Modulation of copper site properties by remote residues determines the stability of plastocyanins

Muñoz-López, Francisco J.; Frutos-Beltrán, Estrella; Díaz‐Moreno, Sofía; Dı́az-Moreno, Irene; Subı́as, G.; Rosa, Miguel Á. De la; Díaz-Quintana, Antonio

doi:10.1016/j.febslet.2010.04.013

Cited by 6 publications

(11 citation statements)

References 40 publications

(51 reference statements)

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“…Plastocyanin peaks tend to be broader, as expected for either a distribution of tunneling distances between the protein copper center and the electrode surface, or for a distribution of environments of the adsorbed protein [16]. Standard potential values of the immobilized proteins at 20°C (see Table 1) are~20 mV more positive (in the case of plastocyanin), or more negative (in the case of azurin), than their reported values in solution [17,18]. These standard potential shifts indicate a further stabilization of the reduced form of plastocyanin and of the oxidized form of azurin, upon adsorption at the graphite surface.…”

Section: Methodsmentioning

confidence: 79%

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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Section: Methodsmentioning

confidence: 79%

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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“…According to their T m values, the oxidized form of Pho -Pc is more stable in solution than the reduced one, whereas the mesophilic variant shows the opposite trend, in agreement with previous works. 6,7,11,15 Interestingly, the V48I mutation increases the thermal stability of Syn -Pc. In particular, the oxidized V48I mutant is characterized by a higher T m value than the oxidized Syn -Pc WT protein, whereas the T m values of the reduced mutant and WT proteins were similar.…”

Section: Resultsmentioning

confidence: 98%

“…This indirect control was evident when inducing a thermal destabilization of the thermophilic protein after introducing a single mutation in the east patch . Further X-ray absorption spectroscopy investigations revealed that this mutation induces a subtle change in the local geometry of the Cu-binding site, which then causes the thermal stabilization .…”

Section: Introductionmentioning

confidence: 99%

“…This indirect control was evident when inducing a thermal destabilization of the thermophilic protein after introducing a single mutation in the east patch. 15 Further X-ray absorption spectroscopy investigations revealed that this mutation induces a subtle change in the local geometry of the Cu-binding site, which then causes the thermal stabilization. 16 Nevertheless, the mechanism that allows this flexible region, located far from the metal active center, to regulate the protein’s thermal stability is not fully understood.…”

Section: Introductionmentioning

confidence: 99%

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Key Role of the Local Hydrophobicity in the East Patch of Plastocyanins on Their Thermal Stability and Redox Properties

et al. 2018

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Understanding the molecular basis of the thermal stability and functionality of redox proteins has important practical applications. Here, we show a distinct thermal dependence of the spectroscopic and electrochemical properties of two plastocyanins from the thermophilic cyanobacterium Phormidium laminosum and their mesophilic counterpart from Synechocystis sp. PCC 6803, despite the similarity of their molecular structures. To explore the origin of these differences, we have mimicked the local hydrophobicity in the east patch of the thermophilic protein by replacing a valine of the mesophilic plastocyanin by isoleucine. Interestingly, the resulting mutant approaches the thermal stability, redox thermodynamics, and dynamic coupling of the flexible site motions of the thermophilic protein, indicating the existence of a close connection between the hydrophobic packing of the east patch region of plastocyanin and the functional control and stability of the oxidized and reduced forms of the protein.

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“…Its thermostability has also been probed by spectroscopic techniques in a broad temperature range. 47,48 Based on these findings, this protein appears to be a good candidate to assess the influence of temperature on its ET kinetics.…”

Section: Toc Graphicsmentioning

confidence: 99%

Temperature-Driven Changeover in the Electron-Transfer Mechanism of a Thermophilic Plastocyanin

Olloqui‐Sariego

Moreno‐Beltrán

Díaz-Quintana

et al. 2014

J. Phys. Chem. Lett.

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Electron-transfer kinetics of the thermophilic protein Plastocyanin from Phormidium laminosum adsorbed on 1,ω-alkanedithiol self-assembled monolayers (SAMs) deposited on gold have been investigated. The standard electron-transfer rate constant has been determined as a function of electrode-protein distance and solution viscosity over a broad temperature range (0-90 °C). For either thin or thick SAMs, the electron-transfer regime remains invariant with temperature, whereas for the 1,11-undecanethiol SAM of intermediate chain length, a kinetic regime changeover from a gated or friction-controlled mechanism at low temperature (0-30 °C) to a nonadiabatic mechanism above 40 °C is observed. To the best of our knowledge, this is the first time a thermal-induced transition between these two kinetic regimes is reported for a metalloprotein.

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Modulation of copper site properties by remote residues determines the stability of plastocyanins

Cited by 6 publications

References 40 publications

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

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

Key Role of the Local Hydrophobicity in the East Patch of Plastocyanins on Their Thermal Stability and Redox Properties

Temperature-Driven Changeover in the Electron-Transfer Mechanism of a Thermophilic Plastocyanin

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