Abstract
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.
Original language | English |
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Pages (from-to) | 9766-9774 |
Number of pages | 9 |
Journal | Journal of Physical Chemistry Letters |
Volume | 11 |
Issue number | 22 |
DOIs | |
State | Published - 19 Nov 2020 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2020 American Chemical Society.
Funding
Z.F. was supported by EPSRC (EP/M001946/1) and by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 682539/SOFTCHARGE). X.J. was supported by a Ph.D. studentship cosponsored by the Chinese Scholarship Council and University College London. J.H.v.W. was supported by EPSRC (EP/M001989/1). I.I. and H.I. were supported by JSPS KAKENHI Grant 16H04222. M.S. and D.C. thank the Israel Science Foundation and the German Science Foundation (DFG) for partial support. Via UCL-group membership of the UK’s HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202, EP/R029431), this work used the ARCHER UK National Supercomputing Service ( http://www.archer.ac.uk ). We are grateful to the UK Materials and Molecular Modelling Hub for computational resources, which is partially funded by EPSRC (EP/P020194/1).
Funders | Funder number |
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Chinese Scholarship Council | |
German Science Foundation | |
Horizon 2020 Framework Programme | 682539 |
Engineering and Physical Sciences Research Council | EP/M001946/1 |
University College London | EP/M001989/1 |
European Commission | |
Deutsche Forschungsgemeinschaft | EP/P020194/1, EP/R029431, EP/L000202 |
Japan Society for the Promotion of Science | 16H04222 |
Israel Science Foundation |