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| | ==Solution structure of alpha-conotoxin SI== | | ==Solution structure of alpha-conotoxin SI== |
| - | <StructureSection load='1qmw' size='340' side='right' caption='[[1qmw]], [[NMR_Ensembles_of_Models | 36 NMR models]]' scene=''> | + | <StructureSection load='1qmw' size='340' side='right'caption='[[1qmw]]' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1qmw]] is a 1 chain structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QMW OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1QMW FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1qmw]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Conus_striatus Conus striatus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QMW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QMW FirstGlance]. <br> |
| - | </td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><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, 36 models</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=1qmw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qmw OCA], [http://pdbe.org/1qmw PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1qmw RCSB], [http://www.ebi.ac.uk/pdbsum/1qmw PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1qmw ProSAT]</span></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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=1qmw FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qmw OCA], [https://pdbe.org/1qmw PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1qmw RCSB], [https://www.ebi.ac.uk/pdbsum/1qmw PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1qmw ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/CAS1_CONST CAS1_CONST]] Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. This toxin blocks muscular nAChRs alpha-1/gamma and alpha-1/delta subunits. | + | [https://www.uniprot.org/uniprot/CA1_CONST CA1_CONST] Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them (PubMed:3196703). Is active on muscle nAChR (IC(50)=113 nM on adult subtype (alpha-1-beta-1-gamma-delta/CHRNA1-CHRNB1-CHRNG-CHRND) and IC(50)=142 nM on fetal subtype (alpha-1-beta-1-delta-epsilon/CHRNA1-CHRNB1-CHRND-CHRNE)) (PubMed:35357806, PubMed:9174364). On mice muscle receptors, its higher affinity site is the alpha/delta nAChR subunit interface (PubMed:9174364). On Torpedo receptors, it does not distinguish between alpha/delta and alpha/gamma acetylcholine-binding sites (PubMed:9174364). In vivo, causes paralysis followed by death when injected into goldfish (PubMed:3196703). In contrast, has no effect on mice, when similar doses are intraperitoneally or intracerebrally injected (PubMed:3196703).<ref>PMID:3196703</ref> <ref>PMID:35357806</ref> <ref>PMID:9174364</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: Barany, G]] | + | [[Category: Conus striatus]] |
| - | [[Category: Benie, A J]] | + | [[Category: Large Structures]] |
| - | [[Category: Hargittai, B]] | + | [[Category: Barany G]] |
| - | [[Category: Janes, R W]] | + | [[Category: Benie AJ]] |
| - | [[Category: Whitford, D]] | + | [[Category: Hargittai B]] |
| - | [[Category: Conotoxin]] | + | [[Category: Janes RW]] |
| - | [[Category: Nicotinic acetylcholine receptor]] | + | [[Category: Whitford D]] |
| - | [[Category: Toxin]]
| + | |
| - | [[Category: Venom]]
| + | |
| Structural highlights
Function
CA1_CONST Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them (PubMed:3196703). Is active on muscle nAChR (IC(50)=113 nM on adult subtype (alpha-1-beta-1-gamma-delta/CHRNA1-CHRNB1-CHRNG-CHRND) and IC(50)=142 nM on fetal subtype (alpha-1-beta-1-delta-epsilon/CHRNA1-CHRNB1-CHRND-CHRNE)) (PubMed:35357806, PubMed:9174364). On mice muscle receptors, its higher affinity site is the alpha/delta nAChR subunit interface (PubMed:9174364). On Torpedo receptors, it does not distinguish between alpha/delta and alpha/gamma acetylcholine-binding sites (PubMed:9174364). In vivo, causes paralysis followed by death when injected into goldfish (PubMed:3196703). In contrast, has no effect on mice, when similar doses are intraperitoneally or intracerebrally injected (PubMed:3196703).[1] [2] [3]
Publication Abstract from PubMed
The nuclear magnetic resonance solution structure of alpha-conotoxin SI has been determined at pH 4.2. The 36 lowest energy structures show that alpha-conotoxin SI exists in a single major solution conformation and is stabilized by six hydrogen bonds. Comparisons are made between the SI solution structure and the solution and crystal structures of alpha-conotoxin GI. Surprisingly, a high degree of similarity between the backbone conformations of the GI crystal and the SI solution structures is seen in the region of lowest sequence homology, namely residues Gly-8 to Ser-12. This similarity is more surprising when considering that in SI a proline replaces the Arg-9 found in GI. The correspondence in conformation in this region provides the definitive evidence that it is the loss of the arginine basic charge at residue 9 which determines the differences in toxicity between GI and SI, rather than any changes in conformation induced by the cyclic proline residue.
Solution structure of alpha-conotoxin SI.,Benie AJ, Whitford D, Hargittai B, Barany G, Janes RW FEBS Lett. 2000 Jul 7;476(3):287-95. PMID:10913630[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Zafaralla GC, Ramilo C, Gray WR, Karlstrom R, Olivera BM, Cruz LJ. Phylogenetic specificity of cholinergic ligands: alpha-conotoxin SI. Biochemistry. 1988 Sep 6;27(18):7102-5. PMID:3196703 doi:10.1021/bi00418a065
- ↑ Wilhelm P, Luna-Ramirez K, Chin YK, Dekan Z, Abraham N, Tae HS, Chow CY, Eagles DA, King GF, Lewis RJ, Adams DJ, Alewood PF. Cysteine-Rich α-Conotoxin SII Displays Novel Interactions at the Muscle Nicotinic Acetylcholine Receptor. ACS Chem Neurosci. 2022 Apr 20;13(8):1245-1250. PMID:35357806 doi:10.1021/acschemneuro.1c00857
- ↑ Groebe DR, Gray WR, Abramson SN. Determinants involved in the affinity of alpha-conotoxins GI and SI for the muscle subtype of nicotinic acetylcholine receptors. Biochemistry. 1997 May 27;36(21):6469-74. PMID:9174364 doi:10.1021/bi970195w
- ↑ Benie AJ, Whitford D, Hargittai B, Barany G, Janes RW. Solution structure of alpha-conotoxin SI. FEBS Lett. 2000 Jul 7;476(3):287-95. PMID:10913630
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