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Tiangang Liu - One of the best experts on this subject based on the ideXlab platform.
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Marker-Free System Using Ribosomal Promoters Enhanced Xylose/Glucose Isomerase Production in Streptomyces rubiginosus.
Biotechnology journal, 2019Co-Authors: Xiaojie Wang, Zixin Deng, Tiangang LiuAbstract:Xylose/Glucose Isomerases are important industrial enzymes that are most widely used in food industries; however, their previously reported expression levels do not meet the requirements for industrial application. Here, an antibiotic resistance marker (ARM)-free system driven by ribosomal RNA (rRNA) promoters is developed to obtain high-level xylose/Glucose Isomerase (XI/GI) expression in Streptomyces rubiginosus (S. rubiginosus). The rRNA promoter rrnD yields the highest Glucose Isomerase production titer of XIs/GIs, which is eight times higher than that of ermEp* and 2.6 times higher than that of kasOp*. The integrated ARM gene is removed by further introduction of the Cre plasmid with a temperature-sensitive replicon. The production titer of XIs/GIs is further improved by replacing the xylR gene with an additional expression Glucose Isomerase cassette at the xylR locus. Ultimately, the Glucose Isomerase activity reaches up to 79.7 ± 7.5 U mL-1 at 96 h. The results support the robustness and stability of XI/GI production with this ARM-free system using optimal ribosomal promoters in S. rubiginosus, demonstrating strong potential in large-scale industrial applications. Besides, the results imply that rRNA promoters are strong promoters that can be used for protein engineering or metabolic engineering.
J. G. Zeikus - One of the best experts on this subject based on the ideXlab platform.
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Purification and characterization of thermostable Glucose Isomerase from Clostridium thermosulfurogenes and Thermoanaerobacter strain B6A.
Biochemical Journal, 1991Co-Authors: Chanyong Lee, J. G. ZeikusAbstract:Glucose Isomerases produced by Thermoanaerobacter strain B6A and Clostridium thermosulfurogenes strain 4B were purified 10-11-fold to homogeneity and their physicochemical and catalytic properties were determined. Both purified enzymes displayed very similar properties (native Mr 200,000, tetrameric subunit composition, and apparent pH optima 7.0-7.5). The enzymes were stable at pH 5.5-12.0, and maintained more than 90% activity after incubation at high temperature (85 degrees C) for 1 h in the presence of metal ions. The N-terminal amino acid sequences of both thermostable Glucose Isomerases were Met-Asn-Lys-Tyr-Phe-Glu-Asn and were not similar to that of the thermolabile Bacillus subtilis enzyme. The Glucose Isomerase from C. thermosulfurogenes and Thermoanaerobacter displayed pI values of 4.9 and 4.8, and their kcat. and Km values for D-Glucose at 65 degrees C were 1040 and 1260 min-1 and 140 and 120 mM respectively. Both enzymes displayed higher kcat. and lower Km values for D-xylose than for D-Glucose. The C. thermosulfurogenes enzyme required Co2+ or Mg2+ for thermal stability and Glucose Isomerase activity, and Mn2+ or these metals for xylose Isomerase activity. Crystals of C. thermosulfurogenes Glucose Isomerase were formed at room temperature by the hanging-drop method using 16-18% poly(ethylene glycol) (PEG) 4000 in 0.1 M-citrate buffer.
Xiaojie Wang - One of the best experts on this subject based on the ideXlab platform.
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Marker-Free System Using Ribosomal Promoters Enhanced Xylose/Glucose Isomerase Production in Streptomyces rubiginosus.
Biotechnology journal, 2019Co-Authors: Xiaojie Wang, Zixin Deng, Tiangang LiuAbstract:Xylose/Glucose Isomerases are important industrial enzymes that are most widely used in food industries; however, their previously reported expression levels do not meet the requirements for industrial application. Here, an antibiotic resistance marker (ARM)-free system driven by ribosomal RNA (rRNA) promoters is developed to obtain high-level xylose/Glucose Isomerase (XI/GI) expression in Streptomyces rubiginosus (S. rubiginosus). The rRNA promoter rrnD yields the highest Glucose Isomerase production titer of XIs/GIs, which is eight times higher than that of ermEp* and 2.6 times higher than that of kasOp*. The integrated ARM gene is removed by further introduction of the Cre plasmid with a temperature-sensitive replicon. The production titer of XIs/GIs is further improved by replacing the xylR gene with an additional expression Glucose Isomerase cassette at the xylR locus. Ultimately, the Glucose Isomerase activity reaches up to 79.7 ± 7.5 U mL-1 at 96 h. The results support the robustness and stability of XI/GI production with this ARM-free system using optimal ribosomal promoters in S. rubiginosus, demonstrating strong potential in large-scale industrial applications. Besides, the results imply that rRNA promoters are strong promoters that can be used for protein engineering or metabolic engineering.
B. A. Tashpulatova - One of the best experts on this subject based on the ideXlab platform.
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Isolation and some properties of Glucose Isomerase from a hybrid strain ofStreptomyces atratus
Chemistry of Natural Compounds, 1996Co-Authors: Zh. Tashpulatov, I. G. Sultanova, Ya. U. Yurabova, B. A. TashpulatovaAbstract:A highly effective easily reproducible method of obtaining high purity preparations of Glucose Isomerase from initial and hybrid strains of Streptomyces atratus has been developed. Two enzymes have been characterized, with molecular masses of 160 and 120 kDa, isoelectric points of 5.2 and 5.0, pH optima of 8.0 and 9.0, and temperature optima of 80 and 90°C, respectively. The activity of Glucose Isomerase preparations obtained by purification from a hybrid strain of Streptomyces atratus was 60–70% greater than that of analogous preparations from the initial parental strain.
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Immobilization ofStreptomyces atratus Glucose Isomerase on various supports
Chemistry of Natural Compounds, 1994Co-Authors: B. A. Tashpulatova, Zh. Tashpulatov, I. G. Sultanova, N. Yu. ZukhrutdinovaAbstract:The immobilization ofStreptomycs atratus Glucose Isomerase has been achieved and the periods of half-life of the immobilized Glucose Isomerase have been determined on various supports, among which the most acceptable are cotton lint and polyurethane. The stability of the immobilized preparations has been demonstrated.
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Characteristics of the Glucose Isomerase from Streptomyces atratus
Chemistry of Natural Compounds, 1991Co-Authors: B. A. Tashpulatova, K. D. Dravranov, L. G. Mezhlum'yanAbstract:The molecular mass (Mr) of highly purified Glucose Isomerase fromStreptomyces atratus has been determined. The native Glucose Isomerase, which has affinity for xylose, consists of an oligomeric protein containing 1552 amino acid residues and formed of four subunits. The enzyme is stable in the range of temperatures from 40 to 80°C and at pH values of from 6.0 to 11.0.
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INFLUENCE OF METAL IONS ON THE ACTIVITY AND STABILITY OF THE Glucose Isomerase FROM Streptomyces atratus
Chemistry of Natural Compounds, 1991Co-Authors: B. A. Tashpulatova, K. D. DavranovaAbstract:The influence of a number of bivalent metals on the activity ofStreptomyces atratus Glucose Isomerase has been studied. Mg2+ ions are activators and Co2+ ions are stabilizers of the Glucose Isomerase activity. The effective kinetic parameters for the action of the enzyme have been determined.
Maciej Kozak - One of the best experts on this subject based on the ideXlab platform.
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Glucose Isomerase from streptomyces rubiginosus potential molecular weight standard for small angle x ray scattering
Journal of Applied Crystallography, 2005Co-Authors: Maciej KozakAbstract:Stability of solutions of Glucose Isomerase from Streptomyces rubiginosus on long-term storage and on exposure to synchrotron radiation has been studied by the small-angle X-ray scattering (SAXS) method. The values of the radii of gyration and forward scattering do not change significantly on storage and on exposure to synchrotron radiation. The mean value of the radius of gyration characterizing Glucose Isomerase is RG = 3.27 ± 0.02 nm. For comparison, a SAXS study of monodispersive and aggregated bovine serum albumin (BSA) has been carried out. The results show that Glucose Isomerase could be a more stable molecular weight standard for SAXS than BSA.