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| - | [[Image:1n8m.jpg|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1n8m| PDB=1n8m | SCENE= }} | | {{STRUCTURE_1n8m| PDB=1n8m | SCENE= }} |
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| - | '''Solution structure of Pi4, a four disulfide bridged scorpion toxin active on potassium channels'''
| + | ===Solution structure of Pi4, a four disulfide bridged scorpion toxin active on potassium channels=== |
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| - | ==Overview==
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| - | 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.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_12930984}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 12930984 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_12930984}} |
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| | ==About this Structure== | | ==About this Structure== |
| - | 1N8M is a [[Single protein]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N8M OCA]. | + | 1N8M is a [[Single protein]] structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1N8M OCA]. |
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| | ==Reference== | | ==Reference== |
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| | [[Category: Disulfide bridge stabilized alpha beta motif]] | | [[Category: Disulfide bridge stabilized alpha beta motif]] |
| | [[Category: Potassium channel blocker]] | | [[Category: Potassium channel blocker]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 02:13:41 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 11:19:02 2008'' |
Revision as of 08:19, 29 July 2008
Template:STRUCTURE 1n8m
Solution structure of Pi4, a four disulfide bridged scorpion toxin active on potassium channels
Template:ABSTRACT PUBMED 12930984
About this Structure
1N8M is a Single protein structure. Full experimental information is available from OCA.
Reference
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
Page seeded by OCA on Tue Jul 29 11:19:02 2008
