Structural Elucidation and Mechanisms-Guided Engineering of a Promiscuous Esterase for Enhanced Polyurethane Depolymerization

Polyurethane (PU) is highly resistant to biodegradation, primarily due to the intrinsic stability of its urethane bond. Aside from a small number of amidases reported to hydrolyze (poly)urethane bonds, several promiscuous esterases have also been found to catalyze PU degradation. In this study, we clarified the ligand-free crystal structure of Aes72, an esterase enzyme that exhibits promiscuous hydrolytic activity toward carbamate and amide bonds, at a high resolution of 1.80 Å. We investigated the catalytic mechanism underlying urethane bond cleavage by Aes72 using multiscale quantum mechanics/molecular mechanics (QM/MM) simulations. Our findings indicate that the reaction mechanism consists of four concerted…

• NN
  National Natural Science Foundation of China

  Awards: 22278219, 22478184, U23A20126, 22408168
• NS
  Natural Science Foundation of Jiangsu Province

  Award: BK20250030
• JN
  Jiangsu National Synergistic Innovation Center for Advanced Materials
• NK
  National Key Research and Development Program of China

  Award: 2023YFC3905003