title: The His-His sequence of the antimicrobial peptide demegen P-113 makes it very attractive ligand for Cu2+.
abstract: Histatins are a family of histidine-rich, cationic peptides up to 38 amino acids long. As other antimicrobial peptides histatins exhibit in vitro activity against both bacteria and yeasts. A 12 amino acid amidated fragment of histatin 5, designated P-113 or demegen, has been identified as the smallest fragment retaining antimicrobial activity comparable to the parent compound. Demegen, AKRHHGYKRKFH, has three His and a N-terminal group known to participate in copper ion coordination. In this study potentiometric and spectroscopic (UV-vis, CD, EPR, NMR) measurements were used to evaluate the stability constants, stoichiometry and structures of Cu(2+) complexes with demegen P-113 and its analogues in aqueous solution. The main aim of this work was to understand the role of two adjacent histidine residues in metal ion binding. The comparison with results for modified ligands showed that two histydyl residues are basic for complex formation in the 4.5-7 pH range.
authors.affiliation: Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
authors.forename: Kinga
authors.initials: K
authors.lastname: Kulon
authors.forename: Daniela
authors.initials: D
authors.lastname: Valensin
authors.forename: Wojciech
authors.initials: W
authors.lastname: Kamysz
authors.forename: Gianni
authors.initials: G
authors.lastname: Valensin
authors.forename: Piotr
authors.initials: P
authors.lastname: Nadolski
authors.forename: Elena
authors.initials: E
authors.lastname: Porciatti
authors.forename: Elena
authors.initials: E
authors.lastname: Gaggelli
authors.forename: Henryk
authors.initials: H
authors.lastname: Kozłowski
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry*; D008024:Ligands; D008969:Molecular Sequence Data
chemical_list: D000890:Anti-Infective Agents; D008024:Ligands; D006639:Histidine; D003300:Copper