Structural and functional characterization of dsPETase05 for the degradation of Polyethylene terephthalate

The enzymatic degradation of polyethylene terephthalate (PET) represents a promising sustainable strategy to address global plastic pollution. Among various plastic-degrading enzymes, PETase has been one of the most extensively studied and widely applied. Discovering novel PETase variants and elucidating their structure-function relationships are essential for developing more efficient enzymes. Here, we studied dsPETase05, a deep-sea PET hydrolase that was previously reported, which exhibits significantly enhanced PET degradation activity compared to the wild-type Ideonella sakaiensis PETase (IsPETase). This improvement was corroborated by atomic force microscopy (AFM) analysis of PET surface erosion and high-performance liquid chromatography (HPLC) quantification of hydrolysis products. We heterologously expressed and biochemically characterized dsPETase05, and resolved its crystal structure at 1.93 Å resolution. Structural analysis revealed that dsPETase05 adopts the typical α/β-hydrolase architecture found in PET-degrading enzymes, with distinctive amino acid substitutions near the catalytic triad that may contribute to its elevated activity. Our findings highlight the potential of marine-derived PETase for enzymatic plastic waste remediation and expand the repertoire of biocatalysts available for sustainable PET degradation.