New Copper(II) Complexes of Peptides: DNA Binding and Photocleavage Studies

Abstract

Peptides were synthesized by the reaction of Fmoc-amino acid chloride and aminoacid ester hydrochloride in DCM. The obtained peptide ligands were characterized by elemental analysis, NMR, IR and mass spectra. Three copper complexes of peptides Fmoc.Ala-val-OH (F-AVOH), Fmoc-Phe-Leu-Ome (F-PLOMe) and Z-Ala-Phe-CO-NH2 (Z-APCONH2) and have been synthesized and characterized by elemental analysis, IR and mass spectral data. The IR spectral results shows that the –NH group of peptides chain involved in bonding with metal ion. The binding of the complexes with calf thymus DNA have been investigated using absorption spectroscopy, viscosity measurements and thermal denaturation methods. The results suggest that the complexes bound to CT-DNA by partial intercalation with binding constant ≈ 3.9 - 4.8x104 M-1. The photonuclease activities of the complexes were assayed on pUC19 DNA and they exhibit efficient photonuclease properties.