Arginine-Modified Hemin Enhances G-Quadruplex DNAzyme Peroxidase Activity for High Sensitivity Detection
Résumé
Hemin/G-quadruplex (hG4) complexes are frequently used as artificial peroxidase-like enzymatic systems (referred to as G4 DNAzymes) in many biosensing applications, in spite of a rather low efficiency, notably in terms of detection limits. To tackle this issue, we report herein on a strategy in which hemin is chemically modified with the amino acids found in the active site of parent horseradish peroxidase (HRP), in the aim of recreating an environment conducive to a high catalytic activity. When hemin conjugated with a single arginine, it associates with G4 to create an arginine-hemin/G4 (R-hG4) DNAzyme that exhibits improved catalytic performances, characterized by kinetic analysis and DFT calculations. The practical relevance of this system was demonstrated with the implementation of biosensing assays enabling the chemiluminescent detection of G4-containing DNA and colorimetry detection of FEN1 enzyme with a high efficiency and sensitivity. Our results thus provide a guide for future enzyme engineering campaigns to create ever more efficient peroxidase-mimicking DNA-based systems.