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| | ==NMR STUDY OF OMEGA-CONOTOXIN MVIIA== | | ==NMR STUDY OF OMEGA-CONOTOXIN MVIIA== |
| - | <StructureSection load='1omg' size='340' side='right' caption='[[1omg]], [[NMR_Ensembles_of_Models | 13 NMR models]]' scene=''> | + | <StructureSection load='1omg' size='340' side='right'caption='[[1omg]]' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[1omg]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Conus_magus Conus magus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OMG OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1OMG FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[1omg]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Conus_magus Conus magus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OMG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1OMG 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, 13 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=1omg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1omg OCA], [http://www.rcsb.org/pdb/explore.do?structureId=1omg RCSB], [http://www.ebi.ac.uk/pdbsum/1omg PDBsum]</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=1omg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1omg OCA], [https://pdbe.org/1omg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1omg RCSB], [https://www.ebi.ac.uk/pdbsum/1omg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1omg ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/CXO7A_CONMA CXO7A_CONMA]] Omega-conotoxins act at presynaptic membranes, they bind and block voltage-gated calcium channels. This toxin blocks N-type calcium channels (Cav2.2/CACNA1B). | + | [https://www.uniprot.org/uniprot/O17A_CONMA O17A_CONMA] Omega-conotoxins act at presynaptic membranes, they bind and block voltage-gated calcium channels. This toxin blocks Cav2.2/CACNA1B calcium channels (IC(50)=0.67-208 nM) (PubMed:26344359, PubMed:34589389, PubMed:7826361). It acts by neutralizing the outer electronegativity and sterically hindering the ion access path to the entrance of the channel selectivity filter (PubMed:34234349). It also shows antiproliferative effects on different glioma cell lines (M059J, U-138MG and U-251MG) (PubMed:28202361). In vivo, is lethal to fish (PubMed:26344359, PubMed:34589389). In vivo, injection into mammals induces adverse effects, such as tremor, diminution of spontaneous locomotor activity and bad coordinated locomotion (PubMed:26344359). In addition, it causes reduction of tumor area in the mouse glioma model, that is induced by the orthotopic injection of GL261 cells into the brain (PubMed:28202361).<ref>PMID:26344359</ref> <ref>PMID:34234349</ref> <ref>PMID:7826361</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> |
| | </div> | | </div> |
| | + | <div class="pdbe-citations 1omg" style="background-color:#fffaf0;"></div> |
| | == References == | | == References == |
| | <references/> | | <references/> |
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| | </StructureSection> | | </StructureSection> |
| | [[Category: Conus magus]] | | [[Category: Conus magus]] |
| - | [[Category: Kim, J I]] | + | [[Category: Large Structures]] |
| - | [[Category: Kobayashi, K]] | + | [[Category: Kim J-I]] |
| - | [[Category: Kodera, Y]] | + | [[Category: Kobayashi K]] |
| - | [[Category: Kohno, T]] | + | [[Category: Kodera Y]] |
| - | [[Category: Maeda, T]] | + | [[Category: Kohno T]] |
| - | [[Category: Sato, K]] | + | [[Category: Maeda T]] |
| - | [[Category: Presynaptic neurotoxin]]
| + | [[Category: Sato K]] |
| Structural highlights
Function
O17A_CONMA Omega-conotoxins act at presynaptic membranes, they bind and block voltage-gated calcium channels. This toxin blocks Cav2.2/CACNA1B calcium channels (IC(50)=0.67-208 nM) (PubMed:26344359, PubMed:34589389, PubMed:7826361). It acts by neutralizing the outer electronegativity and sterically hindering the ion access path to the entrance of the channel selectivity filter (PubMed:34234349). It also shows antiproliferative effects on different glioma cell lines (M059J, U-138MG and U-251MG) (PubMed:28202361). In vivo, is lethal to fish (PubMed:26344359, PubMed:34589389). In vivo, injection into mammals induces adverse effects, such as tremor, diminution of spontaneous locomotor activity and bad coordinated locomotion (PubMed:26344359). In addition, it causes reduction of tumor area in the mouse glioma model, that is induced by the orthotopic injection of GL261 cells into the brain (PubMed:28202361).[1] [2] [3]
Publication Abstract from PubMed
The three-dimensional solution structure of omega-conotoxin MVIIA, a 25-mer peptide antagonist of N-type calcium channels, was determined by two-dimensional 1H NMR spectroscopy with simulated annealing calculations. A total of 13 converged structures of omega-conotoxin MVIIA were obtained on the basis of 273 experimental constraints, including 232 distance constraints obtained from nuclear Overhauser effect (NOE) connectivities, 22 torsion angle (phi, chi 1) constraints, and 19 constraints associated with hydrogen bonds and disulfide bonds. The atomic root mean square difference about the averaged coordinate positions is 0.47 +/- 0.08 A for the backbone atoms (N, C alpha, C) and 1.27 +/- 0.14 A for all heavy atoms of the entire peptide. The molecular structure of omega-conotoxin MVIIA is composed of a short triple-stranded antiparallel beta-sheet. The overall beta-sheet topology is +2x, -1, which is the same as that reported for omega-conotoxin GVIA, another N-type calcium channel blocker. The orientation of beta-stranded structure is similar to each other, suggesting that the conserved disulfide bond combination is essential for the molecular folding. We have recently determined by using alanine substitution analyses that Tyr 13 is essential for the activity of both toxins. On the basis of functional and structural analysis, it is shown that both omega-conotoxin MVIIA and GVIA retain a similar conformation to locate Tyr 13 in the appropriate position to allow binding to N-type calcium channels. These results provide a molecular basis for understanding the mechanism of calcium channel modulation through the toxin-channel interaction and insight into the discrimination of different subtypes of calcium channels.
Three-dimensional structure in solution of the calcium channel blocker omega-conotoxin MVIIA.,Kohno T, Kim JI, Kobayashi K, Kodera Y, Maeda T, Sato K Biochemistry. 1995 Aug 15;34(32):10256-65. PMID:7640281[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Wang F, Yan Z, Liu Z, Wang S, Wu Q, Yu S, Ding J, Dai Q. Molecular basis of toxicity of N-type calcium channel inhibitor MVIIA. Neuropharmacology. 2016 Feb;101:137-45. PMID:26344359 doi:10.1016/j.neuropharm.2015.08.047
- ↑ Gao S, Yao X, Yan N. Structure of human Ca(v)2.2 channel blocked by the painkiller ziconotide. Nature. 2021 Aug;596(7870):143-147. PMID:34234349 doi:10.1038/s41586-021-03699-6
- ↑ Kim JI, Takahashi M, Ohtake A, Wakamiya A, Sato K. Tyr13 is essential for the activity of omega-conotoxin MVIIA and GVIA, specific N-type calcium channel blockers. Biochem Biophys Res Commun. 1995 Jan 17;206(2):449-54. PMID:7826361 doi:10.1006/bbrc.1995.1063
- ↑ Kohno T, Kim JI, Kobayashi K, Kodera Y, Maeda T, Sato K. Three-dimensional structure in solution of the calcium channel blocker omega-conotoxin MVIIA. Biochemistry. 1995 Aug 15;34(32):10256-65. PMID:7640281
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