Calmodulin

Calmodulin is a Ca²⁺-binding protein that is a key component of the Ca²⁺ second-messenger system and is involved in the regulation of many biochemical and physiological processes.

Calmodulin is a small, acidic protein approximately 148 amino acids long and, as such, is a favorite for testing protein simulation software. It contains four EF-hand domains, each of which binds a Ca²⁺ ion. It typically binds 0, 2, or 4 calcium ions, and binds and regulates different proteins in each state. There are over a hundred proteins known to bind calmodulin. It is highly conserved across all eukaryotes, and its expression is essential for biological cells to progress through mitosis.

Calmodulin-stimulated protein phosphatase (EC 3.1.3.16) is the major calmodulin-binding protein in the brain.

Other calcium-binding proteins

Calmodulin belongs to one of the two main groups of calcium-binding proteins, called EF hand proteins. The other group, called annexins, bind calcium and phospholipid (e.g., lipocortin). Many other proteins bind calcium, although binding calcium may not be considered their principal function in the cell.

External links

http://structbio.vanderbilt.edu/cabp_database/general/prot_pages/calmod.html