1ont
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NMDA RECEPTOR ANTAGONIST, CONANTOKIN-T, NMR, 17 STRUCTURES
OverviewOverview
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+).
About this StructureAbout this Structure
1ONT is a Single protein structure of sequence from Conus tulipa with NH2 as ligand. Full crystallographic information is available from OCA.
ReferenceReference
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
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