A rationally designed peptoid for the selective chelation of Zn(2+) over Cu(2+)

The selective removal of Zn(2+) from proteins by using a synthetic chelator is a promising therapeutic approach for the treatment of various diseases including cancer. Although the chelation of Zn(2+) is well known, its removal from a protein in the presence of potential competing biologically relevant ions such as Cu(2+) is hardly explored. Herein we present a peptoid – N-substituted glycine trimer – incorporating a picolyl group at the N-terminus, a non-coordinating but structurally directing benzyl group at the C-terminus and a 2,2':6′,2′′-terpyridine group in the second position, that selectively binds Zn(2+) ions in the presence of excess Cu(2+) ions in water. We further demonstrate that this chelator can selectively bind Zn(2+) from a pool of excess biologically relevant and competitive ions (Cu(2+), Fe(3+), Ca(2+), Mg(2+), Na(+), and K(+)) in a simulated body fluid (SBF), and also its ability to remove Zn(2+) from a natural zinc protein domain (PYKCPECGKSFSQKSDLVKHQRTHTG) in a SBF.