Copper binding and redox chemistry of the Ab16 peptide and its variants: insights into determinants of copper-dependent reactivity†

Abstract

The metal-binding sites of Ab peptides are dictated primarily by the coordination preferences of the metal ion. Consequently, Cu(I) is typically bound with two His ligands in a linear mode while Cu(II) forms a pseudo-square planar stereochemistry with the N-terminal amine nitrogen acting as an anchoring ligand. Several distinct combinations of other groups can act as co-ligands for Cu(II). A population of multiple binding modes is possible with the equilibrium position shifting sensitively with solution pH and the nature of the residues in the N-terminal region. This work examined the Cu(II) chemistry of the Ab16 peptide and several variants that targeted these binding modes. The results are..