Importance of protein rearrangement in the electron-transfer reaction between the physiological partners cytochrome f and plastocyanin

Qin, Ling; Kostić, Nenad M.

doi:10.1021/bi00074a019

Cited by 103 publications

(87 citation statements)

References 67 publications

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“…Interestingly, the complex with the most stable configuration did not display the most efficient path for electron transfer, thus, a rearrangement of the complex is required in order to enable electron transfer. Such a rearrangement is in agreement with experimental results (Qin and Kostić 1993) obtained on this complex. The strategy that was followed to analyze computationally the complex between plastocyanin and cytochrome f allowed to get a detailed understanding of the electron transfer mechanism on a structural basis and enabled to explain experimental results.…”

Section: Docking Of Electron Transfer Proteinssupporting

confidence: 92%

Investigating the mechanisms of photosynthetic proteins using continuum electrostatics

et al. 2008

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Computational methods based on continuum electrostatics are widely used in theoretical biochemistry to analyze the function of proteins. Continuum electrostatic methods in combination with quantum chemical and molecular mechanical methods can help to analyze even very complex biochemical systems. In this article, applications of these methods to proteins involved in photosynthesis are reviewed. After giving a short introduction to the basic concepts of the continuum electrostatic model based on the Poisson-Boltzmann equation, we describe the application of this approach to the docking of electron transfer proteins, to the comparison of isofunctional proteins, to the tuning of absorption spectra, to the analysis of the coupling of electron and proton transfer, to the analysis of the effect of membrane potentials on the energetics of membrane proteins, and to the kinetics of charge transfer reactions. Simulations as those reviewed in this article help to analyze molecular mechanisms on the basis of the structure of the protein, guide new experiments, and provide a better and deeper understanding of protein functions.

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Section: Docking Of Electron Transfer Proteinssupporting

confidence: 92%

Investigating the mechanisms of photosynthetic proteins using continuum electrostatics

et al. 2008

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“…This effect has also been observed by Meyer et al (34) and Kannt et al (5) and was interpreted using a widely accepted rearrangement model (cf. ref 35). The optimum in k 2 is explained by an equilibrium between an initial electrostatic binding complex which is unfavorable for electron transfer and a tight electron-transfer complex.…”

Section: Discussionmentioning

confidence: 99%

Role of Electrostatics in the Interaction between Cytochrome f and Plastocyanin of the Cyanobacterium Phormidium laminosum

2002

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The role of charged residues on the surface of plastocyanin from the cyanobacterium Phormidium laminosum in the reaction with soluble cytochrome f in vitro was studied using site-directed mutagenesis. The charge on each of five residues on the eastern face of plastocyanin was neutralized and/or inverted, and the effect of the mutation on midpoint potentials was determined. The dependence of the overall rate constant of reaction, k(2), on ionic strength was investigated using stopped-flow spectrophotometry. Removing negative charges (D44A or D45A) accelerated the reaction and increased the dependence on ionic strength, whereas removing positive charges slowed it down. Two mutations (K46A, K53A) each almost completely abolished any influence of ionic strength on k(2), and three mutations (R93A, R93Q, R93E) each converted electrostatic attraction into repulsion. At low ionic strength, wild type and all mutants showed an inhibition which might be due to changes in the interaction radius as a consequence of ionic strength dependence of the Debye length or to effects on the rate constant of electron transfer, k(et). The study shows that the electrostatics of the interaction between plastocyanin and cytochrome f of P. laminosum in vitro are not optimized for k(2). Whereas electrostatics are the major contributor to k(2) in plants [Kannt, A., et al. (1996) Biochim. Biophys. Acta 1277, 115-126], this role is taken by nonpolar interactions in the cyanobacterium, leading to a remarkably high rate at infinite ionic strength (3.2 x 10(7) M(-1) s(-1)).

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“…From these reaction studies and comparative investigations using the acidic patch mutants, it has been suggested that a physiological electron donor, cytochrome f, might interact with the acidic patch of plastocyanin. Qin and Kostic (19,20) have suggested that the rearrangement of the electron transfer site between * This work was supported by Grants-in-Aid for Science Research on Priority Areas from the Ministry of Education, Science, Sports and Culture, Japan, by the Joint Studies of Program (1997) of the Institute for Molecular Science, and by the Grant-in-Aid for the Ground Experiment for the Space Utilization from the Japan Space Forum and National Space Developments Agency of Japan to Kohzuma. The costs of publication of this article were defrayed in part by the payment of page charges.…”

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confidence: 99%

The Structure and Unusual pH Dependence of Plastocyanin from the Fern Dryopteris crassirhizoma

Kohzuma¹,

Inoue²,

Yoshizaki³

et al. 1999

Journal of Biological Chemistry

114

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Spectroscopic properties, amino acid sequence, electron transfer kinetics, and crystal structures of the oxidized (at 1.7 Å resolution) and reduced form (at 1.8 Å resolution) of a novel plastocyanin from the fern Dryopteris crassirhizoma are presented. Kinetic studies show that the reduced form of Dryopteris plastocyanin remains redox-active at low pH, under conditions where the oxidation of the reduced form of other plastocyanins is inhibited by the protonation of a solvent-exposed active site residue, His 87 (equivalent to His 90 in Dryopteris plastocyanin). The x-ray crystal structure analysis of Dryopteris plastocyanin reveals -stacking between Phe 12 and His 90 , suggesting that the active site is uniquely protected against inactivation. Like higher plant plastocyanins, Dryopteris plastocyanin has an acidic patch, but this patch is located closer to the solvent-exposed active site His residue, and the total number of acidic residues is smaller. In the reactions of Dryopteris plastocyanin with inorganic redox reagents, the acidic patch (the "remote" site) and the hydrophobic patch surrounding His 90 (the "adjacent" site) are equally efficient for electron transfer. These results indicate the significance of the lack of protonation at the active site of Dryopteris plastocyanin, the equivalence of the two electron transfer sites in this protein, and a possibility of obtaining a novel insight into the photosynthetic electron transfer system of the first vascular plant fern, including its molecular evolutionary aspects. This is the first report on the characterization of plastocyanin and the first three-dimensional protein structure from fern plant.

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Importance of protein rearrangement in the electron-transfer reaction between the physiological partners cytochrome f and plastocyanin

Cited by 103 publications

References 67 publications

Investigating the mechanisms of photosynthetic proteins using continuum electrostatics

Investigating the mechanisms of photosynthetic proteins using continuum electrostatics

Role of Electrostatics in the Interaction between Cytochrome f and Plastocyanin of the Cyanobacterium Phormidium laminosum

The Structure and Unusual pH Dependence of Plastocyanin from the Fern Dryopteris crassirhizoma

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