4eed: Difference between revisions
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[[ | ==CorA coiled-coil mutant under Mg2+ presence== | ||
<StructureSection load='4eed' size='340' side='right' caption='[[4eed]], [[Resolution|resolution]] 3.92Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4eed]] 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=4EED OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4EED FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> | |||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4eeb|4eeb]], [[2bbj|2bbj]], [[2iub|2iub]], [[2hn2|2hn2]]</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'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4eed FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4eed OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4eed RCSB], [http://www.ebi.ac.uk/pdbsum/4eed PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
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. | |||
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> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
== References == | |||
<references/> | |||
== | __TOC__ | ||
</StructureSection> | |||
[[Category: Thermotoga maritima]] | [[Category: Thermotoga maritima]] | ||
[[Category: Pai, E F | [[Category: Pai, E F]] | ||
[[Category: Pfoh, R | [[Category: Pfoh, R]] | ||
[[Category: Coiled-coil]] | [[Category: Coiled-coil]] | ||
[[Category: Membrane]] | [[Category: Membrane]] | ||
