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DOI	10.1073/pnas.2101160118
	Characterization and engineering of a two-enzyme system for plastics depolymerization
	Knott B.C.; Erickson E.; Allen M.D.; Gado J.E.; Graham R.; Kearns F.L.; Pardo I.; Topuzlu E.; Anderson J.J.; Austin H.P.; Dominick G.; Johnson C.W.; Rorrer N.A.; Szostkiewicz C.J.; Copié V.; Payne C.M.; Woodcock H.L.; Donohoe B.S.; Beckham G.T.; McGeehan J.E.
发表日期	2021
ISSN	0027-8424
卷号	118 期号:28
英文摘要	Plastics pollution represents a global environmental crisis. In response, microbes are evolving the capacity to utilize synthetic polymers as carbon and energy sources. Recently, Ideonella sakaiensis was reported to secrete a two-enzyme system to deconstruct polyethylene terephthalate (PET) to its constituent monomers. Specifically, the I. sakaiensis PETase depolymerizes PET, liberating soluble products, including mono(2-hydroxyethyl) terephthalate (MHET), which is cleaved to terephthalic acid and ethylene glycol by MHETase. Here, we report a 1.6 Å resolution MHETase structure, illustrating that the MHETase core domain is similar to PETase, capped by a lid domain. Simulations of the catalytic itinerary predict that MHETase follows the canonical two-step serine hydrolase mechanism. Bioinformatics analysis suggests that MHETase evolved from ferulic acid esterases, and two homologous enzymes are shown to exhibit MHET turnover. Analysis of the two homologous enzymes and the MHETase S131G mutant demonstrates the importance of this residue for accommodation of MHET in the active site. We also demonstrate that the MHETase lid is crucial for hydrolysis of MHET and, furthermore, that MHETase does not turnover mono(2-hydroxyethyl)furanoate or mono(2-hydroxyethyl)-isophthalate. A highly synergistic relationship between PETase and MHETase was observed for the conversion of amorphous PET film to monomers across all nonzero MHETase concentrations tested. Finally, we compare the performance of MHETase:PETase chimeric proteins of varying linker lengths, which all exhibit improved PET and MHET turnover relative to the free enzymes. Together, these results offer insights into the two-enzyme PET depolymerization system and will inform future efforts in the biological deconstruction and upcycling of mixed plastics. © 2021 National Academy of Sciences. All rights reserved.
英文关键词	Biodegradation; Polyethylene terephthalate; Recycling; Serine hydrolase; Upcycling
语种	英语
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/238483
作者单位	Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401, United States; Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom; Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, United States; Department of Chemistry, University of South Florida, Tampa, FL 33620, United States; Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, United States; Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, United States
推荐引用方式 GB/T 7714	Knott B.C.,Erickson E.,Allen M.D.,et al. Characterization and engineering of a two-enzyme system for plastics depolymerization[J],2021,118(28).
APA	Knott B.C..,Erickson E..,Allen M.D..,Gado J.E..,Graham R..,...&McGeehan J.E..(2021).Characterization and engineering of a two-enzyme system for plastics depolymerization.Proceedings of the National Academy of Sciences of the United States of America,118(28).
MLA	Knott B.C.,et al."Characterization and engineering of a two-enzyme system for plastics depolymerization".Proceedings of the National Academy of Sciences of the United States of America 118.28(2021).