http://www.cnr.it/ontology/cnr/individuo/prodotto/ID341

The redox chemistry of the covalently immobilized native and low-pH forms of yeast iso-1-cytochrome c (Articolo in rivista)

Type

Prodotto della ricerca (Classe)
Articolo in rivista (Classe)

Label

The redox chemistry of the covalently immobilized native and low-pH forms of yeast iso-1-cytochrome c (Articolo in rivista) (literal)

Anno

2006-01-01T00:00:00+01:00 (literal)

Alternative label

Bortolotti, CA; Battistuzzi, G; Borsari, M; Facci, P; Ranieri, A; Sola, M (2006)
The redox chemistry of the covalently immobilized native and low-pH forms of yeast iso-1-cytochrome c
in Journal of the American Chemical Society (Print)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

Bortolotti, CA; Battistuzzi, G; Borsari, M; Facci, P; Ranieri, A; Sola, M (literal)

Pagina inizio

5444 (literal)

Pagina fine

5451 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

128 (literal)

Rivista

Journal of the American Chemical Society (Rivista)

Note

ISI Web of Science (WOS) (literal)

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Univ Modena, Dept Chem, I-41100 Modena, Italy; Univ Modena, SCS Ctr, I-41100 Modena, Italy; CNR, INFM, Natl Ctr Nanostruct & Biosyst Surfaces S3, I-41100 Modena, Italy (literal)

Titolo

The redox chemistry of the covalently immobilized native and low-pH forms of yeast iso-1-cytochrome c (literal)

Abstract

Cyclic voltammetry experiments were carried out on native Saccharomyces cerevisiae iso-1-cytochrome c and its C102T/N62C variant immobilized on bare polycrystalline gold electrode through the S-Au bond formed by a surface cysteine. Experiments were carried out at different temperatures (5-65 degrees C) and pH values (1.5-7). The E-o' value at pH 7 (+370 mV vs SHE) is approximately 100 mV higher than that for the protein in solution. This difference is enthalpic in origin and is proposed to be the result of the electrostatic repulsion among the densely packed molecules onto the electrode surface. Two additional electrochemical waves are observed upon lowering the pH below 5 (E-o' = +182 mV) and 3 (E-o', = +71 mV), which are attributed to two conformers (referred to as 'intermediate' and 'acidic', respectively) featuring an altered heme axial ligation. This is the first determination of the reduction potential for low-pH conformers of cytochrome c in the absence of denaturants. Since the native form of cytochrome c can be restored, bringing back the pH to neutrality, the possibility offered by this transition to reversibly modulate the redox potential of cytochrome c is appealing for bioelectronic applications. The immobilized C102T/N62C variant, which differs from the native protein in the orientation of the heme group with respect to the electrode, shows very similar reduction thermodynamics. For both species, the rate constant for electron transfer between the heme and the electrode increases for the acidic conformer, which is also found to act as a biocatalytic interface for dioxygen reduction. (literal)

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