Calmodulin (CAM)
entry list
alignment
Calmodulin (CAM) is inferred to be encoded in all eukaryotes and
expressed in most cells. In its four calcium form it activates over
twenty target enzymes or structural proteins [6]. Pairs of domains 1&2
are connected to lobe 3-4 by an eight residues linker. Helix F2, the
linker, and helix E3 form a seven turn _-helix. The linker serves as a
flexible tether. In the apo-form both lobes are in the closed
conformation and the tether is extended; CAM is then dumbbell shaped.
In the Ca4-form the tether is bent, both lobes are in an open
conformation, and the two lobes enfold a helix of the target protein
[7]. The ten subfamilies (CAM, TNC, ELC, RLC TPNV, CLAT, SQUD, CDC,
CAL, and CAST) are congruent (figure 5).