Electronic Conductance Resonance in Non-Redox-Active Proteins

Area of Science:

• Bioelectronics
• Molecular Biophysics
• Protein Conduction

Background:

• Bioelectronics research traditionally focuses on redox-active proteins for biological charge transport.
• Electronic conductance in redox proteins peaks at their specific redox potential.
• Recent findings indicate non-redox-active proteins also exhibit significant electronic conductivity, but the mechanism remains unclear.

Purpose of the Study:

• To investigate the mechanism of electronic conduction in non-redox-active proteins.
• To measure single-molecule conductance of non-redox-active proteins under controlled electron injection.
• To understand the factors governing charge transport in proteins lacking redox activity.

Main Methods:

• Single-molecule conductance measurements.
• Potentiostatic control of proteins in solution.
• Varying electron injection energy to probe conductance characteristics.

Main Results:

• Three non-redox-active proteins were measured.
• A consistent conductance resonance was observed for all tested proteins.
• This resonance occurred at an electron injection potential approximately 0.7 V shifted from the nearest amino acid oxidation potential.

Conclusions:

• The observed conductance resonance suggests a novel charge transport mechanism in non-redox-active proteins.
• The potential shift may indicate reduced reorganization energy within the protein interior.
• This finding could explain long-range conductance in proteins when charge carriers are injected internally.