View source for 4mku


==Frog M ferritin mutant H54Q==
<StructureSection load='4mku' size='340' side='right'caption='[[4mku]], [[Resolution|resolution]] 1.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4mku]] is a 1 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=4MKU OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4MKU FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></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=4mku FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4mku OCA], [https://pdbe.org/4mku PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4mku RCSB], [https://www.ebi.ac.uk/pdbsum/4mku PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4mku ProSAT]</span></td></tr>
</table>
== 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.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Ferritin superfamily protein cages reversibly synthesize internal biominerals, Fe2O3.H2O. Fe(2+) and O2 (or H2O2) substrates bind at oxidoreductase sites in the cage, initiating biomineral synthesis to concentrate iron and prevent potentially toxic reactions products from Fe(2+)and O2 or H2O2 chemistry. By freezing ferritin crystals of Rana catesbeiana ferritin M (RcMf) at different time intervals after exposure to a ferrous salt, a series of high-resolution anomalous X-ray diffraction data sets were obtained that led to crystal structures that allowed the direct observation of ferrous ions entering, moving along and binding at enzyme sites in the protein cages. The ensemble of crystal structures from both aerobic and anaerobic conditions provides snapshots of the iron substrate bound at different cage locations that vary with time. The observed differential occupation of the two iron sites in the enzyme oxidoreductase centre (with Glu23 and Glu58, and with Glu58, His61 and Glu103 as ligands, respectively) and other iron-binding sites (with Glu53, His54, Glu57, Glu136 and Asp140 as ligands) reflects the approach of the Fe(2+) substrate and its progression before the enzymatic cycle 2Fe(2+) + O2 --&gt; Fe(3+)-O-O-Fe(3+) --&gt; Fe(3+)-O(H)-Fe(3+) and turnover. The crystal structures also revealed different Fe(2+) coordination compounds bound to the ion channels located at the threefold and fourfold symmetry axes of the cage.

Time-lapse anomalous X-ray diffraction shows how Fe(2+) substrate ions move through ferritin protein nanocages to oxidoreductase sites.,Pozzi C, Di Pisa F, Lalli D, Rosa C, Theil E, Turano P, Mangani S Acta Crystallogr D Biol Crystallogr. 2015 Apr;71(Pt 4):941-53. doi:, 10.1107/S1399004715002333. Epub 2015 Mar 27. PMID:25849404<ref>PMID:25849404</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4mku" style="background-color:#fffaf0;"></div>

==See Also==
*[[Ferritin 3D structures|Ferritin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Lithobates catesbeianus]]
[[Category: Di Pisa F]]
[[Category: Lalli D]]
[[Category: Mangani S]]
[[Category: Pozzi C]]
[[Category: Turano P]]