View source for 1ne5


==Solution Structure of HERG Specific Scorpion Toxin CnErg1==
<StructureSection load='1ne5' size='340' side='right' caption='[[1ne5]], [[NMR_Ensembles_of_Models | 20 NMR models]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ne5]] is a 1 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NE5 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1NE5 FirstGlance]. <br>
</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=1ne5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ne5 OCA], [http://pdbe.org/1ne5 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1ne5 RCSB], [http://www.ebi.ac.uk/pdbsum/1ne5 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1ne5 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/KGX11_CENNO KGX11_CENNO]] Blocks human and rat Kv11.1/KCNH2/ERG1 and Kv11.3/KCNH7/ERG3, as well as rat (but not human) Kv11.2/KCNH6/ERG2 (PubMed:11755529, PubMed:11864985, PubMed:16497878, PubMed:17369411, PubMed:20600425) by binding to channel outer vestibule (S5P domain) with a 1:1 stoichiometry (PubMed:11755529, PubMed:11864985, PubMed:17369411, PubMed:20600425). Inhibition data are the following: hERG1 (reversible, IC(50)~7 nM) (PubMed:11755529, PubMed:11864985, PubMed:16497878, PubMed:17369411, PubMed:20600425), rERG1 (reversible, Kd=6.8 nM) (PubMed:16497878), rERG2 (irreversible, Kd=2.8 nM) (PubMed:16497878), hERG3 (irreversible, Kd=4.05 nM) (PubMed:16497878) and rERG3 (reversible, Kd=38.1 nM) (PubMed:16497878) potassium channels. The toxin potency is not affected by elevating potassium ion concentration from 2 to 98 mM (PubMed:11864985). This toxin only blocks channels in a closed state (PubMed:12860380). At high toxin concentrations, block of Kv11.1/KCNH2/ERG1 macroscopic current is incomplete (93.5%). This suggests a kinetic mechanism model with two different states of toxin-channel binding (T+C=TC*=TC; in the TC* state, the toxin binds the channel but does not occlude the pore, whereas in the TC state the toxin binds and occludes the pore). In this model, incomplete block is explained by the relatively fast dissociation rate from the blocked channel conformation (TC) relative to the rate of conversion of the toxin-channel encounter complex (TC*) to the blocked channel conformation (TC) (PubMed:17369411).<ref>PMID:10224238</ref> <ref>PMID:11755529</ref> <ref>PMID:11864985</ref> <ref>PMID:12860380</ref> <ref>PMID:16497878</ref> <ref>PMID:17369411</ref> <ref>PMID:20600425</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/ne/1ne5_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/main_output.php?pdb_ID=1ne5 ConSurf].
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== Publication Abstract from PubMed ==
The three-dimensional structure of chemically synthesized CnErg1 (Ergtoxin), which specifically blocks HERG (human ether-a-go-go-related gene) K+ channels, was determined by nuclear magnetic resonance spectroscopy. CnErg1 consists of a triple-stranded beta-sheet and an alpha-helix, as is typical of K+ channel scorpion toxins. The peptide structure differs from the canonical structures in that the first beta-strand is shorter and is nearer to the second beta-strand rather than to the third beta-strand on the C-terminus. There is also a large hydrophobic patch on the surface of the toxin, surrounding a central lysine residue, Lys13. We postulate that this hydrophobic patch is likely to form part of the binding surface of the toxin.

Solution structure of CnErg1 (Ergtoxin), a HERG specific scorpion toxin.,Torres AM, Bansal P, Alewood PF, Bursill JA, Kuchel PW, Vandenberg JI FEBS Lett. 2003 Mar 27;539(1-3):138-42. PMID:12650941<ref>PMID:12650941</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Alewood, P]]
[[Category: Kuchel, P W]]
[[Category: Paramjit, B]]
[[Category: Torres, A M]]
[[Category: Vandenberg, J I]]
[[Category: Alpha-helix]]
[[Category: Toxin]]
[[Category: Triple-stranded beta-sheet]]