Calmodulin as an Affinity Purification Tag

Calmodulin is a small (148 amino acids, 17 kDa) ubiquitous protein in eukaryotes, and is considered the primary intracellular calcium sensor, making it a key regulator of intracellular signal transduction. Upon calcium binding, calmodulin can interact with a variety of proteins (1 ), mediating effects on gene regulation, DNA synthesis, cell cycle progression, mitosis, cytokinesis, cytoskeletal organization, muscle contraction, and metabolic regulation. Calmodulin is remarkably conserved throughout evolution. Amino acid sequences in multicellular organisms are nearly identical (>90% among mammals, insects and plants). Moreover, the three existing gene copies of calmodulin in humans code for proteins of identical amino acid sequence.