Thermodynamics and kinetics of the electron transfer process of spinach plastocyanin adsorbed on a modified gold electrode

Ranieri, Antonio; Battistuzzi, Gianantonio; Borsari, Marco; Casalini, Stefano; Fontanesi, Claudio; Monari, Stefano; Siwek, Michal Jan; Sola, Marcó

doi:10.1016/j.jelechem.2008.12.001

Cited by 14 publications

(19 citation statements)

References 66 publications

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“…7 The observation that the ligand recombination rate constant linearly depends on the concentration of the incoming ligand, the chloride ion, implies that the ligand exchange reaction (eq 2) proceeds either through the associative or associative interchange mechanisms (eqs 4a,b). In our experiments, only the single form of copper(II) trichloro complex is observed whereas intermediate species are not kinetically detected, which leads to the conclusion that ligand exchange between a [CuCl 3 CH 3 …”

Section: Discussionmentioning

confidence: 55%

“…Therefore, the potential energy barrier of the addition arises as the result of columbic repulsion between two negatively charged ions, Figure 10 and Table 3. At the same time, the potential energy barrier for the addition of a chloride ion to a tetracoordinated [CuCl 3 CH 3 …”

Section: Cn]mentioning

confidence: 99%

“…2−4 In general, these transfer properties are associated with the ability of a copper ion to change its oxidation number reversibly. 3 However, plastocyanin is a rather complicated system for studying the photoinduced transformation of the copper proteins. On the other hand, copper(II) chloro complexes are known as model compounds to understand the photochemistry of more complex copper species, and potentially, they can be useful for better understanding of copper proteins.…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of Formation of Copper(II) Chloro Complexes Revealed by Transient Absorption Spectroscopy and DFT/TDDFT Calculations

et al. 2015

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Copper(II) complexes are extremely labile with typical ligand exchange rate constants on the order of 10 6 −10 9 M −1 s −1 . As a result, it is often difficult to identify the actual formation mechanism of these complexes. In this work, using UV−vis transient absorption when probing in a broad time range (20 ps to 8 μs) in conjunction with DFT/TDDFT calculations, we studied the dynamics and underlying reaction mechanisms of the formation of extremely labile copper(II) CuCl 4 2− chloro complexes from copper(II) CuCl 3 − trichloro complexes and chloride ions. These two species, produced via photochemical dissociation of CuCl 4 2− upon 420 nm excitation into the ligand-to-metal-charge-transfer electronic state, are found to recombine into parent complexes with bimolecular rate constants of (9.0 ± 0.1) × 10 7 and (5.3 ± 0.4) × 10 8 M −1 s −1 in acetonitrile and dichloromethane, respectively. In dichloromethane, recombination occurs via a simple one-step addition. In acetonitrile, where [CuCl 3 ]− reacts with the solvent to form a [CuCl 3 CH 3 CN] − complex in less than 20 ps, recombination takes place via ligand exchange described by the associative interchange mechanism that involves a [CuCl 4 CH 3 CN] 2− intermediate. In both solvents, the recombination reaction is potential energy controlled.

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Section: Discussionmentioning

confidence: 55%

Section: Cn]mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Mechanism of Formation of Copper(II) Chloro Complexes Revealed by Transient Absorption Spectroscopy and DFT/TDDFT Calculations

et al. 2015

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“…Electron transfer rate constants for plastocyanin and azurin at 20°C are listed in Table 1. As it is often the case with members of this protein family [12,20], electron exchange is about ten times faster for azurin than for plastocyanin.…”

Section: Fig 1 Illustrates Typical Voltammograms Of Adsorbed Plastocmentioning

confidence: 90%

“…Their thermostability has been investigated by spectroscopic techniques in a broad temperature range [4][5][6][7][8], but electrochemical methods, and particularly voltammetry, have been used only up to 50°C [9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Voltammetric study of the adsorbed thermophilic plastocyanin from Phormidium laminosum up to 90°C

Olloqui‐Sariego

Frutos-Beltrán

Roldán

et al. 2012

Electrochemistry Communications

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Redox thermodynamics and kinetics of plastocyanin from Phormidium laminosum, and of azurin from Pseudonomas aeruginosa, have been investigated as a function of temperature by protein film voltammetry. To this purpose, both proteins have been physisorbed on a pyrolytic graphite edge electrode. A pronounced negative shift of the plastocyanin standard potential, compared to a slight shift in the case of azurin, has been found upon increasing the temperature. Hence, significant conformational and/or solvation changes accompany the redox conversion of plastocyanin. Lower electron transfer rate constants (by c.a. one order of magnitude) and higher activation enthalpies have been found for plastocyanin as compared to azurin. The voltammetric response of azurin vanishes irreversibly at temperatures close to 60°C, whereas the redox properties of plastocyanin remain unaltered, except for some loss of electroactive protein, after heating the electrode at temperatures as high as 90°C.

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Electron Transfer and Electrocatalytic Properties of the Immobilized Met80Ala Cytochrome c Variant in Dimethylsulfoxide

et al. 2021

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The electrode-immobilized Met80Ala variant of yeast iso-1 cytochrome c in mixed water/dimethylsulfoxide (DMSO) solutions up to 60 % v/v DMSO shows thermodynamic and kinetic parameters of electron exchange and electrocatalytic properties towards O 2 reduction fully comparable to those in water. This is the result of moderate protein conformational changes thanks to immobilization that, to a certain extent, preserves protein structure, possibly due to the constraints on protein mobility/ flexibility induced by the electrostatic interactions with the electrode-coating SAM. Upon increasing the DMSO content of the mixed solution beyond 60 %, a much larger perturbation occurs that leads to the progressive loss of the electrocatalytic ability. Therefore, under these conditions, the organic solvent remarkably affects the structure and properties of the protein probably involving major conformational changes or even the replacement of the 6 th axial hydroxide ligand of the heme iron with a strong protein ligand, possibly a lysine residue.

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Thermodynamics and kinetics of the electron transfer process of spinach plastocyanin adsorbed on a modified gold electrode

Cited by 14 publications

References 66 publications

Mechanism of Formation of Copper(II) Chloro Complexes Revealed by Transient Absorption Spectroscopy and DFT/TDDFT Calculations

Mechanism of Formation of Copper(II) Chloro Complexes Revealed by Transient Absorption Spectroscopy and DFT/TDDFT Calculations

Voltammetric study of the adsorbed thermophilic plastocyanin from Phormidium laminosum up to 90°C

Electron Transfer and Electrocatalytic Properties of the Immobilized Met80Ala Cytochrome c Variant in Dimethylsulfoxide

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