View source for 3ldd


==High resolution open MthK pore structure crystallized in 100 mM K+ and further soaked in 99 mM Na+/1 mM K+.==
<StructureSection load='3ldd' size='340' side='right'caption='[[3ldd]], [[Resolution|resolution]] 1.45&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3ldd]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Methanothermobacter_thermautotrophicus_str._Delta_H Methanothermobacter thermautotrophicus str. Delta H]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3LDD OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3LDD 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]] 1.45&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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=3ldd FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ldd OCA], [https://pdbe.org/3ldd PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ldd RCSB], [https://www.ebi.ac.uk/pdbsum/3ldd PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ldd ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MTHK_METTH MTHK_METTH] Calcium-gated potassium channel.
== 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/ld/3ldd_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=3ldd ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
K+ channels are highly selective for K+ over Na+. Here we present several crystal structures of the MthK K+ channel pore at up to 1.45-A resolution. The MthK selectivity filter maintains a conductive conformation even in the absence of K+, allowing the channel to conduct Na+. The high-resolution structures, along with single-channel recordings, allow for an accurate analysis of how K+ competes with Na+ in a conductive selectivity filter. At high K+ concentrations, two K+ ions equivalently occupy the four sites in the selectivity filter, whereas at low K+/high Na+ concentrations, a single K+ ion remains bound in the selectivity filter, preferably at site 1 or site 3. This single K+ binding at low concentration effectively blocks the permeation of Na+, providing a structural basis for the anomalous mole-fraction effect, a key property of multi-ion pores.

Novel insights into K+ selectivity from high-resolution structures of an open K+ channel pore.,Ye S, Li Y, Jiang Y Nat Struct Mol Biol. 2010 Aug;17(8):1019-23. Epub 2010 Aug 1. PMID:20676101<ref>PMID:20676101</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3ldd" style="background-color:#fffaf0;"></div>

==See Also==
*[[Potassium channel 3D structures|Potassium channel 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Methanothermobacter thermautotrophicus str. Delta H]]
[[Category: Ye S]]