1iaz

From Proteopedia

EQUINATOXIN II

Overview

BACKGROUND: Membrane pore-forming toxins have a remarkable property: they, adopt a stable soluble form structure, which, when in contact with a, membrane, undergoes a series of transformations, leading to an active, membrane-bound form. In contrast to bacterial toxins, no structure of a, pore-forming toxin from an eukaryotic organism has been determined so far, an indication that structural studies of equinatoxin II (EqtII) may, unravel a novel mechanism. RESULTS: The crystal structure of the soluble, form of EqtII from the sea anemone Actinia equina has been determined at, 1.9 A resolution. EqtII is shown to be a single-domain protein based on a, 12 strand beta sandwich fold with a hydrophobic core and a pair of alpha, helices, each of which is associated with the face of a beta sheet., CONCLUSIONS: The structure of the 30 N-terminal residues is the largest, segment that can adopt a different structure without disrupting the fold, of the beta sandwich core. This segment includes a three-turn alpha helix, that lies on the surface of a beta sheet and ends in a stretch of three, positively charged residues, Lys-30, Arg-31, and Lys-32. On the basis of, gathered data, it is suggested that this segment forms the membrane pore, whereas the beta sandwich structure remains unaltered and attaches to a, membrane as do other structurally related extrinsic membrane proteins or, their domains. The use of a structural data site-directed mutagenesis, study should reveal the residues involved in membrane pore formation.

About this Structure

1IAZ is a Single protein structure of sequence from Actinia equina with SO4 as ligand. Full crystallographic information is available from OCA.

Reference

Crystal structure of the soluble form of equinatoxin II, a pore-forming toxin from the sea anemone Actinia equina., Athanasiadis A, Anderluh G, Macek P, Turk D, Structure. 2001 Apr 4;9(4):341-6. PMID:11525171

Page seeded by OCA on Tue Nov 20 17:13:47 2007