3RB7 image
Entry Detail
PDB ID:
3RB7
Title:
Crystal structure of CBD12 from CALX1.2
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2011-03-28
Release Date:
2011-11-02
Method Details:
Experimental Method:
Resolution:
2.90 Å
R-Value Free:
0.27
R-Value Work:
0.23
Space Group:
H 3
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Na/Ca exchange protein
Chain IDs:A, B, C (auth: E), D (auth: G)
Chain Length:298
Number of Molecules:4
Biological Source:Drosophila melanogaster
Primary Citation
Structural Basis of the Ca(2+) Inhibitory Mechanism of Drosophila Na(+)/Ca(2+) Exchanger CALX and Its Modification by Alternative Splicing.
Structure 19 1509 1517 (2011)
PMID: 22000518 DOI: 10.1016/j.str.2011.07.008

Abstact

The Na(+)/Ca(2+) exchanger CALX promotes Ca(2+) efflux in Drosophila sensory neuronal cells to facilitate light-mediated Ca(2+) homeostasis. CALX activity is negatively regulated by specific Ca(2+) interaction within its two intracellular Ca(2+) regulatory domains CBD1 and CBD2, yet how the Ca(2+) binding is converted to molecular motion to operate the exchanger is unknown. Here, we report crystal structures of the entire Ca(2+) regulatory domain CBD12 from two alternative splicing isoforms, CALX 1.1 and 1.2, exhibiting distinct regulatory Ca(2+) dependency. The structures show an open V-shaped conformation with four Ca(2+) ions bound on the CBD domain interface, confirmed by LRET analysis. The structures together with Ca(2+)-binding analysis support that the Ca(2+) inhibition of CALX is achieved by interdomain conformational changes induced by Ca(2+) binding at CBD1. The conformational difference between the two isoforms also indicates that alternative splicing adjusts the interdomain orientation angle to modify the Ca(2+) regulatory property of the exchangers.

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Primary Citation of related structures