scholarly journals Distance dependence of photoinduced long-range electron transfer in zinc/ruthenium-modified myoglobins

1988 ◽  
Vol 110 (2) ◽  
pp. 435-439 ◽  
Author(s):  
Andrew W. Axup ◽  
Michael. Albin ◽  
Stephen L. Mayo ◽  
Robert J. Crutchley ◽  
Harry B. Gray
Keyword(s):  
Electron Transfer ◽  
Long Range ◽  
Distance Dependence

Peptide-mediated intramolecular electron transfer: long-range distance dependence

1992 ◽  
Vol 92 (3) ◽  
pp. 381-394 ◽  
Author(s):  
Stephan S. Isied ◽  
Michael Y. Ogawa ◽  
James F. Wishart
Keyword(s):  
Electron Transfer ◽  
Long Range ◽  
Intramolecular Electron Transfer ◽  
Distance Dependence

scholarly journals Distance dependence of long-range electron transfer through helical peptides

2007 ◽  
Vol 14 (2) ◽  
pp. 192-202 ◽  
Author(s):  
Minako Kai ◽  
Kazuki Takeda ◽  
Tomoyuki Morita ◽  
Shunsaku Kimura
Keyword(s):  
Electron Transfer ◽  
Long Range ◽  
Helical Peptides ◽  
Distance Dependence

Shallow Distance Dependence for Proton-Coupled Tyrosine Oxidation in Oligoproline Peptides

2020 ◽  
Author(s):  
Brian Koronkiewicz ◽  
John R. Swierk ◽  
Kevin P. Regan ◽  
James Mayer
Keyword(s):  
Electron Transfer ◽  
Proton Transfer ◽  
Long Range ◽  
Rate Constants ◽  
High Energy ◽  
Transfer Distance ◽  
Tyrosine Oxidation ◽  
Donor And Acceptor ◽  
Distance Dependence ◽  
Biological Electron Transfer

We have explored the kinetic effect of increasing electron transfer distance in a biomimetic, proton coupled electron transfer system (PCET). Biological electron transfer is often simultaneous with proton transfer in order to avoid the high-energy, charged intermediates resulting from the stepwise transfer of protons and electrons. These concerted proton electron transfer (CPET) reactions are implicated in numerous biological electron transfer pathways. In many cases, proton transfer is coupled to long-range electron transfer. While many studies have shown that the rate of electron transfer is sensitive to the distance between the electron donor and acceptor, extensions to biological CPET reactions are sparse. The possibility of a unique electron transfer distance dependence for CPET reactions deserves further exploration, as this could have implications for how we understand biological electron transfer. We therefore explored the electron transfer distance dependence for the CPET oxidation of tyrosine in a model system. We prepared a series of metallopeptides with a tyrosine separated from a Ru(bpy)<sub>3</sub><sup>2+</sup> complex by an oligoproline bridge of increasing length. Rate constants for intramolecular tyrosine oxidation were measured using the flash-quench transient absorption technique in aqueous solutions. The rate constants for tyrosine oxidation decreased by 125-fold with three added prolines residues between tyrosine and the oxidant. By comparison, related intramolecular ET rate constants in very similar constructs were reported to decrease by 4-5 orders of magnitude over the same number of prolines. The observed shallow distance dependence for tyrosine oxidation is proposed to originate, at least in part, from the requirement for stronger oxidants, leading to a smaller hole transfer tunneling barrier height. The shallow distance dependence observed here and extensions to distance dependent CPET reactions have far-reaching implications for long-range charge transfers

scholarly journals Overpotential-induced lability of the electronic overlap factor in long-range electrochemical electron transfer: charge and distance dependence

2000 ◽  
Vol 2 (1) ◽  
pp. 141-144 ◽  
Author(s):  
Alexei A. Kornyshev ◽  
Alexander M. Kuznetsov ◽  
Jens U. Nielsen ◽  
J. Ulstrup
Keyword(s):  
Electron Transfer ◽  
Long Range ◽  
Distance Dependence ◽  
Overlap Factor

Shallow Distance Dependence for Proton-Coupled Tyrosine Oxidation in Oligoproline Peptides

2020 ◽  
Author(s):  
Brian Koronkiewicz ◽  
John R. Swierk ◽  
Kevin P. Regan ◽  
James Mayer
Keyword(s):  
Electron Transfer ◽  
Proton Transfer ◽  
Long Range ◽  
Rate Constants ◽  
High Energy ◽  
Transfer Distance ◽  
Tyrosine Oxidation ◽  
Donor And Acceptor ◽  
Distance Dependence ◽  
Biological Electron Transfer

We have explored the kinetic effect of increasing electron transfer distance in a biomimetic, proton coupled electron transfer system (PCET). Biological electron transfer is often simultaneous with proton transfer in order to avoid the high-energy, charged intermediates resulting from the stepwise transfer of protons and electrons. These concerted proton electron transfer (CPET) reactions are implicated in numerous biological electron transfer pathways. In many cases, proton transfer is coupled to long-range electron transfer. While many studies have shown that the rate of electron transfer is sensitive to the distance between the electron donor and acceptor, extensions to biological CPET reactions are sparse. The possibility of a unique electron transfer distance dependence for CPET reactions deserves further exploration, as this could have implications for how we understand biological electron transfer. We therefore explored the electron transfer distance dependence for the CPET oxidation of tyrosine in a model system. We prepared a series of metallopeptides with a tyrosine separated from a Ru(bpy)<sub>3</sub><sup>2+</sup> complex by an oligoproline bridge of increasing length. Rate constants for intramolecular tyrosine oxidation were measured using the flash-quench transient absorption technique in aqueous solutions. The rate constants for tyrosine oxidation decreased by 125-fold with three added prolines residues between tyrosine and the oxidant. By comparison, related intramolecular ET rate constants in very similar constructs were reported to decrease by 4-5 orders of magnitude over the same number of prolines. The observed shallow distance dependence for tyrosine oxidation is proposed to originate, at least in part, from the requirement for stronger oxidants, leading to a smaller hole transfer tunneling barrier height. The shallow distance dependence observed here and extensions to distance dependent CPET reactions have far-reaching implications for long-range charge transfers

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