1vcl
From Proteopedia
(New page: 200px<br /><applet load="1vcl" size="450" color="white" frame="true" align="right" spinBox="true" caption="1vcl, resolution 1.70Å" /> '''Crystal Structure of...) |
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| - | [[Image:1vcl.gif|left|200px]]<br /><applet load="1vcl" size=" | + | [[Image:1vcl.gif|left|200px]]<br /><applet load="1vcl" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1vcl, resolution 1.70Å" /> | caption="1vcl, resolution 1.70Å" /> | ||
'''Crystal Structure of Hemolytic Lectin CEL-III'''<br /> | '''Crystal Structure of Hemolytic Lectin CEL-III'''<br /> | ||
==Overview== | ==Overview== | ||
| - | CEL-III is a Ca(2+)-dependent and galactose-specific lectin purified from | + | CEL-III is a Ca(2+)-dependent and galactose-specific lectin purified from the sea cucumber, Cucumaria echinata, which exhibits hemolytic and hemagglutinating activities. Six molecules of CEL-III are assumed to oligomerize to form an ion-permeable pore in the cell membrane. We have determined the crystal structure of CELIII by using single isomorphous replacement aided by anomalous scattering in lead at 1.7 A resolution. CEL-III consists of three distinct domains as follows: the N-terminal two carbohydrate-binding domains (1 and 2), which adopt beta-trefoil folds such as the B-chain of ricin and are members of the (QXW)(3) motif family; and domain 3, which is a novel fold composed of two alpha-helices and one beta-sandwich. CEL-III is the first Ca(2+)-dependent lectin structure with two beta-trefoil folds. Despite sharing the structure of the B-chain of ricin, CEL-III binds five Ca(2+) ions at five of the six subdomains in both domains 1 and 2. Considering the relatively high similarity among the five subdomains, they are putative binding sites for galactose-related carbohydrates, although it remains to be elucidated whether bound Ca(2+) is directly involved in interaction with carbohydrates. The paucity of hydrophobic interactions in the interfaces between the domains and biochemical data suggest that these domains rearrange upon carbohydrate binding in the erythrocyte membrane. This conformational change may be responsible for oligomerization of CEL-III molecules and hemolysis in the erythrocyte membranes. |
==About this Structure== | ==About this Structure== | ||
| - | 1VCL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Cucumaria_echinata Cucumaria echinata] with CA, MG, CL and BTB as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1VCL is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Cucumaria_echinata Cucumaria echinata] with <scene name='pdbligand=CA:'>CA</scene>, <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=CL:'>CL</scene> and <scene name='pdbligand=BTB:'>BTB</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1VCL OCA]. |
==Reference== | ==Reference== | ||
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[[Category: pore-forming]] | [[Category: pore-forming]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:33:52 2008'' |
Revision as of 13:33, 21 February 2008
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Crystal Structure of Hemolytic Lectin CEL-III
Overview
CEL-III is a Ca(2+)-dependent and galactose-specific lectin purified from the sea cucumber, Cucumaria echinata, which exhibits hemolytic and hemagglutinating activities. Six molecules of CEL-III are assumed to oligomerize to form an ion-permeable pore in the cell membrane. We have determined the crystal structure of CELIII by using single isomorphous replacement aided by anomalous scattering in lead at 1.7 A resolution. CEL-III consists of three distinct domains as follows: the N-terminal two carbohydrate-binding domains (1 and 2), which adopt beta-trefoil folds such as the B-chain of ricin and are members of the (QXW)(3) motif family; and domain 3, which is a novel fold composed of two alpha-helices and one beta-sandwich. CEL-III is the first Ca(2+)-dependent lectin structure with two beta-trefoil folds. Despite sharing the structure of the B-chain of ricin, CEL-III binds five Ca(2+) ions at five of the six subdomains in both domains 1 and 2. Considering the relatively high similarity among the five subdomains, they are putative binding sites for galactose-related carbohydrates, although it remains to be elucidated whether bound Ca(2+) is directly involved in interaction with carbohydrates. The paucity of hydrophobic interactions in the interfaces between the domains and biochemical data suggest that these domains rearrange upon carbohydrate binding in the erythrocyte membrane. This conformational change may be responsible for oligomerization of CEL-III molecules and hemolysis in the erythrocyte membranes.
About this Structure
1VCL is a Single protein structure of sequence from Cucumaria echinata with , , and as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of the hemolytic lectin CEL-III isolated from the marine invertebrate Cucumaria echinata: implications of domain structure for its membrane pore-formation mechanism., Uchida T, Yamasaki T, Eto S, Sugawara H, Kurisu G, Nakagawa A, Kusunoki M, Hatakeyama T, J Biol Chem. 2004 Aug 27;279(35):37133-41. Epub 2004 Jun 11. PMID:15194688
Page seeded by OCA on Thu Feb 21 15:33:52 2008
Categories: Cucumaria echinata | Single protein | Eto, S. | Hatakeyama, T. | Kurisu, G. | Kusunoki, M. | Nakagawa, A. | Sugawara, H. | Uchida, T. | Yamasaki, T. | BTB | CA | CL | MG | Calcium | Cel-iii | Hemagglutination | Hemolysis | Lectin | Pore-forming
