1ywt
From Proteopedia
(New page: 200px<br /> <applet load="1ywt" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ywt, resolution 2.40Å" /> '''Crystal structure o...) |
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| - | [[Image:1ywt.gif|left|200px]]<br /> | + | [[Image:1ywt.gif|left|200px]]<br /><applet load="1ywt" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1ywt" size=" | + | |
caption="1ywt, resolution 2.40Å" /> | caption="1ywt, resolution 2.40Å" /> | ||
'''Crystal structure of the human sigma isoform of 14-3-3 in complex with a mode-1 phosphopeptide'''<br /> | '''Crystal structure of the human sigma isoform of 14-3-3 in complex with a mode-1 phosphopeptide'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The 14-3-3 family of proteins includes seven isotypes in mammalian cells | + | The 14-3-3 family of proteins includes seven isotypes in mammalian cells that play numerous diverse roles in intracellular signaling. Most 14-3-3 proteins form homodimers and mixed heterodimers between different isotypes, with overlapping roles in ligand binding. In contrast, one mammalian isoform, 14-3-3sigma, expressed primarily in epithelial cells, appears to play a unique role in the cellular response to DNA damage and in human oncogenesis. The biological and structural basis for these 14-3-3sigma-specific functions is unknown. We demonstrate that endogenous 14-3-3sigma preferentially forms homodimers in cells. We have solved the x-ray crystal structure of 14-3-3sigma bound to an optimal phosphopeptide ligand at 2.4 angstroms resolution. The structure reveals the presence of stabilizing ring-ring and salt bridge interactions unique to the 14-3-3sigma homodimer structure and potentially destabilizing electrostatic interactions between subunits in 14-3-3sigma-containing heterodimers, rationalizing preferential homodimerization of 14-3-3sigma in vivo. The interaction of the phosphopeptide with 14-3-3 reveals a conserved mechanism for phospho-dependent ligand binding, implying that the phosphopeptide binding cleft is not the critical determinant of the unique biological properties of 14-3-3sigma. Instead, the structure suggests a second ligand binding site involved in 14-3-3sigma-specific ligand discrimination. We have confirmed this by site-directed mutagenesis of three sigma-specific residues that uniquely define this site. Mutation of these residues to the alternative sequence that is absolutely conserved in all other 14-3-3 isotypes confers upon 14-3-3sigma the ability to bind to Cdc25C, a ligand that is known to bind to other 14-3-3 proteins but not to sigma. |
==About this Structure== | ==About this Structure== | ||
| - | 1YWT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | + | 1YWT is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] 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=1YWT OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Artim, S | + | [[Category: Artim, S C.]] |
| - | [[Category: Grant, R | + | [[Category: Grant, R A.]] |
| - | [[Category: Wilker, E | + | [[Category: Wilker, E W.]] |
| - | [[Category: Yaffe, M | + | [[Category: Yaffe, M B.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: 14-3-3]] | [[Category: 14-3-3]] | ||
[[Category: protein-phosphopeptide complex]] | [[Category: protein-phosphopeptide complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:09:55 2008'' |
Revision as of 14:09, 21 February 2008
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Crystal structure of the human sigma isoform of 14-3-3 in complex with a mode-1 phosphopeptide
Overview
The 14-3-3 family of proteins includes seven isotypes in mammalian cells that play numerous diverse roles in intracellular signaling. Most 14-3-3 proteins form homodimers and mixed heterodimers between different isotypes, with overlapping roles in ligand binding. In contrast, one mammalian isoform, 14-3-3sigma, expressed primarily in epithelial cells, appears to play a unique role in the cellular response to DNA damage and in human oncogenesis. The biological and structural basis for these 14-3-3sigma-specific functions is unknown. We demonstrate that endogenous 14-3-3sigma preferentially forms homodimers in cells. We have solved the x-ray crystal structure of 14-3-3sigma bound to an optimal phosphopeptide ligand at 2.4 angstroms resolution. The structure reveals the presence of stabilizing ring-ring and salt bridge interactions unique to the 14-3-3sigma homodimer structure and potentially destabilizing electrostatic interactions between subunits in 14-3-3sigma-containing heterodimers, rationalizing preferential homodimerization of 14-3-3sigma in vivo. The interaction of the phosphopeptide with 14-3-3 reveals a conserved mechanism for phospho-dependent ligand binding, implying that the phosphopeptide binding cleft is not the critical determinant of the unique biological properties of 14-3-3sigma. Instead, the structure suggests a second ligand binding site involved in 14-3-3sigma-specific ligand discrimination. We have confirmed this by site-directed mutagenesis of three sigma-specific residues that uniquely define this site. Mutation of these residues to the alternative sequence that is absolutely conserved in all other 14-3-3 isotypes confers upon 14-3-3sigma the ability to bind to Cdc25C, a ligand that is known to bind to other 14-3-3 proteins but not to sigma.
About this Structure
1YWT is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.
Reference
A structural basis for 14-3-3sigma functional specificity., Wilker EW, Grant RA, Artim SC, Yaffe MB, J Biol Chem. 2005 May 13;280(19):18891-8. Epub 2005 Feb 24. PMID:15731107
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