Insight into how PETase Functions at the Solid-Liquid Interface and an Activity-Stability Trade-Off.

Abstract

Enzymatic degradation of poly(ethylene terephthalate) (PET) has garnered considerable interest in plastic recycling efforts. However, the underlying molecular mechanism governing PETase-catalyzed PET depolymerization at the solid-liquid interface remains elusive, hampering the rational design of highly efficient enzymes. Here, we comprehensively elucidate the catalytic pathway of PETase, detailing steps from initial enzyme adsorption at the PET interface, subsequent substrate fragment capture, conformational refinement, to the ultimate cleavage of ester bonds. We uncover an intrinsic trade-off between the activity and stability of the enzyme's PET-binding loops, which negatively impacts overall PET degradation efficiency. By strategically reshaping the loop dynamics of PETase, we successfully overcome this compromise, simultaneously enhancing both enzymatic activity and structural stability. Collectively, this work provides critical insights into PETase functionality at solid-liquid interfaces and establishes valuable guidelines for the rational design of efficient plastic-degrading enzymes.