Structural Insights into (Tere)phthalate-Ester Hydrolysis by a Carboxylesterase and Its Role in Promoting PET Depolymerization

Investor logo
Investor logo

Warning

This publication doesn't include Faculty of Education. It includes Faculty of Science. Official publication website can be found on muni.cz.
Authors

VON HAUGWITZ Gerlis HAN Xu PFAFF Lara LI Qian WEI Hongli GAO Jian METHLING Karen AO Yufei BRACK Yannik MIČAN Jan FEILER Christian G WEISS Manfred S BEDNÁŘ David PALM Gottfried J. LALK Michael LAMMERS Michael DAMBORSKÝ Jiří WEBER Gert LIU Weidong BORNSCHEUER Uwe T. WEI Ren

Year of publication 2022
Type Article in Periodical
Magazine / Source ACS Catalysis
MU Faculty or unit

Faculty of Science

Citation
Web https://doi.org/10.1021/acscatal.2c03772
Doi http://dx.doi.org/10.1021/acscatal.2c03772
Keywords PET hydrolysis; plastic; dual enzyme system; carboxylesterase; structure; enzyme engineering
Attached files
Description TfCa, a promiscuous carboxylesterase from Thermobifida fusca, was found to hydrolyze polyethylene terephthalate (PET) degradation intermediates such as bis(2-hydroxyethyl) terephthalate (BHET) and mono-(2-hydroxyethyl)-terephthalate (MHET). In this study, we elucidated the structures of TfCa in its apo form, as well as in complex with a PET monomer analogue and with BHET. The structure–function relationship of TfCa was investigated by comparing its hydrolytic activity on various ortho- and para-phthalate esters of different lengths. Structure-guided rational engineering of amino acid residues in the substrate-binding pocket resulted in the TfCa variant I69W/V376A (WA), which showed 2.6-fold and 3.3-fold higher hydrolytic activity on MHET and BHET, respectively, than the wild-type enzyme. TfCa or its WA variant was mixed with a mesophilic PET depolymerizing enzyme variant [Ideonella sakaiensis PETase (IsPETase) PM] to degrade PET substrates of various crystallinity. The dual enzyme system with the wild-type TfCa or its WA variant produced up to 11-fold and 14-fold more terephthalate (TPA) than the single IsPETase PM, respectively. In comparison to the recently published chimeric fusion protein of IsPETase and MHETase, our system requires 10% IsPETase and one-fourth of the reaction time to yield the same amount of TPA under similar PET degradation conditions. Our simple dual enzyme system reveals further advantages in terms of cost-effectiveness and catalytic efficiency since it does not require time-consuming and expensive cross-linking and immobilization approaches.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.