1b8c: Difference between revisions
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{{STRUCTURE_1b8c| PDB=1b8c | SCENE= }} | |||
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'''PARVALBUMIN''' | '''PARVALBUMIN''' | ||
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[[Category: Li, Q.]] | [[Category: Li, Q.]] | ||
[[Category: Potter, J D.]] | [[Category: Potter, J D.]] | ||
[[Category: | [[Category: Calcium binding protein]] | ||
[[Category: | [[Category: Calcium-binding]] | ||
[[Category: | [[Category: Ef-hand protein]] | ||
[[Category: | [[Category: Parvalbumin]] | ||
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Revision as of 11:11, 2 May 2008
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. 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 Page seeded by OCA on Fri May 2 11:11:48 2008