Cationic peptides and their cu(Ii) and ni(ii) complexes: Coordination and biological characteristics

Abstract

Antimicrobial peptides are a promising group of compounds used for the treatment of infections. In some cases, metal ions are essential to activate these molecules. Examples of metal-loantibiotics are, for instance, bleomycin and dermcidin. This study is focused on three new pseu-dopeptides with potential biological activity. The coordination behavior of all ligands with Cu(II) and Ni(II) ions has been examined. Various analytical methods such as potentiometric titration, UV-Vis and CD spectroscopies, and mass spectrometry were used. All compounds are convenient che-lators for metal ion-binding. Two of the ligands tested have histidine residues. Surprisingly, imid-azole nitrogen is not involved in the coordination of the metal ion. The N-terminal amino group, Dab side chains, and amide nitrogen atoms of the peptide bonds coordinated Cu(II) and Ni(II) in all the complexes formed. The cytotoxicity of three pseudopeptides and their complexes was eval-uated. Moreover, their other model allowed for assessing the attenuation of LPS-induced cytotoxi-city and anti-inflammatory activities were also evaluated, the results of which revealed to be very promising.