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Publication Abstract from PubMed

The extreme durability of polyethylene terephthalate (PET) debris has rendered it a long-term environmental burden. At the same time, current recycling efforts still lack sustainability. Two recently discovered bacterial enzymes that specifically degrade PET represent a promising solution. First, Ideonella sakaiensis PETase, a structurally well-characterized consensus alpha/beta-hydrolase fold enzyme, converts PET to mono-(2-hydroxyethyl) terephthalate (MHET). MHETase, the second key enzyme, hydrolyzes MHET to the PET educts terephthalate and ethylene glycol. Here, we report the crystal structures of active ligand-free MHETase and MHETase bound to a nonhydrolyzable MHET analog. MHETase, which is reminiscent of feruloyl esterases, possesses a classic alpha/beta-hydrolase domain and a lid domain conferring substrate specificity. In the light of structure-based mapping of the active site, activity assays, mutagenesis studies and a first structure-guided alteration of substrate specificity towards bis-(2-hydroxyethyl) terephthalate (BHET) reported here, we anticipate MHETase to be a valuable resource to further advance enzymatic plastic degradation.

Structure of the plastic-degrading Ideonella sakaiensis MHETase bound to a substrate.,Palm GJ, Reisky L, Bottcher D, Muller H, Michels EAP, Walczak MC, Berndt L, Weiss MS, Bornscheuer UT, Weber G Nat Commun. 2019 Apr 12;10(1):1717. doi: 10.1038/s41467-019-09326-3. PMID:30979881^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.