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Steviol is a diterpene isolated from the plant Stevia rebaudiana that has a potential role as an antihyperglycemic agent by stimulating insulin secretion from pancreatic beta cells and also has significant potential to diminish the renal clearance of anionic drugs and their metabolites. In this study, the lacS gene, which encodes a thermostable β-glycosidase (SSbgly) enzyme from the extremely thermoacidophillic archaeon Sulfolobus solfataricus, was cloned and expressed in E. coli Rossetta BL21(DE3)pLyS using lactose as an inducer. Through fermentation, SSbgly was expressed as a 61kDa protein with activity of 24.3U/mg and the OD of 23 was reached after 18h induction with 10mM lactose. Purified protein was obtained by Ni-Sepharose chromatography with a yield of 92.3%. SSbgly hydrolyzed steviol glycosides to produce steviol with a yield of 99.2%. The optimum conditions for steviol production were 50U/ml SSbgly and 90mg/ml Ste at 75°C as determined by the response surface method.
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http://dx.doi.org/10.1016/j.enzmictec.2016.08.013 | DOI Listing |
Protein Expr Purif
August 2025
Key Laboratory for Food Science & Engineering, Harbin University of Commerce, Harbin, 150028, China. Electronic address:
The DNA polymerase from Thermococcus kodakarensis KOD1 (KOD) is widely utilized in polymerase chain reaction (PCR) due to its high processivity and fidelity. However, like many other B-family DNA polymerases, it faces limitations in extension efficiency, amplicon length, and resistance to PCR inhibitors. In order to further enhance its capability, novel mutants were engineered by fusing a 7 kDa nonspecific double-stranded DNA (dsDNA)-binding protein from Sulfolobus tokodaii (Sto7d) to the C-terminus of KOD via distinct peptide linkers, resulting in a set of KOD-Sto7d polymerase variants.
View Article and Find Full Text PDFExtremophiles
July 2025
Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, 2393 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0795, Japan.
The gene (SSO1457) encoding a L-glutamate dehydrogenase (GDH) homolog from the thermoacidophilic archaeon Saccharolobus solfataricus P2 was overexpressed in Escherichia coli. At a substrate concentration of 50 mM, the enzyme (SSO1457) produced exhibited much higher specific activity toward L-norvaline than L-glutamate at temperatures between 55 and 75°C, whereas the enzyme showed higher activity for L-glutamate than L-norvaline at 85°C. The crystal structures of both NAD/2-oxovalerate-bound and NAD/2-oxoglutarate-bound SSO1457 were determined.
View Article and Find Full Text PDFActa Crystallogr F Struct Biol Commun
May 2025
Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 516, Little Rock, AR 72205, USA.
DNA replication is tightly regulated to ensure genomic stability and prevent several diseases, including cancers. Eukaryotes and archaea partly achieve this regulation by strictly controlling the activation of hexameric minichromosome maintenance (MCM) helicase rings that unwind DNA during its replication. In eukaryotes, MCM activation critically relies on the sequential recruitment of the essential factors Cdc45 and a tetrameric GINS complex at the onset of the S-phase to generate a larger CMG complex.
View Article and Find Full Text PDFNat Commun
January 2025
Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole polytechnique, Institut Polytechnique de Paris, Palaiseau, 91120, France.
The archaeal ribosome is of the eukaryotic type. TACK and Asgard superphyla, the closest relatives of eukaryotes, have ribosomes containing eukaryotic ribosomal proteins not found in other archaea, eS25, eS26 and eS30. Here, we investigate the case of Saccharolobus solfataricus, a TACK crenarchaeon, using mainly leaderless mRNAs.
View Article and Find Full Text PDFFront Microbiol
November 2024
Molecular Enzyme Technology and Biochemistry (MEB), Environmental Microbiology and Biotechnology (EMB), Centre for Water and Environmental Research (CWE), Faculty of Chemistry, University of Duisburg-Essen, Essen, Germany.
, a thermoacidophilic archaeon of the phylum Thermoproteota (former Crenarchaeota), is a widely used model organism for gene deletion studies and recombinant protein production. Previous research has demonstrated the efficacy of the promoter (P), providing low basal activity and high pentose-dependent induction. However, the available expression vector does not include a 5'-terminal untranslated region (5'-UTR), a typical element found in bacterial expression vectors that usually enhances protein production in bacteria.
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