title: Electron transport via cytochrome c on Si-H surfaces: roles of Fe and heme.
abstract: Monolayers of the redox protein Cytochrome C (CytC) can be electrostatically formed on an H-terminated Si substrate, if the protein- and Si-surface are prepared so as to carry opposite charges. With such monolayers we study electron transport (ETp) via CytC, using a solid-state approach with macroscopic electrodes. We have revealed that currents via holo-CytC are almost 3 orders of magnitude higher than via the heme-depleted protein (→ apo-CytC). This large difference in currents is attributed to loss of the proteins' secondary structure upon heme removal. While removal of only the Fe ion (→ porphyrin-CytC) does not significantly change the currents via this protein at room temperature, the 30-335 K temperature dependence suggests opening of a new ETp pathway, which dominates at high temperatures (>285 K). These results suggest that the cofactor plays a major role in determining the ETp pathway(s) within CytC.
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Nadav
authors.initials: N
authors.lastname: Amdursky
authors.forename: Israel
authors.initials: I
authors.lastname: Pecht
authors.forename: Mordechai
authors.initials: M
authors.lastname: Sheves
authors.forename: David
authors.initials: D
authors.lastname: Cahen
mesh_terms: D001059:Apoproteins / Q000737:chemistry; D002942:Circular Dichroism; D045304:Cytochromes c / Q000737:chemistry*; D004579:Electron Transport; D006418:Heme / Q000737:chemistry*; D006859:Hydrogen; D007501:Iron / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D056951:Photoelectron Spectroscopy; D011166:Porphyrins / Q000737:chemistry; D012828:Silicones / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013696:Temperature
chemical_list: D001059:Apoproteins; D011166:Porphyrins; D012828:Silicones; D006418:Heme; D006859:Hydrogen; D045304:Cytochromes c; D007501:Iron