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==Solution Structure of a K+-Channel Blocker from the Scorpion Toxin of Tityus cambridgei==
<StructureSection load='1jlz' size='340' side='right'caption='[[1jlz]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1jlz]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Tityus_obscurus Tityus obscurus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JLZ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JLZ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 15 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=1jlz FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jlz OCA], [https://pdbe.org/1jlz PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jlz RCSB], [https://www.ebi.ac.uk/pdbsum/1jlz PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jlz ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/KA131_TITOB KA131_TITOB] Blocks reversibly Shaker B potassium channels. Also displaces binding of noxiustoxin to mouse brain synaptosome membranes.<ref>PMID:11113450</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
A new K(+)-channel blocking peptide identified from the scorpion venom of Tityus cambridgei (Tc1) is composed of 23 amino acid residues linked with three disulfide bridges. Tc1 is the shortest known toxin from scorpion venom that recognizes the Shaker B K(+) channels and the voltage-dependent K(+) channels in the brain. Synthetic Tc1 was produced using solid-phase synthesis, and its activity was found to be the same as that of native Tc1. The pairings of three disulfide bridges in the synthetic Tc1 were identified by NMR experiments. The NMR solution structures of Tc1 were determined by simulated annealing and energy-minimization calculations using the X-PLOR program. The results showed that Tc1 contains an alpha-helix and a 3(10)-helix at N-terminal Gly(4)-Lys(10) and a double-stranded beta-sheet at Gly(13)-Ile(16) and Arg(19)-Tyr(23), with a type I' beta-turn at Asn(17)-Gly(18). Superposition of each structure with the best structure yielded an average root mean square deviation of 0.26 +/- 0.05 A for the backbone atoms and of 1.40 +/- 0.23 A for heavy atoms in residues 2 to 23. The three-dimensional structure of Tc1 was compared with two structurally and functionally related scorpion toxins, charybdotoxin (ChTx) and noxiustoxin (NTx). We concluded that the C-terminal structure is the most important region for the blocking activity of voltage-gated (Kv-type) channels for scorpion K(+)-channel blockers. We also found that some of the residues in the larger scorpion K(+)-channel blockers (31 to 40 amino acids) are not involved in K(+)-channel blocking activity.

Solution structure of a K(+)-channel blocker from the scorpion Tityus cambridgei.,Wang I, Wu SH, Chang HK, Shieh RC, Yu HM, Chen C Protein Sci. 2002 Feb;11(2):390-400. PMID:11790849<ref>PMID:11790849</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1jlz" style="background-color:#fffaf0;"></div>

==See Also==
*[[Potassium channel toxin 3D structures|Potassium channel toxin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Tityus obscurus]]
[[Category: Chang H-K]]
[[Category: Chen C]]
[[Category: Shieh R-C]]
[[Category: Wang I]]
[[Category: Wu S-H]]
[[Category: Yu H-M]]