Abstract: The interactions of the buckwheat pollen peptide and its analogues with dansyl labeled calmodulin(D-CaM) were studied in the presence of Ca²⁺. All peptides except BP-1 can associate with D-CaM to form complexes peptide-calmodulin. The dissociation constants K_dfor the complexes were determined using the fluorescence spectra. Among the tested peptides, BP-13 showed a stronger inhibitory effect on CaM, with IC₅₀of 2.2 μmol/Land K_dof 4.6×10^-2μmol/L. The effects of the hydrophobicity and the behavior being predicated to have a higher α-helical propensities on their affinities were further studied. We have found that D-alanine substitution in BP-1 results in affinity enhancement. The result will be helpful to improving our ability to design peptides possessing anticalmodulin activity.

Key words: Pollen peptide, Calmodulin, Calmodulin antagonist