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| | ==RECOMBINANT ERABUTOXIN A, S8G MUTANT== | | ==RECOMBINANT ERABUTOXIN A, S8G MUTANT== |
| - | <StructureSection load='2era' size='340' side='right' caption='[[2era]], [[Resolution|resolution]] 1.81Å' scene=''> | + | <StructureSection load='2era' size='340' side='right'caption='[[2era]], [[Resolution|resolution]] 1.81Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[2era]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Black-banded_sea_krait Black-banded sea krait]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ERA OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2ERA FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[2era]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Laticauda_semifasciata Laticauda semifasciata]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2ERA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2ERA 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=2era FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2era OCA], [http://pdbe.org/2era PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=2era RCSB], [http://www.ebi.ac.uk/pdbsum/2era PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=2era ProSAT]</span></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.81Å</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=2era FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2era OCA], [https://pdbe.org/2era PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2era RCSB], [https://www.ebi.ac.uk/pdbsum/2era PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2era ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/NXSA_PSSEM NXSA_PSSEM]] Binds with high affinity to muscular nicotinic acetylcholine receptors (nAChRs) and with low affinity to neuronal alpha-7 nAChRs and inhibit acetylcholine from binding to the receptor, thereby impairing neuromuscular transmission. Produces peripheral paralysis by blocking neuromuscular transmission at the postsynaptic site. Blocks the extracellular increase of dopamine evoked by nicotine at 4.2 uM concentrations.<ref>PMID:9305882</ref> <ref>PMID:9840221</ref> | + | [https://www.uniprot.org/uniprot/3S1EA_LATSE 3S1EA_LATSE] Binds with high affinity to muscular nicotinic acetylcholine receptors (nAChRs) (tested on Torpedo marmorata, Kd=21 uM) and with low affinity to neuronal alpha-7/CHRNA7 nAChRs (tested on chimeric alpha-7/CHRNA7, Kd=0.07 nM) and inhibits acetylcholine from binding to the receptor, thereby impairing neuromuscular transmission (PubMed:7721859). Blocks the extracellular increase of dopamine evoked by nicotine at 4.2 uM concentrations (PubMed:9840221). In vivo, produces peripheral paralysis.<ref>PMID:7721859</ref> <ref>PMID:9305882</ref> <ref>PMID:9840221</ref> |
| | == Evolutionary Conservation == | | == Evolutionary Conservation == |
| | [[Image:Consurf_key_small.gif|200px|right]] | | [[Image:Consurf_key_small.gif|200px|right]] |
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| | <jmolCheckbox> | | <jmolCheckbox> |
| | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/er/2era_consurf.spt"</scriptWhenChecked> | | <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/er/2era_consurf.spt"</scriptWhenChecked> |
| - | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | + | <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked> |
| | <text>to colour the structure by Evolutionary Conservation</text> | | <text>to colour the structure by Evolutionary Conservation</text> |
| | </jmolCheckbox> | | </jmolCheckbox> |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Black-banded sea krait]] | + | [[Category: Large Structures]] |
| - | [[Category: Arnoux, B]] | + | [[Category: Laticauda semifasciata]] |
| - | [[Category: Ducruix, A]] | + | [[Category: Arnoux B]] |
| - | [[Category: Gaucher, J F]] | + | [[Category: Ducruix A]] |
| - | [[Category: Menez, A]] | + | [[Category: Gaucher JF]] |
| - | [[Category: Menez, R]] | + | [[Category: Menez A]] |
| - | [[Category: Neurotoxin]]
| + | [[Category: Menez R]] |
| - | [[Category: Postsynaptic neurotoxin]]
| + | |
| - | [[Category: Snake neurotoxin]]
| + | |
| - | [[Category: Venom]]
| + | |
| Structural highlights
Function
3S1EA_LATSE Binds with high affinity to muscular nicotinic acetylcholine receptors (nAChRs) (tested on Torpedo marmorata, Kd=21 uM) and with low affinity to neuronal alpha-7/CHRNA7 nAChRs (tested on chimeric alpha-7/CHRNA7, Kd=0.07 nM) and inhibits acetylcholine from binding to the receptor, thereby impairing neuromuscular transmission (PubMed:7721859). Blocks the extracellular increase of dopamine evoked by nicotine at 4.2 uM concentrations (PubMed:9840221). In vivo, produces peripheral paralysis.[1] [2] [3]
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
A previous mutational analysis of erabutoxin a (Ea), a curaremimetic toxin from sea snake venom, showed that the substitutions S8G and S8T caused, respectively, 176-fold and 780-fold affinity decreases for the nicotinic acetylcholine receptor (AchR). In view of the fact that the side-chain of Ser8 is buried in the wild-type toxin, we wondered whether these affinity changes reflect a direct binding contribution of S8 to the receptor and/or conformational changes that could have occurred in Ea as a result of the introduced mutations. To approach this question, we solved X-ray structures of the two mutants S8G and S8T at high resolution (0.18 nm and 0.17 nm, with R factors of 18.0% and 17.9%, respectively). The data show that none of the mutations significantly modified the toxin structure. Even within the site where the toxin binds to the receptor the backbone conformation remained unchanged. Therefore, the low affinities of the mutants S8T and S8G cannot be explained by a large conformational change of the toxin structure. Although we cannot exclude the possibility that undetectable structural changes have occurred in the toxin mutants, our data support the view that, although buried between loop I and II, S8 is part of the functional epitope of the toxin.
High resolution x-ray analysis of two mutants of a curaremimetic snake toxin.,Gaucher JF, Menez R, Arnoux B, Pusset J, Ducruix A Eur J Biochem. 2000 Mar;267(5):1323-9. PMID:10691969[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tremeau O, Lemaire C, Drevet P, Pinkasfeld S, Ducancel F, Boulain JC, Menez A. Genetic engineering of snake toxins. The functional site of Erabutoxin a, as delineated by site-directed mutagenesis, includes variant residues. J Biol Chem. 1995 Apr 21;270(16):9362-9. PMID:7721859
- ↑ Servent D, Winckler-Dietrich V, Hu HY, Kessler P, Drevet P, Bertrand D, Menez A. Only snake curaremimetic toxins with a fifth disulfide bond have high affinity for the neuronal alpha7 nicotinic receptor. J Biol Chem. 1997 Sep 26;272(39):24279-86. PMID:9305882
- ↑ Dajas-Bailador F, Costa G, Dajas F, Emmett S. Effects of alpha-erabutoxin, alpha-bungarotoxin, alpha-cobratoxin and fasciculin on the nicotine-evoked release of dopamine in the rat striatum in vivo. Neurochem Int. 1998 Oct;33(4):307-12. PMID:9840221
- ↑ Gaucher JF, Menez R, Arnoux B, Pusset J, Ducruix A. High resolution x-ray analysis of two mutants of a curaremimetic snake toxin. Eur J Biochem. 2000 Mar;267(5):1323-9. PMID:10691969
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