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| | ==CorA coiled-coil mutant under Mg2+ absence== | | ==CorA coiled-coil mutant under Mg2+ absence== |
| - | <StructureSection load='4eeb' size='340' side='right' caption='[[4eeb]], [[Resolution|resolution]] 3.80Å' scene=''> | + | <StructureSection load='4eeb' size='340' side='right'caption='[[4eeb]], [[Resolution|resolution]] 3.80Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4eeb]] is a 5 chain structure with sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4EEB OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4EEB FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4eeb]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4EEB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4EEB FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CS:CESIUM+ION'>CS</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3.8Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4eed|4eed]], [[2bbj|2bbj]], [[2iub|2iub]], [[2hn2|2hn2]]</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CS:CESIUM+ION'>CS</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">corA, TM_0561 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=2336 Thermotoga maritima])</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=4eeb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4eeb OCA], [https://pdbe.org/4eeb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4eeb RCSB], [https://www.ebi.ac.uk/pdbsum/4eeb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4eeb ProSAT]</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=4eeb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4eeb OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4eeb RCSB], [http://www.ebi.ac.uk/pdbsum/4eeb PDBsum]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/CORA_THEMA CORA_THEMA]] Mediates influx of magnesium ions (By similarity). | + | [https://www.uniprot.org/uniprot/CORA_THEMA CORA_THEMA] Mediates influx of magnesium ions (By similarity). |
| - | <div style="background-color:#fffaf0;">
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| - | == Publication Abstract from PubMed ==
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| - | Magnesium ions (Mg(2+)) are essential for life, but the mechanisms regulating their transport into and out of cells remain poorly understood. The CorA-Mrs2-Alr1 superfamily of Mg(2+) channels represents the most prevalent group of proteins enabling Mg(2+) ions to cross membranes. Thermotoga maritima CorA (TmCorA) is the only member of this protein family whose complete 3D fold is known. Here, we report the crystal structure of a mutant in the presence and absence of divalent ions and compare it with previous divalent ion-bound TmCorA structures. With Mg(2+) present, this structure shows binding of a hydrated Mg(2+) ion to the periplasmic Gly-Met-Asn (GMN) motif, revealing clues of ion selectivity in this unique channel family. In the absence of Mg(2+), TmCorA displays an unexpected asymmetric conformation caused by radial and lateral tilts of protomers that leads to bending of the central, pore-lining helix. Molecular dynamics simulations support these movements, including a bell-like deflection. Mass spectrometric analysis confirms that major proteolytic cleavage occurs within a region that is selectively exposed by such a bell-like bending motion. Our results point to a sequential allosteric model of regulation, where intracellular Mg(2+) binding locks TmCorA in a symmetric, transport-incompetent conformation and loss of intracellular Mg(2+) causes an asymmetric, potentially influx-competent conformation of the channel.
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| - | Structural asymmetry in the magnesium channel CorA points to sequential allosteric regulation.,Pfoh R, Li A, Chakrabarti N, Payandeh J, Pomes R, Pai EF Proc Natl Acad Sci U S A. 2012 Oct 29. PMID:23112165<ref>PMID:23112165</ref>
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| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| - | </div>
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| - | == References ==
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| - | <references/>
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| | + | [[Category: Large Structures]] |
| | [[Category: Thermotoga maritima]] | | [[Category: Thermotoga maritima]] |
| - | [[Category: Pai, E F]] | + | [[Category: Pai EF]] |
| - | [[Category: Pfoh, R]] | + | [[Category: Pfoh R]] |
| - | [[Category: Cesium binding]]
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| - | [[Category: Coiled-coil]]
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| - | [[Category: Membrane]]
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| - | [[Category: Metal transport]]
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| - | [[Category: Mg2+ channel]]
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| - | [[Category: Trans-membrane protein]]
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