1dm5
From Proteopedia
(New page: 200px<br /><applet load="1dm5" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dm5, resolution 1.93Å" /> '''ANNEXIN XII E105K HO...) |
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| - | [[Image:1dm5.gif|left|200px]]<br /><applet load="1dm5" size=" | + | [[Image:1dm5.gif|left|200px]]<br /><applet load="1dm5" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1dm5, resolution 1.93Å" /> | caption="1dm5, resolution 1.93Å" /> | ||
'''ANNEXIN XII E105K HOMOHEXAMER CRYSTAL STRUCTURE'''<br /> | '''ANNEXIN XII E105K HOMOHEXAMER CRYSTAL STRUCTURE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Annexins are a family of calcium- and phospholipid-binding proteins | + | Annexins are a family of calcium- and phospholipid-binding proteins involved with numerous cellular processes including membrane fusion, ion channel activity, and heterocomplex formation with other proteins. The annexin XII (ANXB12) crystal structure presented evidence that calcium mediates the formation of a hexamer through a novel intermolecular calcium-binding site [Luecke et al. (1995) Nature 378, 512-515]. In an attempt to disrupt hexamerization, we mutated a conserved key ligand in the intermolecular calcium-binding site, Glu105, to lysine. Despite its occurrence in a new spacegroup, the 1.93 A resolution structure reveals a hexamer with the Lys105 epsilon-amino group nearly superimposable with the original intermolecular calcium position. Our analysis shows that the mutation is directly involved in stabilizing the hexamer. The local residues are reoriented to retain affinity between the two trimers via a pH-dependent switch residue, Glu76, which is now protonated, allowing it to form tandem hydrogen bonds with the backbone carbonyl and nitrogen atoms of Thr103 located across the trimer interface. The loss of the intermolecular calcium-binding site is recuperated by extensive hydrogen bonding favoring hexamer stabilization. The presence of this mutant structure provides further evidence for hexameric annexin XII, and possible in vivo roles are discussed. |
==About this Structure== | ==About this Structure== | ||
| - | 1DM5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Hydra_vulgaris Hydra vulgaris] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1DM5 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Hydra_vulgaris Hydra vulgaris] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DM5 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Hydra vulgaris]] | [[Category: Hydra vulgaris]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Cartailler, J | + | [[Category: Cartailler, J P.]] |
| - | [[Category: Haigler, H | + | [[Category: Haigler, H T.]] |
[[Category: Luecke, H.]] | [[Category: Luecke, H.]] | ||
[[Category: CA]] | [[Category: CA]] | ||
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[[Category: novel ph-dependent hexamerization switch e76]] | [[Category: novel ph-dependent hexamerization switch e76]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:18:03 2008'' |
Revision as of 10:18, 21 February 2008
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ANNEXIN XII E105K HOMOHEXAMER CRYSTAL STRUCTURE
Overview
Annexins are a family of calcium- and phospholipid-binding proteins involved with numerous cellular processes including membrane fusion, ion channel activity, and heterocomplex formation with other proteins. The annexin XII (ANXB12) crystal structure presented evidence that calcium mediates the formation of a hexamer through a novel intermolecular calcium-binding site [Luecke et al. (1995) Nature 378, 512-515]. In an attempt to disrupt hexamerization, we mutated a conserved key ligand in the intermolecular calcium-binding site, Glu105, to lysine. Despite its occurrence in a new spacegroup, the 1.93 A resolution structure reveals a hexamer with the Lys105 epsilon-amino group nearly superimposable with the original intermolecular calcium position. Our analysis shows that the mutation is directly involved in stabilizing the hexamer. The local residues are reoriented to retain affinity between the two trimers via a pH-dependent switch residue, Glu76, which is now protonated, allowing it to form tandem hydrogen bonds with the backbone carbonyl and nitrogen atoms of Thr103 located across the trimer interface. The loss of the intermolecular calcium-binding site is recuperated by extensive hydrogen bonding favoring hexamer stabilization. The presence of this mutant structure provides further evidence for hexameric annexin XII, and possible in vivo roles are discussed.
About this Structure
1DM5 is a Single protein structure of sequence from Hydra vulgaris with as ligand. Full crystallographic information is available from OCA.
Reference
Annexin XII E105K crystal structure: identification of a pH-dependent switch for mutant hexamerization., Cartailler JP, Haigler HT, Luecke H, Biochemistry. 2000 Mar 14;39(10):2475-83. PMID:10704197
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