Mechanistic Origins of Enhanced PET Hydrolase Activity from Molecular Dynamics and Deep Learning-Assisted Network...

Polyethylene terephthalate (PET) hydrolase-based biodegradation offers a promising route for plastic waste remediation, yet the dynamic origins of high activity and their linkage across catalytic stages still require further elucidation. Here, we focus on the Leaf-Branch Compost Cutinase (LCC) system to reveal the possible mechanistic origins underlying the elevated activity of the LCC variants. By integrating molecular dynamics simulations, enhanced sampling, and deep learning-assisted network analysis, we systematically investigate the critical prereactive stage of amorphous PET adsorption and substrate binding. We identify three mechanistic origins underlying the high activity of LCC-LANL in the prereactive state and clarify its structure-dynamics-function relationship: (i) enhanced interaction strength coupled with an active-pocket orientation that, despite not directly facing the amorphous PET surface, maintains closer proximity to it than LCC-WT, thus promoting substrate recruitment; (ii) higher occupancy of the PET ester bond near the catalytic triad, which forms the basis for catalysis, coupled with the efficient dynamic interchange between the "W" and coiled conformations near the catalytic triad; and (iii) the enhancement of prereactive organization through long-range allosteric communication by distal mutations in LCC-LANL. Additionally, we propose a region-specific cooperative optimization strategy tailored to domain-specific functional roles and distill six design principles for efficient PETases. In summary, this work elucidates the prereactive origins underlying the high activity of LCC-LANL, paving the way for future studies on actual catalytic PET hydrolysis.