Iron Storage Proteins and Their Biological Mechanisms

Iron storage proteins, chiefly ferritins and bacterioferritins, are ubiquitous supramolecular assemblies that secure cellular iron homeostasis by oxidising, storing and releasing iron ions within a proteinaceous nanocage. Each ferritin shell comprises 24 subunits arranged around a central cavity, into which thousands of ferric iron atoms are deposited as a mineral core, typically ferrihydrite. The ferroxidase centres within these subunits catalyse the rapid oxidation of Fe2+ to Fe3+, coupling iron uptake with controlled mineralisation. Channels at the protein interfaces enable iron transit into and out of the core, while structural variations between heavy (H) and light (L) chains modulate catalytic efficiency, stability and iron release kinetics. Bacterioferritins incorporate additional heme groups that facilitate electron transfer during reductive mobilisation of iron, demonstrating an integrated mechanism for iron release. Together, these proteins prevent iron‐catalysed free-radical formation, support metabolic demands and contribute to immune defence, neurobiology and plant physiology. Recent advances have revealed how subunit composition, channel architecture and cofactor interplay govern mineral core morphology, iron dynamics and potential nanotechnological applications, underscoring the global significance of understanding iron storage mechanisms for biotechnology and medicine.

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Iron Storage Proteins and Their Biological Mechanisms publication trend

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Technical terms

Ferritin: A 24-subunit protein nanocage that oxidises Fe2+ and stores iron as a ferric mineral within its central cavity.

Bacterioferritin: A ferritin homologue incorporating heme prosthetic groups that facilitate electron transfer during iron release.

Ferroxidase centre: An intrasubunit diiron catalytic site responsible for the oxidation of ferrous iron and initial mineral nucleation.

Apo-ferritin: The iron-depleted form of ferritin prior to iron loading.

Holo-ferritin: The iron-loaded form of ferritin containing a mineralised ferric core.

References

1. The Ferroxidase Centre of Escherichia coli Bacterioferritin Plays a Key Role in the Reductive Mobilisation of the Mineral Iron Core. Angewandte Chemie International Edition (2024).
2. Optical Monitoring of In Situ Iron Loading into Single, Native Ferritin Proteins. Nano Letters (2023).
3. Ferritin at different iron loading: From biological to nanotechnological applications. International Journal of Biological Macromolecules (2024).