Date of Award
12-1-2024
Degree Name
Master of Science
Department
Physics
First Advisor
Jayasekera, Thushari
Abstract
Polyethylene Terephthalate (PET) is a common synthetic polymer from petroleum, used in packaging and clothing. Inadequate plastic waste management has increased plastic pollution, and current recycling methods are not advanced enough to enable effective plastic reuse, rendering recycling efforts insufficient to tackle the problem. The discovery of plastic degradation enzymes enables PET’s biological recycling or upcycling, which shows a promise to achieve a complete cycle of plastic use. For instance, Ideonella sakaiensis (I.S.), which expresses dual enzymes PETase and MHETase, catalyzes PET depolymerization and converts PET into original monomers, terephthalate acid (TPA) and ethylene glycol (EG). However, its conversion efficiency must be improved for promising industrial use. In this regard, engineering existing enzymes or searching for novel enzymes is of timely interest. Mle046 is a promising, yet relatively less studied enzyme from a marine microbial consortium which is a homolog to MHETase with an ability to depolymerize MHET into its building blocks, TPA and EG.We report the results from Molecular Docking and Molecular Dynamics Simulations for the characterization and engineering of Mle046. This study is based on the three-dimensional configuration obtained through homology modeling, as the experimental structure is not yet available. Multiple sequence alignment with its homologs indicates that the active sites of Mle046 remain conserved, displaying a catalytic triad consisting of SER, HIS, and ASP, similar to the known PET hydrolases. In this study, we report on the possibility of improving the enzyme’s stability by adding a disulfide bond. Further, by analyzing the PET binding surface in Mle046, we will show potential mutations that will enhance PET depolymerization activity.
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