Fig. 1: Design of the artificial hydrolytic enzyme ZAF(Ser).

a Schematic illustration of natural hydrolytic enzyme carboxypeptidase (CPA) and its active site, in which the imidazole group in a metal complex forms a secondary coordination sphere with the adjacent amino acid (AA) residue. b Dual catalytic active site moieties are located in the primary coordination sphere and secondary coordination sphere of ZAF(Ser), which resemble the Lewis acidic active site and the typical oxygen anion active site mediated by hydrogen bonding in hydrolase, respectively.