Abstract
Metalloproteins, proteins containing a transition metal ion cofactor, are electron transfer agents that perform key functions in cells. Inspired by this fact, electron transport across these proteins has been widely studied in solid-state settings, triggering the interest in examining potential use of proteins as building blocks in bioelectronic devices. Here, we report results of low-temperature (10 K) electron transport measurements via monolayer junctions based on the blue copper protein azurin (Az), which strongly suggest quantum tunneling of electrons as the dominant charge transport mechanism. Specifically, we show that, weakening the protein–electrode coupling by introducing a spacer, one can switch the electron transport from off-resonant to resonant tunneling. This is a consequence of reducing the electrode’s perturbation of the Cu(II)localized electronic state, a pattern that has not been observed before in protein-based junctions. Moreover, we identify vibronic features of the Cu(II) coordination sphere in transport characteristics that show directly the active role of the metal ion in resonance tunneling. Our results illustrate how quantum mechanical effects may dominate electron transport via protein-based junctions.
| Original language | English |
|---|---|
| Pages (from-to) | E4577-E4583 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 115 |
| Issue number | 20 |
| DOIs | |
| State | Published - 15 May 2018 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2018 National Academy of Sciences. All rights reserved.
Funding
ACKNOWLEDGMENTS. We thank Prof. Spiros Skourtis (University of Cyprus), Dr. Cunlan Guo, and Mr. Ben Kayser (Weizmann Institute of Science) for fruitful discussions. J.A.F. thanks the Azrieli Foundation for the award of an Azrieli Fellowship. M.S. and D.C. thank the Israel Science Foundation, the Minerva Foundation, the Nancy and Stephen Grand Center for Sensors and Security, the Benoziyo Endowment Fund for the Advancement of Science, and J & R Center for Scientific Research for partial support. M.S. holds the Katzir–Makineni Chair in Chemistry; D.C. held the Schaefer Professorial Chair in Energy Research. J.C.C. acknowledges funding from the Spanish Ministry of Economy, Industry, and Competitiveness (Projects FIS2014-53488-P and FIS2017-84057-P) and thanks the German Research Foundation (DFG) and Collaborative Research Center (SFB) 767 for sponsoring his stay at the University of Konstanz as a Mercator Fellow. We thank Prof. Spiros Skourtis (University of Cyprus) Dr. Cunlan Guo, and Mr. Ben Kayser (Weizmann Institute of Science) for fruitful discussions. J.A.F. thanks the Azrieli Foundation for the award of an Azrieli Fellowship. M.S. and D.C. thank the Israel Science Foundation, the Minerva Foundation, the Nancy and Stephen Grand Center for Sensors and Security, the Benoziyo Endowment Fund for the Advancement of Science, and J & R Center for Scientific Research for partial support. M.S. holds the Katzir–Makineni Chair in Chemistry; D.C. held the Schaefer Professorial Chair in Energy Research. J.C.C. acknowledges funding from the Spanish Ministry of Economy, Industry, and Competitiveness (Projects FIS2014-53488-P and FIS2017-84057-P) and thanks the German Research Foundation (DFG) and Collaborative Research Center (SFB) 767 for sponsoring his stay at the University of Konstanz as a Mercator Fellow.
| Funders | Funder number |
|---|---|
| Benoziyo Endowment Fund for the Advancement of Science | |
| J & R Center for Scientific Research | |
| Nancy and Stephen Grand Center for Sensors and Security | |
| Minerva Foundation | |
| Deutsche Forschungsgemeinschaft | |
| Dementia Collaborative Research Centres, Australia | |
| Israel Science Foundation | |
| Azrieli Foundation | |
| Ministerio de Economía, Industria y Competitividad, Gobierno de España | FIS2014-53488-P, FIS2017-84057-P |
Keywords
- Bioelectronics
- Protein IETS
- Protein junctions
- Resonance tunneling
- Temperature dependence