Calcium-free Calmodulin

Calcium-free Calmodulin

General Information

Calmodulin is a molecule that has been studied extensively in its functions within the cell, and has an important role in relaying Ca2+ signals within the cytosol. ^[1] It does this by binding to Ca2+, undergoing a conformational change, and may interact with various proteins within the cell.^[1][2][3] Once bound to a target protein, it undergoes a further conformational change and may activate certain systems. For example, there is a Ca2+ pump in the plasma membrane pump that is activated by the binding of Ca2+-bound calmodulin, and then uses ATP to drive the Ca2+ out of the cell. ^[4]

Calcium-bound Calmodulin

The structure of calcium-bound calmodulin had previously been discovered using x-ray crystallography ^[3]. It was then theorized that knowledge of the structure of calcium-free calmodulin would give greater insight into the function of the protein. Attempts were made to crystallize the calcium-free (or apo) form,

spinqualitylabelsall models PDB ID 1cfc Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
1cfc, 25 NMR models ()
Related:	1cfd
Structural annotation: Resources: CATH : 1Cfc000 InterPro : Ipr001125, Ipr002048, Ipr011992 Pfam : PF00036 SCOP : d1cfc__ UniProt : P62155
Functional annotation: Molecular function: protein binding calcium ion binding
Evolutionary conservation: Toggle Conservation Colors: Rows = identical sequences: Further Information: Caveats, Explanation, Complete Results at ConSurfDB
Resources:	FirstGlance, OCA, RCSB, PDBsum
Coordinates:	save as pdb, mmCIF, xml

References

1. ↑ ^{1.0 1.1} Hoeflich, K.P., & Ikura, M.. Calmodulin in action: diversity in target recognition and activation mechanisms, Cell. 2002 108:739-742
2. ↑ Kuboniwa H, Tjandra N, Grzesiek S, Ren H, Klee CB, Bax A. Solution structure of calcium-free calmodulin. Nat Struct Biol. 1995 Sep;2(9):768-76. PMID:7552748
3. ↑ ^{3.0 3.1} Babu YS, Bugg CE, Cook WJ. Structure of calmodulin refined at 2.2 A resolution. J Mol Biol. 1988 Nov 5;204(1):191-204. PMID:3145979
4. ↑ Berridge MJ, Bootman MD, Roderick HL. Calcium signalling: dynamics, homeostasis and remodelling. Nat Rev Mol Cell Biol. 2003 Jul;4(7):517-29. PMID:12838335 doi:10.1038/nrm1155

• Babu YS, Bugg CE, Cook WJ. Structure of calmodulin refined at 2.2 A resolution. J Mol Biol. 1988 Nov 5;204(1):191-204. PMID:3145979

• Kuboniwa H, Tjandra N, Grzesiek S, Ren H, Klee CB, Bax A. Solution structure of calcium-free calmodulin. Nat Struct Biol. 1995 Sep;2(9):768-76. PMID:7552748