Influence of the position of two dehydro-amino acids residues in the oligopeptide sequence on the binding ability towards Cu(II) ions
Abstract Studies on the binding ability of bis-dehydro-hexa- and pentapeptides have shown that the hexapeptides bind Cu+2 with similar efficacy as pentapeptides. The increase of distance between two dehydro-amino acid residues in the peptide backbone has no impact on the efficacy in metal ion binding. The type of isomeration [(Z) or (E)] has an influence on the coordination of the metal ion only to the first amide nitrogen.
Pneumococcal HxxHxH triad – Copper(II) interactions – How important is the ‘x’?
Abstract PhtA, a Streptococcus pneumoniae polyhistidine triad protein, which contributes to virulence by interacting with components of the immune system, by being involved in adherence of bacteria and in Zn(II) uptake, contains five copies of the HxxHxH sequence. Since this motif is also present in numerous Cu(II) binding proteins, we decided to focus on the bioinorganic chemistry of copper(II) with three of such PhtA repeats, in order to understand which of the PhtA triads binds Cu(II) with the highest affinity and explain if Cu(II) would be able to outcompete Zn(II) from its native binding site under physiological metal concentrations.