Title: Characterization and engineering of a plastic-degrading aromatic polyesterase

Abstract

Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability is a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 A resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral a/..beta..-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PETmore » replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters.« less

Authors:

Austin, Harry P. ^[1]; Allen, Mark D. ^[1]; Donohoe, Bryon S.  ^[2];

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• Search DOE PAGES for ORCID "0000-0002-2272-5059"
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Rorrer, Nicholas A. ^[3]; Kearns, Fiona L. ^[4]; Silveira, Rodrigo L. ^[5]; Pollard, Benjamin C. ^[4]; Dominick, Graham ^[3]; Duman, Ramona  ^[6];

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• Search DOE PAGES for ORCID "0000-0002-3566-8698"
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El Omari, Kamel ^[6]; Mykhaylyk, Vitaliy ^[6]; Wagner, Armin  ^[6];

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• Search DOE PAGES for ORCID "0000-0001-8995-7324"
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Michener, William E. ^[3]; Amore, Antonella ^[2]; Skaf, Munir S. ^[7]; Crowley, Michael F. ^[2]; Thorne, Alan W. ^[1]; Johnson, Christopher W. ^[3]; Woodcock, H. Lee ^[4]; McGeehan, John E.  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-6750-1462"
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more »; Beckham, Gregg T.  ^[3]

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• Search DOE PAGES for ORCID "0000-0002-3480-212X"
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+ Show Author Affiliations

1. Molecular Biophysics Laboratories, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth PO1 2DY, United Kingdom,
2. Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401,
3. National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401,
4. Department of Chemistry, University of South Florida, Tampa, FL 33620-5250,
5. Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401,, Institute of Chemistry, University of Campinas, Campinas, 13083-970 Sao Paulo, Brazil,
6. Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
7. Institute of Chemistry, University of Campinas, Campinas, 13083-970 Sao Paulo, Brazil,

Publication Date:

2018-04-17

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE; USDOE Office of Energy Efficiency and Renewable Energy (EERE), NREL Laboratory Directed Research and Development (LDRD)

OSTI Identifier:

1433403

Alternate Identifier(s):

OSTI ID: 1435703

Report Number(s):

NREL/JA-5100-70516
Journal ID: ISSN 0027-8424

Grant/Contract Number:  

LDRD; AC36-08GO28308

Resource Type:

Published Article

Journal Name:

Proceedings of the National Academy of Sciences of the United States of America

Additional Journal Information:

Journal Name: Proceedings of the National Academy of Sciences of the United States of America Journal Volume: 115 Journal Issue: 19; Journal ID: ISSN 0027-8424

Publisher:

Proceedings of the National Academy of Sciences

Country of Publication:

United States

Language:

English

Subject:

09 BIOMASS FUELS; biodegradation; poly(ethylene terephthalate); poly(ethylene furanoate); plastics; recycling; cutinase