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Iron binding to human heavy-chain ferritin

DOI: 10.1107/S1399004715013073 DOI Help
PMID: 2632738 PMID Help

Authors: Cecilia Pozzi (University of Siena) , Flavio Di Pisa (University of Siena) , Caterina Bernacchioni (Università di Firenze) , Silvia Ciambellotti (Università di Firenze) , Paola Turano (Università di Firenze) , Stefano Mangani (University of Siena)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Acta Crystallographica Section D Biological Crystallography , VOL 71 , PAGES 1909 - 1920

State: Published (Approved)
Published: September 2015
Diamond Proposal Number(s): 8574

Abstract: Maxi-ferritins are ubiquitous iron-storage proteins with a common cage architecture made up of 24 identical subunits of five α-helices that drive iron biomineralization through catalytic iron(II) oxidation occurring at oxido­reductase sites (OS). Structures of iron-bound human H ferritin were solved at high resolution by freezing ferritin crystals at different time intervals after exposure to a ferrous salt. Multiple binding sites were identified that define the iron path from the entry ion channels to the oxidoreductase sites. Similar data are available for another vertebrate ferritin: the M protein from Rana catesbeiana. A comparative analysis of the iron sites in the two proteins identifies new reaction intermediates and underlines clear differences in the pattern of ligands that define the additional iron sites that precede the oxidoreductase binding sites along this path. Stopped-flow kinetics assays revealed that human H ferritin has different levels of activity compared with its R. catesbeiana counterpart. The role of the different pattern of transient iron-binding sites in the OS is discussed with respect to the observed differences in activity across the species

Journal Keywords: Ferritin; Human Heavy Chain; Iron; Mechanism.

Subject Areas: Chemistry

Instruments: I04-1-Macromolecular Crystallography (fixed wavelength)