1cnn | pdb_00001cnn

OMEGA-CONOTOXIN MVIIC FROM CONUS MAGUS

spinqualitylabelsall models 1cnn Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1cnn is a 1 chain structure with sequence from Conus magus. 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 O17C_CONMA Omega-conotoxins act at presynaptic membranes, they bind and block voltage-gated calcium channels (Cav). This toxin preferentially blocks P/Q-type calcium channels (Cav2.1/CACNA1A) (IC(50)=0.60 nM) (PubMed:1352986, PubMed:10938268). Shows also an inhibition on Cav2.2/CACNA1A channels (IC(50)=7.0 nM) (PubMed:10938268). Publication Abstract from PubMed The omega-conotoxins are a set of structurally related, four-loop, six cysteine containing peptides, that have a range of selectivities for different subtypes of the voltage-sensitive calcium channel (VSCC). To investigate the basis of the selectivity displayed by these peptides, we have studied the binding affinities of two naturally occurring omega-conotoxins, MVIIA and MVIIC and a series of 14 MVIIA/MVIIC loop hybrids using radioligand binding assays for N and P/Q-type Ca2+channels in rat brain tissue. A selectivity profile was developed from the ratio of relative potencies at N-type VSCCs (using [125I]GVIA radioligand binding assays) and P/Q-type VSCCs (using [125I]MVIIC radioligand binding assays). In these peptides, loops 2 and 4 make the greatest contribution to VSCC subtype selectivity, while the effects of loops 1 and 3 are negligible. Peptides with homogenous combinations of loop 2 and 4 display clear selectivity preferences, while those with heterogeneous combinations of loops 2 and 4 are less discriminatory. 1H NMR spectroscopy revealed that the global folds of MVIIA, MVIIC and the 14 loop hybrid peptides were similar; however, several differences in local structure were identified. Based on the binding data and the 3D structures of MVIIA, GVIA and MVIIC, we have developed a preliminary pharmacophore based on the omega-conotoxin residues most likely to interact with the N-type VSCC. Structure-activity relationships of omega-conotoxins MVIIA, MVIIC and 14 loop splice hybrids at N and P/Q-type calcium channels.,Nielsen KJ, Adams D, Thomas L, Bond T, Alewood PF, Craik DJ, Lewis RJ J Mol Biol. 1999 Jun 25;289(5):1405-21. PMID:10373375 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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