Rational design of IsPETase variant toward efficient poly(ethylene terephthalate) ambient degradation

Area of Science:

• Biotechnology
• Environmental Science
• Biochemistry

Background:

• Poly(ethylene terephthalate) (PET) accumulation presents a significant environmental challenge.
• Current high-performance PET degradation relies on thermophilic enzymes, lacking energy efficiency.
• Low-temperature PET degradation is crucial for sustainable and energy-saving waste treatment.

Purpose of the Study:

• To enhance the PET degradation activity of a mesophilic enzyme at lower temperatures.
• To develop an energy-efficient method for centralized PET waste treatment.
• To engineer a superior PET hydrolase variant through rational design.

Main Methods:

• Rational design strategies including salt bridge construction and hydrophobic engineering were employed.
• An engineered mesophilic enzyme, IsPETase^S121P/D186A, served as the baseline.
• Molecular dynamics (MD) simulations were used to analyze enzyme-protein interactions and energy barriers.

Main Results:

• A novel variant, PADFL (IsPETase^{S121P/D186A/N246D/Y87F/N233L}), was successfully engineered.
• PADFL exhibited an 8.37-fold increase in PET degradation activity compared to the baseline enzyme.
• MD simulations indicated enhanced PET binding affinity and a reduced acylation energy barrier for PADFL.

Conclusions:

• The engineered PADFL variant demonstrates significantly improved PET degradation efficiency under mild conditions.
• Rational design based on energy principles is effective for optimizing enzyme activity.
• PADFL represents a promising candidate for efficient and sustainable PET waste management.