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==Solution structure of Pi4, a four disulfide bridged scorpion toxin active on potassium channels== | |||
<StructureSection load='1n8m' size='340' side='right' caption='[[1n8m]], [[NMR_Ensembles_of_Models | 10 NMR models]]' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1n8m]] is a 1 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N8M OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1N8M 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=1n8m FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1n8m OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1n8m RCSB], [http://www.ebi.ac.uk/pdbsum/1n8m PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Pi4 is a short toxin found at very low abundance in the venom of Pandinus imperator scorpions. It is a potent blocker of K(+) channels. Like the other members of the alpha-KTX6 subfamily to which it belongs, it is cross-linked by four disulfide bonds. The synthetic analog (sPi4) and the natural toxin (nPi4) have been obtained by solid-phase synthesis or from scorpion venom, respectively. Analysis of two-dimensional (1)H NMR spectra of nPi4 and sPi4 indicates that both peptides have the same structure. Moreover, electrophysiological recordings of the blocking of Shaker B K(+) channels by sPi4 (K(D) = 8.5 nM) indicate that sPi4 has the same blocking activity of nPi4 (K(D) = 8.0 nM), previously described. The disulfide bonds have been independently determined by NMR and structure calculations, and by Edman-degradation/mass-spectrometry identification of peptides obtained by proteolysis of nPi4. Both approaches indicate that the pairing of the half-cystines is (6)C-(27)C, (12)C-(32)C, (16)C-(34)C, and (22)C-(37)C. The structure of the toxin has been determined by using 705 constraints derived from NMR data on sPi4. The structure, which is well defined, shows the characteristic alpha/beta scaffold of scorpion toxins. It is compared to the structure of the other alpha-KTX6 subfamily members and, in particular, to the structure of maurotoxin, which shows a different pattern of disulfide bridges despite its high degree of sequence identity (76%) with Pi4. The structure of Pi4 and the high amounts of synthetic peptide available, will enable the detailed analysis of the interaction of Pi4 with K(+) channels. | |||
Solution structure of Pi4, a short four-disulfide-bridged scorpion toxin specific of potassium channels.,Guijarro JI, M'Barek S, Gomez-Lagunas F, Garnier D, Rochat H, Sabatier JM, Possani L, Delepierre M Protein Sci. 2003 Sep;12(9):1844-54. PMID:12930984<ref>PMID:12930984</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Potassium channel toxin|Potassium channel toxin]] | *[[Potassium channel toxin|Potassium channel toxin]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
[[Category: Barek, S M | </StructureSection> | ||
[[Category: Delepierre, M | [[Category: Barek, S M]] | ||
[[Category: Garnier, D | [[Category: Delepierre, M]] | ||
[[Category: Gomez-Lagunas, F | [[Category: Garnier, D]] | ||
[[Category: Guijarro, J I | [[Category: Gomez-Lagunas, F]] | ||
[[Category: Olamendi-Portugal, T | [[Category: Guijarro, J I]] | ||
[[Category: Possani, L D | [[Category: Olamendi-Portugal, T]] | ||
[[Category: Rochat, H | [[Category: Possani, L D]] | ||
[[Category: Sabatier, J M | [[Category: Rochat, H]] | ||
[[Category: Sabatier, J M]] | |||
[[Category: Disulfide bridge stabilized alpha beta motif]] | [[Category: Disulfide bridge stabilized alpha beta motif]] | ||
[[Category: Potassium channel blocker]] | [[Category: Potassium channel blocker]] | ||
[[Category: Toxin]] | [[Category: Toxin]] | ||
Revision as of 17:18, 17 December 2014
Solution structure of Pi4, a four disulfide bridged scorpion toxin active on potassium channelsSolution structure of Pi4, a four disulfide bridged scorpion toxin active on potassium channels
Structural highlights
Publication Abstract from PubMedPi4 is a short toxin found at very low abundance in the venom of Pandinus imperator scorpions. It is a potent blocker of K(+) channels. Like the other members of the alpha-KTX6 subfamily to which it belongs, it is cross-linked by four disulfide bonds. The synthetic analog (sPi4) and the natural toxin (nPi4) have been obtained by solid-phase synthesis or from scorpion venom, respectively. Analysis of two-dimensional (1)H NMR spectra of nPi4 and sPi4 indicates that both peptides have the same structure. Moreover, electrophysiological recordings of the blocking of Shaker B K(+) channels by sPi4 (K(D) = 8.5 nM) indicate that sPi4 has the same blocking activity of nPi4 (K(D) = 8.0 nM), previously described. The disulfide bonds have been independently determined by NMR and structure calculations, and by Edman-degradation/mass-spectrometry identification of peptides obtained by proteolysis of nPi4. Both approaches indicate that the pairing of the half-cystines is (6)C-(27)C, (12)C-(32)C, (16)C-(34)C, and (22)C-(37)C. The structure of the toxin has been determined by using 705 constraints derived from NMR data on sPi4. The structure, which is well defined, shows the characteristic alpha/beta scaffold of scorpion toxins. It is compared to the structure of the other alpha-KTX6 subfamily members and, in particular, to the structure of maurotoxin, which shows a different pattern of disulfide bridges despite its high degree of sequence identity (76%) with Pi4. The structure of Pi4 and the high amounts of synthetic peptide available, will enable the detailed analysis of the interaction of Pi4 with K(+) channels. Solution structure of Pi4, a short four-disulfide-bridged scorpion toxin specific of potassium channels.,Guijarro JI, M'Barek S, Gomez-Lagunas F, Garnier D, Rochat H, Sabatier JM, Possani L, Delepierre M Protein Sci. 2003 Sep;12(9):1844-54. PMID:12930984[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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