View source for 2qks


==Crystal structure of a Kir3.1-prokaryotic Kir channel chimera==
<StructureSection load='2qks' size='340' side='right'caption='[[2qks]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2qks]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus] and [https://en.wikipedia.org/wiki/Paraburkholderia_xenovorans_LB400 Paraburkholderia xenovorans LB400]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2QKS OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2QKS 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]] 2.2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=BNG:B-NONYLGLUCOSIDE'>BNG</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</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=2qks FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2qks OCA], [https://pdbe.org/2qks PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2qks RCSB], [https://www.ebi.ac.uk/pdbsum/2qks PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2qks ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/KCNJ3_MOUSE KCNJ3_MOUSE] This potassium channel is controlled by G proteins. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. This receptor plays a crucial role in regulating the heartbeat.[https://www.uniprot.org/uniprot/Q146M9_PARXL Q146M9_PARXL] 
== 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/qk/2qks_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=2qks ConSurf].
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== Publication Abstract from PubMed ==
The Kir3.1 K(+) channel participates in heart rate control and neuronal excitability through G-protein and lipid signaling pathways. Expression in Escherichia coli has been achieved by replacing three fourths of the transmembrane pore with the pore of a prokaryotic Kir channel, leaving the cytoplasmic pore and membrane interfacial regions of Kir3.1 origin. Two structures were determined at 2.2 A. The selectivity filter is identical to the Streptomyces lividans K(+) channel within error of measurement (r.m.s.d.&lt;0.2 A), suggesting that K(+) selectivity requires extreme conservation of three-dimensional structure. Multiple K(+) ions reside within the pore and help to explain voltage-dependent Mg(2+) and polyamine blockade and strong rectification. Two constrictions, at the inner helix bundle and at the apex of the cytoplasmic pore, may function as gates: in one structure the apex is open and in the other, it is closed. Gating of the apex is mediated by rigid-body movements of the cytoplasmic pore subunits. Phosphatidylinositol 4,5-biphosphate-interacting residues suggest a possible mechanism by which the signaling lipid regulates the cytoplasmic pore.

Crystal structure of a Kir3.1-prokaryotic Kir channel chimera.,Nishida M, Cadene M, Chait BT, MacKinnon R EMBO J. 2007 Sep 5;26(17):4005-15. Epub 2007 Aug 16. PMID:17703190<ref>PMID:17703190</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 2qks" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Mus musculus]]
[[Category: Paraburkholderia xenovorans LB400]]
[[Category: MacKinnon R]]
[[Category: Nishida M]]