EF-hand: Helix-loop-helix motif obeying a 29-residue consensus sequence with hydrophobic and Ca2+-ligating residues in defined positions, typically forming a pentagonal bipyramidal coordination sphere
Ca2+-signaling proteins: Proteins for which Ca2+ binding preferentially stabilizes a form that activates other proteins
Domain: Independent folding unit
Chromophoric chelator: A metal-binding dye which changes its optical spectrum upon chelation
The discovery of calmodulin (CaM) was reported in 1970 independently by Cheung and by Kakiuchi, Yamazaki, and Nakajima. They found that cyclic nucleotide phosphodiesterase was modulated by a Ca2+-dependent activator protein, which was named calmodulin for calcium-modulated protein.
CaM is a 17-kDa protein ubiquitously expressed in eukaryotic cells constituting at least 0.1% of total cellular protein, with higher abundance in brain and...