Wydział Chemii

Monika Katarzyna Lesiów

Katarzyna Krupa

2021

New Journal of Chemistry

45

8543-8556

10.1039/d1nj00617g

Naukowa

Angielski

Artykuł

The coordination process of Cu(II) ions to the terminally blocked Ac-H¹WKGPLR-NH₂ (L1), Ac-EH²KA-NH₂ (L2), and Ac-KEH³K-NH₂ (L3) peptides containing a histidyl residue at different positions of the peptide chain (the first, second, or third, respectively) was studied by potentiometry, spectroscopic techniques (UV-Vis, CD and EPR), and mass spectrometry. L3 peptide after binding Cu(II) ions (1 : 1 M : L molar ratio) at pH 7.2 (colon and intracellular brain pH) forms the most stable complex with the 3N {N_Im, 2N⁻} coordination mode. The binding process of the metal ion by L1 and L2 ligands proceeds towards the C-terminus, while for L3 peptide towards the N-terminus. The formation of bis-complexes for L2 and L3 ligands at 1 : 2 metal-to-ligand molar ratio was noted. The Cu(II) bis-complexes with 2N {2N_Im} binding sites are characterized by similar stability. The ability of Cu(II) complexes in the presence of hydrogen peroxide (H₂O₂) or ascorbic acid (Asc) to produce reactive oxygen species (ROS) was also investigated. The generation of hydroxyl radicals (˙OH) was monitored by luminescence with terephthalic acid (TA) as the detector. Moreover, the rate of ascorbate consumption by the studied compounds and their ability to produce ˙OH radicals were compared. Gel electrophoresis was also carried out to determine the type of ROS formed. It was confirmed that all selected Cu(II) peptide complexes in the presence of H₂O₂ or Asc produce ˙OH, while the complex with the L1 ligand additionally generates ¹O₂ in the system. Moreover, the produced ROS cause single- and double-strand DNA damage.

http://dx.doi.org/10.1039/d1nj00617g

https://www.rsc.org/