Two novel esterases from the anaerobe Clostridium botulinum ATCC 3502 (Cbotu_EstA and Cbotu_EstB) were expressed in Escherichia coli BL21-Gold(DE3) and were found to hydrolyze the polyester poly(butylene adipate-co-butylene terephthalate) (PBAT). The active site residues (triad Ser, Asp, His) are present in both enzymes at the same location only with some amino acid variations near the active site at the surrounding of aspartate. Yet, Cbotu_EstA showed higher kcat values on para-nitrophenyl butyrate and para-nitrophenyl acetate and was considerably more active (sixfold) on PBAT. The entrance to the active site of the modeled Cbotu_EstB appears more narrowed compared to the crystal structure of Cbotu_EstA and the N-terminus is shorter which could explain its lower activity on PBAT. The Cbotu_EstA crystal structure consists of two regions that may act as movable cap domains and a zinc metal binding site.
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http://dx.doi.org/10.1002/bit.25874 | DOI Listing |
In the leucine (Leu) biosynthesis pathway, homeostasis is achieved through a feedback regulatory mechanism facilitated by the binding of the end-product Leu at the C-terminal regulatory domain of the first committed enzyme, isopropylmalate synthase (IPMS). In vitro studies have shown that removing the regulatory domain abolishes the feedback regulation on plant IPMS while retaining its catalytic activity. However, the physiological consequences and underlying molecular regulation on Leu flux upon removing the IPMS C-terminal domain remain to be explored in plants.
View Article and Find Full Text PDFAcc Chem Res
January 2025
The Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, United States.
ConspectusIn the search for efficient and selective electrocatalysts capable of converting greenhouse gases to value-added products, enzymes found in naturally existing bacteria provide the basis for most approaches toward electrocatalyst design. Ni,Fe-carbon monoxide dehydrogenase (Ni,Fe-CODH) is one such enzyme, with a nickel-iron-sulfur cluster named the C-cluster, where CO binds and is converted to CO at high rates near the thermodynamic potential. In this Account, we divide the enzyme's catalytic contributions into three categories based on location and function.
View Article and Find Full Text PDFChem Biodivers
January 2025
Kasetsart University - Bangkhen Campus, Chemistry, 50 Ngamwongwan Road, 10900, Bangkok, THAILAND.
A terpene synthase gene (mtas) from Menisporopsis theobromae BCC 4162 was heterologously expressed in Aspergillus oryzae NSAR1, resulting in the production of (+)-aristolochene. Mutations were introduced in MtAS at aromatic residues (Y83, F103, F169, and W323) surrounding the active site, which are critical for precursor cyclisation and intermediate stabilisation during aristolochene biosynthesis. Transformants harbouring mutated mtas, specifically F103W, F169A and F169W, produced (2R,4S,5R,7S)-2-hydroxyaristolochene as the major product, along with aristolochene and other tentative metabolites, including germacrene A and sesquiterpenoids.
View Article and Find Full Text PDFGlob Chang Biol
January 2025
Department of River Ecology and Conservation, Senckenberg Research Institute and Natural History Museum Frankfurt, Gelnhausen, Germany.
Freshwater ecosystems face significant threats, including pollution, habitat loss, invasive species, and climate change. To address these challenges, management strategies and restoration efforts have been broadly implemented. Across Europe, such efforts have resulted in overall improvements in freshwater biodiversity, but recovery has stalled or failed to occur in many localities, which may be partly caused by the limited dispersal capacity of many species.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Molecular Biomimetics, Department of Chemistry, Ångström Laboratory, Uppsala University, P.O. Box 523, Uppsala SE-75120, Sweden.
[FeFe] hydrogenases make up a structurally diverse family of metalloenzymes that catalyze proton/dihydrogen interconversion. They can be classified into phylogenetically distinct groups denoted A-G, which differ in structure and reactivity. Prototypical Group A hydrogenases have high turnover rates and remarkable energy efficiency.
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