2IU2: Recombinant Human H Ferritin, K86q, E27d And E107d Mutant, Soaked With Zn Ions

Ferritins 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.
PDB ID: 2IU2Download
MMDB ID: 43447
PDB Deposition Date: 2006/5/26
Updated in MMDB: 2012/10
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 2IU2: 24-meric; determined by author and by software (PQS)
Molecular Components in 2IU2
Label Count Molecule
Proteins (24 molecules)
Ferritin Heavy Chain(Gene symbol: FTH1)
Molecule annotation
Chemicals (167 molecules)
* Click molecule labels to explore molecular sequence information.

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