期刊
SCIENCE ADVANCES
卷 8, 期 19, 页码 -出版社
AMER ASSOC ADVANCEMENT SCIENCE
DOI: 10.1126/sciadv.abm7193
关键词
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资金
- NSF CAREER award [1749662]
- NSF EAGER award [2038000]
- National Institutes of Health Director's New Innovator award [1DP2AI138259-01]
- Defense Advanced Research Project Agency (DARPA) Army Research Office (ARO)
- Air Force Office of Scientific Research [FA9550-17-0198]
- Extreme Science and Engineering Discovery Environment (XSEDE) [TG-CHE170024]
- NSF [2017224445]
- [W911NF-18-2-0100]
- Direct For Biological Sciences
- Div Of Molecular and Cellular Bioscience [1749662] Funding Source: National Science Foundation
- Direct For Biological Sciences
- Div Of Molecular and Cellular Bioscience [2038000] Funding Source: National Science Foundation
Geobacter sulfurreducens transports respiratory electrons over micrometers through nanowires composed of polymerized cytochrome OmcS. Individual nanowires exhibit hopping conductance and show a significant increase in their intrinsic conductance upon cooling. The cooling effect is caused by the rearrangement of hydrogen bonding networks in the nanowires, resulting in a temperature-sensitive switch for charge transport controlled by the protein surrounding the hemes.
Although proteins are considered as nonconductors that transfer electrons only up to 1 to 2 nanometers via tunneling, Geobacter sulfurreducens transports respiratory electrons over micrometers, to insoluble acceptors or syntrophic partner cells, via nanowires composed of polymerized cytochrome OmcS. However, the mechanism enabling this long-range conduction is unclear. Here, we demonstrate that individual nanowires exhibit theoretically predicted hopping conductance, at rate (>10(10) s(-1)) comparable to synthetic molecular wires, with negligible carrier loss over micrometers. Unexpectedly, nanowires show a 300-fold increase in their intrinsic conductance upon cooling, which vanishes upon deuteration. Computations show that cooling causes a massive rearrangement of hydrogen bonding networks in nanowires. Cooling makes hemes more planar, as revealed by Raman spectroscopy and simulations, and lowers their reduction potential. We find that the protein surrounding the hemes acts as a temperature-sensitive switch that controls charge transport by sensing environmental perturbations. Rational engineering of heme environments could enable systematic tuning of extracellular respiration.
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