BhrPETase catalyzed polyethylene terephthalate depolymerization: A quantum mechanics/molecular mechanics approach.

Area of Science:

• Biotechnology
• Biochemistry
• Materials Science

Background:

• Polyethylene terephthalate (PET) is a prevalent plastic with significant environmental waste concerns.
• Enzymatic conversion presents a promising green strategy for PET degradation and recycling.

Purpose of the Study:

• To elucidate the depolymerization mechanism of the thermophilic cutinase BhrPETase.
• To compare BhrPETase with other cutinases like LCC^ICCG for enhanced PET degradation efficiency.

Main Methods:

• Combined theoretical approach using molecular dynamics (MD) simulations.
• Quantum mechanics/molecular mechanics (QM/MM) calculations to analyze the reaction mechanism and energy barriers.

Main Results:

• Identified the catalytic triad assisted nucleophilic attack as the rate-determining step for BhrPETase, with an energy barrier of 18.2 kcal/mol.
• Key features such as charge C_His@N1 and angle A_{PET@C1-Ser@O1-His@H1} were found to significantly influence BhrPETase depolymerization efficiency.
• Analysis revealed insights into non-covalent interactions and distortion effects impacting enzyme performance.

Conclusions:

• The study provides a detailed mechanistic understanding of BhrPETase in PET depolymerization.
• Findings offer valuable insights for enzyme engineering to optimize PET waste recycling.
• This research contributes to advancing the plastic bio-recycling economy and promoting resource sustainability.