Electron-transfer kinetics of pentaammineruthenium(III)(histidine-33)-ferricytochrome c. Measurement of the rate of intramolecular electron transfer between redox centers separated by 15.ANG. in a protein

Abstract

A central problem in metalloprotein oxidation-reduction chemistry is the elucidation of the relationship between electron-transfer rate and redox-center separation.2"4 The most direct way to address this problem is to make measurements of intramolecular electron-transfer rates between redox centers in proteins in cases where the separation distance is known. An attractive system in this regard is Ru(NH3) s(His-3 3)3+-ferricytochrome c (PFenl-RuIn), whose redox centers are separated by 15 Á (Figure

Long-range electron transfer

“…In 1982, we demonstrated long-range electron tunneling through Ru-modified cytochrome (cyt) c (27). Subsequent work in our laboratory has focused on the elucidation of distant electronic couplings between redox sites in several Ru-proteins (7,(28)(29)(30)(31)(32).…”

Heme–copper oxidases use tunneling pathways

“…The electron tunneling probability is determined by the chemical structure of the tunneling barrier (3)(4)(5)(6)(7). Extensive theoretical and experimental work over the last 20 years has revealed fascinating symmetry, energy, and distance dependences of these tunneling propensities (7)(8)(9)(10).…”

“…The invention of selective metallolabeling methods (8) paved the way for experimental (9) and theoretical (10) determinations of the protein medium dependence of distant donor-acceptor electronic couplings. Importantly, a structure-dependent pathway model was developed to describe how the protein structure affects the ET kinetics (10).…”

Tuning electronic transport via hepta-alanine peptides junction by tryptophan doping

“…oligopeptide | electron transport | self-assembled monolayer | inelastic electron tunneling spectroscopy | doping E lectron transfer (ET) processes taking place between prosthetic groups across the polypeptide matrices of proteins (1-3) have been extensively explored by, e.g., time-resolved photolysis (4,5), pulse radiolysis (6, 7), scanning tunneling microscopy (8,9), electrochemical methods (10)(11)(12), and by theoretical studies (13)(14)(15)(16). The surprisingly fast and efficient ET over considerable distances (up to ∼25 Å) (17) via peptide matrices in proteins suggests possible development of peptide-and protein-based bioelectronics with diverse functionality and relative ease of modification (18,19).…”