title: Selective control of Cu(II) complex stability in histidine peptides by β-alanine.
abstract: The cooperativity of formation of 5-membered and 6-membered chelate rings is the driving force for specificity and selectivity in Cu(II) peptidic complexes. α-Amino acids enable the formation of 5-membered rings, while a 6-membered ring is provided by the coordination of the His side chain imidazole. Introduction of β-alanine is another way of creating a 6-membered ring in the Cu(II) complex. The potentiometric and spectroscopic (UV-vis and CD) study of Cu(II) complexation by a series of four peptides, AAH-am, ABH-am, BAH-am, and BBH-am (where B stands for β-alanine, and -am for C-terminal amide) revealed a very strong effect of the sizes of individual rings, with the order of complex stability AAH-am (5,5,6)>BAH-am (6,5,6)>ABH-am (5,6,6)≫BBH-am (6,6,6). The stabilities of ABH-am and BAH-am complexes are intermediate between those of strong His-3 peptides but these complexes are still able to saturate the coordination sphere of the Cu(II) ion at neutral pH. This fact opens up new possibilities in engineering specific peptide-based chelates.
authors.affiliation: University of Wrocław, Joliot-Curie, Wrocław, Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Nagaj
authors.forename: Kamila
authors.initials: K
authors.lastname: Stokowa-Sołtys
authors.forename: Izabela
authors.initials: I
authors.lastname: Zawisza
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Jeżowska-Bojczuk
authors.forename: Arkadiusz
authors.initials: A
authors.lastname: Bonna
authors.forename: Wojciech
authors.initials: W
authors.lastname: Bal
mesh_terms: D002413:Cations, Divalent; D002942:Circular Dichroism; D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D011199:Potentiometry; D055550:Protein Stability; D015091:beta-Alanine / Q000737:chemistry*
chemical_list: D002413:Cations, Divalent; D056831:Coordination Complexes; D009842:Oligopeptides; D015091:beta-Alanine; D006639:Histidine; D003300:Copper