2cn6
Recombinant human H ferritin, K86Q and E107D mutant, soaked with Zn ions
Structural highlights
FunctionFRIH_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. Also plays a role in delivery of iron to cells. Mediates iron uptake in capsule cells of the developing kidney (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedFerritins are a family of proteins distributed widely in nature. In bacterial, plant, and animal cells, ferritin appears to serve as a soluble, bioavailable, and non-toxic form of iron provider. Ferritins from animal sources are heteropolymers composed of two types of subunit, H and L, which differ mainly by the presence (H) or absence (L) of active ferroxidase centres. We report the crystallographic structures of four human H apoferritin variants at a resolution of up to 1.5 Angstrom. Crystal derivatives using Zn(II) as redox-stable alternative for Fe(II), allows us to characterize the different metal-binding sites. The ferroxidase centre, which is composed of sites A and B, binds metal with a preference for the A site. In addition, distinct Zn(II)-binding sites were found in the 3-fold axes, 4-fold axes and on the cavity surface near the ferroxidase centre. To study the importance of the distance of the two metal atoms in the ferroxidase centre, single and double replacement of glutamate 27 (site A) and glutamate 107 (site B), the two axial ligands, by aspartate residues have been carried out. The consequences for metal binding and the correlation with Fe(II) oxidation rates are discussed. High-resolution X-ray structures of human apoferritin H-chain mutants correlated with their activity and metal-binding sites.,Toussaint L, Bertrand L, Hue L, Crichton RR, Declercq JP J Mol Biol. 2007 Jan 12;365(2):440-52. Epub 2006 Oct 7. PMID:17070541[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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