
David Cahen,
Jochen Blumberger
Publication year - 2020
Publication title -
the journal of physical chemistry letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.563
H-Index - 203
ISSN - 1948-7185
DOI - 10.1021/acs.jpclett.0c02686
Subject(s) - delocalized electron , chemical physics , electron , quantum tunnelling , heme , electron transport chain , chemistry , atomic orbital , materials science , nanotechnology , optoelectronics , physics , biochemistry , organic chemistry , quantum mechanics , enzyme
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.