title: Functional characterization and structural modeling of synthetic polyester-degrading hydrolases from Thermomonospora curvata.
abstract: Thermomonospora curvata is a thermophilic actinomycete phylogenetically related to Thermobifida fusca that produces extracellular hydrolases capable of degrading synthetic polyesters. Analysis of the genome of T. curvata DSM43183 revealed two genes coding for putative polyester hydrolases Tcur1278 and Tcur0390 sharing 61% sequence identity with the T. fusca enzymes. Mature proteins of Tcur1278 and Tcur0390 were cloned and expressed in Escherichia coli TOP10. Tcur1278 and Tcur0390 exhibited an optimal reaction temperature against p-nitrophenyl butyrate at 60°C and 55°C, respectively. The optimal pH for both enzymes was determined at pH 8.5. Tcur1278 retained more than 80% and Tcur0390 less than 10% of their initial activity following incubation for 60 min at 55°C. Tcur0390 showed a higher hydrolytic activity against poly(ε-caprolactone) and polyethylene terephthalate (PET) nanoparticles compared to Tcur1278 at reaction temperatures up to 50°C. At 55°C and 60°C, hydrolytic activity against PET nanoparticles was only detected with Tcur1278. In silico modeling of the polyester hydrolases and docking with a model substrate composed of two repeating units of PET revealed the typical fold of α/β serine hydrolases with an exposed catalytic triad. Molecular dynamics simulations confirmed the superior thermal stability of Tcur1278 considered as the main reason for its higher hydrolytic activity on PET.
authors.affiliation: Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany.
authors.forename: Ren
authors.initials: R
authors.lastname: Wei
authors.affiliation: Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Oeser
authors.affiliation: Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Then
authors.affiliation: Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany.
authors.forename: Nancy
authors.initials: N
authors.lastname: Kühn
authors.affiliation: Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Barth
authors.affiliation: Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Schmidt
authors.affiliation: Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Zimmermann
keywords: Polyester hydrolase; Polyethylene terephthalate (PET); Synthetic polyester; Thermomonospora curvata