1tk6

Iron-oxo clusters biomineralizing on protein surfaces. Structural analysis of H.salinarum DpsA in its low and high iron states

spinqualitylabelsall models 1tk6, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1tk6 is a 4 chain structure with sequence from Halobacterium salinarum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.2Å Ligands: FE, MG, NA, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DPS_HALSA Protects DNA from oxidative damage by sequestering intracellular Fe(2+) ion and storing it in the form of Fe(3+) oxyhydroxide mineral. One hydrogen peroxide oxidizes two Fe(2+) ions, which prevents hydroxyl radical production by the Fenton reaction (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 PubMed The crystal structure of the Dps-like (Dps, DNA-protecting protein during starvation) ferritin protein DpsA from the halophile Halobacterium salinarum was determined with low endogenous iron content at 1.6-A resolution. The mechanism of iron uptake and storage was analyzed in this noncanonical ferritin by three high-resolution structures at successively increasing iron contents. In the high-iron state of the DpsA protein, up to 110 iron atoms were localized in the dodecameric protein complex. For ultimate iron storage, the archaeal ferritin shell comprises iron-binding sites for iron translocation, oxidation, and nucleation. Initial iron-protein interactions occur through acidic residues exposed along the outer surface in proximity to the iron entry pore. This narrow pore permits translocation of ions toward the ferroxidase centers via two discrete steps. Iron oxidation proceeds by transient formation of tri-iron ferroxidase centers. Iron storage by biomineralization inside the ferritin shell occurs at two iron nucleation centers. Here, a single iron atom provides a structural seed for iron-oxide cluster formation. The clusters with up to five iron atoms adopt a geometry that is different from natural biominerals like magnetite but resembles iron clusters so far known only from bioinorganic model compounds. Iron-oxo clusters biomineralizing on protein surfaces: structural analysis of Halobacterium salinarum DpsA in its low- and high-iron states.,Zeth K, Offermann S, Essen LO, Oesterhelt D Proc Natl Acad Sci U S A. 2004 Sep 21;101(38):13780-5. Epub 2004 Sep 13. PMID:15365182 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ferritin 3D structures

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