A kinetic model of proton transport in a multi-redox centre protein: cytochrome coxidase

Srajer, Johannes; Schwaighofer, Andreas; Hildenbrandt, David M.; Kibrom, Asmorom; Naumann, Renate L.C.
March 2013
Progress in Reaction Kinetics & Mechanism;Mar2013, Vol. 38 Issue 1, p32
Academic Journal
We use chemical reaction kinetics to explore the stepwise electron and proton transfer reactions of cytochrome c oxidase (CcO) from R. sphaeroides. Proton transport coupled to electron transport (ET) is investigated in terms of a sequence of protonation-dependent second-order redox reactions. Thereby, we assume fixed rather than shifting dissociation constants of the redox sites. Proton transport can thus be simulated particularly when separate proton uptake and release sites are assumed rather than the same proton pump site for every ET step. In order to test these assumptions, we make use of a model system introduced earlier, which allows us to study direct ET of redox enzymes by electrochemistry. A four-electron transfer model of CcO had been developed before, according to which electrons are transferred from the electrode to CuA. Thereafter, electrons are transferred along the sequence heme a, heme a3 and CuB. In the present investigation, we consider protonation equilibria of the oxidised and reduced species for each of the four centres. Moreover, we add oxygen/H2O as the terminal (fifth) redox couple including protonation of reduced oxygen to water. Finally we arrive at a kinetic model comprising five protonation-dependent redox couples. The results from the simulations are compared with experimental data obtained in the absence and presence of oxygen. As a result, we can show that proton transport can be modelled in terms of protonation-dependent redox kinetics.


Related Articles

  • Two phases of proton translocation. Rousseau, Denis L. // Nature;7/29/1999, Vol. 400 Issue 6743, p412 

    Discusses the molecular mechanism by which oxygen reduction is coupled to proton translocation, the redox linkage. Reference to a study by Wikstrom et al in this issue on a time frame for the relationship between the chemical steps and the translocation of protons; The four redox centers of...

  • Electron and proton transfer in the catalytic aniline benzoylation. Kalninsh, K. K.; Panarin, E. F. // Doklady Chemistry;May2011, Vol. 438 Issue 1, p133 

    The article discusses the transmission of proton and electron particles in the catalytic aniline benzoylation. It mentions proton transfer as the vital elementary process conforming the simple linear relationships in the acid-base catalysis theory. It also cites the formation of catalytic...

  • Model system-bath Hamiltonian and nonadiabatic rate constants for proton-coupled electron transfer at electrode-solution interfaces. Navrotskaya, Irina; Soudackov, Alexander V.; Hammes-Schiffer, Sharon // Journal of Chemical Physics;6/28/2008, Vol. 128 Issue 24, p244712 

    An extension of the Anderson–Newns–Schmickler model for electrochemical proton-coupled electron transfer (PCET) is presented. This model describes reactions in which electron transfer between a solute complex in solution and an electrode is coupled to proton transfer within the...

  • Ascorbate-induced oxidation of formate by peroxodisulfate: product yields, kinetics and mechanism. Curtin, Maria A.; Taub, Irwin A.; Kustin, Kenneth; Sao, Narith; Duvall, Jeremy R.; Davies, Katherine I.; Doona, ChristopherJ.; Ross, Edward W. // Research on Chemical Intermediates;2004, Vol. 30 Issue 6, p647 

    The slow reaction between peroxodisulfate and formate is significantly accelerated by ascorbate at room temperature. The products of this induced oxidation, CO2 and oxalate (C2O2–4), were analyzed by several methods and the kinetics of this reaction were measured. The overall mechanism...

  • Kinetics and mechanism of formyl- and acetylferrocene oxidation with molecular oxygen in organic solvents. Fomin, V.; Shirokov, A. // Russian Journal of General Chemistry;Jun2012, Vol. 82 Issue 6, p1080 

    Kinetic laws and the products of autoxidation of formyl- and acetylferrocene in organic solvents in the presence of strong and weak Brønsted acids were investigated. The special feature of the studied reactions is the extreme dependence of the metal complex oxidation rate on the strong acid...

  • Acid and complex-forming properties of tetrapyrazinoporphyrazines. Kokareva, E. A.; Petrov, O. A.; Khelevina, O. G. // Russian Journal of General Chemistry;Nov2009, Vol. 79 Issue 11, p2440 

    The reactions of octaethyl- and octaphenyltetrapyrazinoporphyrazines with dimethyl sulfoxide were studied. The compositions of the resulting complexes with proton-transfer were determined. The reaction of the formation of a magnesium(II) octaethyltetrapyrazinoporphyrazine complex in pyridine was...

  • Reactions of O-aryl S-aryl dithiocarbonates with secondary alicyclic amines in aqueous ethanol. Kinetics and mechanism. Castro, Enrique A.; Gazitúa, Marcela; Santos, José G. // Journal of Physical Organic Chemistry;Jun2011, Vol. 24 Issue 6, p466 

    The reactions of O-(4-methylphenyl) S-(4-nitrophenyl), O-(4-chlorophenyl) (4-nitrophenyl), O-(4-chlorophenyl) S-phenyl, and O-(4-methylphenyl) S-phenyl dithiocarbonates (, , , and , respectively) with a series of secondary alicyclic (SA) amines are subjected to a kinetic investigation in 44 wt%...

  • Analysis of kinetic isotope effects for nonadiabatic reactions. Hyojoon Kim; Hanna, Gabriel; Kapral, Raymond // Journal of Chemical Physics;8/28/2006, Vol. 125 Issue 8, p084509 

    Factors influencing the rates of quantum mechanical particle transfer reactions in many-body systems are discussed. The investigations are carried out on a simple model for a proton transfer reaction that captures generic features seen in more realistic models of condensed phase systems. The...

  • Proton transport in biological systems can be probed by two-dimensional infrared spectroscopy. Liang, Chungwen; Jansen, Thomas L. C.; Knoester, Jasper // Journal of Chemical Physics;1/28/2011, Vol. 134 Issue 4, p044502 

    We propose a new method to determine the proton transfer (PT) rate in channel proteins by two-dimensional infrared (2DIR) spectroscopy. Proton transport processes in biological systems, such as proton channels, trigger numerous fundamental biochemical reactions. Due to the limitation in both...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics