This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1b8l
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1b8l" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b8l, resolution 1.70Å" /> '''Calcium-bound D51A/E...)
Next diff →
Revision as of 09:20, 20 November 2007
|
Calcium-bound D51A/E101D/F102W Triple Mutant of Beta Carp Parvalbumin
Overview
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
1B8L is a Single protein structure of sequence from Cyprinus carpio with CO3 and CA as ligands. Full crystallographic information is available from OCA.
Reference
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 Tue Nov 20 11:27:15 2007
