Investigations of cyclophilin interactions with oligopeptides containing proline by affinity capillary electrophoresis

Affinity capillary electrophoresis using mobility-shift analysis was utilized to characterize the binding of peptide ligands to cyclophilins, which are members of the enzyme family of peptidyl-prolyl cis/trans isomerases. Peptides derived from the human immunodeficiency virus capsid protein p24 exhibited different affinities to the isoenzymes cyclophilin18 and cyclophilin20. For the interaction of the peptide hormone bradykinin with cyclophilin18, a dissociation constant of 1.4±0.1 mM was determined. Finally, the affinity of cyclophilin20 to peptides from a cellulose-bound peptide library scanning the sequence of Drosophila melanogaster protein cappuccino was investigated. The affinities of selected peptides to cyclophilin20 and a green fluorescent fusion protein with cyclophilin20 were compared.