The unusual coordination abilities of the peptides with βxaaHisGlyHis sequence. the influence of structural modification of the peptide chain on the copper(ii) binding

摘要

The coordination abilities of tetrapeptides containing β-amino acids towards Cu(ii) ions are presented. The studied tetrapeptides were: Ac-βAlaHisGlyHis, βAlaHisGlyHis, Ac-βAspHisGlyHis, βAspHisGlyHis, Ac-βAspHisGly-dHis and βAspHisGly-dHis. Thorough potentiometric titrations were carried out to establish the stoichiometry of the resulting metal-ligand complexes and the role of free -αCOO~- side chain group in metal binding. The copper(ii) coordination mode of the complexes was investigated by performing detailed spectroscopic analyses (UV-Vis, EPR, CD) in strict correlation with potentiometric measurements.