Temperature-Dependent Active-Site Rearrangements of PETaseSM14: Insights from Molecular Dynamics Simulations

Area of Science:

• Biotechnology
• Enzyme Engineering
• Environmental Science

Background:

• Polyethylene terephthalate (PET) pollution is a significant environmental issue due to its persistence.
• PETase enzymes offer a sustainable solution for PET degradation and recycling.
• PETaseSM14 exhibits salt tolerance and thermal stability, showing promise for PET biodegradation.

Purpose of the Study:

• To elucidate the substrate recognition mechanism of PETaseSM14.
• To understand the molecular basis of PETaseSM14's temperature-dependent activity.
• To identify strategies for enhancing PETase efficiency through rational engineering.

Main Methods:

• All-atom molecular dynamics simulations were conducted at 300, 320, and 340 K.
• Analysis of protein fold stability, local fluctuations, and conformational changes.
• Investigation of active site accessibility and catalytic triad integrity at different temperatures.

Main Results:

• The overall α/β fold of PETaseSM14 remained stable across tested temperatures.
• Temperature-dependent conformational changes in the substrate-binding cleft and N-terminal region were observed.
• At 300-320 K, Tyr88 shifts exposed the catalytic Ser156, forming a binding cleft. At 340 K, His234 conformational changes disrupted the catalytic triad.

Conclusions:

• PETaseSM14's active site undergoes significant temperature-dependent rearrangements.
• Understanding these dynamics provides insights for engineering improved PET-degrading enzymes.
• This research paves the way for more efficient enzymatic PET recycling solutions.