View source for 2jk5

==Potassium Channel KcsA in complex with Tetrabutylammonium in high K==
<StructureSection load='2jk5' size='340' side='right' caption='[[2jk5]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2jk5]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/"actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965] and [http://en.wikipedia.org/wiki/Lk3_transgenic_mice Lk3 transgenic mice]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2JK5 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2JK5 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CO:COBALT+(II)+ION'>CO</scene>, <scene name='pdbligand=F09:NONAN-1-OL'>F09</scene>, <scene name='pdbligand=HP6:HEPTANE'>HP6</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=L2C:(2S)-3-HYDROXY-2-(NONANOYLOXY)PROPYL+LAURATE'>L2C</scene>, <scene name='pdbligand=TBA:TETRABUTYLAMMONIUM+ION'>TBA</scene></td></tr>
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1r3k|1r3k]], [[2a9h|2a9h]], [[1k4d|1k4d]], [[1k4c|1k4c]], [[2hg5|2hg5]], [[2bob|2bob]], [[1f6g|1f6g]], [[2boc|2boc]], [[1jq2|1jq2]], [[1r3j|1r3j]], [[1jvm|1jvm]], [[1jq1|1jq1]], [[2ih3|2ih3]], [[1zwi|1zwi]], [[1bl8|1bl8]], [[1r3i|1r3i]], [[2w0f|2w0f]], [[2ih1|2ih1]], [[1j95|1j95]], [[2h8p|2h8p]], [[1r3l|1r3l]], [[2atk|2atk]], [[4uuj|4uuj]]</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=2jk5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2jk5 OCA], [http://pdbe.org/2jk5 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2jk5 RCSB], [http://www.ebi.ac.uk/pdbsum/2jk5 PDBsum]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/KCSA_STRLI KCSA_STRLI]] Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+).<ref>PMID:7489706</ref>  
== 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/jk/2jk5_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/chain_selection.php?pdb_ID=2ata ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Potassium channels allow for the passive movement of potassium ions across the cell membrane and are instrumental in controlling the membrane potential in all cell types. Quaternary ammonium (QA) compounds block potassium channels and have long been used to study the functional and structural properties of these channels. Here we describe the interaction between three symmetrical hydrophobic QAs and the prokaryotic potassium channel KcsA. The structures demonstrate the presence of a hydrophobic pocket between the inner helices of KcsA and provide insight into the binding site and blocking mechanism of hydrophobic QAs. The structures also reveal a structurally hidden pathway between the central cavity and the outside membrane environment reminiscent of the lateral fenestration observed in sodium channels that can be accessed through small conformational changes in the pore wall. We propose that the hydrophobic binding pocket stabilizes the alkyl chains of long-chain QA molecules and may play a key role in hydrophobic drug binding in general.

Structures of KcsA in Complex with Symmetrical Quaternary Ammonium Compounds Reveal a Hydrophobic Binding Site.,Lenaeus MJ, Burdette D, Wagner T, Focia PJ, Gross A Biochemistry. 2014 Aug 19;53(32):5365-73. doi: 10.1021/bi500525s. Epub 2014 Aug, 8. PMID:25093676<ref>PMID:25093676</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 2jk5" style="background-color:#fffaf0;"></div>

==See Also==
*[[Monoclonal Antibody|Monoclonal Antibody]]
*[[Potassium Channel|Potassium Channel]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Actinomyces lividans krasil'nikov et al. 1965]]
[[Category: Lk3 transgenic mice]]
[[Category: Focia, P J]]
[[Category: Gross, A]]
[[Category: Lenaeus, M J]]
[[Category: Wagner, T]]
[[Category: Immune system-metal transport complex]]
[[Category: Ion transport]]
[[Category: Ionic channel]]
[[Category: Protein-antibody fab complex]]
[[Category: Quaternary ammonium]]