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| | ==NMR Structue of alpha-conotoxin EI== | | ==NMR Structue of alpha-conotoxin EI== |
| - | <StructureSection load='1k64' size='340' side='right'caption='[[1k64]], [[NMR_Ensembles_of_Models | 20 NMR models]]' scene=''> | + | <StructureSection load='1k64' size='340' side='right'caption='[[1k64]]' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1k64]] is a 1 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K64 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1K64 FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1k64]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Conus_ermineus Conus ermineus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K64 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1K64 FirstGlance]. <br> |
| - | </td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=HYP:4-HYDROXYPROLINE'>HYP</scene>, <scene name='pdbligand=NH2:AMINO+GROUP'>NH2</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[1plp|1plp]], [[1qs3|1qs3]], [[1dg2|1dg2]]</div></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HYP:4-HYDROXYPROLINE'>HYP</scene>, <scene name='pdbligand=NH2:AMINO+GROUP'>NH2</scene></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=1k64 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k64 OCA], [https://pdbe.org/1k64 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1k64 RCSB], [https://www.ebi.ac.uk/pdbsum/1k64 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1k64 ProSAT]</span></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=1k64 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k64 OCA], [https://pdbe.org/1k64 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1k64 RCSB], [https://www.ebi.ac.uk/pdbsum/1k64 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1k64 ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[https://www.uniprot.org/uniprot/CA1_CONER CA1_CONER]] Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. Blocks mammalian nAChR composed of alpha-1/gamma and alpha-1/delta subunits. Blocks central nervous system nAChR composed of alpha-4/beta-2 subunits and peripheral nervous system nAChR composed of alpha-3/beta-4 subunits. Low toxin concentrations potentiate currents in muscle nAChR composed of alpha-1/beta-1/gamma/delta subunits and central nervous system nAChR composed of alpha-4/beta-2 subunits, but not peripheral nervous system nAChR composed of alpha-3/beta-4 subunits.<ref>PMID:17635581</ref> <ref>PMID:7578057</ref>
| + | [https://www.uniprot.org/uniprot/CA1A_CONER CA1A_CONER] Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. Probable competitive antagonist of fish muscle acetylcholine receptor (PubMed:32245200). Inhibits postsynaptic nicotinic acetylcholine receptors (nAChRs) from zebrafish (IC(50)=58-100 nM) (PubMed:32245200). Blocks mammalian nAChR composed of alpha-1/gamma and alpha-1/delta subunits. Blocks central nervous system nAChR composed of alpha-4-beta-2/CHRNA4-CHRNB2 subunits and peripheral nervous system nAChR composed of alpha-3-beta-4/CHRNA3-CHRNB4 subunits. Low toxin concentrations potentiate currents in muscle nAChR composed of alpha-1-beta-1-gamma-delta (CHRNA1-CHRNB1-CHRNG-CHRND) subunits and central nervous system nAChR composed of alpha-4-beta-2/CHRNA4-CHRNB2 subunits, but not peripheral nervous system nAChR composed of alpha-3-beta-4 subunits. Also exhibits inhibition of D.melanogaster alpha-7/CHRNA7 nAChRs (PubMed:25466886). Has possibly a distinct nAChR binding mode from other alpha-conotoxins, due to a different three residue motif (lacks the Ser-Xaa-Pro motif) (By similarity).[UniProtKB:Q2I2R8]<ref>PMID:17635581</ref> <ref>PMID:25466886</ref> <ref>PMID:32245200</ref> <ref>PMID:7578057</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| | + | [[Category: Conus ermineus]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Gray, W R]] | + | [[Category: Gray WR]] |
| - | [[Category: Han, K H]] | + | [[Category: Han KH]] |
| - | [[Category: Jacobsen, R]] | + | [[Category: Jacobsen R]] |
| - | [[Category: McIntosh, J M]] | + | [[Category: McIntosh JM]] |
| - | [[Category: Park, K H]] | + | [[Category: Park KH]] |
| - | [[Category: Suk, J E]] | + | [[Category: Suk JE]] |
| - | [[Category: Omega-shaped containing a-helix]]
| + | |
| - | [[Category: Toxin]]
| + | |
| Structural highlights
Function
CA1A_CONER Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. Probable competitive antagonist of fish muscle acetylcholine receptor (PubMed:32245200). Inhibits postsynaptic nicotinic acetylcholine receptors (nAChRs) from zebrafish (IC(50)=58-100 nM) (PubMed:32245200). Blocks mammalian nAChR composed of alpha-1/gamma and alpha-1/delta subunits. Blocks central nervous system nAChR composed of alpha-4-beta-2/CHRNA4-CHRNB2 subunits and peripheral nervous system nAChR composed of alpha-3-beta-4/CHRNA3-CHRNB4 subunits. Low toxin concentrations potentiate currents in muscle nAChR composed of alpha-1-beta-1-gamma-delta (CHRNA1-CHRNB1-CHRNG-CHRND) subunits and central nervous system nAChR composed of alpha-4-beta-2/CHRNA4-CHRNB2 subunits, but not peripheral nervous system nAChR composed of alpha-3-beta-4 subunits. Also exhibits inhibition of D.melanogaster alpha-7/CHRNA7 nAChRs (PubMed:25466886). Has possibly a distinct nAChR binding mode from other alpha-conotoxins, due to a different three residue motif (lacks the Ser-Xaa-Pro motif) (By similarity).[UniProtKB:Q2I2R8][1] [2] [3] [4]
Publication Abstract from PubMed
A high resolution structure of alpha-conotoxin EI has been determined by (1)H NMR spectroscopy and molecular modeling. alpha-Conotoxin EI has the same disulfide framework as alpha 4/7 conotoxins targeting neuronal nicotinic acetylcholine receptors but antagonizes the neuromuscular receptor as do the alpha 3/5 and alpha A conotoxins. The unique binding preference of alpha-conotoxin EI to the alpha(1)/delta subunit interface of Torpedo neuromuscular receptor makes it a valuable structural template for superposition of various alpha-conotoxins possessing distinct receptor subtype specificities. Structural comparison of alpha-conotoxin EI with the gamma-subunit favoring alpha-conotoxin GI suggests that the Torpedo delta-subunit preference of the former originates from its second loop. Superposition of three-dimensional structures of seven alpha-conotoxins reveals that the estimated size of the toxin-binding pocket in nicotinic acetylcholine receptor is approximately 20 A (height) x 20 A (width) x 15 A (thickness).
Solution conformation of alpha-conotoxin EI, a neuromuscular toxin specific for the alpha 1/delta subunit interface of torpedo nicotinic acetylcholine receptor.,Park KH, Suk JE, Jacobsen R, Gray WR, McIntosh JM, Han KH J Biol Chem. 2001 Dec 28;276(52):49028-33. Epub 2001 Oct 18. PMID:11641403[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lopez-Vera E, Aguilar MB, Schiavon E, Marinzi C, Ortiz E, Restano Cassulini R, Batista CV, Possani LD, Heimer de la Cotera EP, Peri F, Becerril B, Wanke E. Novel alpha-conotoxins from Conus spurius and the alpha-conotoxin EI share high-affinity potentiation and low-affinity inhibition of nicotinic acetylcholine receptors. FEBS J. 2007 Aug;274(15):3972-85. Epub 2007 Jul 16. PMID:17635581 doi:http://dx.doi.org/10.1111/j.1742-4658.2007.05931.x
- ↑ Heghinian MD, Mejia M, Adams DJ, Godenschwege TA, Marí F. Inhibition of cholinergic pathways in Drosophila melanogaster by α-conotoxins. FASEB J. 2015 Mar;29(3):1011-8. PMID:25466886 doi:10.1096/fj.14-262733
- ↑ Rybin MJ, O'Brien H, Ramiro IBL, Azam L, McIntosh JM, Olivera BM, Safavi-Hemami H, Yoshikami D. αM-Conotoxin MIIIJ Blocks Nicotinic Acetylcholine Receptors at Neuromuscular Junctions of Frog and Fish. Toxins (Basel). 2020 Mar 21;12(3):197. PMID:32245200 doi:10.3390/toxins12030197
- ↑ Martinez JS, Olivera BM, Gray WR, Craig AG, Groebe DR, Abramson SN, McIntosh JM. alpha-Conotoxin EI, a new nicotinic acetylcholine receptor antagonist with novel selectivity. Biochemistry. 1995 Nov 7;34(44):14519-26. PMID:7578057
- ↑ Park KH, Suk JE, Jacobsen R, Gray WR, McIntosh JM, Han KH. Solution conformation of alpha-conotoxin EI, a neuromuscular toxin specific for the alpha 1/delta subunit interface of torpedo nicotinic acetylcholine receptor. J Biol Chem. 2001 Dec 28;276(52):49028-33. Epub 2001 Oct 18. PMID:11641403 doi:10.1074/jbc.M107798200
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