1not
From Proteopedia
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THE 1.2 ANGSTROM STRUCTURE OF G1 ALPHA CONOTOXIN
Overview
Predatory marine snails of the genus Conus paralyze their fish prey by, injecting a potent toxin. The alpha-conotoxin GI is a 13-residue peptide, isolated from venom of Conus geographus. It functions by blocking the, postsynaptic nicotinic acetylcholine receptor. After crystallization in, deionized water, the three-dimensional structure of the GI neurotoxin was, determined to 1.2 A resolution by X-ray crystallography. This structure, which can be described as a triangular slab, shows overall similarities to, those derived by NMR, CD, and predictive methods. The principal framework, of the molecule is provided by two disulfide bonds, one linking Cys 2 and, Cys 7 and the other Cys 3 and Cys 13. Opposite ends of the sequence are, drawn together even further by hydrogen bonds between Glu 1 and Cys 13 and, between Cys 2 and Ser 12. Since the C-terminus is amidated, only one, negative charge is present (carboxylate of Glu 1), and this is not, implicated in receptor binding. Two positively charged regions (the, alpha-amino group of Glu 1 and the guanido group of Arg 9) are situated 15, A apart at the corners of the triangular face of the molecule. phi, psi, angles characteristic of a 3(10) helix were observed for residues 5-7. For, residues 8-11, these angles were consistent with either a type I beta-turn, or a distorted 3(10) helix.
About this Structure
1NOT is a Single protein structure of sequence from Conus geographus with NH2 as ligand. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of the alpha-conotoxin GI at 1.2 A resolution., Guddat LW, Martin JA, Shan L, Edmundson AB, Gray WR, Biochemistry. 1996 Sep 3;35(35):11329-35. PMID:8784187
Page seeded by OCA on Tue Nov 20 22:26:30 2007
