title: Ferroxidase Activity in Eukaryotic Ferritin is Controlled by Accessory-Iron-Binding Sites in the Catalytic Cavity.
abstract: Ferritins are iron-storage nanocage proteins that catalyze the oxidation of Fe2+to Fe3+at ferroxidase sites. By a combination of structural and spectroscopic techniques, Asp140, together with previously identified Glu57 and Glu136, is demonstrated to be an essential residue to promote the iron oxidation at the ferroxidase site. However, the presence of these three carboxylate moieties in close proximity to the catalytic centers is not essential to achieve binding of the Fe2+substrate to the diferric ferroxidase sites with the same coordination geometries as in the wild-type cages.
authors.affiliation: CERM and Department of Chemistry, University of Florence, Via Sacconi 6 Sesto Fiorentino, Firenze, 50019, Italy.
authors.forename: Caterina
authors.identifier: http://orcid.org/0000-0002-1023-0067
authors.initials: C
authors.lastname: Bernacchioni
authors.affiliation: Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, Siena, 53100, Italy.
authors.forename: Cecilia
authors.identifier: http://orcid.org/0000-0003-2574-3911
authors.initials: C
authors.lastname: Pozzi
authors.affiliation: Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, Siena, 53100, Italy.
authors.forename: Flavio
authors.identifier: http://orcid.org/0000-0003-2302-1464
authors.initials: F
authors.lastname: Di Pisa
authors.affiliation: Dipartimento di Biotecnologie, Chimica e Farmacia, University of Siena, Via Aldo Moro 2, Siena, 53100, Italy. stefano.mangani@unisi.it.
authors.forename: Stefano
authors.identifier: http://orcid.org/0000-0003-4824-7478
authors.initials: S
authors.lastname: Mangani
authors.affiliation: CERM and Department of Chemistry, University of Florence, Via Sacconi 6 Sesto Fiorentino, Firenze, 50019, Italy. turano@cerm.unifi.it.
authors.forename: Paola
authors.identifier: http://orcid.org/0000-0002-7683-8614
authors.initials: P
authors.lastname: Turano
keywords: X-ray diffraction; ferritin; ferroxidase; iron; protein structures