Redox potentials of recombinant manganese peroxidase from Phanerochaetes chrysosporium have been measured by cyclic voltammetry as a function of pH, between pH 4.5 and pH 10.5. They display a bimodal behaviour (characterized by an 'alkaline' and an 'acid' transition), which indicates that (at least) two protonating groups change their pK(t) values upon reduction (and/or oxidation) of the iron atom in haem. Analogous measurements have been carried out on four site-directed mutants involving residues in close proximity to the proximal ligand, His(173), in order to investigate the role played by residues of the proximal haem pocket on the redox properties of this enzyme. Results obtained suggest that the protonation state of N-delta of the proximal imidazole group is redox-linked and that it is crucial in regulating the 'alkaline' transition. On the other hand, none of the proximal mutants alters the 'acid' transition, suggesting that it is modulated by groups located in a different portion of the protein.

Santucci, R., Bongiovanni, C., Marini, S., Del Conte, R., Tien, M., Banci, L., et al. (2000). Redox equilibria of manganese peroxidase from Phanerochaetes chrysosporium: functional role of residues on the proximal side of the haem pocket. BIOCHEMICAL JOURNAL, 349(1), 85-90 [10.1042/0264-6021:3490085].

Redox equilibria of manganese peroxidase from Phanerochaetes chrysosporium: functional role of residues on the proximal side of the haem pocket

SANTUCCI, ROBERTO;MARINI, STEFANO;COLETTA, MASSIMILIANO
2000-01-01

Abstract

Redox potentials of recombinant manganese peroxidase from Phanerochaetes chrysosporium have been measured by cyclic voltammetry as a function of pH, between pH 4.5 and pH 10.5. They display a bimodal behaviour (characterized by an 'alkaline' and an 'acid' transition), which indicates that (at least) two protonating groups change their pK(t) values upon reduction (and/or oxidation) of the iron atom in haem. Analogous measurements have been carried out on four site-directed mutants involving residues in close proximity to the proximal ligand, His(173), in order to investigate the role played by residues of the proximal haem pocket on the redox properties of this enzyme. Results obtained suggest that the protonation state of N-delta of the proximal imidazole group is redox-linked and that it is crucial in regulating the 'alkaline' transition. On the other hand, none of the proximal mutants alters the 'acid' transition, suggesting that it is modulated by groups located in a different portion of the protein.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/10
English
Con Impact Factor ISI
Manganese peroxidase; pH dependence; Proximal haem pocket; Redox potentiometry; Site-directed mutants
Santucci, R., Bongiovanni, C., Marini, S., Del Conte, R., Tien, M., Banci, L., et al. (2000). Redox equilibria of manganese peroxidase from Phanerochaetes chrysosporium: functional role of residues on the proximal side of the haem pocket. BIOCHEMICAL JOURNAL, 349(1), 85-90 [10.1042/0264-6021:3490085].
Santucci, R; Bongiovanni, C; Marini, S; Del Conte, R; Tien, M; Banci, L; Coletta, M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/49990
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