Dubois JL

References (3)

Title : Sourcing thermotolerant poly(ethylene terephthalate) hydrolase scaffolds from natural diversity - Erickson_2022_Nat.Commun_13_7850
Author(s) : Erickson E , Gado JE , Avilan L , Bratti F , Brizendine RK , Cox PA , Gill R , Graham R , Kim DJ , Konig G , Michener WE , Poudel S , Ramirez KJ , Shakespeare TJ , Zahn M , Boyd ES , Payne CM , Dubois JL , Pickford AR , Beckham GT , McGeehan JE
Ref : Nat Commun , 13 :7850 , 2022
Abstract : Enzymatic deconstruction of poly(ethylene terephthalate) (PET) is under intense investigation, given the ability of hydrolase enzymes to depolymerize PET to its constituent monomers near the polymer glass transition temperature. To date, reported PET hydrolases have been sourced from a relatively narrow sequence space. Here, we identify additional PET-active biocatalysts from natural diversity by using bioinformatics and machine learning to mine 74 putative thermotolerant PET hydrolases. We successfully express, purify, and assay 51 enzymes from seven distinct phylogenetic groups; observing PET hydrolysis activity on amorphous PET film from 37 enzymes in reactions spanning pH from 4.5-9.0 and temperatures from 30-70 degreesC. We conduct PET hydrolysis time-course reactions with the best-performing enzymes, where we observe differences in substrate selectivity as function of PET morphology. We employed X-ray crystallography and AlphaFold to examine the enzyme architectures of all 74 candidates, revealing protein folds and accessory domains not previously associated with PET deconstruction. Overall, this study expands the number and diversity of thermotolerant scaffolds for enzymatic PET deconstruction.
ESTHER : Erickson_2022_Nat.Commun_13_7850
PubMedSearch : Erickson_2022_Nat.Commun_13_7850
PubMedID: 36543766
Gene_locus related to this paper: 9arch-PETcan211 , 9cren-PETcan204 , 9cyan-305pEE028 , 9bact-102Pee006 , 9chlr-7QJM202 , 9bact-a0a656d8b6 , 9actn-a0a1t4kk94 , 9burk-PET11 , 9bact-c3ryl0 , thecs-711Erick , 9actn-RII04304 , 9actn-h6wx58 , thecd-d1a9g5 , thecd-d1a2h1 , 9acto-d4q9n1 , 9acto-f7ix06 , 9gamm-a0a3l8bw54 , 9actn-a0a0n0my27 , 9burk-a0a1e4lw26 , 9actn-Alr407 , 9gamm-a0a3l8bdt3 , 9gamm-a0a2k9lit3 , 9bact-g9by57 , bacsu-pnbae , thefu-q6a0i4 , 9actn-a0a0n0ney5 , 9pseu-a0a1i6nu60 , thefu-q6a0i3 , 9actn-a0a147kjy8 , 9actn-e9upm2

Title : A flexible kinetic assay efficiently sorts prospective biocatalysts for PET plastic subunit hydrolysis - Lusty_2022_RSC.Adv_12_8119
Author(s) : Lusty Beech J , Clare R , Kincannon WM , Erickson E , McGeehan JE , Beckham GT , Dubois JL
Ref : RSC Adv , 12 :8119 , 2022
Abstract : Esterase enzymes catalyze diverse hydrolysis reactions with important biological, commercial, and biotechnological applications. For the improvement of these biocatalysts, there is a need for widely accessible, inexpensive, and adaptable activity screening assays that identify enzymes with particular substrate specificities. Natural systems for biopolymer bioconversion, and likely those designed to mimic them, depend on cocktails of enzymes, each of which specifically targets the intact material as well as water-soluble subunits of varying size. In this work, we have adapted a UV/visible assay using pH-sensitive sulfonphthalein dyes for the real-time quantification of ester hydrolysis of bis-(2-hydroxyethyl) terephthalate (BHET), a subunit of polyethylene terephthalate (PET) plastic. We applied this method to a diverse set of known PET hydrolases and commercial esterases in a microplate format. The approach identified four PET hydrolases and one commercial esterase with high levels of specificity for BHET hydrolysis. Five additional PET hydrolases and three commercial esterases, including a thermophilic enzyme, effectively hydrolyzed both BHET and its monoester product MHET (mono-(2-hydroxyethyl) terephthalate). Specific activities were discernible within one hour and reactions reached an unequivocal endpoint well within 24 hours. The results from the UV/visible method correlated well with conventional HPLC analysis of the reaction products. We examined the suitability of the method toward variable pH, temperature, enzyme preparation method, mono- and multi-ester substrate type, and level of sensitivity versus stringency, finding the assay to be easily adaptable to diverse screening conditions and kinetic measurements. This method offers an accurate, easily accessible, and cost-effective route towards high-throughput library screening to support the discovery, directed evolution, and protein engineering of these critical biocatalysts.
ESTHER : Lusty_2022_RSC.Adv_12_8119
PubMedSearch : Lusty_2022_RSC.Adv_12_8119
PubMedID: 35424733

Title : Insights into the unique carboxylation reactions in the metabolism of propylene and acetone - Mus_2020_Biochem.J_477_2027
Author(s) : Mus F , Wu HH , Alleman AB , Shisler KA , Zadvornyy OA , Bothner B , Dubois JL , Peters JW
Ref : Biochemical Journal , 477 :2027 , 2020
Abstract : Alkenes and ketones are two classes of ubiquitous, toxic organic compounds in natural environments produced in several biological and anthropogenic processes. In spite of their toxicity, these compounds are utilized as primary carbon and energy sources or are generated as intermediate metabolites in the metabolism of other compounds by many diverse bacteria. The aerobic metabolism of some of the smallest and most volatile of these compounds (propylene, acetone, isopropanol) involves novel carboxylation reactions resulting in a common product acetoacetate. Propylene is metabolized in a four-step pathway involving five enzymes where the penultimate step is a carboxylation reaction catalyzed by a unique disulfide oxidoreductase that couples reductive cleavage of a thioether linkage with carboxylation to produce acetoacetate. The carboxylation of isopropanol begins with conversion to acetone via an alcohol dehydrogenase. Acetone is converted to acetoacetate in a single step by an acetone carboxylase which couples the hydrolysis of MgATP to the activation of both acetone and bicarbonate, generating highly reactive intermediates that are condensed into acetoacetate at a Mn2+ containing the active site. Acetoacetate is then utilized in central metabolism where it is readily converted to acetyl-coenzyme A and subsequently converted into biomass or utilized in energy metabolism via the tricarboxylic acid cycle. This review summarizes recent structural and biochemical findings that have contributed significant insights into the mechanism of these two unique carboxylating enzymes.
ESTHER : Mus_2020_Biochem.J_477_2027
PubMedSearch : Mus_2020_Biochem.J_477_2027
PubMedID: 32497192