An Artificial Peroxidase based on the Biotin-Streptavidin Technology that Rivals the Efficiency of Natural Peroxidases

Horseradish peroxidase (HRP) is an archetypal heme-containing metalloenzyme that uses peroxide to oxidize various substrates. Capitalizing on a well-established catalytic mechanism, diverse peroxidase mimics have been widely investigated and optimized. Herein, we report on the design, assembly, characterization, and genetic engineering of an artificial heme-based peroxidase relying on the biotin-streptavidin technology. The crystal structure of both the wild-type and the best-performing double mutant of artificial peroxidase provided valuable insight regarding the nearby residues that were strategically mutated to optimize the peroxidase activity (i.e. Sav S112E K121H). We hypothesize that these two residues mimic the two key second coordination residues involved in activating the bound peroxide in HRP (i.e. Arg 38 and His 42). The evolved artificial peroxidase exhibited best-in-class activity for oxidizing two standard substrates (TMB and ABTS) in the presence of hydrogen peroxide.