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2i61

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Revision as of 08:23, 18 October 2017

Depressant anti-insect neurotoxin, LqhIT2 from Leiurus quinquestriatus hebraeus

Structural highlights

2i61 is a 1 chain structure with sequence from Leiqh. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Ligands:	, , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

[SIX2_LEIQH] Depressant insect beta-toxins cause a transient contraction paralysis followed by a slow flaccid paralysis. They bind voltage-independently at site-4 of sodium channels (Nav) and shift the voltage of activation toward more negative potentials thereby affecting sodium channel activation and promoting spontaneous and repetitive firing. This toxin is active only on insects.^[1]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Scorpion depressant beta-toxins show high preference for insect voltage-gated sodium channels (Na(v)s) and modulate their activation. Although their pharmacological and physiological effects were described, their three-dimensional structure and bioactive surface have never been determined. We utilized an efficient system for expression of the depressant toxin LqhIT2 (from Leiurus quinquestriatushebraeus), mutagenized its entire exterior, and determined its X-ray structure at 1.2 A resolution. The toxin molecule is composed of a conserved cysteine-stabilized alpha/beta-core (core-globule), and perpendicular to it an entity constituted from the N and C-terminal regions (NC-globule). The surface topology and overall hydrophobicity of the groove between the core and NC-globules (N-groove) is important for toxin activity and plays a role in selectivity to insect Na(v)s. The N-groove is flanked by Glu24 and Tyr28, which belong to the "pharmacophore" of scorpion beta-toxins, and by the side-chains of Trp53 and Asn58 that are important for receptor site recognition. Substitution of Ala13 by Trp in the N-groove uncoupled activity from binding, suggesting that this region of the molecule is also involved in "voltage-sensor trapping", the mode of action that typifies scorpion beta-toxins. The involvement of the N-groove in recognition of the receptor site, which seems to require a defined topology, as well as in sensor trapping, which involves interaction with a moving channel region, is puzzling. On the basis of the mutagenesis studies we hypothesize that following binding to the receptor site, the toxin undergoes a conformational change at the N-groove region that facilitates the trapping of the voltage-sensor in its activated position.

X-ray structure and mutagenesis of the scorpion depressant toxin LqhIT2 reveals key determinants crucial for activity and anti-insect selectivity.,Karbat I, Turkov M, Cohen L, Kahn R, Gordon D, Gurevitz M, Frolow F J Mol Biol. 2007 Feb 16;366(2):586-601. Epub 2006 Nov 10. PMID:17166514^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Benkhalifa R, Stankiewicz M, Lapied B, Turkov M, Zilberberg N, Gurevitz M, Pelhate M. Refined electrophysiological analysis suggests that a depressant toxin is a sodium channel opener rather than a blocker. Life Sci. 1997;61(8):819-30. PMID:9275012
↑ Karbat I, Turkov M, Cohen L, Kahn R, Gordon D, Gurevitz M, Frolow F. X-ray structure and mutagenesis of the scorpion depressant toxin LqhIT2 reveals key determinants crucial for activity and anti-insect selectivity. J Mol Biol. 2007 Feb 16;366(2):586-601. Epub 2006 Nov 10. PMID:17166514 doi:10.1016/j.jmb.2006.10.085

1 Structural highlights
2 Function
3 Evolutionary Conservation
4 Publication Abstract from PubMed
5 References

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/2i61"

@@ Line 1: / Line 1: @@
 ==Depressant anti-insect neurotoxin, LqhIT2 from Leiurus quinquestriatus hebraeus==
 <StructureSection load='2i61' size='340' side='right' caption='[[2i61]], [[Resolution|resolution]] 1.20&Aring;' scene=''>
@@ Line 4: / Line 5: @@
 <table><tr><td colspan='2'>[[2i61]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Leiqh Leiqh]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2I61 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2I61 FirstGlance]. <br>
 </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACY:ACETIC+ACID'>ACY</scene>, <scene name='pdbligand=CO2:CARBON+DIOXIDE'>CO2</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=LI:LITHIUM+ION'>LI</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></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=2i61 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2i61 OCA], [http://pdbe.org/2i61 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2i61 RCSB], [http://www.ebi.ac.uk/pdbsum/2i61 PDBsum]</span></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=2i61 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2i61 OCA], [http://pdbe.org/2i61 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2i61 RCSB], [http://www.ebi.ac.uk/pdbsum/2i61 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2i61 ProSAT]</span></td></tr>
 </table>
 == Function ==

2i61

From Proteopedia

Revision as of 08:23, 18 October 2017

Depressant anti-insect neurotoxin, LqhIT2 from Leiurus quinquestriatus hebraeus

Structural highlights

Function

Evolutionary Conservation

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

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