Copper(II) Complexes with ATCUN Peptide Analogues: Studies on Redox Activity in Different Solutions
Magdalena Z. Wiloch, Iwona Ufnalska, Arkadiusz Bonna, Wojciech Bal, Wojciech Wróblewski, Urszula Elżbieta Wawrzyniak · Journal of The Electrochemical Society · 2017
Copper(II) complexes of peptides containing a histidine (His) residue at the third position (known as ATCUN or NTS motif) gain interest for their biological roles and biotechnological applications. We characterized three such peptides, Ala-Ala-His-NH 2 (AAH-am), Ala-βAla-His-NH 2 (ABH-am) and βAla-Ala-His-NH 2 (BAH-am) by cyclic voltammetry in order to assess the influence of substitution of the α-alanine residue (Ala) by β-alanine (βAla) on their redox properties. The obtained results, complementary to the previously reported potentiometric and spectroscopic studies confirmed strong effects of size and position of component chelate rings, 5-membered for Ala and 6-membered for βAla, on the Cu(II) binding affinity and redox properties. The detailed voltammetric study revealed the effects of the composition of the supporting electrolyte and the selection of starting potential on the observed redox processes. The conclusions are relevant for designing artificial nucleases and proteases and for proper practice of studies of redox properties of complexes of Cu(II) carried out in buffer solutions.