View source for 1jq2


==POTASSIUM CHANNEL (KCSA) OPEN GATE MODEL==
<StructureSection load='1jq2' size='340' side='right'caption='[[1jq2]], [[NMR_Ensembles_of_Models | 50 NMR models]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1jq2]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/"actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JQ2 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1JQ2 FirstGlance]. <br>
</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1jq1|1jq1]]</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=1jq2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jq2 OCA], [http://pdbe.org/1jq2 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1jq2 RCSB], [http://www.ebi.ac.uk/pdbsum/1jq2 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1jq2 ProSAT]</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>  
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== Publication Abstract from PubMed ==
Ion channels catalyze the selective transfer of ions across the membrane in response to a variety of stimuli. These channels gate by controlling the access of ions to a centrally located water-filled pore. The crystal structure of the Streptomyces lividans potassium channel (KcsA) has allowed a molecular exploration of this mechanism. Electron paramagnetic resonance (EPR) studies have uncovered significant conformational changes at the intracellular end of the second transmembrane helix (TM2) upon gating. We have used site-directed spin labeling (SDSL) and EPR spectroscopy in an attempt to quantify the structural rearrangements of the KcsA TM2 bundle underlying the transition from the closed to the open state. Under conditions favoring the closed and open conformations, 10 intersubunit distances were obtained across TM2 segments from tandem dimer constructs. Analysis of these data points to a mechanism in which each TM2 helix tilts away from the permeation pathway, towards the membrane plane, and rotates about its helical axis, supporting a scissoring-type motion with a pivot point near residues 107-108. These movements are accompanied by a large increase in the diameter of the vestibule below the central water-filled cavity.

Structure of the KcsA channel intracellular gate in the open state.,Liu YS, Sompornpisut P, Perozo E Nat Struct Biol. 2001 Oct;8(10):883-7. PMID:11573095<ref>PMID:11573095</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 1jq2" style="background-color:#fffaf0;"></div>

==See Also==
*[[Glutamate receptor (GluA2)|Glutamate receptor (GluA2)]]
*[[Potassium Channel|Potassium Channel]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Actinomyces lividans krasil'nikov et al. 1965]]
[[Category: Large Structures]]
[[Category: Liu, Y S]]
[[Category: Perozo, E]]
[[Category: Sompornpisut, P]]
[[Category: Integral membrane protein]]
[[Category: Membrane protein]]
[[Category: Open state]]
[[Category: Potassium channel]]