Peptide-copper co-assembled metalloenzyme mimics with superior laccase-like activity for efficient aflatoxin B₁...

Aflatoxin B₁ (AFB₁), a potent natural carcinogen, poses a severe and widespread threat to global food safety and public health. To address this challenge, the rational design of robust artificial catalysts for efficient AFB₁ degradation represents a promising strategy. Inspired by the multicopper active center of natural laccase, we herein fabricated high-performance metalloenzyme mimics via a biomimetic interfacial co-assembly strategy for efficient AFB₁ degradation. De novo designed peptides, incorporating histidine and cysteine as cooperative metal-binding motifs within a self-assembling LK peptide framework, underwent coordinative co-assembly with Cu²⁺ ions. Driven by synergistic metal-ligand interactions-primarily the imidazole groups of histidine and thiol groups of cysteine-the assembly process enabled the formation of well-defined, copper-enriched catalytic interfaces that accurately recapitulated the geometric architecture and electronic structure of laccase's active center, yielding peptide-copper colloidal nanoassemblies with remarkable laccase-mimicking activity. In comparison with natural laccase, the optimized metalloenzyme mimic displayed superior catalytic efficiency, as well as enhanced pH tolerance and thermal stability, enabling complete degradation of AFB₁ within 90 min under optimal conditions. The transformation products of AFB₁ showed markedly reduced cytotoxicity relative to parent mycotoxin. Importantly, the metalloenzyme mimic exhibited excellent practical performance, efficiently degrading AFB₁ in contaminated grain and nut samples and reducing residual concentrations to meet the strict safety limits set by the European Union. This work not only provides a potent biocatalyst for mycotoxin remediation but also elucidates a fundamental co-assembly pathway for engineering functional colloidal materials with tailored catalytic interfaces, offering broad implications for designing bio-inspired solutions in environmental and food chemistry.