1b45

ALPHA-CNIA CONOTOXIN FROM CONUS CONSORS, NMR, 43 STRUCTURES

spinqualitylabelsall models 1b45 Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1b45 is a 1 chain structure with sequence from Conus consors. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, 43 models Ligands: NH2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CA1A_CONCN Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. CnIA and CnIB block muscular nAChR alpha-1/gamma and alpha-1/delta subunits. Publication Abstract from PubMed Two novel alpha-conotoxins were purified and characterized from the venom of the fish-hunting cone snail Conus consors. These peptides were identified by screening HPLC fractions of the crude venom and by binding experiments with Torpedo nicotinic acetylcholine receptor. The toxins named alpha-CnIA and alpha-CnIB exhibited sequences of 14 and 12 amino acids, respectively. The alpha-CnIA represents the main alpha-conotoxin contained in the venom, whereas alpha-CnIB is present in a relatively small amount. Chemical synthesis of alpha-CnIA was carried out using the Fmoc methodology by selective disulfide bond formation. The biological activity of the toxin was assessed in fish and mice. The alpha-CnIA inhibited the fixation of iodinated alpha-bungarotoxin to Torpedo nicotinic acetylcholine receptors with an IC50 of 0.19 microM which can be compared to the IC50 of 0.31 microM found for the previously characterized alpha-MI isolated from the piscivorous Conus magus. The synthetic alpha-CnIA blocked spontaneous and evoked synaptic potentials in frog and mouse isolated neuromuscular preparations at sub-micromolar concentrations. Solution NMR of this toxin indicated a conformational heterogeneity with the existence of different conformers in solution, at slow and intermediate exchange rates relative to the NMR chemical shift time scale, similar to that reported for alpha-GI and alpha-MI. NMR structures were calculated for the major NMR signals representing more than 80% of the population at 5 degrees C. Biochemical characterization and nuclear magnetic resonance structure of novel alpha-conotoxins isolated from the venom of Conus consors.,Favreau P, Krimm I, Le Gall F, Bobenrieth MJ, Lamthanh H, Bouet F, Servent D, Molgo J, Menez A, Letourneux Y, Lancelin JM Biochemistry. 1999 May 11;38(19):6317-26. PMID:10320362 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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