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.
1iaz
From Proteopedia
(New page: 200px<br /><applet load="1iaz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1iaz, resolution 1.9Å" /> '''EQUINATOXIN II'''<br ...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1iaz.gif|left|200px]]<br /><applet load="1iaz" size=" | + | [[Image:1iaz.gif|left|200px]]<br /><applet load="1iaz" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1iaz, resolution 1.9Å" /> | caption="1iaz, resolution 1.9Å" /> | ||
'''EQUINATOXIN II'''<br /> | '''EQUINATOXIN II'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Membrane pore-forming toxins have a remarkable property: they | + | 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== | ==About this Structure== | ||
| - | 1IAZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Actinia_equina Actinia equina] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1IAZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Actinia_equina Actinia equina] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IAZ OCA]. |
==Reference== | ==Reference== | ||
| Line 20: | Line 20: | ||
[[Category: beta-sandwich]] | [[Category: beta-sandwich]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:09:52 2008'' |
Revision as of 11:09, 21 February 2008
|
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 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 Thu Feb 21 13:09:52 2008
