Relationships of ligand binding, redox properties, and protonation in Coprinus cinereus peroxidase

Chiara Ciaccio, Antonella Rosati, Giampiero De Sanctis, Federica Sinibaldi, Stefano Marini, Roberto Santucci, Paolo Ascenzi, Karen G. Welinder, Massimo Coletta

Research output: Contribution to journalArticlepeer-review


The pH dependence of the redox potentials and kinetics for CO association and dissociation was determined between pH 3.0 and 13.0 at 25 °C for the wild-type Coprinus cinereus fungal peroxidase and for a site-directed mutant in which Asp245, which is H-bonded to Nδ of the imidazole of the proximal His183, was substituted with Asn. The determination of these functional properties allowed this information to be merged in a self-consistent fashion and to formulate for the first time a complete scheme employing the minimum number of groups required to describe the whole proton-linked behavior of both redox and ligand binding properties. The overall pH dependence can be accounted for by four redox- and ligand-linked groups. The proximal H-bond, which is strictly conserved in all peroxidases, will still be present in the site-specific mutant, but will no longer have an ionic character, and this event will bring about an alteration of redox equilibria and CO binding kinetics, envisaging a relevant role played by this H-bond also in modulating redox properties and ligand binding equilibria.

Original languageEnglish
Pages (from-to)18730-18737
Number of pages8
JournalJournal of Biological Chemistry
Issue number21
Publication statusPublished - May 23 2003

ASJC Scopus subject areas

  • Biochemistry


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