1tzq
From Proteopedia
(New page: 200px<br /><applet load="1tzq" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tzq, resolution 2.3Å" /> '''Crystal structure of ...) |
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| - | [[Image:1tzq.gif|left|200px]]<br /><applet load="1tzq" size=" | + | [[Image:1tzq.gif|left|200px]]<br /><applet load="1tzq" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1tzq, resolution 2.3Å" /> | caption="1tzq, resolution 2.3Å" /> | ||
'''Crystal structure of the equinatoxin II 8-69 double cysteine mutant'''<br /> | '''Crystal structure of the equinatoxin II 8-69 double cysteine mutant'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Actinoporins are eukaryotic pore-forming proteins that create 2-nm pores | + | Actinoporins are eukaryotic pore-forming proteins that create 2-nm pores in natural and model lipid membranes by the self-association of four monomers. The regions that undergo conformational change and form part of the transmembrane pore are currently being defined. It was shown recently that the N-terminal region (residues 10-28) of equinatoxin, an actinoporin from Actinia equina, participates in building of the final pore wall. Assuming that the pore is formed solely by a polypeptide chain, other parts of the toxin should constitute the conductive channel and here we searched for these regions by disulfide scanning mutagenesis. Only double cysteine mutants where the N-terminal segment 1-30 was attached to the beta-sandwich exhibited reduced hemolytic activity upon disulfide formation, showing that other parts of equinatoxin, particularly the beta-sandwich and importantly the C-terminal alpha-helix, do not undergo large conformational rearrangements during the pore formation. The role of the beta-sandwich stability was independently assessed via destabilization of a part of its hydrophobic core by mutations of the buried Trp117. These mutants were considerably less stable than the wild-type but exhibited similar or slightly lower permeabilizing activity. Collectively these results show that a flexible N-terminal region and stable beta-sandwich are pre-requisite for proper pore formation by the actinoporin family. |
==About this Structure== | ==About this Structure== | ||
| - | 1TZQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Actinia_equina Actinia equina]. Full crystallographic information is available from [http:// | + | 1TZQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Actinia_equina Actinia equina]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TZQ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Anderluh, G.]] | [[Category: Anderluh, G.]] | ||
| - | [[Category: Gonzalez-Maas, J | + | [[Category: Gonzalez-Maas, J M.]] |
[[Category: Guncar, G.]] | [[Category: Guncar, G.]] | ||
[[Category: Gutirrez-Aguirre, I.]] | [[Category: Gutirrez-Aguirre, I.]] | ||
[[Category: Hojnik, V.]] | [[Category: Hojnik, V.]] | ||
[[Category: Kristan, K.]] | [[Category: Kristan, K.]] | ||
| - | [[Category: Lakey, J | + | [[Category: Lakey, J H.]] |
[[Category: Podlesek, Z.]] | [[Category: Podlesek, Z.]] | ||
| - | [[Category: Turk, D | + | [[Category: Turk, D A.]] |
[[Category: beta-sandwich]] | [[Category: beta-sandwich]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:19:08 2008'' |
Revision as of 13:19, 21 February 2008
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Crystal structure of the equinatoxin II 8-69 double cysteine mutant
Overview
Actinoporins are eukaryotic pore-forming proteins that create 2-nm pores in natural and model lipid membranes by the self-association of four monomers. The regions that undergo conformational change and form part of the transmembrane pore are currently being defined. It was shown recently that the N-terminal region (residues 10-28) of equinatoxin, an actinoporin from Actinia equina, participates in building of the final pore wall. Assuming that the pore is formed solely by a polypeptide chain, other parts of the toxin should constitute the conductive channel and here we searched for these regions by disulfide scanning mutagenesis. Only double cysteine mutants where the N-terminal segment 1-30 was attached to the beta-sandwich exhibited reduced hemolytic activity upon disulfide formation, showing that other parts of equinatoxin, particularly the beta-sandwich and importantly the C-terminal alpha-helix, do not undergo large conformational rearrangements during the pore formation. The role of the beta-sandwich stability was independently assessed via destabilization of a part of its hydrophobic core by mutations of the buried Trp117. These mutants were considerably less stable than the wild-type but exhibited similar or slightly lower permeabilizing activity. Collectively these results show that a flexible N-terminal region and stable beta-sandwich are pre-requisite for proper pore formation by the actinoporin family.
About this Structure
1TZQ is a Single protein structure of sequence from Actinia equina. Full crystallographic information is available from OCA.
Reference
Pore formation by equinatoxin, a eukaryotic pore-forming toxin, requires a flexible N-terminal region and a stable beta-sandwich., Kristan K, Podlesek Z, Hojnik V, Gutierrez-Aguirre I, Guncar G, Turk D, Gonzalez-Manas JM, Lakey JH, Macek P, Anderluh G, J Biol Chem. 2004 Nov 5;279(45):46509-17. Epub 2004 Aug 20. PMID:15322132
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