1jwd
Ca2+-induced Structural Changes in Calcyclin: High-resolution Solution Structure of Ca2+-bound Calcyclin.
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OverviewOverview
Calcyclin is a homodimeric protein belonging to the S100 subfamily of, EF-hand Ca(2+)-binding proteins, which function in Ca(2+) signal, transduction processes. A refined high-resolution solution structure of, Ca(2+)-bound rabbit calcyclin has been determined by heteronuclear, solution NMR. In order to understand the Ca(2+)-induced structural changes, in S100 proteins, in-depth comparative structural analyses were used to, compare the apo and Ca(2+)-bound states of calcyclin, the closely related, S100B, and the prototypical Ca(2+)-sensor protein calmodulin. Upon Ca(2+), binding, the position and orientation of helix III in the second EF-hand, is altered, whereas the rest of the protein, including the dimer, interface, remains virtually unchanged. This Ca(2+)-induced structural, change is much less drastic than the "opening" of the globular EF-hand, domains that occurs in classical Ca(2+) sensors, such as calmodulin. Using, homology models of calcyclin based on S100B, a binding site in calcyclin, has been proposed for the N-terminal domain of annexin XI and the, C-terminal domain of the neuronal calcyclin-binding protein. The, structural basis for the specificity of S100 proteins is discussed in, terms of the variation in sequence of critical contact residues in the, common S100 target-binding site.
About this StructureAbout this Structure
1JWD is a Single protein structure of sequence from Oryctolagus cuniculus. Full crystallographic information is available from OCA.
ReferenceReference
A structural basis for S100 protein specificity derived from comparative analysis of apo and Ca(2+)-calcyclin., Maler L, Sastry M, Chazin WJ, J Mol Biol. 2002 Mar 22;317(2):279-90. PMID:11902843
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