View source for 4hqa


==Crystal structure of PAS domain from the human ERG (hERG) potassium channel==
<StructureSection load='4hqa' size='340' side='right'caption='[[4hqa]], [[Resolution|resolution]] 1.96&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4hqa]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4HQA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4HQA 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]] 1.96&#8491;</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=4hqa FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4hqa OCA], [https://pdbe.org/4hqa PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4hqa RCSB], [https://www.ebi.ac.uk/pdbsum/4hqa PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4hqa ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/KCNH2_HUMAN KCNH2_HUMAN] Defects in KCNH2 are the cause of long QT syndrome type 2 (LQT2) [MIM:[https://omim.org/entry/613688 613688]. Long QT syndromes are heart disorders characterized by a prolonged QT interval on the ECG and polymorphic ventricular arrhythmias. They cause syncope and sudden death in response to exercise or emotional stress. Deafness is often associated with LQT2.<ref>PMID:16361248</ref> <ref>PMID:9600240</ref> <ref>PMID:7889573</ref> <ref>PMID:8914737</ref> <ref>PMID:8635257</ref> <ref>PMID:8877771</ref> <ref>PMID:9024139</ref> <ref>PMID:9693036</ref> <ref>PMID:9544837</ref> <ref>PMID:9452080</ref> <ref>PMID:10086971</ref> <ref>PMID:10220144</ref> <ref>PMID:10187793</ref> <ref>PMID:10517660</ref> <ref>PMID:10735633</ref> <ref>PMID:10973849</ref> <ref>PMID:10862094</ref> <ref>PMID:10753933</ref> <ref>PMID:12062363</ref> <ref>PMID:12354768</ref> <ref>PMID:12621127</ref> <ref>PMID:15051636</ref> <ref>PMID:15840476</ref> <ref>PMID:22314138</ref>   Defects in KCNH2 are the cause of short QT syndrome type 1 (SQT1) [MIM:[https://omim.org/entry/609620 609620]. Short QT syndromes are heart disorders characterized by idiopathic persistently and uniformly short QT interval on ECG in the absence of structural heart disease in affected individuals. They cause syncope and sudden death.<ref>PMID:14676148</ref> <ref>PMID:15828882</ref> 
== Function ==
[https://www.uniprot.org/uniprot/KCNH2_HUMAN KCNH2_HUMAN] Pore-forming (alpha) subunit of voltage-gated inwardly rectifying potassium channel. Channel properties are modulated by cAMP and subunit assembly. Mediates the rapidly activating component of the delayed rectifying potassium current in heart (IKr). Isoform 3 has no channel activity by itself, but modulates channel characteristics when associated with isoform 1.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
KCNH channels form an important family of voltage gated potassium channels. These channels include a N-terminal Per-Arnt-Sim (PAS) domain with unknown function. In other proteins PAS domains are implicated in cellular responses to environmental queues through small molecule binding or involvement in signaling cascades. To better understand their role we characterized the structural properties of several channel PAS domains. We determined high resolution structures of PAS domains from the mouse EAG (mEAG), drosophila ELK (dELK) and human ERG (hERG) channels and also of the hERG domain without the first nine amino acids. We analyzed these structures for features connected to ligand binding and signaling in other PAS domains. In particular, we have found cavities in the hERG and mEAG structures that share similarities with the ligand binding sites from other PAS domains. These cavities are lined by polar and apolar chemical groups and display potential flexibility in their volume. We have also found that the hydrophobic patch on the domain beta-sheet is a conserved feature and appears to drive the formation of protein-protein contacts. In addition, the structures of the dELK domain and of the truncated hERG domain revealed the presence of N-terminal helices. These helices are equivalent to the helix described in the hERG NMR structures and are known to be important for channel function. Overall, these channel domains retain many of the PAS domain characteristics known to be important for cell signaling.

Structural properties of PAS domains from the KCNH potassium channels.,Adaixo R, Harley CA, Castro-Rodrigues AF, Morais-Cabral JH PLoS One. 2013;8(3):e59265. doi: 10.1371/journal.pone.0059265. Epub 2013 Mar 15. PMID:23555008<ref>PMID:23555008</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 4hqa" style="background-color:#fffaf0;"></div>

==See Also==
*[[Potassium channel 3D structures|Potassium channel 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Adaixo R]]
[[Category: Harley CA]]
[[Category: Morais-Cabral JH]]