1hvw
From Proteopedia
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| - | [[Image:1hvw.gif|left|200px]] | ||
| - | + | ==HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A== | |
| - | + | <StructureSection load='1hvw' size='340' side='right'caption='[[1hvw]]' scene=''> | |
| - | + | == Structural highlights == | |
| - | + | <table><tr><td colspan='2'>[[1hvw]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Hadronyche_versuta Hadronyche versuta]. 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 [https://proteopedia.org/fgij/fg.htm?mol=1HVW 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=1hvw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1hvw OCA], [https://pdbe.org/1hvw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1hvw RCSB], [https://www.ebi.ac.uk/pdbsum/1hvw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1hvw ProSAT]</span></td></tr> | |
| - | + | </table> | |
| - | + | == Function == | |
| - | + | [https://www.uniprot.org/uniprot/TO1A_HADVE TO1A_HADVE] Reversibly and voltage-independently blocks both mid-low- (M-LVA) and high-voltage-activated (HVA) calcium channels in cockroach DUM neurons (PubMed:17610847). Is lethal to many insect species but not toxic to mammals (PubMed:16779650, PubMed:9228949). 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:17141372</ref> <ref>PMID:17610847</ref> <ref>PMID:9228949</ref> | |
| - | + | <div style="background-color:#fffaf0;"> | |
| - | + | == Publication Abstract from PubMed == | |
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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. | 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<ref>PMID:11313356</ref> | |
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| - | Functional significance of the beta hairpin in the insecticidal neurotoxin omega-atracotoxin-Hv1a., Tedford HW, Fletcher JI, King GF | + | |
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| - | + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |
| + | </div> | ||
| + | <div class="pdbe-citations 1hvw" style="background-color:#fffaf0;"></div> | ||
| + | == References == | ||
| + | <references/> | ||
| + | __TOC__ | ||
| + | </StructureSection> | ||
| + | [[Category: Hadronyche versuta]] | ||
| + | [[Category: Large Structures]] | ||
| + | [[Category: Fletcher JI]] | ||
| + | [[Category: King GF]] | ||
Current revision
HAIRPINLESS MUTANT OF OMEGA-ATRACOTOXIN-HV1A
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