Biocombinatorial selection of metal ion-chelating peptides

A phage-displayed library selection was performed to obtain metal ion-chelating peptides. A dodecamer (12-mer) random peptide library was displayed on the surface of filamentous bacterial phage and subjected to an affinity selection. Four rounds of the selection gave fourteen Zn²⁺-positive phage clones. Enzyme-linked immunosorbent assay showed that the selected clones specifically bound to Zn²⁺ and Ni²⁺, but not to Cu²⁺ and Fe³⁺. Deduced amino acid sequences of the clones had histidinerich consensus motifs. These chelating peptides should be applied to designing for metal ion-trapping biomaterials.