PCL enzymatic hydrolysis: a mechanistic study

TL;DR

This study uses molecular dynamics and QM/MM simulations to investigate how the thermophilic esterase from Archaeoglobus fulgidus hydrolyzes polycaprolactone, providing insights for designing enzymes to degrade synthetic polyesters.

Contribution

It offers the first atomic-level mechanistic understanding of PCL hydrolysis by AfEST, aiding enzyme engineering for polyester biodegradation.

Findings

Identified key catalytic residues involved in PCL hydrolysis.

Demonstrated enzyme stability at high temperatures.

Provided a detailed reaction pathway for ester bond cleavage.

Abstract

Accumulation of plastic waste is a major environmental problem. Enzymes, particularly esterases, play an important role in the biodegradation of polyesters. These enzymes are usually only active on aliphatic polyesters, but a few have showed catalytic activity for semi-aromatic polyesters. Due to the importance of these processes, an atomic level characterization of how common polyesters are degraded by esterases is necessary. Hereby, we present a Molecular dynamics (MD) and Quantum Mechanics/Molecular Mechanics (QM/MM) MD study of the hydrolysis of a model of polycaprolactone (PCL), one of the most widely used biomaterials, by the thermophilic esterase from the archaeon Archaeoglobus fulgidus (AfEST). This enzyme is particularly interesting because it can withstand temperatures well above the glass transition of many polyesters. Our insights about the reaction mechanism are important for the design of customized enzymes able to degrade different synthetic polyesters.