7O68

Crystal structure of human mitochondrial ferritin (hMTF) Fe(II)-loaded for 120 minutes showing either a dioxygen or a superoxide anion coordinated to iron ions in the ferroxidase site.

Summary for 7O68

• Entry DOI: 10.2210/pdb7o68/pdb
• Related: 7O63 7O64
• Descriptor: Ferritin, mitochondrial, FE (II) ION, OXYGEN MOLECULE, ... (6 entities in total)
• Functional Keywords: human mitochondrial ferritin, hmtf, time-controlled iron loading, ferroxidase site, dioxygen, superoxide anion, oxidoreductase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 1
• Total formula weight: 21919.98

Authors

Pozzi, C.,Ciambellotti, S.,Tassone, G.,Turano, P.,Mangani, S. (deposition date: 2021-04-09, release date: 2021-10-13, Last modification date: 2024-01-31)

Primary citation

Ciambellotti, S.,Pratesi, A.,Tassone, G.,Turano, P.,Mangani, S.,Pozzi, C.
Iron Binding in the Ferroxidase Site of Human Mitochondrial Ferritin.
Chemistry, 27:14690-14701, 2021

PubMed Abstract: Ferritins are nanocage proteins that store iron ions in their central cavity as hydrated ferric oxide biominerals. In mammals, further the L (light) and H (heavy) chains constituting cytoplasmic maxi-ferritins, an additional type of ferritin has been identified, the mitochondrial ferritin (MTF). Human MTF (hMTF) is a functional homopolymeric H-like ferritin performing the ferroxidase activity in its ferroxidase site (FS), in which Fe(II) is oxidized to Fe(III) in the presence of dioxygen. To better investigate its ferroxidase properties, here we performed time-lapse X-ray crystallography analysis of hMTF, providing structural evidence of how iron ions interact with hMTF and of their binding to the FS. Transient iron binding sites, populating the pathway along the cage from the iron entry channel to the catalytic center, were also identified. Furthermore, our kinetic data at variable iron loads indicate that the catalytic iron oxidation reaction occurs via a diferric peroxo intermediate followed by the formation of ferric-oxo species, with significant differences with respect to human H-type ferritin.

PubMed: 34343376
DOI: 10.1002/chem.202102270

Experimental method

X-RAY DIFFRACTION (1.68 Å)