posted on 2020-03-23, 16:04authored byBintian Zhang, Weisi Song, Jesse Brown, Robert Nemanich, Stuart Lindsay
Bioelectronics research has mainly
focused on redox-active proteins
because of their role in biological charge transport. In these proteins,
electronic conductance is a maximum when electrons are injected at
the known redox potential of the protein. It has been shown recently
that many non-redox-active proteins are good electronic conductors,
though the mechanism of conduction is not yet understood. Here, we
report single-molecule measurements of the conductance of three non-redox-active
proteins, maintained under potential control in solution, as a function
of electron injection energy. All three proteins show a conductance
resonance at a potential ∼0.7 V removed from the nearest oxidation
potential of their constituent amino acids. If this shift reflects
a reduction of reorganization energy in the interior of the protein,
it would account for the long-range conductance observed when carriers
are injected into the interior of a protein.