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Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Temperature-dependent solid-state electron transport through bacteriorhodopsin: experimental evidence for multiple
Lior Sepunaru1, Noga Friedman, Israel Pecht
1Department of Materials and Interfaces, Weizmann Institute of Science, POB 26, Rehovot 76100, Israel.
Journal of the American Chemical Society
|February 3, 2012
Summary
Electron transport (ETp) across bacteriorhodopsin (bR) exhibits temperature-dependent behavior, shifting from thermally activated to temperature-independent. This protein facilitates high current densities, suggesting a generalized electron transport mechanism in proteins.
Area of Science:
- Biophysics
- Protein Electron Transfer
- Molecular Electronics
Background:
- Bacteriorhodopsin (bR) functions as a natural proton pump.
- Electron transport (ETp) in solid-state protein monolayers is crucial for bioelectronic applications.
- Understanding temperature-dependent ETp in proteins is key to their functional characterization.
Purpose of the Study:
- To investigate the temperature dependence of electron transport across bacteriorhodopsin in a dry monolayer.
- To elucidate the mechanisms governing electron transport in bR under varying thermal conditions.
- To propose a generalized model for protein-mediated electron transport.
Main Methods:
- Studying electron transport across bacteriorhodopsin monolayers as a function of temperature.
- Analyzing transport behavior at temperatures above 200 K and below 130 K.
- Investigating the impact of altering the retinal chromophore on electron transport.
Main Results:
- Electron transport in bR transitions from thermally activated (T > 200 K) to temperature-independent (T < 130 K).
- bR demonstrates high current densities and temperature stability above room temperature.
- Modifying the retinal group introduced alternative thermally activated transport pathways.
Conclusions:
- A generalized mechanism for ETp across proteins involves coexisting tunneling and hopping transport regimes.
- The findings highlight bR's potential for high-performance bioelectronic devices.
- Protein structure and chromophore modifications significantly influence electron transport pathways.
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