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5hxr

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==Structural mechanisms of extracellular ion exchange and induced binding-site occlusion in the sodium-calcium exchanger NCX_Mj soaked with 2.5 mM Na+ and 10mM Ca2+==
==Structural mechanisms of extracellular ion exchange and induced binding-site occlusion in the sodium-calcium exchanger NCX_Mj soaked with 2.5 mM Na+ and 10mM Ca2+==
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<StructureSection load='5hxr' size='340' side='right' caption='[[5hxr]], [[Resolution|resolution]] 2.46&Aring;' scene=''>
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<StructureSection load='5hxr' size='340' side='right'caption='[[5hxr]], [[Resolution|resolution]] 2.46&Aring;' scene=''>
== Structural highlights ==
== Structural highlights ==
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<table><tr><td colspan='2'>[[5hxr]] is a 1 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5HXR OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5HXR FirstGlance]. <br>
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<table><tr><td colspan='2'>[[5hxr]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii_DSM_2661 Methanocaldococcus jannaschii DSM 2661]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5HXR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5HXR FirstGlance]. <br>
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</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MYS:PENTADECANE'>MYS</scene>, <scene name='pdbligand=OLC:(2R)-2,3-DIHYDROXYPROPYL+(9Z)-OCTADEC-9-ENOATE'>OLC</scene>, <scene name='pdbligand=PGE:TRIETHYLENE+GLYCOL'>PGE</scene></td></tr>
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</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.463&#8491;</td></tr>
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<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[5hya|5hya]], [[5hxs|5hxs]], [[5hxh|5hxh]], [[5hxe|5hxe]], [[5hxc|5hxc]], [[5hwy|5hwy]], [[5hwx|5hwx]]</td></tr>
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<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=MYS:PENTADECANE'>MYS</scene>, <scene name='pdbligand=OLC:(2R)-2,3-DIHYDROXYPROPYL+(9Z)-OCTADEC-9-ENOATE'>OLC</scene>, <scene name='pdbligand=PGE:TRIETHYLENE+GLYCOL'>PGE</scene></td></tr>
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<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=5hxr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5hxr OCA], [http://pdbe.org/5hxr PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5hxr RCSB], [http://www.ebi.ac.uk/pdbsum/5hxr PDBsum]</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=5hxr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5hxr OCA], [https://pdbe.org/5hxr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5hxr RCSB], [https://www.ebi.ac.uk/pdbsum/5hxr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5hxr ProSAT]</span></td></tr>
</table>
</table>
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== Function ==
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[https://www.uniprot.org/uniprot/Y091_METJA Y091_METJA]
<div style="background-color:#fffaf0;">
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
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Sodium/calcium (Na(+)/Ca(2+)) exchangers (NCX) are membrane transporters that play an essential role in maintaining the homeostasis of cytosolic Ca(2+) for cell signaling. We demonstrated the Na(+)/Ca(2+)-exchange function of an NCX from Methanococcus jannaschii (NCX_Mj) and report its 1.9 angstrom crystal structure in an outward-facing conformation. Containing 10 transmembrane helices, the two halves of NCX_Mj share a similar structure with opposite orientation. Four ion-binding sites cluster at the center of the protein: one specific for Ca(2+) and three that likely bind Na(+). Two passageways allow for Na(+) and Ca(2+) access to the central ion-binding sites from the extracellular side. Based on the symmetry of NCX_Mj and its ability to catalyze bidirectional ion-exchange reactions, we propose a structure model for the inward-facing NCX_Mj.
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Na+/Ca2+ exchangers use the Na+ electrochemical gradient across the plasma membrane to extrude intracellular Ca2+ and play a central role in Ca2+ homeostasis. Here, we elucidate their mechanisms of extracellular ion recognition and exchange through a structural analysis of the exchanger from Methanococcus jannaschii (NCX_Mj) bound to Na+, Ca2+ or Sr2+ in various occupancies and in an apo state. This analysis defines the binding mode and relative affinity of these ions, establishes the structural basis for the anticipated 3:1 Na+/Ca2+-exchange stoichiometry and reveals the conformational changes at the onset of the alternating-access transport mechanism. An independent analysis of the dynamics and conformational free-energy landscape of NCX_Mj in different ion-occupancy states, based on enhanced-sampling molecular dynamics simulations, demonstrates that the crystal structures reflect mechanistically relevant, interconverting conformations. These calculations also reveal the mechanism by which the outward-to-inward transition is controlled by the ion occupancy, thereby explaining the emergence of strictly coupled Na+/Ca2+ antiport.
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Structural insight into the ion-exchange mechanism of the sodium/calcium exchanger.,Liao J, Li H, Zeng W, Sauer DB, Belmares R, Jiang Y Science. 2012 Feb 10;335(6069):686-90. PMID:22323814<ref>PMID:22323814</ref>
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Mechanism of extracellular ion exchange and binding-site occlusion in a sodium/calcium exchanger.,Liao J, Marinelli F, Lee C, Huang Y, Faraldo-Gomez JD, Jiang Y Nat Struct Mol Biol. 2016 May 16. doi: 10.1038/nsmb.3230. PMID:27183196<ref>PMID:27183196</ref>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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__TOC__
__TOC__
</StructureSection>
</StructureSection>
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[[Category: Faraldo-Gomez, J D]]
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[[Category: Large Structures]]
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[[Category: Jiang, Y X]]
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[[Category: Methanocaldococcus jannaschii DSM 2661]]
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[[Category: Liao, J]]
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[[Category: Faraldo-Gomez JD]]
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[[Category: Calcium signalling]]
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[[Category: Jiang YX]]
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[[Category: Induced conformational change]]
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[[Category: Liao J]]
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[[Category: Membrane protein]]
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[[Category: Membrane transporter]]
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[[Category: Na+/ca2+ exchange]]
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Current revision

Structural mechanisms of extracellular ion exchange and induced binding-site occlusion in the sodium-calcium exchanger NCX_Mj soaked with 2.5 mM Na+ and 10mM Ca2+

PDB ID 5hxr

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