1b8c: Difference between revisions
New page: left|200px<br /><applet load="1b8c" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b8c, resolution 2.00Å" /> '''PARVALBUMIN'''<br />... |
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[[Image:1b8c.gif|left|200px]]<br /><applet load="1b8c" size=" | [[Image:1b8c.gif|left|200px]]<br /><applet load="1b8c" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1b8c, resolution 2.00Å" /> | caption="1b8c, resolution 2.00Å" /> | ||
'''PARVALBUMIN'''<br /> | '''PARVALBUMIN'''<br /> | ||
==Overview== | ==Overview== | ||
BACKGROUND: The EF-hand family is a large set of Ca(2+)-binding proteins | BACKGROUND: The EF-hand family is a large set of Ca(2+)-binding proteins that contain characteristic helix-loop-helix binding motifs that are highly conserved in sequence. Members of this family include parvalbumin and many prominent regulatory proteins such as calmodulin and troponin C. EF-hand proteins are involved in a variety of physiological processes including cell-cycle regulation, second messenger production, muscle contraction, microtubule organization and vision. RESULTS: We have determined the structures of parvalbumin mutants designed to explore the role of the last coordinating residue of the Ca(2+)-binding loop. An E101D substitution has been made in the parvalbumin EF site. The substitution decreases the Ca(2+)-binding affinity 100-fold and increases the Mg(2+)-binding affinity 10-fold. Both the Ca(2+)- and Mg(2+)-bound structures have been determined, and a structural basis has been proposed for the metal-ion-binding properties. CONCLUSIONS: The E101D mutation does not affect the Mg(2+) coordination geometry of the binding loop, but it does pull the F helix 1.1 A towards the loop. The E101D-Ca(2+) structure reveals that this mutant cannot obtain the sevenfold coordination preferred by Ca(2+), presumably because of strain limits imposed by tertiary structure. Analysis of these results relative to previously reported structural information supports a model wherein the characteristics of the last coordinating residue and the plasticity of the Ca(2+)-binding loop delimit the allowable geometries for the coordinating sphere. | ||
==About this Structure== | ==About this Structure== | ||
1B8C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Cyprinus_carpio Cyprinus carpio] with MG as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http:// | 1B8C is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Cyprinus_carpio Cyprinus carpio] with <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B8C OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: Cyprinus carpio]] | [[Category: Cyprinus carpio]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Berry, M | [[Category: Berry, M B.]] | ||
[[Category: Cates, M | [[Category: Cates, M S.]] | ||
[[Category: Ho, E | [[Category: Ho, E L.]] | ||
[[Category: Jr., G | [[Category: Jr., G N.Phillips.]] | ||
[[Category: Li, Q.]] | [[Category: Li, Q.]] | ||
[[Category: Potter, J | [[Category: Potter, J D.]] | ||
[[Category: MG]] | [[Category: MG]] | ||
[[Category: calcium binding protein]] | [[Category: calcium binding protein]] | ||
| Line 25: | Line 25: | ||
[[Category: parvalbumin]] | [[Category: parvalbumin]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:52:35 2008'' | ||
Revision as of 12:52, 21 February 2008
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PARVALBUMIN
OverviewOverview
BACKGROUND: The EF-hand family is a large set of Ca(2+)-binding proteins that contain characteristic helix-loop-helix binding motifs that are highly conserved in sequence. Members of this family include parvalbumin and many prominent regulatory proteins such as calmodulin and troponin C. EF-hand proteins are involved in a variety of physiological processes including cell-cycle regulation, second messenger production, muscle contraction, microtubule organization and vision. RESULTS: We have determined the structures of parvalbumin mutants designed to explore the role of the last coordinating residue of the Ca(2+)-binding loop. An E101D substitution has been made in the parvalbumin EF site. The substitution decreases the Ca(2+)-binding affinity 100-fold and increases the Mg(2+)-binding affinity 10-fold. Both the Ca(2+)- and Mg(2+)-bound structures have been determined, and a structural basis has been proposed for the metal-ion-binding properties. CONCLUSIONS: The E101D mutation does not affect the Mg(2+) coordination geometry of the binding loop, but it does pull the F helix 1.1 A towards the loop. The E101D-Ca(2+) structure reveals that this mutant cannot obtain the sevenfold coordination preferred by Ca(2+), presumably because of strain limits imposed by tertiary structure. Analysis of these results relative to previously reported structural information supports a model wherein the characteristics of the last coordinating residue and the plasticity of the Ca(2+)-binding loop delimit the allowable geometries for the coordinating sphere.
About this StructureAbout this Structure
1B8C is a Single protein structure of sequence from Cyprinus carpio with as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Metal-ion affinity and specificity in EF-hand proteins: coordination geometry and domain plasticity in parvalbumin., Cates MS, Berry MB, Ho EL, Li Q, Potter JD, Phillips GN Jr, Structure. 1999 Oct 15;7(10):1269-78. PMID:10545326
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