An Emerging Nanozyme Class for à la carte Enzymatic-Like Activities based on Protein-Metal Nanocluster Hybrids

Abstract

In this study, the goal is to fabricate robust and highly efficient peroxidase-like nanozymes that can ultimately be assembled into films for their easy reuse in catalytic cycles. Nanozymes are designed by mimicking the strategy adopted by metalloproteins to accommodate metal cofactors within their protein structure. The engineered consensus tetratricopeptide repeat (CTPR) protein module is selected as the scaffold to guide the growth and the stabilization of a library of in situ synthesized metal nanoclusters. A deep investigation of the interplay between the composition and function of the nanozymes reveals the impact of the protein templates and nanocluster composition on the peroxidase-like activity of the hybrids. Moreover, among a total of 24 hybrids, a top-performing nanozyme results from the growth of Au/Pt bimetallic nanoclusters on a CTPR protein with engineered histidine coordination sites. These nanozymes exhibit improved thermostability and resistance to hydrogen peroxide compared to natural peroxidases like horseradish peroxidase. Finally, it shows the easy fabrication of nanozyme composite films guided throughout the intrinsic self-assembling properties of the CTPR scaffold. These heterogeneous solid materials are reused in several reaction cycles without significant loss of the catalytic performance, proving these protein-templated nanozymes as an advantageous alternative to natural enzymes.