1g2g

MINIMAL CONFORMATION OF THE ALPHA-CONOTOXIN IMI FOR THE ALPHA7 NEURONAL NICOTINIC ACETYLCHOLINE RECEPTOR RECOGNITION

spinqualitylabelsall models 1g2g Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1g2g is a 1 chain structure with sequence from Conus imperialis. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR Ligands: NH2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CA1_CONIM Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. This toxin blocks mammalian neuronal nAChRs (alpha-3/beta-2 > alpha-7 > alpha-3/beta-4). Has no effect on nAChRs composed of alpha-2/beta-2, alpha-3/beta-2, alpha-4/beta-2, alpha-2/beta-4, alpha-3/beta-4, or alpha-4/beta-4 subunits. Acts voltage-independently. Is highly active against the neuromuscular receptor in frog. Publication Abstract from PubMed The alpha-ImI conotoxin, a selective potent inhibitor of the mammalian neuronal alpha7 nicotinic acetylcholine receptor (n-AchR), was shown by point mutation or by L-alanine scanning to display two regions essential for bioactivity: the active site Asp5-Pro6-Arg7 in the first loop and Trp10 in the second loop. The deletion of the Cys3,Cys12 disulfide bond in the alpha-ImI scaffold, e.g. peptide II, had no effect on its binding affinity. CD spectra, NMR studies and structure calculations were carried out on the wild type alpha-ImI, the weakest analog (R7A) and peptide II (equipotent to alpha-ImI) in order to point out the conformational differences between these compounds. Then, an attempt to correlate the conformational data and the affinity results was proposed. CD and NMR data were identical for the R7A analog and alpha-ImI, revealing the crucial functional role of the Arg7 side chain. On the other hand, the scaffold of the first loop in peptide II was shown by NMR to represent the minimal conformation for the optimal interaction of the toxin with the neuronal alpha7 n-AchR. Last, the beta-turn forming property of the 6th residue (Pro) in the active site of the alpha-ImI can be correlated with its affinity. Minimal conformation of the alpha-conotoxin ImI for the alpha7 neuronal nicotinic acetylcholine receptor recognition: correlated CD, NMR and binding studies.,Lamthanh H, Jegou-Matheron C, Servent D, Menez A, Lancelin JM FEBS Lett. 1999 Jul 9;454(3):293-8. PMID:10431825 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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