Kinetic and structural characterization of an intermediate in the biomineralization of bacterioferritin

Abstract
The mechanism by which iron‐storage proteins take up and oxidise iron(II) is not understood. We show by rapid‐kinetic and EPR measurements that iron uptake, in vitro, by a bacterial iron‐storage protein, bacterioferritin, involves at least three kinetically distinguishable phases: phase 1, the binding of Fe(II) ions, probably at a dimeric iron ferroxidase centre; phase 2, oxidation of the Fe(II) dimer and production of mononuclear Fe(III); and phase 3, iron core formation.