Crystal-structure and biochemical characterization of recombinant human calcyphosine delineates a novel EF-hand-containing protein family.
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Dong H, Li X, Lou Z, Xu X, Su D, Zhou X, Zhou W, Bartlam M, Rao Z
Crystal-structure and biochemical characterization of recombinant human calcyphosine delineates a novel EF-hand-containing protein family.
J Mol Biol. 2008 Nov 14;383(3):455-64. doi: 10.1016/j.jmb.2008.08.048. Epub 2008 Aug 27.
- PubMed ID
- 18775726 [ View in PubMed]
- Abstract
Calcyphosine is an EF-hand protein involved in both Ca(2+)-phosphatidylinositol and cyclic AMP signal cascades, as well as in other cellular functions. The crystal structure of Ca(2+)-loaded calcyphosine was determined up to 2.65 A resolution and reveals a protein containing two pairs of Ca(2+)-binding EF-hand motifs. Calcyphosine shares a highly similar overall topology with calmodulin. However, there are striking differences between EF-hand 4, both N-terminal and C-terminal regions, and interdomain linkers. The C-terminal domain of calcyphosine possesses a large hydrophobic pocket in the presence of calcium ions that might be implicated in ligand binding, while its N-terminal hydrophobic pocket is almost shielded by an additional terminal helix. Calcyphosine is largely monomeric, regardless of the presence of Ca(2+). Differences in structure, oligomeric state in the presence and in the absence of Ca(2+), a highly conserved sequence with low similarity to other proteins, and phylogeny define a new EF-hand-containing family of calcyphosine proteins that extends from arthropods to humans.