Chemical Synthesis of the Mirror-Image Fast-PETase by the Enzyme-Cleavable Solubilizing-Tag Strategy.

Mirror-image poly(ethylene terephthalate) (PET) plastic-degrading enzymes have emerged as promising biocatalytic platforms due to their exceptional enzymatic stability and low immunogenicity. Currently, the sole reported mirror-image plastic-degrading enzyme, the D-form of 231-residue PET hydrolase ICCG (engineered leaf-branch compost cutinase variant), suffers from thermophilic activity requirements, which limits its practical applications. Here, the first total chemical synthesis of a mirror-image 271-residue D-Fast-PETase was presented by using an enzyme-cleavable solubilizing tag strategy. Comparative kinetic analysis revealed that D-Fast-PETase showed a remarkable increase (∼20-fold within 24 hours) in PET degradation efficiency compared to D-ICCG at temperatures of 37 °C, making it a promising candidate for prolonged PET decomposition in open environments and holding potential in addressing microplastic-related health issues within the biomedical field. This work not only expands the chemical biology toolbox for mirror-image enzyme synthesis but also establishes D-Fast-PETase as a candidate in combating the dual crises of global plastic pollution and microplastic-associated health risks.