View source for 4p18


==Crystal Structure of frog M ferritin mutant D80K==
<StructureSection load='4p18' size='340' side='right'caption='[[4p18]], [[Resolution|resolution]] 1.91&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4p18]] 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=4P18 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4P18 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]] 1.91&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=4p18 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4p18 OCA], [https://pdbe.org/4p18 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4p18 RCSB], [https://www.ebi.ac.uk/pdbsum/4p18 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4p18 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.
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== Publication Abstract from PubMed ==
Functional ferritins are 24-mer nanocages that self-assemble with extended contacts between pairs of 4-helix bundle subunits coupled in an antiparallel fashion along the C2 axes. The largest intersubunit interaction surface in the ferritin nanocage involves helices, but contacts also occur between groups of three residues midway in the long, solvent-exposed L-loops of facing subunits. The anchor points between intersubunit L-loop pairs are the salt bridges between the symmetry-related, conserved residues Asp80 and Lys82. The resulting quaternary structure of the cage is highly soluble and thermostable. Substitution of negatively charged Asp80 with a positively charged Lys in homopolymeric M ferritin introduces electrostatic repulsions that inhibit the oligomerization of the ferritin subunits. D80K ferritin was present in inclusion bodies under standard overexpressing conditions in E. coli, contrasting with the wild type protein. Small amounts of fully functional D80K nanocages formed when expression was slowed. The more positively charged surface results in a different solubility profile and D80K crystallized in a crystal form with a low density packing. The 3D structure of D80K variant is the same as wild type except for the side chain orientations of Lys80 and facing Lys82. When three contiguous Lys groups are introduced in D80KI81K ferritin variant the nanocage assembly is further inhibited leading to lower solubility and reduced thermal stability. Here, we demonstrate that the electrostatic pairing at the center of the L-loops has a specific kinetic role in the self-assembly of ferritin nanocages.

Loop Electrostatics Modulates the Intersubunit Interactions in Ferritin.,Bernacchioni C, Ghini V, Pozzi C, Di Pisa F, Theil EC, Turano P ACS Chem Biol. 2014 Aug 29. PMID:25148224<ref>PMID:25148224</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4p18" style="background-color:#fffaf0;"></div>

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