This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1not
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1not" size="450" color="white" frame="true" align="right" spinBox="true" caption="1not, resolution 1.2Å" /> '''THE 1.2 ANGSTROM STRU...)
Next diff →
Revision as of 20:19, 20 November 2007
|
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
