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 ...) |
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| - | [[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== | ||
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[[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
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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
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