PDBsum entry 1jwd

Metal binding protein

PDB id: 1jwd

Contents

Protein chains

90 a.a. *

* Residue conservation analysis

PDB id:

1jwd

Name:

Metal binding protein

Title:

Ca2+-induced structural changes in calcyclin: high-resolution solution structure of ca2+-bound calcyclin.

Structure:

Calcyclin. Chain: a, b. Synonym: lung 10 kda protein. Engineered: yes

Source:

Oryctolagus cuniculus. Rabbit. Organism_taxid: 9986. Organ: lung. Gene: r-s100a6. Expressed in: escherichia coli. Expression_system_taxid: 562.

NMR struc:

22 models

Authors:

L.Maler,M.Sastry,W.J.Chazin

Key ref:

L.Mäler et al. (2002). A structural basis for S100 protein specificity derived from comparative analysis of apo and Ca(2+)-calcyclin. J Mol Biol, 317, 279-290. PubMed id: 11902843 DOI: 10.1006/jmbi.2002.5421

Date:

04-Sep-01 Release date: 27-Mar-02

Protein chains

P30801  (S10A6_RABIT) -  Protein S100-A6 from Oryctolagus cuniculus

Seq: 90 a.a.

Struc: 90 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1006/jmbi.2002.5421

J Mol Biol 317:279-290 (2002)

PubMed id: 11902843

A structural basis for S100 protein specificity derived from comparative analysis of apo and Ca(2+)-calcyclin.

L.Mäler, M.Sastry, W.J.Chazin.

ABSTRACT

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.

Selected figure(s)

Figure 3.
Figure 3. Ca 2+ -induced changes in the side-chain packing of calcyclin. Overlay of the ensemble of apo and Ca 2+ -bound calcyclin structures showing side- chains involved in the interfaces between (a) helices I and IV and (b) helices III and IV. The apo protein is blue and the Ca 2+ -bound state is red.

Figure 4.
Figure 4. Comparison of the Ca 2+ -induced structural changes in calcyclin and S100B, and the N-terminal domain of calmodulin. Apo structures are shown in blue and Ca 2+ -loaded structures in red. Superpositions were made using all backbone atoms. The left-hand panel shows the changes in the N-terminal EF-hand and the right-hand panel shows the changes in the C-term- inal EF-hand of (a) calcyclin, (b) S100B, and (c) calmodu- lin.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2002, 317, 279-290) copyright 2002.

Figures were selected by the author.

Author's comment

This high resolution solution structure supersedes the previous lower resolution structure described in PDB code 1cnp (Nat. Struct. Biol., 2, 790-796 (1995), PubMed id: 7552751) .