7o67
From Proteopedia
Crystal structure of human mitochondrial ferritin (hMTF) Fe(II)-loaded for 15 minutes showing either a dioxygen or a superoxide anion coordinated to iron ions in the ferroxidase site
Structural highlights
FunctionFTMT_HUMAN Stores iron in a soluble, non-toxic, readily available form. Important for iron homeostasis. Has ferroxidase activity. Iron is taken up in the ferrous form and deposited as ferric hydroxides after oxidation.[1] [2] Publication Abstract from PubMedFerritins 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. Iron Binding in the Ferroxidase Site of Human Mitochondrial Ferritin.,Ciambellotti S, Pratesi A, Tassone G, Turano P, Mangani S, Pozzi C Chemistry. 2021 Aug 3. doi: 10.1002/chem.202102270. PMID:34343376[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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