8ekg
MHETase variant Thr159Val, Met192Tyr, Tyr252Phe, Tyr503Trp
Structural highlights
FunctionMHETH_PISS1 Involved in the degradation and assimilation of the plastic poly(ethylene terephthalate) (PET), which allows I.sakaiensis to use PET as its major energy and carbon source for growth. Likely acts synergistically with PETase to depolymerize PET. Catalyzes the hydrolysis of mono(2-hydroxyethyl) terephthalate (MHET) into its two environmentally benign monomers, terephthalate and ethylene glycol. Does not show activity against PET, bis(hydroxyethyl) terephthalate (BHET), pNP-aliphatic esters or typical aromatic ester compounds catalyzed by the tannase family enzymes, such as ethyl gallate and ethyl ferulate.[1] Publication Abstract from PubMedThe mono(2-hydroxyethyl) terephthalate hydrolase (MHETase) from Ideonella sakaiensis carries out the second step in the enzymatic depolymerization of poly(ethylene terephthalate) (PET) plastic into the monomers terephthalic acid (TPA) and ethylene glycol (EG). Despite its potential industrial and environmental applications, poor recombinant expression of MHETase has been an obstacle to its industrial application. To overcome this barrier, we developed an assay allowing for the medium-throughput quantification of MHETase activity in cell lysates and whole-cell suspensions, which allowed us to screen a library of engineered variants. Using consensus design, we generated several improved variants that exhibit over 10-fold greater whole-cell activity than wild-type (WT) MHETase. This is revealed to be largely due to increased soluble expression, which biochemical and structural analysis indicates is due to improved protein folding. Increasing the Soluble Expression and Whole-Cell Activity of the Plastic-Degrading Enzyme MHETase through Consensus Design.,Saunders JW, Damry AM, Vongsouthi V, Spence MA, Frkic RL, Gomez C, Yates PA, Matthews DS, Tokuriki N, McLeod MD, Jackson CJ Biochemistry. 2024 Jul 2;63(13):1663-1673. doi: 10.1021/acs.biochem.4c00165. Epub , 2024 Jun 17. PMID:38885634[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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