Figure 1.

Molecular structure of CaM protein. (A) Three-dimensional structure of CaM protein with Ca²⁺ ligands bind to the EF-hands. (B) CaM protein binding to the Ca²⁺ ion in the D-x-D motif. Three water molecules (vertices -X) are present adjacent to the Ca²⁺ ion with strong hydrogen bonding. The molecular structure of CaM protein was elucidated using calmodulin protein 1UP5 as reported by Rupp et al., (1996) [28].