1a0m

1.1 ANGSTROM CRYSTAL STRUCTURE OF A-CONOTOXIN [TYR15]-EPI

spinqualitylabelsall models 1a0m, resolution 1.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1a0m is a 2 chain structure with sequence from Conus episcopatus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.1Å Ligands: NH2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CA1A_CONEP Alpha-conotoxins act on postsynaptic membranes, they bind to the nicotinic acetylcholine receptors (nAChR) and thus inhibit them. This native peptide blocks mammalian nicotinic acetylcholine receptors composed of alpha-3-beta-2/CHRNA3-CHRNB2 and alpha-3-beta-4/CHRNA3-CHRNB4 subunits (PubMed:9624161). Publication Abstract from PubMed Conotoxins are valuable probes of receptors and ion channels because of their small size and highly selective activity. alpha-Conotoxin EpI, a 16-residue peptide from the mollusk-hunting Conus episcopatus, has the amino acid sequence GCCSDPRCNMNNPDY(SO3H)C-NH2 and appears to be an extremely potent and selective inhibitor of the alpha3beta2 and alpha3beta4 neuronal subtypes of the nicotinic acetylcholine receptor (nAChR). The desulfated form of EpI ([Tyr15]EpI) has a potency and selectivity for the nAChR receptor similar to those of EpI. Here we describe the crystal structure of [Tyr15]EpI solved at a resolution of 1.1 A using SnB. The asymmetric unit has a total of 284 non-hydrogen atoms, making this one of the largest structures solved de novo by direct methods. The [Tyr15]EpI structure brings to six the number of alpha-conotoxin structures that have been determined to date. Four of these, [Tyr15]EpI, PnIA, PnIB, and MII, have an alpha4/7 cysteine framework and are selective for the neuronal subtype of the nAChR. The structure of [Tyr15]EpI has the same backbone fold as the other alpha4/7-conotoxin structures, supporting the notion that this conotoxin cysteine framework and spacing give rise to a conserved fold. The surface charge distribution of [Tyr15]EpI is similar to that of PnIA and PnIB but is likely to be different from that of MII, suggesting that [Tyr15]EpI and MII may have different binding modes for the same receptor subtype. The 1.1 A resolution crystal structure of [Tyr15]EpI, a novel alpha-conotoxin from Conus episcopatus, solved by direct methods.,Hu SH, Loughnan M, Miller R, Weeks CM, Blessing RH, Alewood PF, Lewis RJ, Martin JL Biochemistry. 1998 Aug 18;37(33):11425-33. PMID:9708977 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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