View source for 1koz


==SOLUTION STRUCTURE OF OMEGA-GRAMMOTOXIN SIA==
<StructureSection load='1koz' size='340' side='right'caption='[[1koz]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1koz]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Grammostola_rosea Grammostola rosea]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KOZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KOZ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 20 models</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=1koz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1koz OCA], [https://pdbe.org/1koz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1koz RCSB], [https://www.ebi.ac.uk/pdbsum/1koz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1koz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/WGRTX_GRARO WGRTX_GRARO] Inhibits P/Q- (Cav2.1/CACNA1A) and N-type (Cav2.2/CACNA1B) voltage-gated calcium channel by modifying voltage-dependent gating. It selectively and reversibly blocks the calcium channels coupled to glutamate release. Also inhibits potassium channels (Kv2.1/KCNB1) with lower affinity.<ref>PMID:21740921</ref> <ref>PMID:8394998</ref> <ref>PMID:8848236</ref> <ref>PMID:9415720</ref> <ref>PMID:9671721</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
omega-Grammotoxin SIA (GrTx) is a 36 amino acid residue protein toxin from spider venom that inhibits P/Q and N-type voltage-gated Ca(2+) channels by modifying voltage-dependent gating. We determined the three-dimensional structure of GrTx using NMR spectroscopy. The toxin adopts an "inhibitor cystine knot" motif composed of two beta-strands (Leu19-Cys21 and Cys30-Trp32) and a beta-bulge (Trp6, Gly7-Cys30) with a +2x, -1 topology, which are connected by four chain reversals. Although GrTx was originally identified as an inhibitor of voltage-gated Ca(2+) channel, it also binds to K(+) channels with lower affinity. A similar cross-reaction was observed for Hanatoxin1 (HaTx), which binds to the voltage-sensing domains of K(+) and Ca(2+) channels with different affinities. A detailed comparison of the GrTx and HaTx structures identifies a conserved face containing a large hydrophobic patch surrounded by positively charged residues. The slight differences in the surface shape, which result from the orientation of the surface aromatic residues and/or the distribution of the charged residues, may explain the differences in the binding affinity of these gating modifiers with different voltage-gated ion channels.

Solution structure of omega-grammotoxin SIA, a gating modifier of P/Q and N-type Ca(2+) channel.,Takeuchi K, Park E, Lee C, Kim J, Takahashi H, Swartz K, Shimada I J Mol Biol. 2002 Aug 16;321(3):517-26. PMID:12162963<ref>PMID:12162963</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1koz" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Grammostola rosea]]
[[Category: Large Structures]]
[[Category: Kim JI]]
[[Category: Lee CW]]
[[Category: Park EJ]]
[[Category: Shimada I]]
[[Category: Swartz KJ]]
[[Category: Takahashi H]]
[[Category: Takeuchi K]]