View source for 9x15


==Crystal structure of Frog M-ferritin E130A_L165D_K168E_H169D mutants==
<StructureSection load='9x15' size='340' side='right'caption='[[9x15]], [[Resolution|resolution]] 1.45&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[9x15]] 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=9X15 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=9X15 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]] 1.45&#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=9x15 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=9x15 OCA], [https://pdbe.org/9x15 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=9x15 RCSB], [https://www.ebi.ac.uk/pdbsum/9x15 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=9x15 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/FRI2_AQUCT FRI2_AQUCT] 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 ==
Ferritins are symmetrical, hollow nanocaged iron storage proteins, which sequester and concentrate iron as a hydrated ferric oxyhydroxide (ferrihydrite) biomineral. Spontaneous self-assembly of 24 subunits in eukaryotic ferritins leads to the formation of symmetrical pores, i.e., eight hydrophilic 3-fold pores and six hydrophobic 4-fold pores. However, unlike the relatively wider 3-fold pores, which drive Fe(2+) inside, the functions of narrow 4-fold pores are relatively understudied. The current work investigates the role of 4-fold pores by gradual alterations of specific amino acids using site-directed mutagenesis, structural analysis by X-ray crystallography, and solution-based kinetic studies. Increasing the negative charge in ferritin 4-fold pore retained the cage integrity and iron-loading capability despite altering the pore structure/size/electrostatics. As additional substitutions accumulated within the same channel, the aperture widens further and the electrostatic environment became progressively more acidic around the pore lining. These gradual alterations resulted in an enhanced rate of iron mobilization (up to approximately 10-fold), possibly due to remodeling of the 4-fold (C4) pore, leading to a progressive increase in 4-fold pore diameter. Moreover, these modifications decreased cage stability, both thermally ( approximately 5 degrees C) and chemically ( approximately 3-4 folds), and increased iron-induced ferritin precipitation, similar to the case of neuroferritinopathy.

Gradual Modification of Ferritin 4-Fold Pore Promotes Cage Instability, Fe(2+) Exit, and Iron-Induced Protein Precipitation.,Subhadarshanee B, Jagdev MK, Bhattacharyya G, Parida A, Mohanty A, Vasudevan D, Behera RK Biochemistry. 2026 Mar 3;65(5):614-625. doi: 10.1021/acs.biochem.5c00744. Epub , 2026 Feb 17. PMID:41700891<ref>PMID:41700891</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 9x15" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Lithobates catesbeianus]]
[[Category: Jagdev MK]]
[[Category: Vasudevan D]]