Download MendeleyCrystal 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.(2001) Structure 9: 341-346
- PubMed: 11525171 Search on PubMed
- DOI: https://doi.org/10.1016/s0969-2126(01)00592-5
- Primary Citation Related Structures:
1IAZ - PubMed Abstract:
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. 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. 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.
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Ljubljana, Slovenia.
Organizational Affiliation:
