Browsing by Subject "electron transport"

Article

Biological charge transfer via flickering resonance

Zhang, Y.; Liu, C.; Balaeff, A.; Skourtis, Spiros S.; Beratan, David N. (2014)

Biological electron-transfer (ET) reactions are typically described in the framework of coherent two-state electron tunneling or multistep hopping. However, these ET reactions may involve multiple redox cofactors in van ...

Article

Charge transfer in dynamical biosystems, or the treachery of (static) images

Beratan, David N.; Liu, C.; Migliore, A.; Polizzi, N. F.; Skourtis, Spiros S.; Zhang, P.; Zhang, Y. (2015)

ConspectusThe image is not the thing. Just as a pipe rendered in an oil painting cannot be smoked, quantum mechanical coupling pathways rendered on LCDs do not convey electrons. The aim of this Account is to examine some ...

Article

Dexter Energy transfer pathways

Skourtis, Spiros S.; Liu, C.; Antoniou, Pavlos; Virshup, A. M.; Beratan, David N. (2016)

Energy transfer with an associated spin change of the donor and acceptor, Dexter energy transfer, is critically important in solar energy harvesting assemblies, damage protection schemes of photobiology, and organometallic ...

Article

Dielectric relaxation in an enzyme active site: Molecular dynamics simulations interpreted with a macroscopic continuum model

Archontis, Georgios Z.; Simonson, T. (2001)

Dielectric relaxation plays an important role in many chemical processes in proteins, including acid-base titration, ligand binding, and charge transfer reactions. Its complexity makes experimental characterization difficult, ...

Article

Electron transfer mechanisms

Beratan, David N.; Skourtis, Spiros S. (1998)

The tunneling pathway framework description of protein electron transfer reactions has prompted a lively discussion of how structure and evolution influence electron transfer rates. Recent protein and model system experiments, ...

Article

Fluctuations in biological and bioinspired electron-transfer reactions

Skourtis, Spiros S.; Waldeck, D. H.; Beratan, David N. (2010)

Central to theories of electron transfer (ET) is the idea that nuclear motion generates a transition state that enables electron flow to proceed, but nuclear motion also induces fluctuations in the donor-acceptor (DA) ...

Article

High and low resolution theories of protein electron transfer

Skourtis, Spiros S.; Beratan, David N. (1997)

Protein-mediated electronic interactions facilitate biological electron transfer (ET) reactions. Theory and experiment are being used extensively to establish atomic-scale descriptions of these reactions. The last 20 years ...

Article

Highly efficient spin filtering of ballistic electrons

Steinmuller, S. J.; Trypiniotis, Theodossis; Cho, W. S.; Hirohata, A.; Lew, W. S.; Vaz, C. A. F.; Bland, J. A. C. (2004)

Spin dependent electron transport in hybrid Au/Co/Cu/NiFe/n-GaAs spin valve Schottky barrier structures was investigated using photoexcitation at various wavelengths. For excitation with the photon energy well above the ...

Article

Long-range charge transport in single G-quadruplex DNA molecules

Livshits, G. I.; Stern, A.; Rotem, D.; Borovok, N.; Eidelshtein, G.; Migliore, A.; Penzo, E.; Wind, S. J.; Di Felice, R.; Skourtis, Spiros S.; Cuevas, J. C.; Gurevich, L.; Kotlyar, A. B.; Porath, D. (2014)

DNA and DNA-based polymers are of interest in molecular electronics because of their versatile and programmable structures. However, transport measurements have produced a range of seemingly contradictory results due to ...

Article

Modulating unimolecular charge transfer by exciting bridge vibrations

Lin, Z.; Lawrence, C. M.; Xiao, D.; Kireev, V. V.; Skourtis, Spiros S.; Sessler, J. L.; Beratan, David N.; Rubtsov, I. V. (2009)

(Figure Presented) Ultrafast UV-vibrational spectroscopy was used to investigate how vibrational excitation of the bridge changes photoinduced electron transfer between donor (dimethylaniline) and acceptor (anthracene) ...

Article

The origin of the Fe IV = O intermediates in cytochrome aa 3 oxidase

Pinakoulaki, Eftychia; Daskalakis, Vangelis; Varotsis, Constantinos (2012)

The dioxygen reduction mechanism in cytochrome oxidases relies on proton control of the electron transfer events that drive the process. Proton delivery and proton channels in the protein that are relevant to substrate ...

Article

Pathways, pathway tubes, pathway docking, and propagators in electron transfer proteins

Curry, W. B.; Grabe, M. D.; Kurnikov, I. V.; Skourtis, Spiros S.; Beratan, David N.; Regan, J. J.; Aquino, A. J. A.; Beroza, P.; Onuchic, J. N. (1995)

The simplest views of long-range electron transfer utilize flat one-dimensional barrier tunneling models, neglecting structural details of the protein medium. The pathway model of protein electron transfer reintroduces ...

Article

Photoselected electron transfer pathways in DNA photolyase

Prytkova, T. R.; Beratan, David N.; Skourtis, Spiros S. (2007)

Cyclobutane dimer photolyases are proteins that bind to UV-damaged DNA containing cyclobutane pyrimidine dimer lesions. They repair these lesions by photo-induced electron transfer. The electron donor cofactor of a photolyase ...

Article

Photosynthesis from the protein's perspective

Skourtis, Spiros S.; Beratan, David N. (2007)

Article

Physical constraints on charge transport through bacterial nanowires

Polizzi, N. F.; Skourtis, Spiros S.; Beratan, David N. (2012)

Extracellular appendages of the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1 were recently shown to sustain currents of 10 10 electrons per second over distances of 0.5 microns [El-Naggar et al., Proc. ...

Article

Probing the nitrite and nitric oxide reductase activity of cbb3 oxidase: Resonance Raman detection of a six-coordinate ferrous heme-nitrosyl species in the binuclear b3/CuB center

Loullis, Andreas; Pinakoulaki, Eftychia (2015)

In this work we report the first spectroscopic evidence demonstrating that cbb3 oxidase catalyzes the reduction of nitrite to nitrous oxide under reducing anaerobic conditions. The reaction proceeds through the formation ...

Article

Protein dynamics and electron transfer: Electronic decoherence and non-Condon effects

Skourtis, Spiros S.; Balabin, I. A.; Kawatsu, T.; Beratan, David N. (2005)

We compute the autocorrelation function of the donor-acceptor tunneling matrix element 〈TDA(t)TDA(0)〉 for six Ru-azurin derivatives. Comparison of this decay time to the decay time of the time-dependent Franck-Condon factor ...

Article

The protein effect in the structure of two ferryl-oxo intermediates at the same oxidation level in the heme copper binuclear center of cytochrome c oxidase

Pinakoulaki, Eftychia; Daskalakis, Vangelis; Ohta, T.; Richter, O. -M H.; Budiman, K.; Kitagawa, T.; Ludwig, B.; Varotsis, Constantinos (2013)

Identification of the intermediates and determination of their structures in the reduction of dioxygen to water by cytochrome c oxidase (CcO) are particularly important to understanding both O2 activation and proton pumping ...

Article

Review: Probing protein electron transfer mechanisms from the molecular to the cellular length scales

Skourtis, Spiros S. (2013)

The mechanisms of bridge-mediated electron transfer (ET) reactions vary from coherent deep tunneling to thermally activated hopping. This short review focuses on some developments in the study of protein ET mechanisms at ...

Article

Solid state and aqueous solution characterization of rectangular tetranuclear VIV/V-p-semiquinonate/hydroquinonate complexes exhibiting a proton induced electron transfer

Drouza, Chryssoula; Keramidas, Anastasios D. (2008)

Reaction of the non-innocent dinucleating ligand 2,5-bis[N,N- bis(carboxymethyl) arninomethyl]hydroquinone (H6bicah) with VO 2+ and VO43- salts in water in the pH range 2 to 4.5 provides a series of novel tetranuclear VIV ...