A deletion peptide of melittin and its analogs, Mel15, Mel15(8F) and Mel15(7P), were designed and synthesized. These peptides have very strong affinities for calmodulin, but they have short chains. Therefore they are good model peptides for the binding site of calmodulin-binding proteins. The interactions of calmodulin with them have been studied through spectral methods. The fluorescence emission spectra showed that the environment of Trp residue in Mel15 becomes more hydrophobic when Mel15 interacts with calmodulin, indicating that the Trp residue is close to the hydrophobic surface of calmodulin. The UV absorption difference spectra showed that calmodulin begins to bind Mel15(8F) after calmodulin binds 2 Ca^2^+ ions. The CD spectra showed that the binding of calmodulin with the peptides induces the increase of α-helical content. The stronger is the binding, the more residues are induced to form α-helices.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, POLYPEPTIDE, FLUOROSPECTROPHOTOMETRY, INTERACTIONS, SPECTROMETRY, CALMODULIN