Structural distinction between ferritin and iron-dextran (imferon). An electron diffraction comparison

Area of Science:

• Materials Science
• Biomineralization
• Structural Chemistry

Background:

• Ferritin is a key iron storage protein, and understanding its iron core structure is crucial for biological and medical applications.
• Previous studies suggested structural similarities between ferritin iron and certain iron compounds, necessitating further investigation.
• Iron-dextran complexes like Imferon are used clinically and are often considered in relation to ferritin's iron core.

Purpose of the Study:

• To compare the crystal structure of iron cores in ferritin, ferrihydrite, iron-dextran (Imferon), and beta-FeOOH using electron diffraction.
• To clarify the structural relationship between ferritin iron, ferrihydrite, Imferon, and beta-FeOOH.
• To evaluate the suitability of existing iron-dextran analogs for studying ferritin iron-protein interactions.

Main Methods:

• Acquisition and analysis of electron diffraction data from ferritin, Imferon, ferrihydrite, and beta-FeOOH samples.
• Comparative structural analysis based on the obtained diffraction patterns.

Main Results:

• Electron diffraction data confirm that the iron cores of ferritin and ferrihydrite are structurally identical.
• Imferon and beta-FeOOH exhibit close structural similarity to each other but are distinctly different from ferritin and ferrihydrite.
• The previously suggested unique similarity between ferritin and Imferon was not supported by the data.

Conclusions:

• Ferritin's iron core structure is indistinguishable from ferrihydrite.
• Iron-dextran (Imferon) and beta-FeOOH represent a different structural class of iron oxyhydroxides.
• Ferrihydrite-dextran complexes are proposed as superior analogs for investigating ferritin iron-protein interactions compared to current iron-dextrans.