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1hvw

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Revision as of 01:43, 25 December 2014

HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A

Structural highlights

1hvw is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Related:	1axh
Resources:	FirstGlance, OCA, RCSB, PDBsum

Function

[TOT1A_HADVE] Reversibly and voltage-independently blocks both mid-low- (M-LVA) and high-voltage-activated (HVA) calcium channels in cockroach DUM neurons. Lethal to many insect orders but not toxic to mice or rabbits. May target the insect high-voltage-activated calcium channel Dmca1D. Also inhibits acarines calcium channels. An extremely high toxin concentration partially inhibits Cav1.2/CACNA1C, Cav2.1/CACNA1A and Cav2.2/CACNA1B calcium channel of rats. As for omega-AcTx-Hv2a, the phenotypic effect of injection of this toxin into lone star ticks (Amblyomma americanum) is curling of all eight legs into closed loops.^[1] ^[2] ^[3] ^[4] ^[5]

Publication Abstract from PubMed

omega-Atracotoxin-Hv1a is an insect-specific neurotoxin whose phylogenetic specificity derives from its ability to antagonize insect, but not vertebrate, voltage-gated calcium channels. In order to help understand its mechanism of action and to enhance its utility as a lead compound for insecticide development, we used a combination of protein engineering and site-directed mutagenesis to probe the toxin for key functional regions. First, we constructed a Hairpinless mutant in which the C-terminal beta-hairpin, which is highly conserved in this family of neurotoxins, was excised without affecting the fold of the residual disulfide-rich core of the toxin. The Hairpinless mutant was devoid of insecticidal activity, indicating the functional importance of the hairpin. We subsequently developed a highly efficient system for production of recombinant toxin and then probed the hairpin for key functional residues using alanine-scanning mutagenesis followed by a second round of mutagenesis based on initial "hits" from the alanine scan. This revealed that two spatially proximal residues, Asn(27) and Arg(35), form a contiguous molecular surface that is essential for toxin activity. We propose that this surface of the beta-hairpin is a key site for interaction of the toxin with insect calcium channels.

Functional significance of the beta hairpin in the insecticidal neurotoxin omega-atracotoxin-Hv1a.,Tedford HW, Fletcher JI, King GF J Biol Chem. 2001 Jul 13;276(28):26568-76. Epub 2001 Apr 19. PMID:11313356^[6]

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

References

↑ Bloomquist JR. Mode of action of atracotoxin at central and peripheral synapses of insects. Invert Neurosci. 2003 Nov;5(1):45-50. Epub 2003 Nov 8. PMID:14608494 doi:http://dx.doi.org/10.1007/s10158-003-0027-z
↑ Tedford HW, Gilles N, Menez A, Doering CJ, Zamponi GW, King GF. Scanning mutagenesis of omega-atracotoxin-Hv1a reveals a spatially restricted epitope that confers selective activity against insect calcium channels. J Biol Chem. 2004 Oct 15;279(42):44133-40. Epub 2004 Aug 11. PMID:15308644 doi:http://dx.doi.org/10.1074/jbc.M404006200
↑ Mukherjee AK, Sollod BL, Wikel SK, King GF. Orally active acaricidal peptide toxins from spider venom. Toxicon. 2006 Feb;47(2):182-7. Epub 2005 Dec 5. PMID:16330063 doi:http://dx.doi.org/10.1016/j.toxicon.2005.10.011
↑ Chong Y, Hayes JL, Sollod B, Wen S, Wilson DT, Hains PG, Hodgson WC, Broady KW, King GF, Nicholson GM. The omega-atracotoxins: selective blockers of insect M-LVA and HVA calcium channels. Biochem Pharmacol. 2007 Aug 15;74(4):623-38. Epub 2007 May 25. PMID:17610847 doi:http://dx.doi.org/10.1016/j.bcp.2007.05.017
↑ Tedford HW, Maggio F, Reenan RA, King G. A model genetic system for testing the in vivo function of peptide toxins. Peptides. 2007 Jan;28(1):51-6. Epub 2006 Dec 1. PMID:17141372 doi:http://dx.doi.org/10.1016/j.peptides.2006.08.026
↑ Tedford HW, Fletcher JI, King GF. Functional significance of the beta hairpin in the insecticidal neurotoxin omega-atracotoxin-Hv1a. J Biol Chem. 2001 Jul 13;276(28):26568-76. Epub 2001 Apr 19. PMID:11313356 doi:http://dx.doi.org/10.1074/jbc.M102199200

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

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1hvw"

Categories: Fletcher, J I | King, G F | Beta-hairpin | Cystine knot | Toxin

@@ Line 3: / Line 3: @@
 == Structural highlights ==
 <table><tr><td colspan='2'>[[1hvw]] is a 1 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HVW OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1HVW FirstGlance]. <br>
-</td></tr><tr><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1axh|1axh]]</td></tr>
+</td></tr><tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1axh|1axh]]</td></tr>
-<tr><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1hvw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hvw OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1hvw RCSB], [http://www.ebi.ac.uk/pdbsum/1hvw 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=1hvw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hvw OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1hvw RCSB], [http://www.ebi.ac.uk/pdbsum/1hvw PDBsum]</span></td></tr>
-<table>
+</table>
+== Function ==
+[[http://www.uniprot.org/uniprot/TOT1A_HADVE TOT1A_HADVE]] Reversibly and voltage-independently blocks both mid-low- (M-LVA) and high-voltage-activated (HVA) calcium channels in cockroach DUM neurons. Lethal to many insect orders but not toxic to mice or rabbits. May target the insect high-voltage-activated calcium channel Dmca1D. Also inhibits acarines calcium channels. An extremely high toxin concentration partially inhibits Cav1.2/CACNA1C, Cav2.1/CACNA1A and Cav2.2/CACNA1B calcium channel of rats. As for omega-AcTx-Hv2a, the phenotypic effect of injection of this toxin into lone star ticks (Amblyomma americanum) is curling of all eight legs into closed loops.<ref>PMID:14608494</ref> <ref>PMID:15308644</ref> <ref>PMID:16330063</ref> <ref>PMID:17610847</ref> <ref>PMID:17141372</ref>
 <div style="background-color:#fffaf0;">
 == Publication Abstract from PubMed ==
@@ Line 18: / Line 20: @@
 __TOC__
 </StructureSection>
-[[Category: Fletcher, J I.]]
+[[Category: Fletcher, J I]]
-[[Category: King, G F.]]
+[[Category: King, G F]]
 [[Category: Beta-hairpin]]
 [[Category: Cystine knot]]
 [[Category: Toxin]]

1hvw

From Proteopedia

Revision as of 01:43, 25 December 2014

HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A

Structural highlights

Function

Publication Abstract from PubMed

References

Contents

Proteopedia Page Contributors and Editors (what is this?)

Views

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