title: Polythiol binding to biologically relevant metal ions.
abstract: The coordination properties of three peptides with CXXC motif: Ac-GCASCDNCRACKK-NH(2), Ac-GCASCDNCRAAKK-NH(2) and Ac-GCASCDNARAAKK-NH(2) as donors of four, three and two thiol ligands for Ni(2+),Cd(2+), Zn(2+) and Bi(3+) were studied by potentiometric titrations, UV-Vis and CD spectra measurements. Since the stability of the complexes is closely connected with the amount of the metal-bound cysteine sulfurs, competition plots of the complexes of peptides with 2, 3 and 4 cysteines further prove the involvement of all thiols in the metal ion binding. Furthermore, the sulfur-bound zinc complexes appear to be much more stable than the sulfur-bound nickel ones. The stabilities of the studied complexes decreases in the series Bi(3+) ≫ Cd(2+) > Zn(2+) > Ni(2+).
authors: Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie 14, 50383, Wroclaw, Poland.
authors: Karolina
authors: K
authors: Krzywoszynska
authors: Magdalena
authors: M
authors: Rowinska-Zyrek
authors: Danuta
authors: D
authors: Witkowska
authors: Slawomir
authors: S
authors: Potocki
authors: Marek
authors: M
authors: Luczkowski
authors: Henryk
authors: H
authors: Kozlowski
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008024:Ligands; D008670:Metals / Q000737:chemistry*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D011199:Potentiometry; D011485:Protein Binding; D013816:Thermodynamics
chemical_list: D056831:Coordination Complexes; D007477:Ions; D008024:Ligands; D008670:Metals; D010455:Peptides; D003545:Cysteine