View source for 2b3x


==Structure of an orthorhombic crystal form of human cytosolic aconitase (IRP1)==
<StructureSection load='2b3x' size='340' side='right'caption='[[2b3x]], [[Resolution|resolution]] 2.54&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2b3x]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Human Human]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2B3X OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2B3X FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Aconitate_hydratase Aconitate hydratase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.2.1.3 4.2.1.3] </span></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2b3x FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2b3x OCA], [http://pdbe.org/2b3x PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2b3x RCSB], [http://www.ebi.ac.uk/pdbsum/2b3x PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2b3x ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/ACOC_HUMAN ACOC_HUMAN]] Iron sensor. Binds a 4Fe-4S cluster and functions as aconitase when cellular iron levels are high. Functions as mRNA binding protein that regulates uptake, sequestration and utilization of iron when cellular iron levels are low. Binds to iron-responsive elements (IRES) in target mRNA species when iron levels are low. Binding of a 4Fe-4S cluster precludes RNA binding.<ref>PMID:1946430</ref> <ref>PMID:8041788</ref>   Catalyzes the isomerization of citrate to isocitrate via cis-aconitate. 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/b3/2b3x_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2b3x ConSurf].
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== Publication Abstract from PubMed ==
Iron regulatory proteins (IRPs) control the translation of proteins involved in iron uptake, storage and utilization by binding to specific noncoding sequences of the corresponding mRNAs known as iron-responsive elements (IREs). This strong interaction assures proper iron homeostasis in animal cells under iron shortage. Conversely, under iron-replete conditions, IRP1 binds a [4Fe-4S] cluster and functions as cytosolic aconitase. Regulation of the balance between the two IRP1 activities is complex, and it does not depend only on iron availability. Here, we report the crystal structure of human IRP1 in its aconitase form. Comparison with known structures of homologous enzymes reveals well-conserved folds and active site environments with significantly different surface shapes and charge distributions. The specific features of human IRP1 allow us to propose a tentative model of an IRP1-IRE complex that agrees with a range of previously obtained data.

Crystal structure of human iron regulatory protein 1 as cytosolic aconitase.,Dupuy J, Volbeda A, Carpentier P, Darnault C, Moulis JM, Fontecilla-Camps JC Structure. 2006 Jan;14(1):129-39. PMID:16407072<ref>PMID:16407072</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 2b3x" style="background-color:#fffaf0;"></div>

==See Also==
*[[Aconitase 3D structures|Aconitase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Aconitate hydratase]]
[[Category: Human]]
[[Category: Large Structures]]
[[Category: Dupuy, J]]
[[Category: Fontecilla-Camps, J C]]
[[Category: Volbeda, A]]
[[Category: Irp1 ire-irp1 aconitase activity]]
[[Category: Lyase]]