|
|
| (15 intermediate revisions not shown.) |
| Line 1: |
Line 1: |
| - | [[Image:1q2j.gif|left|200px]]<br /><applet load="1q2j" size="450" color="white" frame="true" align="right" spinBox="true" | |
| - | caption="1q2j" /> | |
| - | '''Structural basis for tetrodotoxin-resistant sodium channel binding by mu-conotoxin SmIIIA'''<br /> | |
| | | | |
| - | ==Overview== | + | ==Structural basis for tetrodotoxin-resistant sodium channel binding by mu-conotoxin SmIIIA== |
| - | SmIIIA is a new micro-conotoxin isolated recently from Conus, stercusmuscarum. Although it shares several biochemical characteristics, with other micro-conotoxins (the arrangement of cysteine residues and a, conserved arginine believed to interact with residues near the channel, pore), it has several distinctive features, including the absence of, hydroxyproline, and is the first specific antagonist of, tetrodotoxin-resistant voltage-gated sodium channels to be characterized., It therefore represents a potentially useful tool to investigate the, functional roles of these channels. We have determined the, three-dimensional structure of SmIIIA in aqueous solution. Consistent with, the absence of hydroxyprolines, SmIIIA adopts a single conformation with, all peptide bonds in the trans configuration. The spatial orientations of, several conserved Arg and Lys side chains, including Arg14 (using a, consensus numbering system), which plays a key role in sodium channel, binding, are similar to those in other micro-conotoxins but the N-terminal, regions differ, reflecting the trans conformation for the peptide bond, preceding residue 8 in SmIIIA, as opposed to the cis conformation in, micro-conotoxins GIIIA and GIIIB. Comparison of the surfaces of SmIIIA, with other micro-conotoxins suggests that the affinity of SmIIIA for, TTX-resistant channels is influenced by the Trp15 side chain, which is, unique to SmIIIA. Arg17, which replaces Lys in the other micro-conotoxins, may also be important. Consistent with these inferences from the, structure, assays of two chimeras of SmIIIA and PIIIA in which their N-, and C-terminal halves were recombined, indicated that residues in the, C-terminal half of SmIIIA confer affinity for tetrodotoxin-resistant, sodium channels in the cell bodies of frog sympathetic neurons. SmIIIA and, the chimera possessing the C-terminal half of SmIIIA also inhibit, tetrodotoxin-resistant sodium channels in the postganglionic axons of, sympathetic neurons, as indicated by their inhibition of C-neuron compound, action potentials that persist in the presence of tetrodotoxin. | + | <StructureSection load='1q2j' size='340' side='right'caption='[[1q2j]]' scene=''> |
| | + | == Structural highlights == |
| | + | <table><tr><td colspan='2'>[[1q2j]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Conus_stercusmuscarum Conus stercusmuscarum]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1Q2J OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1Q2J 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='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</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=1q2j FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1q2j OCA], [https://pdbe.org/1q2j PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1q2j RCSB], [https://www.ebi.ac.uk/pdbsum/1q2j PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1q2j ProSAT]</span></td></tr> |
| | + | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/CM3A_CONSE CM3A_CONSE] Mu-conotoxins block voltage-gated sodium channels (Nav). This toxin blocks rNav1.5/SCN5A (IC(50) is 1.3 uM), rNav1.6/SCN8A (IC(50) is 160 nM), rNav1.7/SCN9A (IC(50) is 1.3 uM), rNav1.1/SCN1A (K(d) is 3.8 nM), rNav1.2/SCN2A (K(d) is 1.3 nM), rNav1.4/SCN4A (K(d) is 0.22 nM), rNav1.6/SCN8A (K(d) is 69 nM), and rNav1.7/SCN9A (K(d) is 260 nM). This toxin is very potent but weakly discriminating among sodium channels. The block of these channels is modified when beta-subunits are coexpressed with alpha subunits. Hence, blocks of channels containing beta-1 and beta-3 subunits are more potent (compared to channels without beta subunits), whereas blocks of channels containing beta-2 and beta-4 subunits are less potent (compared to channels without beta subunits).<ref>PMID:12484778</ref> <ref>PMID:21652775</ref> <ref>PMID:22229737</ref> <ref>PMID:23146020</ref> |
| | + | <div style="background-color:#fffaf0;"> |
| | + | == Publication Abstract from PubMed == |
| | + | SmIIIA is a new micro-conotoxin isolated recently from Conus stercusmuscarum. Although it shares several biochemical characteristics with other micro-conotoxins (the arrangement of cysteine residues and a conserved arginine believed to interact with residues near the channel pore), it has several distinctive features, including the absence of hydroxyproline, and is the first specific antagonist of tetrodotoxin-resistant voltage-gated sodium channels to be characterized. It therefore represents a potentially useful tool to investigate the functional roles of these channels. We have determined the three-dimensional structure of SmIIIA in aqueous solution. Consistent with the absence of hydroxyprolines, SmIIIA adopts a single conformation with all peptide bonds in the trans configuration. The spatial orientations of several conserved Arg and Lys side chains, including Arg14 (using a consensus numbering system), which plays a key role in sodium channel binding, are similar to those in other micro-conotoxins but the N-terminal regions differ, reflecting the trans conformation for the peptide bond preceding residue 8 in SmIIIA, as opposed to the cis conformation in micro-conotoxins GIIIA and GIIIB. Comparison of the surfaces of SmIIIA with other micro-conotoxins suggests that the affinity of SmIIIA for TTX-resistant channels is influenced by the Trp15 side chain, which is unique to SmIIIA. Arg17, which replaces Lys in the other micro-conotoxins, may also be important. Consistent with these inferences from the structure, assays of two chimeras of SmIIIA and PIIIA in which their N- and C-terminal halves were recombined, indicated that residues in the C-terminal half of SmIIIA confer affinity for tetrodotoxin-resistant sodium channels in the cell bodies of frog sympathetic neurons. SmIIIA and the chimera possessing the C-terminal half of SmIIIA also inhibit tetrodotoxin-resistant sodium channels in the postganglionic axons of sympathetic neurons, as indicated by their inhibition of C-neuron compound action potentials that persist in the presence of tetrodotoxin. |
| | | | |
| - | ==About this Structure==
| + | Structural basis for tetrodotoxin-resistant sodium channel binding by mu-conotoxin SmIIIA.,Keizer DW, West PJ, Lee EF, Yoshikami D, Olivera BM, Bulaj G, Norton RS J Biol Chem. 2003 Nov 21;278(47):46805-13. Epub 2003 Sep 10. PMID:12970353<ref>PMID:12970353</ref> |
| - | 1Q2J is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1Q2J OCA].
| + | |
| | | | |
| - | ==Reference==
| + | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> |
| - | Structural basis for tetrodotoxin-resistant sodium channel binding by mu-conotoxin SmIIIA., Keizer DW, West PJ, Lee EF, Yoshikami D, Olivera BM, Bulaj G, Norton RS, J Biol Chem. 2003 Nov 21;278(47):46805-13. Epub 2003 Sep 10. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=12970353 12970353]
| + | </div> |
| - | [[Category: Protein complex]] | + | <div class="pdbe-citations 1q2j" style="background-color:#fffaf0;"></div> |
| - | [[Category: Bulaj, G.]] | + | == References == |
| - | [[Category: Keizer, D.W.]] | + | <references/> |
| - | [[Category: Lee, E.F.]] | + | __TOC__ |
| - | [[Category: Norton, R.S.]] | + | </StructureSection> |
| - | [[Category: Olivera, B.M.]] | + | [[Category: Conus stercusmuscarum]] |
| - | [[Category: West, P.J.]] | + | [[Category: Large Structures]] |
| - | [[Category: Yoshikami, D.]] | + | [[Category: Bulaj G]] |
| - | [[Category: mu-conotoxin]]
| + | [[Category: Keizer DW]] |
| - | | + | [[Category: Lee EF]] |
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Sun Nov 25 03:27:29 2007''
| + | [[Category: Norton RS]] |
| | + | [[Category: Olivera BM]] |
| | + | [[Category: West PJ]] |
| | + | [[Category: Yoshikami D]] |
| Structural highlights
Function
CM3A_CONSE Mu-conotoxins block voltage-gated sodium channels (Nav). This toxin blocks rNav1.5/SCN5A (IC(50) is 1.3 uM), rNav1.6/SCN8A (IC(50) is 160 nM), rNav1.7/SCN9A (IC(50) is 1.3 uM), rNav1.1/SCN1A (K(d) is 3.8 nM), rNav1.2/SCN2A (K(d) is 1.3 nM), rNav1.4/SCN4A (K(d) is 0.22 nM), rNav1.6/SCN8A (K(d) is 69 nM), and rNav1.7/SCN9A (K(d) is 260 nM). This toxin is very potent but weakly discriminating among sodium channels. The block of these channels is modified when beta-subunits are coexpressed with alpha subunits. Hence, blocks of channels containing beta-1 and beta-3 subunits are more potent (compared to channels without beta subunits), whereas blocks of channels containing beta-2 and beta-4 subunits are less potent (compared to channels without beta subunits).[1] [2] [3] [4]
Publication Abstract from PubMed
SmIIIA is a new micro-conotoxin isolated recently from Conus stercusmuscarum. Although it shares several biochemical characteristics with other micro-conotoxins (the arrangement of cysteine residues and a conserved arginine believed to interact with residues near the channel pore), it has several distinctive features, including the absence of hydroxyproline, and is the first specific antagonist of tetrodotoxin-resistant voltage-gated sodium channels to be characterized. It therefore represents a potentially useful tool to investigate the functional roles of these channels. We have determined the three-dimensional structure of SmIIIA in aqueous solution. Consistent with the absence of hydroxyprolines, SmIIIA adopts a single conformation with all peptide bonds in the trans configuration. The spatial orientations of several conserved Arg and Lys side chains, including Arg14 (using a consensus numbering system), which plays a key role in sodium channel binding, are similar to those in other micro-conotoxins but the N-terminal regions differ, reflecting the trans conformation for the peptide bond preceding residue 8 in SmIIIA, as opposed to the cis conformation in micro-conotoxins GIIIA and GIIIB. Comparison of the surfaces of SmIIIA with other micro-conotoxins suggests that the affinity of SmIIIA for TTX-resistant channels is influenced by the Trp15 side chain, which is unique to SmIIIA. Arg17, which replaces Lys in the other micro-conotoxins, may also be important. Consistent with these inferences from the structure, assays of two chimeras of SmIIIA and PIIIA in which their N- and C-terminal halves were recombined, indicated that residues in the C-terminal half of SmIIIA confer affinity for tetrodotoxin-resistant sodium channels in the cell bodies of frog sympathetic neurons. SmIIIA and the chimera possessing the C-terminal half of SmIIIA also inhibit tetrodotoxin-resistant sodium channels in the postganglionic axons of sympathetic neurons, as indicated by their inhibition of C-neuron compound action potentials that persist in the presence of tetrodotoxin.
Structural basis for tetrodotoxin-resistant sodium channel binding by mu-conotoxin SmIIIA.,Keizer DW, West PJ, Lee EF, Yoshikami D, Olivera BM, Bulaj G, Norton RS J Biol Chem. 2003 Nov 21;278(47):46805-13. Epub 2003 Sep 10. PMID:12970353[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ West PJ, Bulaj G, Garrett JE, Olivera BM, Yoshikami D. Mu-conotoxin SmIIIA, a potent inhibitor of tetrodotoxin-resistant sodium channels in amphibian sympathetic and sensory neurons. Biochemistry. 2002 Dec 24;41(51):15388-93. doi: 10.1021/bi0265628. PMID:12484778 doi:http://dx.doi.org/10.1021/bi0265628
- ↑ Wilson MJ, Yoshikami D, Azam L, Gajewiak J, Olivera BM, Bulaj G, Zhang MM. mu-Conotoxins that differentially block sodium channels NaV1.1 through 1.8 identify those responsible for action potentials in sciatic nerve. Proc Natl Acad Sci U S A. 2011 Jun 21;108(25):10302-7. doi:, 10.1073/pnas.1107027108. Epub 2011 Jun 7. PMID:21652775 doi:http://dx.doi.org/10.1073/pnas.1107027108
- ↑ Favreau P, Benoit E, Hocking HG, Carlier L, D'hoedt D, Leipold E, Markgraf R, Schlumberger S, Cordova MA, Gaertner H, Paolini-Bertrand M, Hartley O, Tytgat J, Heinemann SH, Bertrand D, Boelens R, Stocklin R, Molgo J. Pharmacological characterization of a novel mu-conopeptide, CnIIIC, indicates potent and preferential inhibition of sodium channel subtypes (Na(V) 1.2/1.4) and reveals unusual activity on neuronal nicotinic acetylcholine receptors. Br J Pharmacol. 2012 Jan 9. doi: 10.1111/j.1476-5381.2012.01837.x. PMID:22229737 doi:10.1111/j.1476-5381.2012.01837.x
- ↑ Zhang MM, Wilson MJ, Azam L, Gajewiak J, Rivier JE, Bulaj G, Olivera BM, Yoshikami D. Co-expression of Na(V)beta subunits alters the kinetics of inhibition of voltage-gated sodium channels by pore-blocking mu-conotoxins. Br J Pharmacol. 2013 Apr;168(7):1597-610. doi: 10.1111/bph.12051. PMID:23146020 doi:http://dx.doi.org/10.1111/bph.12051
- ↑ Keizer DW, West PJ, Lee EF, Yoshikami D, Olivera BM, Bulaj G, Norton RS. Structural basis for tetrodotoxin-resistant sodium channel binding by mu-conotoxin SmIIIA. J Biol Chem. 2003 Nov 21;278(47):46805-13. Epub 2003 Sep 10. PMID:12970353 doi:http://dx.doi.org/10.1074/jbc.M309222200
|
