Solid-state electron transport via cytochrome c depends on electronic coupling to electrodes and across the protein (original) (raw)

Significance How well a protein conducts electrical current depends on both the chemical nature of the protein and its contacts to the electrodes between which currents are carried. Investigating conduction via protein monolayers, we find that covalent binding to electrodes doubles room temperature conduction and halves its thermal activation energy. At low temperatures, where transport is by tunneling, covalent binding increases conduction up to 10-fold. To examine the electrical conduction across the protein, we used seven different cytochrome c mutants with surface-exposed cysteine, providing distinct electrode–heme orientations and distances. Remarkably, currents do not depend on the electrodes’ separation distance as set by a given protein binding orientation but rather on the distance between the heme and one of the electrodes.