1jwd
From Proteopedia
Ca2+-induced Structural Changes in Calcyclin: High-resolution Solution Structure of Ca2+-bound Calcyclin.
Overview
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 Structure
1JWD is a Single protein structure of sequence from Oryctolagus cuniculus. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Fri May 2 22:00:24 2008
