Near-metallic behavior of warm holoferritin molecules on a gold(111) surface.
Ferritin, the iron-storage protein, holds great potential for bioelectronic applications because of the presence of an electronically conducting iron core. We have applied scanning tunneling microscopy (STM), a high-resolution imaging method based on direct tunneling, to visualize the ferritin molecules both in the iron-containing holo form and in the iron-free apo form, and we have probed the electron flow through the two forms of this protein by measuring the current-voltage response using scanning tunneling spectroscopy (STS). Clear distinctions could be made among the current-voltage responses of the metallic gold(111) substrate surface, holoferritin molecules, and apoferritin molecules at room temperature. When warmed to the near-physiological temperature of 40 °C, the current-voltage response of the holoferritin molecules exhibited no band gap resembling near-metallic behavior, and the apoferritin molecules exhibited only a reduced band gap.
Rakshit
T
T
Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700032, India.
Banerjee
S
S
Mukhopadhyay
R
R
D001052:Apoferritins / Q000737:chemistry; D004553:Electric Conductivity; D004583:Electrons; D005293:Ferritins / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006801:Humans; D016252:Microscopy, Scanning Tunneling; D013499:Surface Properties; D013696:Temperature
D006046:Gold; D005293:Ferritins; D001052:Apoferritins