Supramolecular DNA/amino acid-based oxidase-mimetic nanocatalysts exhibiting drug degradation capability

Abstract

Developing efficient and environmentally benign approaches for the remediation of antibiotic pollutants has become a paramount research imperative, since the extensive use of antibiotics has raised serious concerns due to their potential to induce antibiotic resistance and disrupt the ecological balance. In this work, we report the self-assembly of fluorenylmethyloxycarbonyl-lysine (Fmoc-K) aggregates with natural calf thymus DNA (CT-DNA) and Cu²⁺ to construct a catalyst that possesses copper-dependent active sites, mirroring the catalytic function of laccase, an oxidase known for its ability to degrade phenolic antibiotics. Structural characterization, including circular dichroism, fluorescence spectroscopy, transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR), indicates the association of Fmoc-K with DNA components, facilitating the coordination of Cu²⁺ to both. Kinetic studies revealed that the Fmoc-K/CT-DNA/Cu²⁺ complex exhibited over 13-fold higher catalytic efficiency than either CT-DNA/Cu²⁺ or Fmoc-K/Cu²⁺ alone. Notably, CT-DNA not only serves as a structural scaffold but also promotes the access of antibiotic substrates (including doxorubicin and tetracycline) to the copper center due to its binding affinity for these antibiotics, thereby facilitating efficient oxidative degradation. This work offers a promising strategy for constructing high-performance, environmentally responsive metalloenzyme mimics for pollutant remediation.