A predicted structure of calmodulin suggests an electrostatic basis for its function.

Abstract

By using interactive computer graphics, 2 models for calmodulin were constructed based on the structures of 2 functionally and structurally related proteins, intestinal Ca-binding protein and carp parvalbumin. The 2 models were compared and contrasted to the parent proteins with respect to proportion of solvent-exposed hydrophobic residues, solvent-accessible surface area, and side-chain packing. Electrostatic potential surfaces generated for the models suggest a probable binding site for basic amphiphilic .alpha.-helical peptides located between the last E and F helices in the 2nd domain of calmodulin. Both electrostatic and hydrophobic complementarity can contribute to stabilization of a peptide-protein complex in this region.