Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding

S. Monari, A. Ranieri, G. Di Rocco, G. van der Zwan, S. Peressini, C. Tavagnacco, D. Millo, M. Borsari

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature His-Met intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The much lower E°' value of the bis-histidinate conformer as compared to His-Met ligated species is largely determined by the enthalpic contribution induced by axial ligand substitution. The biphasic E°' versus T profile for the His-Met species is due to a difference in reduction entropy between the conformers at low and high temperatures. Enthalpy-entropy compensation phenomena for the reduction reaction at varying urea concentration for all the forms of the investigated cytochromes c were addressed and discussed. © 2009 Springer Science+Business Media B.V.
LanguageEnglish
Pages2181-2190
JournalJournal of Applied Electrochemistry
Volume39
DOIs
Publication statusPublished - 2009

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Cytochromes c
Urea
Thermodynamics
Proteins
Entropy
Beef
Yeast
Temperature
Enthalpy
Substitution reactions
Ligands
Electrons
Oxidation-Reduction

Cite this

Monari, S., Ranieri, A., Di Rocco, G., van der Zwan, G., Peressini, S., Tavagnacco, C., ... Borsari, M. (2009). Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding. Journal of Applied Electrochemistry, 39, 2181-2190. https://doi.org/10.1007/s10800-009-9804-7
Monari, S. ; Ranieri, A. ; Di Rocco, G. ; van der Zwan, G. ; Peressini, S. ; Tavagnacco, C. ; Millo, D. ; Borsari, M. / Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding. In: Journal of Applied Electrochemistry. 2009 ; Vol. 39. pp. 2181-2190.
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abstract = "The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature His-Met intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The much lower E°' value of the bis-histidinate conformer as compared to His-Met ligated species is largely determined by the enthalpic contribution induced by axial ligand substitution. The biphasic E°' versus T profile for the His-Met species is due to a difference in reduction entropy between the conformers at low and high temperatures. Enthalpy-entropy compensation phenomena for the reduction reaction at varying urea concentration for all the forms of the investigated cytochromes c were addressed and discussed. {\circledC} 2009 Springer Science+Business Media B.V.",
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Monari, S, Ranieri, A, Di Rocco, G, van der Zwan, G, Peressini, S, Tavagnacco, C, Millo, D & Borsari, M 2009, 'Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding', Journal of Applied Electrochemistry, vol. 39, pp. 2181-2190. https://doi.org/10.1007/s10800-009-9804-7

Redox Thermodynamics of Cytochromes c Subjected to Urea Induced Unfolding. / Monari, S.; Ranieri, A.; Di Rocco, G.; van der Zwan, G.; Peressini, S.; Tavagnacco, C.; Millo, D.; Borsari, M.

In: Journal of Applied Electrochemistry, Vol. 39, 2009, p. 2181-2190.

Research output: Contribution to JournalArticleAcademicpeer-review

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AU - Monari, S.

AU - Ranieri, A.

AU - Di Rocco, G.

AU - van der Zwan, G.

AU - Peressini, S.

AU - Tavagnacco, C.

AU - Millo, D.

AU - Borsari, M.

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N2 - The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature His-Met intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The much lower E°' value of the bis-histidinate conformer as compared to His-Met ligated species is largely determined by the enthalpic contribution induced by axial ligand substitution. The biphasic E°' versus T profile for the His-Met species is due to a difference in reduction entropy between the conformers at low and high temperatures. Enthalpy-entropy compensation phenomena for the reduction reaction at varying urea concentration for all the forms of the investigated cytochromes c were addressed and discussed. © 2009 Springer Science+Business Media B.V.

AB - The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature His-Met intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The much lower E°' value of the bis-histidinate conformer as compared to His-Met ligated species is largely determined by the enthalpic contribution induced by axial ligand substitution. The biphasic E°' versus T profile for the His-Met species is due to a difference in reduction entropy between the conformers at low and high temperatures. Enthalpy-entropy compensation phenomena for the reduction reaction at varying urea concentration for all the forms of the investigated cytochromes c were addressed and discussed. © 2009 Springer Science+Business Media B.V.

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