Computational Studies of the Enzymatic Biodegradation of Polyethylene Terephthalate (PET): Exploring the Stability and Efficiency of PETases

• Grant number: 23/13707-7
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: April 25, 2024
• End date: April 24, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Munir Salomao Skaf
• Grantee: Clauber Henrique Souza da Costa
• Supervisor: Vicente Moliner Ibanez
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Universitat Jaume I, Spain
• Associated to the scholarship: 22/04703-5 - Molecular dynamics simulations of enzymes of biotechnological interest, BP.PD

Abstract

Plastics are essential materials for modern society due to their specific properties, but the increasing levels of pollution steaming from plastic residues represents a global environmental crisis. Recently, a bacterium strain of Ideonella sakaiensis 201-F6, was isolated and demonstrated an unusual ability to degrade poly(ethylene terephthalate) (PET). The PETase from I. sakaiensis strain 201-F6 (IsPETase) catalyzes the hydrolysis of PET converting it to mono-(2-hydroxyethyl) terephthalic acid (MHET), releasing bis-2(hydroxyethyl) terephthalate (BHET) and terephthalate (TPA) as products. A second enzyme, MHETase (MHET digesting enzyme), subsequently converts MHET into two monomers: ethylene glycol (EG) and TPA. In this study, we will perform molecular dynamics (MD) simulations to investigate the behavior of native IsPETase and its variants and possibly other enzymes that play key roles in the full PET degradation cycle. Additionally, we will explore how mutations affect thermostability and interaction with the PET substrate. Our goal is to elucidate substrate recognition and binding and the catalytic mechanism of the enzymatic reactions, for which we shall employ hybrid methods that combine quantum mechanics and molecular mechanics (QM/MM) to analyze PETase and its variants in PET degradation. We expect to obtain crucial information that can contribute to the development of new biocatalysts for the biodegradation of PET. These findings can also guide future research into engineering PETase structures to improve polymer recycling efficiency.