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| | <StructureSection load='3rbc' size='340' side='right'caption='[[3rbc]], [[Resolution|resolution]] 2.70Å' scene=''> | | <StructureSection load='3rbc' size='340' side='right'caption='[[3rbc]], [[Resolution|resolution]] 2.70Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3rbc]] is a 24 chain structure with sequence from [https://en.wikipedia.org/wiki/American_bullfrog American bullfrog]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3RBC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3RBC FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3rbc]] is a 24 chain structure with sequence from [https://en.wikipedia.org/wiki/Lithobates_catesbeianus Lithobates catesbeianus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3RBC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3RBC FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.7Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[3ka3|3ka3]], [[3ka4|3ka4]], [[1mfr|1mfr]]</div></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</scene></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Ferroxidase Ferroxidase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.16.3.1 1.16.3.1] </span></td></tr>
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| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3rbc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3rbc OCA], [https://pdbe.org/3rbc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3rbc RCSB], [https://www.ebi.ac.uk/pdbsum/3rbc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3rbc ProSAT]</span></td></tr> | | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3rbc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3rbc OCA], [https://pdbe.org/3rbc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3rbc RCSB], [https://www.ebi.ac.uk/pdbsum/3rbc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3rbc ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[https://www.uniprot.org/uniprot/FRI2_LITCT FRI2_LITCT]] 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.
| + | [https://www.uniprot.org/uniprot/FRI2_LITCT FRI2_LITCT] 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. |
| - | <div style="background-color:#fffaf0;">
| + | |
| - | == Publication Abstract from PubMed ==
| + | |
| - | The first step of iron biomineralization mediated by ferritin is the oxidation at the ferroxidase active site of two ferrous ions to a diferric oxo/hydroxo species. Metal-loaded ferritin crystals obtained by soaking crystals of frog ferritin in FeSO(4) and CuSO(4) solutions followed by flash freezing provided X-ray crystal structures of the tripositive iron and bipositive copper adducts at 2.7 and 2.8 A resolution, respectively. At variance with the already available structures, the crystal form used in this study contains 24 independent subunits in the asymmetric unit permitting comparison between them. For the first time, the diferric species at the ferroxidase site is identified in ferritins from higher eukaryotes. Anomalous difference Fourier maps for crystals (iron crystal 1) obtained after long soaking times in FeSO(4) solution invariantly showed diferric species with a Fe-Fe average distance of 3.1 +/- 0.1 A, strongly indicative of the presence of a mu-oxo/hydroxo bridge between the irons; protein ligands for each iron ion (Fe1 and Fe2) were also unequivocally identified and found to be the same in all subunits. For copper bound ferritin, dicopper(II) centers are also observed. While copper at site 1 is essentially in the same position and has the same coordination environment as Fe1, copper at site 2 is displaced toward His54, now acting as a ligand; this results in an increased intermetal distance (4.3 +/- 0.4 A). His54 coordination and longer metal-metal distances might represent peculiar features of divalent cations at the ferroxidase site. This oxidation-dependent structural information may provide key features for the mechanistic pathway in ferritins from higher eukaryotes that drive uptake of bivalent cation and release of ferric products at the catalytic site. This mechanism is supported by the X-ray picture obtained after only 1 min of soaking in FeSO(4) solutions (iron crystal 2) which reasonably contain the metal at different oxidation states. Here two different di-iron species are trapped in the active site, with intermetal distances corresponding to those of the ferric dimer in crystal 1 and of the dicopper centers and corresponding rearrangement of the His54 side chain.
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| - | Structural insights into the ferroxidase site of ferritins from higher eukaryotes.,Bertini I, Lalli D, Mangani S, Pozzi C, Rosa C, Theil EC, Turano P J Am Chem Soc. 2012 Apr 11;134(14):6169-76. doi: 10.1021/ja210084n. Epub 2012 Mar, 28. PMID:22424302<ref>PMID:22424302</ref>
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| - | | + | |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
| + | |
| - | </div>
| + | |
| - | <div class="pdbe-citations 3rbc" style="background-color:#fffaf0;"></div>
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| | | | |
| | ==See Also== | | ==See Also== |
| | *[[Ferritin 3D structures|Ferritin 3D structures]] | | *[[Ferritin 3D structures|Ferritin 3D structures]] |
| - | == References == | |
| - | <references/> | |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: American bullfrog]] | |
| - | [[Category: Ferroxidase]] | |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Bertini, I]] | + | [[Category: Lithobates catesbeianus]] |
| - | [[Category: Lalli, D]] | + | [[Category: Bertini I]] |
| - | [[Category: Mangani, S]] | + | [[Category: Lalli D]] |
| - | [[Category: Pozzi, C]] | + | [[Category: Mangani S]] |
| - | [[Category: Rosa, C]] | + | [[Category: Pozzi C]] |
| - | [[Category: Turano, P]] | + | [[Category: Rosa C]] |
| - | [[Category: Four-helix bundle]]
| + | [[Category: Turano P]] |
| - | [[Category: Iron storage]]
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| - | [[Category: Oxidoreductase]]
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