View source for 1ont


==NMDA RECEPTOR ANTAGONIST, CONANTOKIN-T, NMR, 17 STRUCTURES==
<StructureSection load='1ont' size='340' side='right'caption='[[1ont]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1ont]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Conus_tulipa Conus tulipa]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1ONT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1ONT FirstGlance]. <br>
</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='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CGU:GAMMA-CARBOXY-GLUTAMIC+ACID'>CGU</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=1ont FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1ont OCA], [https://pdbe.org/1ont PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1ont RCSB], [https://www.ebi.ac.uk/pdbsum/1ont PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1ont ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CKT_CONTU CKT_CONTU] Conantokins inhibit N-methyl-D-aspartate (NMDA) receptors. This toxin inhibits both NR2A and NR2B subunits of N-methyl-D-aspartate (NMDA) receptor-mediated calcium influx in central nervous system neurons. Induces sleep-like symptoms in young mice and hyperactivity in older mice.<ref>PMID:2165278</ref> 
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== Publication Abstract from PubMed ==
Conantokin-G and conantokin-T are two paralytic polypeptide toxins originally isolated from the venom of the fish-hunting cone snails of the genus Conus. Conantokin-G and conantokin-T are the only naturally occurring peptidic compounds which possess N-methyl-D-aspartate receptor antagonist activity, produced by a selective non-competitive antagonism of polyamine responses. They are also structurally unusual in that they contain a disproportionately large number of acid labile post-translational gamma-carboxyglutamic acid (Gla) residues. Although no precise structural information has previously been published for these peptides, early spectroscopic measurements have indicated that both conantokin-G and conantokin-T form alpha-helical structures, although there is some debate whether the presence of calcium ions is required for these peptides to adopt this fold. We now report a detailed structural study of synthetic conantokin-G and conantokin-T in a range of solution conditions using CD and 1H NMR spectroscopy. The three-dimensional structures of conantokin-T and conantokin-G were calculated from 1H NMR-derived distance and dihedral restraints. Both conantokins were found to contain a mixture of alpha- and 310 helix, that give rise to curved and straight helical conformers. Conantokin-G requires the presence of divalent cations (Zn2+, Ca2+, Cu2+, or Mg2+) to form a stable alpha-helix, while conantokin-T adopts a stable alpha-helical structure in aqueous conditions, in the presence or absence of divalent cations (Zn2+, Ca2+, Cu2+, or Mg2+).

Determination of the solution structures of conantokin-G and conantokin-T by CD and NMR spectroscopy.,Skjaerbaek N, Nielsen KJ, Lewis RJ, Alewood P, Craik DJ J Biol Chem. 1997 Jan 24;272(4):2291-9. PMID:8999936<ref>PMID:8999936</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Conus tulipa]]
[[Category: Large Structures]]
[[Category: Alewood PF]]
[[Category: Craik DJ]]
[[Category: Lewis RJ]]
[[Category: Nielsen KJ]]
[[Category: Skjaerbaek N]]