View source for 1c49


==STRUCTURAL AND FUNCTIONAL DIFFERENCES OF TWO TOXINS FROM THE SCORPION PANDINUS IMPERATOR==
<StructureSection load='1c49' size='340' side='right'caption='[[1c49]], [[NMR_Ensembles_of_Models | 18 NMR models]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1c49]] is a 1 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C49 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1C49 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=1c49 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1c49 OCA], [http://pdbe.org/1c49 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1c49 RCSB], [http://www.ebi.ac.uk/pdbsum/1c49 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1c49 ProSAT]</span></td></tr>
</table>
== Function ==
[[http://www.uniprot.org/uniprot/KAX72_PANIM KAX72_PANIM]] Potent inhibitor of the A-type voltage-gated potassium channels. Most potent inhibitor of Kv1.2/KCNA2 channels. Reversibly block the Shaker B potassium-channels (Kv1.1 sub-family), but with a lower affinity than PiTX-K alpha.<ref>PMID:8660410</ref>  
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== Publication Abstract from PubMed ==
The Pandinotoxins, PiTX-K alpha and PiTX-K beta, are members of the Charybdotoxin family of scorpion toxins that can be used to characterize K+ channels. PiTX-K alpha differs from PiTX-K beta, another peptide from Pandinus imperator, by one residue (P10E). When the two toxins are compared in a physiological assay, the affinity of PiTX-K beta for voltage-gated, rapidly inactivating K+ channels in dorsal root ganglia (DRG) neurons is 800-fold lower than that of PiTX-K alpha (K alpha-IC50 = 8.0 nM versus K beta-IC50 = 6,500 nM). To understand this difference, the three-dimensional structure of PiTX-K beta was determined by nuclear magnetic resonance (NMR) spectroscopy and compared to that of PiTX-K alpha. This comparison shows that structural differences between the two toxins occur at a residue that is critical for blocking K+ channels (K27) as well as at the site of the natural mutation (P10E). In PiTX-K beta, the negatively charged carboxylate oxygen of E10 can approach the positive charge of K27 and presumably reduces the net positive charge in this region of the toxin. This is likely the reason why PiTX-K beta binds K+ channels from DRG neurons with a much lower affinity than does PiTX-K alpha.

Structural and functional differences of two toxins from the scorpion Pandinus imperator.,Klenk KC, Tenenholz TC, Matteson DR, Rogowski RS, Blaustein MP, Weber DJ Proteins. 2000 Mar 1;38(4):441-9. PMID:10707030<ref>PMID:10707030</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 1c49" style="background-color:#fffaf0;"></div>

==See Also==
*[[Potassium channel toxin|Potassium channel toxin]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Blaustein, M P]]
[[Category: Klenk, K C]]
[[Category: Matteson, D R]]
[[Category: Rogowski, R S]]
[[Category: Tenenholz, T C]]
[[Category: Weber, D J]]
[[Category: Alpha-k toxin family]]
[[Category: Neurotoxin]]
[[Category: Nmr solution structure]]
[[Category: Potassium channels blocker]]
[[Category: Scorpion toxin]]
[[Category: Toxin]]