Structure Report for: 7OSB

Shakespeare, T.J., Zahn, M., Allen, M.D., McGeehan, J.E.

Title: Comparative performance of PETase as a function of reaction conditions, substrate properties, and product accumulation
Erickson E, Shakespeare TJ, Bratti F, Buss BL, Graham R, Hawkins MA, Konig G, Michener WE, Miscall J and Beckham G <5 more author(s)> Erickson E, Shakespeare TJ, Bratti F, Buss BL, Graham R, Hawkins MA, Konig G, Michener WE, Miscall J, Ramirez KJ, Rorrer NA, Zahn M, Pickford AR, McGeehan JE, Beckham G (- 5)
Ref: ChemSusChem, 15:, 2022 : PubMed
Abstract


ESTHER: Erickson_2022_ChemSusChem_15_e202101932
PubMedSearch: Erickson 2022 ChemSusChem 15 e202101932
PubMedID: 34587366
Gene_locus related to this paper: idesa-peth

Abstract

There is keen interest to develop new technologies to recycle the plastic poly(ethylene terephthalate) (PET). To this end, the use of PET-hydrolyzing enzymes has shown promise for PET deconstruction to its monomers, terephthalate (TPA) and ethylene glycol (EG). Here, we compare the Ideonella sakaiensis PETase wild-type enzyme to a previously reported improved variant (W159H/S238F). We compare the thermostability of each enzyme and describe a 1.45 A resolution structure of the mutant, highlighting changes in the substrate binding cleft compared to the wild-type enzyme. Subsequently, the performance of the wild-type and variant enzyme was compared as a function of temperature, substrate morphology, and reaction mixture composition. These studies show that reaction temperature has the strongest influence on performance between the two enzymes. We also show that both enzymes achieve higher levels of PET conversion for substrates with moderate crystallinity relative to amorphous substrates. Finally, we assess the impact of product accumulation on reaction progress for the hydrolysis of both PET and bis(2-hydroxyethyl) terephthalate (BHET). Each enzyme displays different inhibition profiles to mono(2-hydroxyethyl) terephthalate (MHET) and TPA, while both are sensitive to inhibition by EG. Overall, this study highlights the importance of reaction conditions, substrate selection, and product accumulation for catalytic performance of PET-hydrolyzing enzymes, which have implications for enzyme screening in the development of enzyme- based polyester recycling.