View source for 4qe9


==Open MthK pore structure soaked in 10 mM Ba2+/100 mM K+==
<StructureSection load='4qe9' size='340' side='right'caption='[[4qe9]], [[Resolution|resolution]] 2.15&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4qe9]] 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=4QE9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4QE9 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]] 2.15&#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=4qe9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4qe9 OCA], [https://pdbe.org/4qe9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4qe9 RCSB], [https://www.ebi.ac.uk/pdbsum/4qe9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4qe9 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MTHK_METTH MTHK_METTH] Calcium-gated potassium channel.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The movement and interaction of multiple ions passing through in single file underlie various fundamental K(+) channel properties, from the effective conduction of K(+) ions to channel blockade by Ba(2+) ions. In this study, we used single-channel electrophysiology and x-ray crystallography to probe the interactions of Ba(2+) with permeant ions within the ion conduction pathway of the MthK K(+) channel. We found that, as typical of K(+) channels, the MthK channel was blocked by Ba(2+) at the internal side, and the Ba(2+)-blocking effect was enhanced by external K(+). We also obtained crystal structures of the MthK K(+) channel pore in both Ba(2+)-Na(+) and Ba(2+)-K(+) environments. In the Ba(2+)-Na(+) environment, we found that a single Ba(2+) ion remained bound in the selectivity filter, preferably at site 2, whereas in the Ba(2+)-K(+) environment, Ba(2+) ions were predominantly distributed between sites 3 and 4. These ionic configurations are remarkably consistent with the functional studies and identify a molecular basis for Ba(2+) blockade of K(+) channels.

Ionic interactions of Ba2+ blockades in the MthK K+ channel.,Guo R, Zeng W, Cui H, Chen L, Ye S J Gen Physiol. 2014 Aug;144(2):193-200. doi: 10.1085/jgp.201411192. Epub 2014 Jul, 14. PMID:25024268<ref>PMID:25024268</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4qe9" 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: Chen L]]
[[Category: Cui H]]
[[Category: Guo R]]
[[Category: Ye S]]
[[Category: Zeng W]]