2pta: Difference between revisions
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New page: left|200px<br /><applet load="2pta" size="450" color="white" frame="true" align="right" spinBox="true" caption="2pta" /> '''PANDINUS TOXIN K-A (PITX-KA) FROM PANDINUS I... |
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== | ==PANDINUS TOXIN K-A (PITX-KA) FROM PANDINUS IMPERATOR, NMR, 20 STRUCTURES== | ||
PiTX-K alpha, a 35-residue peptide recently isolated from the venom of | <StructureSection load='2pta' size='340' side='right'caption='[[2pta]]' scene=''> | ||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[2pta]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Pandinus_imperator Pandinus imperator]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2PTA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2PTA 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=2pta FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2pta OCA], [https://pdbe.org/2pta PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2pta RCSB], [https://www.ebi.ac.uk/pdbsum/2pta PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2pta ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/KAX71_PANIM KAX71_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).<ref>PMID:8660410</ref> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
PiTX-K alpha, a 35-residue peptide recently isolated from the venom of Pandinus imperator, blocks the rapidly inactivating (A-type) K+ channel(s) in rat brain synaptosomes and the cloned Kv 1.2 potassium channel at very low toxin concentrations (6 nM and 32 pM, respectively) [Rogowski, R. S., Collins, J. H., O'Neil, T. J., Gustafson, T. A., Werkman, T. A., Rogawski, M. A., Tenenholz, T. C., Weber, D. J., & Blaustein, M. P. (1996) Mol. Pharmacol. 50, 1167-1177]. The three-dimensional structure of PiTX-K alpha was determined using NMR spectroscopy in order to understand its selectivity and affinity toward K+ channels. PiTX-K alpha was found to have an alpha-helix from residues 10 to 21 and two beta-strands (betaI, 26-28; betaII, 33-35) connected by a type II beta-turn to form a small antiparallel beta-sheet. Three disulfide bonds, which are conserved in all members of the charybdotoxin family (alpha-K toxins), anchor one face of the alpha-helix to the beta-sheet. The N-terminal portion of PiTX-K alpha has three fewer residues than other alpha-K toxins such as charybdotoxin. Rather than forming a third beta-strand as found for other alpha-K toxins, the N-terminal region of PiTX-K alpha adopts an extended conformation. This structural difference in PiTX-K alpha together with differences in sequence at Pro-10, Tyr-14, and Asn-25 (versus Ser-10, Trp-14, and Arg-25 in CTX) may explain why PiTX-K alpha does not block maxi-K+ channels. Differences in three-dimensional structure between PiTX-K alpha and charybdotoxin are also observed in both the tight turn and the loop that connects the first beta-strand to the alpha-helix. As a result, side chains of two residues (Tyr-23 and Arg-31) are in regions of PiTX-K alpha that probably interact with rapidly inactivating A-type K+ channels. The analogous residues in charybdotoxin are positioned differently on the toxin surface. Thus, the locations of Tyr-23 and Arg-31 side chains in PiTX-K alpha could explain why this toxin blocks A-type channels at much lower concentrations than does charybdotoxin. | |||
Solution structure for Pandinus toxin K-alpha (PiTX-K alpha), a selective blocker of A-type potassium channels.,Tenenholz TC, Rogowski RS, Collins JH, Blaustein MP, Weber DJ Biochemistry. 1997 Mar 11;36(10):2763-71. PMID:9062103<ref>PMID:9062103</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 2pta" 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: Pandinus imperator]] | [[Category: Pandinus imperator]] | ||
[[Category: Blaustein MP]] | |||
[[Category: Blaustein | [[Category: Collins JH]] | ||
[[Category: Collins | [[Category: Rogowski RS]] | ||
[[Category: Rogowski | [[Category: Tenenholz TC]] | ||
[[Category: Tenenholz | [[Category: Weber DJ]] | ||
[[Category: Weber | |||
