Enzyme inspired polymer functionalized with an artificial catalytic triad

At the heart of an enzyme's structure is the active catalytic site, which, together with the surrounding amino-acid residues, tunes the substrate properties in the electrostatic microenvironment. Taking inspiration from nature's catalytic triad, consisting of a hydroxyl group of a serine residue, an imidazole group of a histidine residue, and a carboxyl group of an aspartic acid, a polymer scaffolded enzyme mimic is incorporated with artificial catalytic triad units. It is demonstrated that controlling the local environment of the artificial triad affects catalytic activity. Compared to a water soluble artificial catalytic triad, enhanced esterolytic activity of p-nitrophenyl benzoate was observed for the polymeric catalyst possibly due to the hydrophobic microenvironment formed by the tertiary structure of the polymer backbone. The different environments were supported by molecular dynamics simulations. It is further demonstrated that the cross-linked catalytic triad functional polystyrene could be used as a reusable solid support catalyst for esterolysis.