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Li X, Jiang J, Li X, Liu D, Han M, Li W, Zhang H. Characterization and Application of a Novel Glucose Dehydrogenase with Excellent Organic Solvent Tolerance for Cofactor Regeneration in Carbonyl Reduction. Appl Biochem Biotechnol 2023; 195:7553-7567. [PMID: 37014512 DOI: 10.1007/s12010-023-04432-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2023] [Indexed: 04/05/2023]
Abstract
An efficient cofactor regeneration system has been developed to provide a hydride source for the preparation of optically pure alcohols by carbonyl reductase-catalyzed asymmetric reduction. This system employed a novel glucose dehydrogenase (BcGDH90) from Bacillus cereus HBL-AI. The gene encoding BcGDH90 was found through the genome-wide functional annotation. Homology-built model study revealed that BcGDH90 was a homo-tetramer, and each subunit was composed of βD-αE-αF-αG-βG motif, which was responsible for substrate binding and tetramer formation. The gene of BcGDH90 was cloned and expressed in Escherichia coli. The recombinant BcGDH90 exhibited maximum activity of 45.3 U/mg at pH 9.0 and 40 °C. BcGDH90 showed high stability in a wide pH range of 4.0-10.0 and was stable after the incubation at 55 °C for 5 h. BcGDH90 was not a metal ion-dependent enzyme, but Zn2+ could seriously inhibit its activity. BcGDH90 displayed excellent tolerance to 90% of acetone, methanol, ethanol, n-propanol, and isopropanol. Furthermore, BcGDH90 was applied to regenerate NADPH for the asymmetric biosynthesis of (S)-(+)-1-phenyl-1,2-ethanediol ((S)-PED) from hydroxyacetophenone (2-HAP) with high concentration, which increased the final efficiency by 59.4%. These results suggest that BcGDH90 is potentially useful for coenzyme regeneration in the biological reduction.
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Affiliation(s)
- Xiaozheng Li
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China
| | - Junpo Jiang
- College of Life Science, Microbial Technology Innovation Center for Feed of Hebei Province, Hebei Agricultural University, Baoding, 071001, China
| | - Xinyue Li
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China
| | - Dexu Liu
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China
| | - Mengnan Han
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China
| | - Wei Li
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China.
| | - Honglei Zhang
- College of Chemistry and Materials Science, Key Laboratory of Chemical Biology of Hebei Province, Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Institute of Life Science and Green Development, Hebei University, Baoding, 071002, China.
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Ferraraccio LS, Bertoncello P. Electrochemiluminescence (ECL) biosensor based on tris(2,2'-bipyridyl)ruthenium(II) with glucose and lactate dehydrogenases encapsulated within alginate hydrogels. Bioelectrochemistry 2023; 150:108365. [PMID: 36638677 DOI: 10.1016/j.bioelechem.2023.108365] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 01/02/2023] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Abstract
Two dehydrogenase enzymes (glucose, GDH, and lactate, LDH, dehydrogenases) encapsulated within alginate hydrogels were deposited on glassy carbon electrodes. The as-prepared enzyme modified alginate hydrogels were utilized as electrochemiluminescence (ECL)-based biosensors for the indirect detection of glucose and lactic acid upon reaction between NADH and tris(2,2'-bipyridyl) ruthenium (II) [Ru(bpy)3]2+. The ECL response was obtained from the redox reaction between the substrate, the cofactor NAD+ and the encapsulated enzyme. The production of NADH resulting from the enzymatic reaction led to the ECL emission upon reaction with [Ru(bpy)3]2+. The biosensors showed good stability and repeatability, with linear range between 0.56 and 4.2 µM and limit of detection of 0.84 µM for glucose, and linear range between 5 and 30 µM with a limit of detection of 2.52 µM for lactic acid. These ECL-based biosensors showed good sensitivity when tested in the presence of common interfering species. These biosensors were utilized in artificial sweat and were characterized by good reproducibility and repeatability. The results herein presented suggest that the dehydrogenases encapsulated within alginate hydrogels have potential for the development of biocompatible sensors for detection of glucose and lactic acid in physiological fluids.
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Affiliation(s)
- Lucia Simona Ferraraccio
- Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Bay Campus, Crymlyn Burrows, Swansea SA1 8EN, United Kingdom
| | - Paolo Bertoncello
- Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Bay Campus, Crymlyn Burrows, Swansea SA1 8EN, United Kingdom; Centre for NanoHealth, Swansea University, Singleton Campus, Swansea SA2 8PP, United Kingdom.
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Feng T, Wang Z, Li H, Li Q, Guo Y, Zhao J, Liu J. Whole-cell biotransformation for simultaneous synthesis of allitol and d-gluconic acid in recombinant Escherichia coli. J Biosci Bioeng 2023; 135:433-439. [DOI: 10.1016/j.jbiosc.2023.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/23/2023] [Accepted: 03/07/2023] [Indexed: 04/03/2023]
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Wu Y, Kawabata H, Kita K, Ishikawa S, Tanaka K, Yoshida KI. Constitutive glucose dehydrogenase elevates intracellular NADPH levels and luciferase luminescence in Bacillus subtilis. Microb Cell Fact 2022; 21:266. [PMID: 36539761 PMCID: PMC9768902 DOI: 10.1186/s12934-022-01993-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Genetic modifications in Bacillus subtilis have allowed the conversion of myo-inositol into scyllo-inositol, which is proposed as a therapeutic agent for Alzheimer's disease. This conversion comprises two reactions catalyzed by two distinct inositol dehydrogenases, IolG and IolW. The IolW-mediated reaction requires the intracellular regeneration of NADPH, and there appears to be a limit to the endogenous supply of NADPH, which may be one of the rate-determining factors for the conversion of inositol. The primary mechanism of NADPH regeneration in this bacterium remains unclear. RESULTS The gdh gene of B. subtilis encodes a sporulation-specific glucose dehydrogenase that can use NADP+ as a cofactor. When gdh was modified to be constitutively expressed, the intracellular NADPH level was elevated, increasing the conversion of inositol. In addition, the bacterial luciferase derived from Photorhabdus luminescens became more luminescent in cells in liquid culture and colonies on culture plates. CONCLUSION The results indicated that the luminescence of luciferase was representative of intracellular NADPH levels. Luciferase can therefore be employed to screen for mutations in genes involved in NADPH regeneration in B. subtilis, and artificial manipulation to enhance NADPH regeneration can promote the production of substances such as scyllo-inositol.
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Affiliation(s)
- Yuzheng Wu
- grid.31432.370000 0001 1092 3077Department of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657 8501 Japan
| | - Honami Kawabata
- grid.31432.370000 0001 1092 3077Department of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657 8501 Japan
| | - Kyosuke Kita
- grid.31432.370000 0001 1092 3077Department of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657 8501 Japan
| | - Shu Ishikawa
- grid.31432.370000 0001 1092 3077Department of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657 8501 Japan
| | - Kan Tanaka
- grid.32197.3e0000 0001 2179 2105Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Tokyo, Japan ,grid.419082.60000 0004 1754 9200Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
| | - Ken-ichi Yoshida
- grid.31432.370000 0001 1092 3077Department of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657 8501 Japan
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Enzymes of an alternative pathway of glucose metabolism in obligate methanotrophs. Sci Rep 2021; 11:8795. [PMID: 33888823 PMCID: PMC8062543 DOI: 10.1038/s41598-021-88202-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/06/2021] [Indexed: 11/09/2022] Open
Abstract
Aerobic methanotrophic bacteria utilize methane as a growth substrate but are unable to grow on any sugars. In this study we have shown that two obligate methanotrophs, Methylotuvimicrobium alcaliphilum 20Z and Methylobacter luteus IMV-B-3098, possess functional glucose dehydrogenase (GDH) and gluconate kinase (GntK). The recombinant GDHs from both methanotrophs were homotetrameric and strongly specific for glucose preferring NAD+ over NADP+. GDH from Mtm. alcaliphilum was most active at pH 10 (Vmax = 95 U/mg protein) and demonstrated very high Km for glucose (91.8 ± 3.8 mM). GDH from Mb. luteus was most active at pH 8.5 (Vmax = 43 U/mg protein) and had lower Km for glucose (16 ± 0.6 mM). The cells of two Mtm. alcaliphilum double mutants with deletions either of the genes encoding GDH and glucokinase (gdh─/glk─) or of the genes encoding gluconate kinase and glucokinase (gntk─/glk─) had the lower glycogen level and the higher contents of intracellular glucose and trehalose compared to the wild type strain. The gntk─/glk─ knockout mutant additionally accumulated gluconic acid. These data, along with bioinformatics analysis, demonstrate that glycogen derived free glucose can enter the Entner–Doudoroff pathway or the pentose phosphate cycle in methanotrophs, bypassing glycolysis via the gluconate shunt.
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Qian WZ, Ou L, Li CX, Pan J, Xu JH, Chen Q, Zheng GW. Evolution of Glucose Dehydrogenase for Cofactor Regeneration in Bioredox Processes with Denaturing Agents. Chembiochem 2020; 21:2680-2688. [PMID: 32324965 DOI: 10.1002/cbic.202000196] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/20/2020] [Indexed: 02/04/2023]
Abstract
Glucose dehydrogenase (GDH) is a general tool for driving nicotinamide (NAD(P)H) regeneration in synthetic biochemistry. An increasing number of synthetic bioreactions are carried out in media containing high amounts of organic cosolvents or hydrophobic substrates/products, which often denature native enzymes, including those for cofactor regeneration. In this work, we attempted to improve the chemical stability of Bacillus megaterium GDH (BmGDHM0 ) in the presence of large amounts of 1-phenylethanol by directed evolution. Among the resulting mutants, BmGDHM6 (Q252L/E170K/S100P/K166R/V72I/K137R) exhibited a 9.2-fold increase in tolerance against 10 % (v/v) 1-phenylethanol. Moreover, BmGDHM6 was also more stable than BmGDHM0 when exposed to hydrophobic and enzyme-inactivating compounds such as acetophenone, ethyl 2-oxo-4-phenylbutyrate, and ethyl (R)-2-hydroxy-4-phenylbutyrate. Coupled with a Candida glabrata carbonyl reductase, BmGDHM6 was successfully used for the asymmetric reduction of deactivating ethyl 2-oxo-4-phenylbutyrate with total turnover number of 1800 for the nicotinamide cofactor, thus making it attractive for commercial application. Overall, the evolution of chemically robust GDH facilitates its wider use as a general tool for NAD(P)H regeneration in biocatalysis.
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Affiliation(s)
- Wen-Zhuo Qian
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China
| | - Ling Ou
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China
| | - Chun-Xiu Li
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China
| | - Jiang Pan
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China
| | - Jian-He Xu
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China
| | - Qi Chen
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China
| | - Gao-Wei Zheng
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Center for Biomanufacturing, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, P. R. China
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Stolarczyk K, Rogalski J, Bilewicz R. NAD(P)-dependent glucose dehydrogenase: Applications for biosensors, bioelectrodes, and biofuel cells. Bioelectrochemistry 2020; 135:107574. [PMID: 32498025 DOI: 10.1016/j.bioelechem.2020.107574] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 05/21/2020] [Accepted: 05/21/2020] [Indexed: 12/13/2022]
Abstract
This review discusses the physical and chemical properties of nicotinamide redox cofactor dependent glucose dehydrogenase (NAD(P) dependent GDH) and its extensive application in biosensors and bio-fuel cells. GDHs from different organisms show diverse biochemical properties (e.g., activity and stability) and preferences towards cofactors, such as nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP+). The (NAD(P)+) play important roles in biological electron transfer, however, there are some difficulties related to their application in devices that originate from their chemical properties and labile binding to the GDH enzyme. This review discusses the electrode modifications aimed at immobilising NAD+ or NADP+ cofactors and GDH at electrodes. Binding of the enzyme was achieved by appropriate protein engineering techniques, including polymerisation, hydrophobisation or hydrophilisation processes. Various enzyme-modified electrodes applied in biosensors, enzymatic fuel cells, and biobatteries are compared. Importantly, GDH can operate alone or as part of an enzymatic cascade, which often improves the functional parameters of the biofuel cell or simply allows use of cheaper fuels. Overall, this review explores how NAD(P)-dependent GDH has recently demonstrated high potential for use in various systems to generate electricity from biological sources for applications in implantable biomedical devices, wireless sensors, and portable electronic devices.
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Affiliation(s)
- Krzysztof Stolarczyk
- Faculty of Chemistry, University of Warsaw, Pasteura St. 1, 02-093 Warsaw, Poland
| | - Jerzy Rogalski
- Department of Biochemistry and Biotechnology, Maria Curie-Sklodowska University, Akademicka Str. 19, 20-031 Lublin, Poland
| | - Renata Bilewicz
- Faculty of Chemistry, University of Warsaw, Pasteura St. 1, 02-093 Warsaw, Poland.
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Halmschlag B, Hoffmann K, Hanke R, Putri SP, Fukusaki E, Büchs J, Blank LM. Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis. Front Bioeng Biotechnol 2020; 7:476. [PMID: 32039180 PMCID: PMC6985040 DOI: 10.3389/fbioe.2019.00476] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/23/2019] [Indexed: 11/13/2022] Open
Abstract
The production of poly-γ-glutamic acid (γ-PGA), a biopolymer consisting of D- and L-glutamic acid monomers, currently relies on L-glutamate, or citrate as carbon substrates. Here we aimed at using plant biomass-derived substrates such as xylose. γ-PGA producing microorganisms including Bacillus subtilis natively metabolize xylose via the isomerase pathway. The Weimberg pathway, a xylose utilization pathway first described for Caulobacter crescentus, offers a carbon-efficient alternative converting xylose to 2-oxoglutarate without carbon loss. We engineered a recombinant B. subtilis strain that was able to grow on xylose with a growth rate of 0.43 h-1 using a recombinant Weimberg pathway. Although ion-pair reversed-phase LC/MS/MS metabolome analysis revealed lower concentrations of γ-PGA precursors such as 2-oxoglutarate, the γ-PGA titer was increased 6-fold compared to the native xylose isomerase strain. Further metabolome analysis indicates a metabolic bottleneck in the phosphoenolpyruvate-pyruvate-oxaloacetate node causing bi-phasic (diauxic) growth of the recombinant Weimberg strain. Flux balance analysis (FBA) of the γ-PGA producing B. subtilis indicated that a maximal theoretical γ-PGA yield is achieved on D-xylose/ D-glucose mixtures. The results of the B. subtilis strain harboring the Weimberg pathway on such D-xylose/ D-glucose mixtures demonstrate indeed resource efficient, high yield γ-PGA production from biomass-derived substrates.
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Affiliation(s)
- Birthe Halmschlag
- Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Kyra Hoffmann
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - René Hanke
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Sastia P Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Jochen Büchs
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Lars M Blank
- Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
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Ferreira CMH, López-Rayo S, Lucena JJ, Soares EV, Soares HMVM. Evaluation of the Efficacy of Two New Biotechnological-Based Freeze-Dried Fertilizers for Sustainable Fe Deficiency Correction of Soybean Plants Grown in Calcareous Soils. FRONTIERS IN PLANT SCIENCE 2019; 10:1335. [PMID: 31781134 PMCID: PMC6857624 DOI: 10.3389/fpls.2019.01335] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 09/25/2019] [Indexed: 05/20/2023]
Abstract
Currently, fertilization with synthetic chelates is the most effective agricultural practice to prevent iron (Fe) deficiencies in crops, especially in calcareous soils. Because these compounds are not biodegradable, they are persistent in the environment, and so, there is the risk of metal leaching from the soils. Thus, new, more environment-friendly efficient solutions are needed to solve iron-deficiency-induced chlorosis (IDIC) in crops grown in calcareous soils. Therefore, the central aim of this work was to prepare new freeze-dried Fe products, using a biotechnological-based process, from two siderophores bacterial (Azotobacter vinelandii and Bacillus subtilis) cultures (which previously evidenced high Fe complexation ability at pH 9) and test their capacity for amending IDIC of soybean grown in calcareous soils. Results have shown that A. vinelandii iron fertilizer was more stable and interacted less with calcareous soils and its components than B. subtilis one. This behavior was noticeable in pot experiments where chlorotic soybean plants were treated with both fertilizer products. Plants treated with A. vinelandii fertilizer responded more significantly than those treated with B. subtilis one, when evaluated by their growth (20% more dry mass than negative control) and chlorophyll development (30% higher chlorophyll index than negative control) and in most parameters similar to the positive control, ethylenediamine-di(o-hydroxyphenylacetic acid). On average, Fe content was also higher in A. vinelandii-treated plants than on B. subtilis-treated ones. Results suggest that this new siderophore-based formulation product, prepared from A. vinelandii culture, can be regarded as a possible viable alternative for replacing the current nongreen Fe-chelating fertilizers and may envisage a sustainable and environment-friendly mending IDIC of soybean plants grown in calcareous soils.
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Affiliation(s)
- Carlos M. H. Ferreira
- REQUIMTE/LAQV, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
- Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Porto, Portugal
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Sandra López-Rayo
- Departamento de Química Agrícola y Bromatología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan J. Lucena
- Departamento de Química Agrícola y Bromatología, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Eduardo V. Soares
- Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Porto, Portugal
- CEB-Centre of Biological Engineering, University of Minho, Braga, Portugal
| | - Helena M. V. M. Soares
- REQUIMTE/LAQV, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, Porto, Portugal
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Chen X, Cui Y, Cheng X, Feng J, Wu Q, Zhu D. Highly Atom Economic Synthesis of d-2-Aminobutyric Acid through an In Vitro Tri-enzymatic Catalytic System. ChemistryOpen 2017; 6:534-540. [PMID: 28794949 PMCID: PMC5542762 DOI: 10.1002/open.201700093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Indexed: 11/11/2022] Open
Abstract
d-2-Aminobutyric acid is an unnatural amino acid serving as an important intermediate in pharmaceutical production. Developing a synthetic method that uses cheaper starting materials and produces less by-product is a pressing demand. A tri-enzymatic catalytic system, which is composed of l-threonine ammonia lyase (l-TAL), d-amino acid dehydrogenase (d-AADH), and formate dehydrogenase (FDH), has thus been developed for the synthesis of d-2-aminobutyric acid with high optical purity. In this cascade reaction, the readily available l-threonine serves as the starting material, carbon dioxide and water are the by-products. d-2-Aminobutyric acid was obtained with >90 % yield and >99 % enantioselective excess, even without adding external ammonia, demonstrating that the ammonia from the first reaction can serve as the amino donor for the reductive amination step. This multi-enzymatic system provides an attractive method with high atomic economy for the synthesis of d-α-amino acids from the corresponding l-α-amino acids, which are readily produced by fermentation.
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Affiliation(s)
- Xi Chen
- National Engineering Laboratory for Industrial Enzymes and Tianjin Engineering Center for Biocatalytic Technology, Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences Tianjin 300308 P.R. China
| | - Yunfeng Cui
- National Engineering Laboratory for Industrial Enzymes and Tianjin Engineering Center for Biocatalytic Technology, Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences Tianjin 300308 P.R. China
| | - Xinkuan Cheng
- National Engineering Laboratory for Industrial Enzymes and Tianjin Engineering Center for Biocatalytic Technology, Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences Tianjin 300308 P.R. China.,University of Chinese Academy of Sciences Beijing 100049 P.R. China
| | - Jinhui Feng
- National Engineering Laboratory for Industrial Enzymes and Tianjin Engineering Center for Biocatalytic Technology, Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences Tianjin 300308 P.R. China
| | - Qiaqing Wu
- National Engineering Laboratory for Industrial Enzymes and Tianjin Engineering Center for Biocatalytic Technology, Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences Tianjin 300308 P.R. China
| | - Dunming Zhu
- National Engineering Laboratory for Industrial Enzymes and Tianjin Engineering Center for Biocatalytic Technology, Tianjin Institute of Industrial Biotechnology Chinese Academy of Sciences Tianjin 300308 P.R. China.,University of Chinese Academy of Sciences Beijing 100049 P.R. China
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Liu L, Xu QM, Chen T, Cheng JS, Yuan YJ. Artificial consortium that produces riboflavin regulates distribution of acetoin and 2,3-butanediol by Paenibacillus polymyxa CJX518. Eng Life Sci 2017; 17:1039-1049. [PMID: 32624854 DOI: 10.1002/elsc.201600239] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 05/23/2017] [Accepted: 05/29/2017] [Indexed: 11/09/2022] Open
Abstract
The introduction of an NADH/NAD+ regeneration system can regulate the distribution between acetoin and 2,3-butanediol. NADH regeneration can also enhance butanol production in coculture fermentation. In this work, a novel artificial consortium of Paenibacillus polymyxa CJX518 and recombinant Escherichia coli LS02T that produces riboflavin (VB2) was used to regulate the NADH/NAD+ ratio and, consequently, the distribution of acetoin and 2,3-butanediol by P. polymyxa. Compared with a pure culture of P. polymyxa, the level of acetoin was increased 76.7% in the P. polymyxa and recombinant E. coli coculture. Meanwhile, the maximum production and yield of acetoin in an artificial consortium with fed-batch fermentation were 57.2 g/L and 0.4 g/g glucose, respectively. Additionally, the VB2 production of recombinant E. coli could maintain a relatively low NADH/NAD+ ratio by changing NADH dehydrogenase activity. It was also found that 2,3-butanediol dehydrogenase activity was enhanced and improved acetoin production by the addition of exogenous VB2 or by being in the artificial consortium that produces VB2. These results illustrate that the coculture of P. polymyxa and recombinant E. coli has enormous potential to improve acetoin production. It was also a novel strategy to regulate the NADH/NAD+ ratio to improve the acetoin production of P. polymyxa.
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Affiliation(s)
- Lei Liu
- Key Laboratory of Systems Bioengineering (Ministry of Education) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China.,SynBio Research Platform Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China
| | - Qiu-Man Xu
- College of Life Science Tianjin Normal University Tianjin People's Republic of China
| | - Tao Chen
- Key Laboratory of Systems Bioengineering (Ministry of Education) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China.,SynBio Research Platform Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China
| | - Jing-Sheng Cheng
- Key Laboratory of Systems Bioengineering (Ministry of Education) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China.,SynBio Research Platform Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China
| | - Ying-Jin Yuan
- Key Laboratory of Systems Bioengineering (Ministry of Education) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China.,SynBio Research Platform Collaborative Innovation Centre of Chemical Science and Engineering (Tianjin) School of Chemical Engineering and Technology Tianjin University Tianjin People's Republic of China
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12
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Liu J, Pang BQW, Adams JP, Snajdrova R, Li Z. Coupled Immobilized Amine Dehydrogenase and Glucose Dehydrogenase for Asymmetric Synthesis of Amines by Reductive Amination with Cofactor Recycling. ChemCatChem 2017. [DOI: 10.1002/cctc.201601446] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ji Liu
- Department of Chemical & Biomolecular Engineering; National University of Singapore; 4 Engineering Drive 4 Singapore 117585 Singapore
| | - Bryan Q. W. Pang
- Department of Chemical & Biomolecular Engineering; National University of Singapore; 4 Engineering Drive 4 Singapore 117585 Singapore
| | - Joseph P. Adams
- Medicines Research Centre; GlaxoSmithKline R&D Ltd; Gunnels Wood Road Stevenage Hertfordshire SG1 2NY UK
| | - Radka Snajdrova
- Medicines Research Centre; GlaxoSmithKline R&D Ltd; Gunnels Wood Road Stevenage Hertfordshire SG1 2NY UK
| | - Zhi Li
- Department of Chemical & Biomolecular Engineering; National University of Singapore; 4 Engineering Drive 4 Singapore 117585 Singapore
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13
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Bao T, Zhang X, Zhao X, Rao Z, Yang T, Yang S. Regulation of the NADH pool and NADH/NADPH ratio redistributes acetoin and 2,3-butanediol proportion in Bacillus subtilis. Biotechnol J 2016; 10:1298-306. [PMID: 26129872 DOI: 10.1002/biot.201400577] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 04/30/2015] [Accepted: 06/26/2015] [Indexed: 01/07/2023]
Abstract
Bacillus subtilis produces acetoin as a major product along with several NADH-dependent byproducts, especially 2,3-butanediol. In this study, the down-regulation of the NADH pool and the redistribution of NADH/NADPH were targeted using external and genetic processes, as a means by which to redistribute the metabolic flux in favor of acetoin synthesis. First, it was found that the use of carbon sources of different oxidation states resulted in very different intracellular NADH/NAD(+) ratios that dictated the total process yield of acetoin. A mixture of glucose and gluconate as substrate produced a relatively low NADH/NAD(+) ratio, and resulted in an increase in acetoin production while byproducts significantly decreased. Metabolic engineering methods using glucose as a substrate could yield a similar effect. Acetoin production was significantly enhanced by overexpression of the oxidative pentose phosphate pathway: increased expression of glucose-6-phosphate dehydrogenase resulted in a decrease in the intracellular NADH/NADPH ratio (1.9-fold) and NADH/NAD(+) ratio (1.7-fold). In fed-batch culture the engineered strain yielded an acetoin concentration of 43.3 g L(-1) , while the production of 2,3-butanediol was only 1.7 g L(-1) . The concept of the manipulation of cofactor levels to redistribute carbon flux by external and genetic means as explored in this paper provides a novel strategy for improving industrial acetoin fermentation.
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Affiliation(s)
- Teng Bao
- The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Xian Zhang
- The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Xiaojing Zhao
- The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Zhiming Rao
- The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China.
| | - Taowei Yang
- The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China
| | - Shangtian Yang
- Department of Chemical Engineering, Ohio State University, Columbus, Ohio, USA
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14
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Pongtharangkul T, Chuekitkumchorn P, Suwanampa N, Payongsri P, Honda K, Panbangred W. Kinetic properties and stability of glucose dehydrogenase from Bacillus amyloliquefaciens SB5 and its potential for cofactor regeneration. AMB Express 2015; 5:68. [PMID: 26538191 PMCID: PMC4633474 DOI: 10.1186/s13568-015-0157-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 10/27/2015] [Indexed: 11/10/2022] Open
Abstract
Glucose dehydrogenases (GluDH) from Bacillus species offer several advantages over other NAD(P)H regeneration systems including high stability, inexpensive substrate, thermodynamically favorable reaction and flexibility to regenerate both NADH and NADPH. In this research, characteristics of GluDH from Bacillus amyloliquefaciens SB5 (GluDH-BA) was reported for the first time. Despite a highly similar amino acid sequence when comparing with GluDH from Bacillus subtilis (GluDH-BS), GluDH-BA exhibited significantly higher specific activity (4.7-fold) and stability when pH was higher than 6. While an optimum activity of GluDH-BA was observed at a temperature of 50 °C, the enzyme was stable only up to 42 °C. GluDH-BA exhibited an extreme tolerance towards n-hexane and its respective alcohols. The productivity of GluDH obtained in this study (8.42 mg-GluDH/g-wet cells; 1035 U/g-wet cells) was among the highest productivity reported for recombinant E. coli. With its low KM-value towards glucose (5.5 mM) and NADP+ (0.05 mM), GluDH-BA was highly suitable for in vivo applications. In this work, a recombinant solvent-tolerant B. subtilis BA overexpressing GluDH-BA was developed and evaluated by coupling with B. subtilis overexpressing an enzyme P450 BM3 F87V for a whole-cell hydroxylation of n-hexane. Significantly higher products obtained clearly proved that B. subtilis BA was an effective cofactor regenerator, a valuable asset for bioproduction of value-added chemicals.
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15
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Tani Y, Miyake R, Yukami R, Dekishima Y, China H, Saito S, Kawabata H, Mihara H. Functional expression of L-lysine α-oxidase from Scomber japonicus in Escherichia coli for one-pot synthesis of L-pipecolic acid from DL-lysine. Appl Microbiol Biotechnol 2014; 99:5045-54. [PMID: 25547835 DOI: 10.1007/s00253-014-6308-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 12/05/2014] [Accepted: 12/09/2014] [Indexed: 11/24/2022]
Abstract
L-Pipecolic acid is a key component of biologically active molecules and a pharmaceutically important chiral building block. It can be stereoselectively produced from L-lysine by a two-step bioconversion involving L-lysine α-oxidase and ∆(1)-piperideine-2-carboxylae (Pip2C) reductase. In this study, we focused on an L-lysine α-oxidase from Scomber japonicus that was originally identified as an apoptosis-inducing protein (AIP) and applied the enzyme to one-pot fermentation of L-pipecolic acid in Escherichia coli. A synthetic gene coding for an AIP was expressed in E. coli, and the recombinant enzyme was purified and characterized. The purified enzyme was determined to be a homodimer with a molecular mass of 133.9 kDa. The enzyme essentially exhibited the same substrate specificity as the native enzyme. Optimal temperature and pH for the enzymatic reaction were 70 °C and 7.4, respectively. The enzyme was stable below 60 °C and at a pH range of 5.5-7.5 but was markedly inhibited by Co(2+). To establish a one-pot fermentation system for the synthesis of optically pure L-pipecolic acid from DL-lysine, an E. coli strain carrying a plasmid encoding AIP, Pip2C reductase from Pseudomonas putida, lysine racemase from P. putida, and glucose dehydrogenase from Bacillus subtilis was constructed. The one-pot process produced 45.1 g/L of L-pipecolic acid (87.4 % yield from DL-lysine) after a 46-h reaction with high optical purity (>99.9 % enantiomeric excess).
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Affiliation(s)
- Yasushi Tani
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
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16
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Basner A, Antranikian G. Isolation and biochemical characterization of a glucose dehydrogenase from a hay infusion metagenome. PLoS One 2014; 9:e85844. [PMID: 24454935 PMCID: PMC3891874 DOI: 10.1371/journal.pone.0085844] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 12/02/2013] [Indexed: 11/19/2022] Open
Abstract
Glucose hydrolyzing enzymes are essential to determine blood glucose level. A high-throughput screening approach was established to identify NAD(P)-dependent glucose dehydrogenases for the application in test stripes and the respective blood glucose meters. In the current report a glucose hydrolyzing enzyme, derived from a metagenomic library by expressing recombinant DNA fragments isolated from hay infusion, was characterized. The recombinant clone showing activity on glucose as substrate exhibited an open reading frame of 987 bp encoding for a peptide of 328 amino acids. The isolated enzyme showed typical sequence motifs of short-chain-dehydrogenases using NAD(P) as a co-factor and had a sequence similarity between 33 and 35% to characterized glucose dehydrogenases from different Bacillus species. The identified glucose dehydrogenase gene was expressed in E. coli, purified and subsequently characterized. The enzyme, belonging to the superfamily of short-chain dehydrogenases, shows a broad substrate range with a high affinity to glucose, xylose and glucose-6-phosphate. Due to its ability to be strongly associated with its cofactor NAD(P), the enzyme is able to directly transfer electrons from glucose oxidation to external electron acceptors by regenerating the cofactor while being still associated to the protein.
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Affiliation(s)
- Alexander Basner
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
| | - Garabed Antranikian
- Institute of Technical Microbiology, Hamburg University of Technology, Hamburg, Germany
- * E-mail:
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17
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A one-pot system for production of L-2-aminobutyric acid from L-threonine by L-threonine deaminase and a NADH-regeneration system based on L-leucine dehydrogenase and formate dehydrogenase. Biotechnol Lett 2013; 36:835-41. [PMID: 24322776 DOI: 10.1007/s10529-013-1424-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/26/2013] [Indexed: 10/25/2022]
Abstract
L-2-Aminobutyric acid (L-ABA) is an unnatural amino acid that is a key intermediate for the synthesis of several important drugs. It can be produced by transaminase or dehydrogenase from α-ketobutyric acid, which can be synthesized enzymatically from the bulk amino acid, L-threonine. Deamination of L-threonine followed by a hydrogenation reaction gave almost the theoretical yield and was estimated to be more cost-effective than the established chemical process. L-Threonine deaminase from Escherichia coli, L-leucine dehydrogenase from Bacillus cereus, and formate dehydrogenase from Pseudomonas sp. were over-expressed in E. coli and used for one-pot production of L-ABA with formate as a co-substrate for NADH regeneration. 30 mol L-threonine were converted to 29.2 mol L-ABA at 97.3 % of theoretical yield and with productivity of 6.37 g l(-1) h(-1) at 50 l. This process offers a promising approach to fulfil industrial requirements for L-ABA.
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18
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Liang B, Lang Q, Tang X, Liu A. Simultaneously improving stability and specificity of cell surface displayed glucose dehydrogenase mutants to construct whole-cell biocatalyst for glucose biosensor application. BIORESOURCE TECHNOLOGY 2013; 147:492-498. [PMID: 24012845 DOI: 10.1016/j.biortech.2013.08.088] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 08/13/2013] [Accepted: 08/14/2013] [Indexed: 06/02/2023]
Abstract
The improved stability and substrate specificity of cell surface displayed glucose dehydrogenase (GDH) mutants by replacing four amino acids from Bacillus subtilis by using site-directed mutagenesis was systematically investigated. A series of mutated GDHs including E170R/Q252L, V149K/E170R/Q252L, E170R/Q252L/G259A and V149K/E170R/Q252L/G259A, were fused to the ice nucleation protein for displaying on cell surface of Eschericia coli. Q252L/E170R/V149K, Q252L/E170R/G259A and Q252L/E170R/V149K/G259A variants were found stable at a wide pH range and shown excellent thermostability. Especially, the Q252L/E170R/V149K/G259A mutant showed half-life of ~3.8days at 70 °C. Q252L/E170R/V149K/G259A variant exhibited the narrowest substrate specificity for d-glucose. The whole cell displayed GDH mutant could be cultured in a large scale with excellent enzyme activity and productivity. In addition, a sensitive and stable electrochemical glucose biosensor can be prepared using the GDH-mutant bacteria modified electrode. Thus, the whole cell biocatalysts are promising candidates for exploitation in a wide range of industrial applications.
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Affiliation(s)
- Bo Liang
- Laboratory for Biosensing, Qingdao Institute of Bioenergy & Bioprocess Technology, and Key Laboratory of Bioenergy, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China
| | - Qiaolin Lang
- Laboratory for Biosensing, Qingdao Institute of Bioenergy & Bioprocess Technology, and Key Laboratory of Bioenergy, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China
| | - Xiangjiang Tang
- Laboratory for Biosensing, Qingdao Institute of Bioenergy & Bioprocess Technology, and Key Laboratory of Bioenergy, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China
| | - Aihua Liu
- Laboratory for Biosensing, Qingdao Institute of Bioenergy & Bioprocess Technology, and Key Laboratory of Bioenergy, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China.
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19
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Solomon KV, Moon TS, Ma B, Sanders TM, Prather KLJ. Tuning primary metabolism for heterologous pathway productivity. ACS Synth Biol 2013; 2:126-35. [PMID: 23656436 DOI: 10.1021/sb300055e] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tuning expression of competing endogenous pathways has been identified as an effective strategy in the optimization of heterologous production pathways. However, intervention at the first step of glycolysis, where no alternate routes of carbon utilization exist, remains unexplored. In this work we have engineered a viable E. coli host that decouples glucose transport and phosphorylation, enabling independent control of glucose flux to a heterologous pathway of interest through glucokinase (glk) expression. Using community sourced and curated promoters, glk expression was varied over a 3-fold range while maintaining cellular viability. The effects of glk expression on the productivity of a model glucose-consuming pathway were also studied. Through control of glycolytic flux we were able to explore a number of cellular phenotypes and vary the yield of our model pathway by up to 2-fold in a controllable manner.
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Affiliation(s)
- Kevin V. Solomon
- Department of Chemical Engineering,
Synthetic Biology Engineering Research Center (SynBERC), Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
| | - Tae Seok Moon
- Department of Chemical Engineering,
Synthetic Biology Engineering Research Center (SynBERC), Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
| | - Brian Ma
- Department of Chemical Engineering,
Synthetic Biology Engineering Research Center (SynBERC), Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
- California
Institute of Technology
Summer Undergraduate Research Fellow (SURF), Department of Bioengineering, California Institute of Technology, Pasadena, California
91125, United States
| | - Tarielle M. Sanders
- Department of Chemical Engineering,
Synthetic Biology Engineering Research Center (SynBERC), Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
- Amgen
Scholars Program, Department
of Chemistry, Norfolk State University,
Norfolk, Virginia 23504, United States
| | - Kristala L. J. Prather
- Department of Chemical Engineering,
Synthetic Biology Engineering Research Center (SynBERC), Massachusetts Institute of Technology, Cambridge, Massachusetts
02139, United States
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20
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Ding HT, Du YQ, Liu DF, Li ZL, Chen XJ, Zhao YH. Cloning and expression in E. coli of an organic solvent-tolerant and alkali-resistant glucose 1-dehydrogenase from Lysinibacillus sphaericus G10. BIORESOURCE TECHNOLOGY 2011; 102:1528-1536. [PMID: 20805024 DOI: 10.1016/j.biortech.2010.08.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2010] [Revised: 07/28/2010] [Accepted: 08/04/2010] [Indexed: 05/29/2023]
Abstract
The gene gdh encoding an organic solvent-tolerant and alkaline-resistant NAD(P)-dependent glucose 1-dehydrogenase (LsGDH) was cloned from Lysinibacillus sphaericus G10 and expressed in Escherichia coli. The recombinant LsGDH exhibited maximum activity at pH 9.5 and 50 °C. LsGDH displayed high stability at a wide pH ranging from 6.5 to 10.0 and was stable after incubation at 30 °C for 1 week in 25 mM sodium phosphate buffer (pH 6.5) in the absence or presence of NaCl. The activity of LsGDH was enhanced by Li+, Na+, K+, NH4+, Mg2+, and EDTA at pH 8.0. LsGDH exhibited high tolerance to 60% DMSO, 30% acetone, 30% methanol, 30% ethanol, 10% n-propanol, 30% isopropanol, 60% n-hexanol and 30% n-hexane. The relationship between stability and chain length of the alcohols fit a Gaussian distribution model (R2≥0.94), and demonstrated lowest enzyme stability in C4-alcohol. The results suggested that LsGDH was potentially useful for coenzyme regeneration in organic solvents or under alkaline conditions.
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Affiliation(s)
- Hai-Tao Ding
- Institute of Microbiology, College of Life Science, Zhejiang University, Hangzhou 310058, China
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21
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Richter N, Neumann M, Liese A, Wohlgemuth R, Weckbecker A, Eggert T, Hummel W. Characterization of a whole-cell catalyst co-expressing glycerol dehydrogenase and glucose dehydrogenase and its application in the synthesis of L-glyceraldehyde. Biotechnol Bioeng 2010; 106:541-52. [PMID: 20198657 DOI: 10.1002/bit.22714] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A whole-cell catalyst using Escherichia coli BL21(DE3) as a host, co-expressing glycerol dehydrogenase (GlyDH) from Gluconobacter oxydans and glucose dehydrogenase (GDH) from Bacillus subtilis for cofactor regeneration, has been successfully constructed and used for the reduction of aliphatic aldehydes, such as hexanal or glyceraldehyde to the corresponding alcohols. This catalyst was characterized in terms of growth conditions, temperature and pH dependency, and regarding the influence of external cofactor and permeabilization. In the case of external cofactor addition we found a 4.6-fold increase in reaction rate caused by the addition of 1 mM NADP(+). Due to the fact that pH and temperature are also factors which may affect the reaction rate, their effect on the whole-cell catalyst was studied as well. Comparative studies between the whole-cell catalyst and the cell-free system were investigated. Furthermore, the successful application of the whole-cell catalyst in repetitive batch conversions could be demonstrated in the present study. Since the GlyDH was recently characterized and successfully applied in the kinetic resolution of racemic glyceraldehyde, we were now able to transfer and establish the process to a whole-cell system, which facilitated the access to L-glyceraldehyde in high enantioselectivity at 54% conversion. All in all, the whole-cell catalyst shows several advantages over the cell-free system like a higher thermal, a similar operational stability and the ability to recycle the catalyst without any loss-of-activity. The results obtained making the described whole-cell catalyst an improved catalyst for a more efficient production of enantiopure L-glyceraldehyde.
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Affiliation(s)
- Nina Richter
- Evocatal GmbH, Merowingerplatz 1a, 40225 Düsseldorf, Germany
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22
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Dingman DW, Stahly DP. Protection of Bacillus larvae from Oxygen Toxicity with Emphasis on the Role of Catalase. Appl Environ Microbiol 2010; 47:1228-37. [PMID: 16346560 PMCID: PMC240202 DOI: 10.1128/aem.47.6.1228-1237.1984] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sporulation of Bacillus larvae NRRL B-3650 occurred only at aeration rates lower than those used for cultivation of most Bacillus species. One possible explanation for the requirement for a low level of aeration in B. larvae is that toxic forms of oxygen such as H(2)O(2) and superoxide are involved. The superoxide dismutase levels of strain B-3650 were similar to those of Bacillus subtilis 168 during sporulation, and no NADH peroxidase was present. Catalase activity was absent during exponential growth and first appeared near the start of the stationary phase. The catalase activity was 2,700 times less than that in B. subtilis 168 at the same stage of development. Therefore, the relative deficiency of catalase (and NADH peroxidase) might be the cause of the apparent O(2) toxicity. It was postulated that B. larvae might accumulate H(2)O(2) in the medium and exhibit more than normal sensitivity to H(2)O(2). Experimental results did not verify either postulate, but the possibilities of intracellular accumulation of H(2)O(2) and unusual sensitivity to endogenous H(2)O(2) were not excluded. The catalase present in early-stationary-phase cells was soluble, heat labile, and inhibited by cyanide, azide, and hydroxylamine. An increase in catalase activity also occurred at the time of appearance of refractile spores in both B. larvae NRRL B-3650 and B. subtilis 168. The level of catalase activity in strain B-3650 was 5,400 times less than that in B. subtilis 168 at this stage. In B. larvae, this second increase occurred primarily within the developing endospore. The activity in spore extracts was particulate, heat stable, and inhibited by hydroxylamine but not by azide or cyanide. Synthesis of catalase in B. larvae was unaffected by H(2)O(2), O(2), or glucose.
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Affiliation(s)
- D W Dingman
- Department of Microbiology, University of Iowa, Iowa City, Iowa 52242
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23
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Castro R, Neves AR, Fonseca LL, Pool WA, Kok J, Kuipers OP, Santos H. Characterization of the individual glucose uptake systems of Lactococcus lactis: mannose-PTS, cellobiose-PTS and the novel GlcU permease. Mol Microbiol 2008; 71:795-806. [PMID: 19054326 DOI: 10.1111/j.1365-2958.2008.06564.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
According to previous reports, Lactococcus lactis imports glucose via two distinct phosphoenolpyruvate:phosphotransferase systems (mannose-PTS and cellobiose-PTS) and one or more unknown non-PTS permease(s). GlcU was identified as the sole non-PTS permease involved in the transport of glucose. Additionally, the biochemical properties of PTS(Man), PTS(Cel) and GlcU were characterized in double knockout mutants with glucose uptake restricted to a single system. Transport susceptibility to protonophores indicated that glucose uptake via GlcU is proton-motive force dependent. Competition assays revealed a high specificity of GlcU for glucose. Furthermore, the permease has low affinity for glucose and displays strong preference for the beta-anomer as shown by the profiles of consumption of the two glucose anomers studied by (13)C-NMR. Similar kinetic properties were found for PTS(Cel), while PTS(Man) is a high-affinity system recognizing equally well the two anomeric forms of glucose. Transcripts of the genes encoding the three transporters are present simultaneously in the parent strain NZ9000 as shown by reverse transcription-PCR. Investigation of the distribution of GlcU homologues among bacteria showed that these proteins are restricted to the low-GC Gram-positive Firmicutes. This work completes the identification of the glucose transport systems in L. lactis MG1363.
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Affiliation(s)
- Rute Castro
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Rua da Quinta Grande 6, Oeiras, Portugal
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24
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The Bacillus subtilis ydjL (bdhA) gene encodes acetoin reductase/2,3-butanediol dehydrogenase. Appl Environ Microbiol 2008; 74:6832-8. [PMID: 18820069 DOI: 10.1128/aem.00881-08] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacillus subtilis is capable of producing 2,3-butanediol from acetoin by fermentation, but to date, the gene encoding the enzyme responsible, acetoin reductase/2,3-butanediol dehydrogenase (AR/BDH), has remained unknown. A search of the B. subtilis genome database with the amino acid sequences of functional AR/BDHs from Saccharomyces cerevisiae and Bacillus cereus resulted in the identification of a highly similar protein encoded by the B. subtilis ydjL gene. A knockout strain carrying a ydjL::cat insertion mutation was constructed, which (i) abolished 2,3-butanediol production in early stationary phase, (ii) produced no detectable AR or BDH activity in vitro, and (iii) accumulated the precursor acetoin in early stationary phase. The ydjL::cat mutation also affected the kinetics of lactate but not acetate production during stationary-phase cultivation with glucose under oxygen limitation. A very small amount of 2,3-butanediol was detected in very-late-stationary-phase (96-hour) cultures of the ydjL::cat mutant, suggesting the existence of a second gene encoding a minor AR activity. From the data, it is proposed that the major AR/BDH-encoding gene ydjL be renamed bdhA.
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25
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Vasudevan P, Weaver A, Reichert ED, Linnstaedt SD, Popham DL. Spore cortex formation in Bacillus subtilis is regulated by accumulation of peptidoglycan precursors under the control of sigma K. Mol Microbiol 2007; 65:1582-94. [PMID: 17714441 DOI: 10.1111/j.1365-2958.2007.05896.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The bacterial endospore cortex peptidoglycan is synthesized between the double membranes of the developing forespore and is required for attainment of spore dehydration and dormancy. The Bacillus subtilis spoVB, spoVD and spoVE gene products are expressed in the mother cell compartment early during sporulation and play roles in cortex synthesis. Here we show that mutations in these genes block synthesis of cortex peptidoglycan and cause accumulation of peptidoglycan precursors, indicating a defect at the earliest steps of peptidoglycan polymerization. Loss of spoIV gene products involved in activation of later, sigma(K)-dependent mother cell gene expression results in decreased synthesis of cortex peptidoglycan, even in the presence of the SpoV proteins that were synthesized earlier, apparently due to decreased precursor production. Data show that activation of sigma(K) is required for increased synthesis of the soluble peptidoglycan precursors, and Western blot analyses show that increases in the precursor synthesis enzymes MurAA, MurB, MurC and MurF are dependent on sigma(K) activation. Overall, our results indicate that a decrease in peptidoglycan precursor synthesis during early sporulation, followed by renewed precursor synthesis upon sigma(K) activation, serves as a regulatory mechanism for the timing of spore cortex synthesis.
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Affiliation(s)
- Pradeep Vasudevan
- Department of Biological Sciences, Virginia Tech, 2119 Derring Hall MC0406, Blacksburg, VA 24061, USA
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26
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Heuser F, Schroer K, Lütz S, Bringer-Meyer S, Sahm H. Enhancement of the NAD(P)(H) Pool inEscherichia coli for Biotransformation. Eng Life Sci 2007. [DOI: 10.1002/elsc.200720203] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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27
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Cha M, Kim EJ, Yun H, Cho BK, Kim BG. Synthesis of enantiopure (S)-2-hydroxyphenylbutanoic acid using novel hydroxy acid dehydrogenase from Enterobacter sp. BK2K. Biotechnol Prog 2007; 23:606-12. [PMID: 17302428 DOI: 10.1021/bp0602404] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enterobacter sp. BK2K, screened from soil samples, can enantioselectively reduce 2-oxo-4-phenylbutanoic acid into (S)-2-hydroxy-4-phenylbutanoic acid. alpha-Hydroxy acid dehydrogenase (HADH) (specific activity 62.6 U/mg) was purified from the crude extract of Enterobacter sp. BK2K, and its gene was cloned and functionally expressed in E. coli BL21. The optimal pH and temperature for the HADH activity were 6.5 and 30 degrees C, respectively. The purified enzyme catalyzes the reduction of various aromatic and aliphatic 2-oxo carboxylic acids to the corresponding (S)-2-hydoxy carboxylic acids using NADH as cofactor. For example, the Km and kcat/Km for 2-oxo-4-phenylbutaonoic acid in the presence of 2 mM NADH were 6.8 mM and 350 M-1 min-1, respectively. For practical applications, a NADH recycle system employing the recombinant formate dehydrogenase from E. coli K12 was coupled with HADH in E. coli BL21. Using the recombinant HADH (110 U of 11 U/mg crude cell extract) and formate dehydrogenase (670 U of 67 U/mg crude cell extract) in 10 mL of 500 mM phosphate buffer (pH 6.5), 96 mM of (S)-phenyllactic acid (> 94% ee) and 95 mM of (S)-2-hydroxy-4-phenylbutanoic acid (> 94% ee) were produced in quantitative yields from 100 mM of phenylpyruvate and 2-oxo-4-phenylbutanoic acid.
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Affiliation(s)
- Minho Cha
- School of Chemical and Biological Engineering and Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea
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Brinster S, Furlan S, Serror P. C-terminal WxL domain mediates cell wall binding in Enterococcus faecalis and other gram-positive bacteria. J Bacteriol 2006; 189:1244-53. [PMID: 16963569 PMCID: PMC1797349 DOI: 10.1128/jb.00773-06] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Analysis of the genome sequence of Enterococcus faecalis clinical isolate V583 revealed novel genes encoding surface proteins. Twenty-seven of these proteins, annotated as having unknown functions, possess a putative N-terminal signal peptide and a conserved C-terminal region characterized by a novel conserved domain designated WxL. Proteins having similar characteristics were also detected in other low-G+C-content gram-positive bacteria. We hypothesized that the WxL region might be a determinant of bacterial cell location. This hypothesis was tested by generating protein fusions between the C-terminal regions of two WxL proteins in E. faecalis and a nuclease reporter protein. We demonstrated that the C-terminal regions of both proteins conferred a cell surface localization to the reporter fusions in E. faecalis. This localization was eliminated by introducing specific deletions into the domains. Interestingly, exogenously added protein fusions displayed binding to whole cells of various gram-positive bacteria. We also showed that the peptidoglycan was a binding ligand for WxL domain attachment to the cell surface and that neither proteins nor carbohydrates were necessary for binding. Based on our findings, we propose that the WxL region is a novel cell wall binding domain in E. faecalis and other gram-positive bacteria.
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Affiliation(s)
- Sophie Brinster
- Unité des Bactéries Lactiques et Pathogènes Opportunistes, INRA, Jouy-en-Josas, France
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Zhu Y, Chen X, Chen T, Shi S, Zhao X. Over-expression of glucose dehydrogenase improves cell growth and riboflavin production in Bacillus subtilis. Biotechnol Lett 2006; 28:1667-72. [PMID: 16912926 DOI: 10.1007/s10529-006-9143-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Accepted: 06/15/2006] [Indexed: 11/27/2022]
Abstract
Ribulose 5-phosphate is a precursor for riboflavin biosynthesis. Alteration of carbon flow into the pentose phosphate pathway will affect the availability of ribulose 5-phosphate and the riboflavin yield. We have modulated carbon flow in Bacillus subtilis through the gluconate bypass by over-expression of glucose dehydrogenase under the control of the constitutively expressed P43 promoter. Over-expression of glucose dehydrogenase resulted in low acid production (acetate and pyruvate). The substantial reduction in acid production is accompanied by increased riboflavin production and an increased rate of growth while glucose consumption remained unchanged. Metabolic analysis indicated that over-expression of glucose dehydrogenase increased intracellular pool of ribulose 5-phosphate. The high concentrations of ribulose 5-phosphate could explain the increased riboflavin production.
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Affiliation(s)
- Yingbo Zhu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, P. R. China
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30
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Yun H, Choi HL, Fadnavis NW, Kim BG. Stereospecific synthesis of (R)-2-hydroxy carboxylic acids using recombinant E. coli BL21 overexpressing YiaE from Escherichia coli K12 and glucose dehydrogenase from Bacillus subtilis. Biotechnol Prog 2005; 21:366-71. [PMID: 15801772 DOI: 10.1021/bp049694w] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The yiaE gene from Escherichia coli K12 was functionally expressed in E. coli BL21 using an IPTG inducible pET expression system (2.1 U/mg), and YiaE was purified to a specific activity of 18 U/mg. The purified enzyme catalyzes reduction of various aromatic and aliphatic 2-oxo carboxylic acids to the corresponding (R)-2-hydoxy carboxylic acids using NADPH. For practical applications, the problem of NADPH recycle was effectively solved by using recombinant E. coli overexpressing YiaE and glucose dehydrogenase from Bacillus subtilis in the same cell. The recombinant E. coli was used to prepare (R)-phenyllactic acid and (R)-2-hydroxy-4-phenylbutanoic acid from the corresponding 2-oxo carboxylic acids (98% ee) while the alpha-carbonyl group of 2,4-dioxo-4-phenylbutyric acid was reduced regio- and stereospecifically to give (R)-2-hydroxy-4-oxo-4-phenylbutyric acid (97% ee) in quantitative yields. The cells could be recycled for 3 days at room temperature in 100 mM phosphate buffer (pH 7.0) without loss of activity, which reduced to 70% after 1 week.
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Affiliation(s)
- Hyungdon Yun
- School of Chemical Engineering and Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea
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31
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Serres MH, Riley M. Gene fusions and gene duplications: relevance to genomic annotation and functional analysis. BMC Genomics 2005; 6:33. [PMID: 15757509 PMCID: PMC555942 DOI: 10.1186/1471-2164-6-33] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2004] [Accepted: 03/09/2005] [Indexed: 11/10/2022] Open
Abstract
Background Escherichia coli a model organism provides information for annotation of other genomes. Our analysis of its genome has shown that proteins encoded by fused genes need special attention. Such composite (multimodular) proteins consist of two or more components (modules) encoding distinct functions. Multimodular proteins have been found to complicate both annotation and generation of sequence similar groups. Previous work overstated the number of multimodular proteins in E. coli. This work corrects the identification of modules by including sequence information from proteins in 50 sequenced microbial genomes. Results Multimodular E. coli K-12 proteins were identified from sequence similarities between their component modules and non-fused proteins in 50 genomes and from the literature. We found 109 multimodular proteins in E. coli containing either two or three modules. Most modules had standalone sequence relatives in other genomes. The separated modules together with all the single (un-fused) proteins constitute the sum of all unimodular proteins of E. coli. Pairwise sequence relationships among all E. coli unimodular proteins generated 490 sequence similar, paralogous groups. Groups ranged in size from 92 to 2 members and had varying degrees of relatedness among their members. Some E. coli enzyme groups were compared to homologs in other bacterial genomes. Conclusion The deleterious effects of multimodular proteins on annotation and on the formation of groups of paralogs are emphasized. To improve annotation results, all multimodular proteins in an organism should be detected and when known each function should be connected with its location in the sequence of the protein. When transferring functions by sequence similarity, alignment locations must be noted, particularly when alignments cover only part of the sequences, in order to enable transfer of the correct function. Separating multimodular proteins into module units makes it possible to generate protein groups related by both sequence and function, avoiding mixing of unrelated sequences. Organisms differ in sizes of groups of sequence-related proteins. A sample comparison of orthologs to selected E. coli paralogous groups correlates with known physiological and taxonomic relationships between the organisms.
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Affiliation(s)
- Margrethe H Serres
- Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA02543-1015, USA
| | - Monica Riley
- Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA02543-1015, USA
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Hilbert DW, Piggot PJ. Compartmentalization of gene expression during Bacillus subtilis spore formation. Microbiol Mol Biol Rev 2004; 68:234-62. [PMID: 15187183 PMCID: PMC419919 DOI: 10.1128/mmbr.68.2.234-262.2004] [Citation(s) in RCA: 249] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gene expression in members of the family Bacillaceae becomes compartmentalized after the distinctive, asymmetrically located sporulation division. It involves complete compartmentalization of the activities of sporulation-specific sigma factors, sigma(F) in the prespore and then sigma(E) in the mother cell, and then later, following engulfment, sigma(G) in the prespore and then sigma(K) in the mother cell. The coupling of the activation of sigma(F) to septation and sigma(G) to engulfment is clear; the mechanisms are not. The sigma factors provide the bare framework of compartment-specific gene expression. Within each sigma regulon are several temporal classes of genes, and for key regulators, timing is critical. There are also complex intercompartmental regulatory signals. The determinants for sigma(F) regulation are assembled before septation, but activation follows septation. Reversal of the anti-sigma(F) activity of SpoIIAB is critical. Only the origin-proximal 30% of a chromosome is present in the prespore when first formed; it takes approximately 15 min for the rest to be transferred. This transient genetic asymmetry is important for prespore-specific sigma(F) activation. Activation of sigma(E) requires sigma(F) activity and occurs by cleavage of a prosequence. It must occur rapidly to prevent the formation of a second septum. sigma(G) is formed only in the prespore. SpoIIAB can block sigma(G) activity, but SpoIIAB control does not explain why sigma(G) is activated only after engulfment. There is mother cell-specific excision of an insertion element in sigK and sigma(E)-directed transcription of sigK, which encodes pro-sigma(K). Activation requires removal of the prosequence following a sigma(G)-directed signal from the prespore.
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Affiliation(s)
- David W Hilbert
- Department of Microbiology and Immunology, Temple University School of Medicine, 3400 N. Broad St., Philadelphia, PA 19140, USA
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Urtiz-Estrada N, Salas-Pacheco JM, Yasbin RE, Pedraza-Reyes M. Forespore-specific expression of Bacillus subtilis yqfS, which encodes type IV apurinic/apyrimidinic endonuclease, a component of the base excision repair pathway. J Bacteriol 2003; 185:340-8. [PMID: 12486072 PMCID: PMC141825 DOI: 10.1128/jb.185.1.340-348.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The temporal and spatial expression of the yqfS gene of Bacillus subtilis, which encodes a type IV apurinic/apyrimidinic endonuclease, was studied. A reporter gene fusion to the yqfS opening reading frame revealed that this gene is not transcribed during vegetative growth but is transcribed during the last steps of the sporulation process and is localized to the developing forespore compartment. In agreement with these results, yqfS mRNAs were mainly detected by both Northern blotting and reverse transcription-PCR, during the last steps of sporulation. The expression pattern of the yqfS-lacZ fusion suggested that yqfS may be an additional member of the Esigma(G) regulon. A primer extension product mapped the transcriptional start site of yqfS, 54 to 55 bp upstream of translation start codon of yqfS. Such an extension product was obtained from RNA samples of sporulating cells but not from those of vegetatively growing cells. Inspection of the nucleotide sequence lying upstream of the in vivo-mapped transcriptional yqfS start site revealed the presence of a sequence with good homology to promoters preceding genes of the sigma(G) regulon. Although yqfS expression was temporally regulated, neither oxidative damage (after either treatment with paraquat or hydrogen peroxide) nor mitomycin C treatment induced the transcription of this gene.
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Affiliation(s)
- Norma Urtiz-Estrada
- Institute of Investigation in Experimental Biology, Faculty of Chemistry, University of Guanajuato, Guanajuato, Gto. 36060, Mexico
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Mendoza-Hernández G, Minauro F, Rendón JL. Aggregation, dissociation and unfolding of glucose dehydrogenase during urea denaturation. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1478:221-31. [PMID: 10825533 DOI: 10.1016/s0167-4838(00)00025-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The effect of urea on glucose dehydrogenase from Bacillus megaterium has been studied by following changes in enzymatic activity, conformation and state of aggregation. It was found that the denaturation process involves several transitions. At very low urea concentrations (below 0.5 M), where the enzyme is fully active and tetrameric, there is a conformational change as monitored by an increase in intensity of the tryptophan fluorescence and a maximum exposure of organized hydrophobic surfaces as reported by the fluorescence of 4,4'-dianilino-1,1'-binaphthyl-5.5'-disulfonic acid. At slightly higher urea concentrations (0.75-2 M), a major conformational transition occurs, as monitored by circular dichroism and fluorescence measurements, in which the enzyme activity is completely lost and is concomitant with the formation of interacting intermediates that lead to a highly aggregated state. Increasing urea concentrations cause a complete dissociation to lead first a partially and eventually the complete unfolded monomer. These phenomena are fully reversible by dilution of denaturant. It is concluded that after urea denaturation, the folding/assembly pathway of glucose dehydrogenase occurs with the formation of intermediate species in which transient higher aggregates appear to be involved.
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Affiliation(s)
- G Mendoza-Hernández
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Apdo. postal 70-159, D.F. 04510, México, Mexico.
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Fiegler H, Bassias J, Jankovic I, Brückner R. Identification of a gene in Staphylococcus xylosus encoding a novel glucose uptake protein. J Bacteriol 1999; 181:4929-36. [PMID: 10438764 PMCID: PMC93981 DOI: 10.1128/jb.181.16.4929-4936.1999] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
By transposon Tn917 mutagenesis, two mutants of Staphylococcus xylosus were isolated that showed higher levels of beta-galactosidase activity in the presence of glucose than the wild type. Both transposons integrated in a gene, designated glcU, encoding a protein involved in glucose uptake in S. xylosus, which is followed by a glucose dehydrogenase gene (gdh). Glucose-mediated repression of beta-galactosidase, alpha-glucosidase, and beta-glucuronidase activities was partially relieved in the mutant strains, while repression by sucrose or fructose remained as strong as in the wild type. In addition to the pleiotropic regulatory effect, integration of the transposons into glcU reduced glucose dehydrogenase activity, suggesting cotranscription of glcU and gdh. Insertional inactivation of the gdh gene and deletion of the glcU gene without affecting gdh expression showed that loss of GlcU function is exclusively responsible for the regulatory defect. Reduced glucose repression is most likely the consequence of impaired glucose uptake in the glcU mutant strains. With cloned glcU, an Escherichia coli mutant deficient in glucose transport could grow with glucose as sole carbon source, provided a functional glucose kinase was present. Therefore, glucose is internalized by glcU in nonphosphorylated form. A gene from Bacillus subtilis, ycxE, that is homologous to glcU, could substitute for glcU in the E. coli glucose growth experiments and restored glucose repression in the S. xylosus glcU mutants. Three more proteins with high levels of similarity to GlcU and YcxE are currently in the databases. It appears that these proteins constitute a novel family whose members are involved in bacterial transport processes. GlcU and YcxE are the first examples whose specificity, glucose, has been determined.
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Affiliation(s)
- H Fiegler
- Mikrobielle Genetik, Universität Tübingen, D-72076 Tübingen, Germany
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Abstract
The open reading frame yqgR (now termed glcK), which had been sequenced as part of the genome project, encodes a glucose kinase of Bacillus subtilis. A 1.1-kb DNA fragment containing glcK complemented an Escherichia coli strain deficient in glucose kinase activity. Insertional mutagenesis of glcK resulted in a complete inactivation of glucose kinase activity in crude protein extracts, indicating that B. subtilis contains one major glucose kinase. The glcK gene encodes a 321-residue protein with a molecular mass of 33.5 kDa. The glucose kinase was overexpressed as a fusion protein to a six-His affinity tag and purified to homogeneity. The enzyme had K(m) values for ATP and glucose of 0.77 and 0.24 mM, respectively, and a Vmax of 93 mumol min-1 mg-1. A B. subtilis strain deficient for glucose kinase grew at the same rate on different carbon sources tested, including disaccharides such as maltose, trehalose, and sucrose.
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Affiliation(s)
- P Skarlatos
- Lehrstuhl für Mikrobiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
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37
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Kim JW, Peterson T, Bee G, Hulett FM. Bacillus licheniformis MC14 alkaline phosphatase I gene with an extended COOH-terminus. FEMS Microbiol Lett 1998; 159:47-58. [PMID: 9485594 DOI: 10.1111/j.1574-6968.1998.tb12840.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacterial alkaline phosphatases (APases), except those isolated from Bacillus licheniformis, are approximately 45-kDa proteins while eucaryotic alkaline phosphatases are 60 kDa. To answer the question of whether the apparent 60-kDa alkaline phosphatase from Bacillus licheniformis accurately reflected the size of the protein, the entire gene was analyzed. DNA sequence analysis of the alkaline phosphatase I (APaseI) gene of B. licheniformis MC14 indicated that the gene could code for a 60-kDa protein of 553 amino acids. The deduced protein sequence of APaseI showed about 32% identity to those of B. subtilis APase III and IV and had apparent sequence homologies in the core structure and active sites that are conserved among APases of various sources. The extra carboxy-terminal sequence of APaseI, which made the enzyme bigger than other procaryotic APases, was not homologous to those of eucaryotic APases. The amino acid composition of APaseI was most similar to that of salt-dependent APase among the isozymes of B. licheniformis MC14. Another open reading frame of 261 amino acids was present 142 nucleotide upstream of the APaseI gene and its predicted amino acid sequence showed 68% identity to that of glucose dehydrogenase of B. megaterium.
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Affiliation(s)
- J W Kim
- Department of Biology, University of Inchon, South Korea
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38
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Bruno JG, Mayo MW. A color image analysis method for assessment of germination based on differential fluorescence staining of bacterial spores and vegetative cells using acridine orange. Biotech Histochem 1995; 70:175-84. [PMID: 8580199 DOI: 10.3109/10520299509107309] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Color fluorescence image analysis of acridine orange (AO) stained germinating Bacillus subtilis var. niger bacteria revealed a cell population initially dominated by small green spores followed by the emergence of at least three additional discernible subpopulations in response to stimulation with D-glucose. These subpopulations were small, round or oblong red cells; intermediate to large metachromatic cells; and large red rods. Large green rods were rarely observed. An increase in red emissions (i.e., putative RNA synthesis) was sometimes seen as early as 90 min after exposure to D-glucose and uptake of AO at room temperature. This may represent either metabolic recovery from quiescence or RNA synthesis associated with germination. In the absence of D-glucose, or using autoclaved bacteria in the presence of glucose, no relative increase in the red signal was observed despite hours of observation. Digital image analysis was used for relative measurement of red, green and blue signals and to correlate the size of various subpopulations with their fluorescence color emissions over time. Image analysis demonstrated a trend toward increasing size and red emission in the presence of glucose. The average red emission was found to be a good discriminator of the various subpopulations, while the average green emission was approximately equal among the subpopulations making it a poor discriminator. These data suggest that AO staining might be used for rapid computer-assisted discrimination of spores vs. vegetative cells.
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Affiliation(s)
- J G Bruno
- U.S. Air Force, Armstrong Laboratory, Edgewood Research, Development and Engineering Center, SCBRD-RTE, Maryland 21010-5423, USA
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H�nerlage W, Hahn D, Zeyer J. Detection of mRNA of nprM in Bacillus megaterium ATCC 14581 grown in soil by whole-cell hybridization. Arch Microbiol 1995. [DOI: 10.1007/bf00393374] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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40
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Abstract
The specificity of DNA-dependent RNA polymerase for target promotes is largely due to the replaceable sigma subunit that it carries. Multiple sigma proteins, each conferring a unique promoter preference on RNA polymerase, are likely to be present in all bacteria; however, their abundance and diversity have been best characterized in Bacillus subtilis, the bacterium in which multiple sigma factors were first discovered. The 10 sigma factors thus far identified in B. subtilis directly contribute to the bacterium's ability to control gene expression. These proteins are not merely necessary for the expression of those operons whose promoters they recognize; in many instances, their appearance within the cell is sufficient to activate these operons. This review describes the discovery of each of the known B. subtilis sigma factors, their characteristics, the regulons they direct, and the complex restrictions placed on their synthesis and activities. These controls include the anticipated transcriptional regulation that modulates the expression of the sigma factor structural genes but, in the case of several of the B. subtilis sigma factors, go beyond this, adding novel posttranslational restraints on sigma factor activity. Two of the sigma factors (sigma E and sigma K) are, for example, synthesized as inactive precursor proteins. Their activities are kept in check by "pro-protein" sequences which are cleaved from the precursor molecules in response to intercellular cues. Other sigma factors (sigma B, sigma F, and sigma G) are inhibited by "anti-sigma factor" proteins that sequester them into complexes which block their ability to form RNA polymerase holoenzymes. The anti-sigma factors are, in turn, opposed by additional proteins which participate in the sigma factors' release. The devices used to control sigma factor activity in B, subtilis may prove to be as widespread as multiple sigma factors themselves, providing ways of coupling sigma factor activation to environmental or physiological signals that cannot be readily joined to other regulatory mechanisms.
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Affiliation(s)
- W G Haldenwang
- Department of Microbiology, University of Texas Health Science Center, San Antonio 78284-7758
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Fischer K, Hahn D, Hönerlage W, Sch nholzer F, Zeyer J. In situ Detection of Spores and Vegetative Cells of Bacillus megaterium in Soil by Whole Cell Hybridization. Syst Appl Microbiol 1995. [DOI: 10.1016/s0723-2020(11)80397-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Pedraza-Reyes M, Gutiérrez-Corona F, Nicholson WL. Temporal regulation and forespore-specific expression of the spore photoproduct lyase gene by sigma-G RNA polymerase during Bacillus subtilis sporulation. J Bacteriol 1994; 176:3983-91. [PMID: 8021181 PMCID: PMC205596 DOI: 10.1128/jb.176.13.3983-3991.1994] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Bacterial spores are highly resistant to killing by UV radiation and exhibit unique DNA photochemistry. UV irradiation of spore DNA results in formation of spore photoproduct (SP), the thymine dimer 5-thyminyl-5,6-dihydrothymine. Repair of SP occurs during germination of Bacillus subtilis spores by two distinct routes, either by the general nucleotide excision repair (uvr) pathway or by a novel SP-specific monomerization reaction mediated by the enzyme SP lyase, which is encoded by the spl gene. Repair of SP occurs early in spore germination and is independent of de novo protein synthesis, suggesting that the SP repair enzymes are synthesized during sporulation and are packaged in the dormant spore. To test this hypothesis, the expression of a translational spl-lacZ fusion integrated at the spl locus was monitored during B. subtilis growth and sporulation. beta-Galactosidase expression from the spl-lacZ fusion was silent during vegetative growth and was not DNA damage inducible, but it was activated at morphological stage III of sporulation specifically in the forespore compartment, coincident with activation of expression of the stage III marker enzyme glucose dehydrogenase. Expression of the spl-lacZ fusion was shown to be dependent upon the sporulation-specific RNA polymerase containing the sigma-G factor (E sigma G), as spl-lacZ expression was abolished in a mutant harboring a deletion in the sigG gene and restored by expression of the sigG gene in trans. Primer extension analysis of spl mRNA revealed a major extension product initiating upstream from a small open reading frame of unknown function which precedes spl, and it revealed two other shorter minor extension products. All three extension products were present in higher quantities during sporulation and after sigG induction. The three putative transcripts are all preceded by sequences which share homology with the consensus sigma-G factor-type promoter sequence, but in vitro transcription by purified sigma-G RNA polymerase was detected only from the promoter corresponding to the major extension product. The open reading frame-spl operon therefore appears to be an additional member of the sigma-G regulon, which also includes as members the small, acid-soluble spore proteins which are in large part responsible for spore DNA photochemistry. Therefore, sporulating bacteria appear to coordinately regulate genes whose products not only alter spore DNA photochemistry but also repair the major spore-specific photoproduct during germination
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Affiliation(s)
- M Pedraza-Reyes
- Institute of Investigation in Experimental Biology, Faculty of Chemistry, University of Guanajuato, Mexico
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Bylund JE, Zhang L, Haines MA, Higgins ML, Piggot PJ. Analysis by fluorescence microscopy of the development of compartment-specific gene expression during sporulation of Bacillus subtilis. J Bacteriol 1994; 176:2898-905. [PMID: 8188591 PMCID: PMC205445 DOI: 10.1128/jb.176.10.2898-2905.1994] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The use of a fluorogenic substrate, 5-octanoylaminofluorescein-di-beta-D-galactopyranoside, for beta-galactosidase has made it possible to visualize enzyme activity in individual cells of sporulating populations of Bacillus subtilis by fluorescence microscopy. lacZ fusions to different sporulation-associated genes have been used to investigate the cell compartmentalization of gene expression during sporulation. A strain with a lacZ fusion to sspA, a gene which is transcribed by E-sigma G at a late stage of sporulation, displayed predominantly compartment-specific fluorescence. Expression of the early-expressed spoIIA locus, which includes the structural gene for sigma F, was seen not to be compartmentalized. Populations of strains with lacZ fusions to gpr and dacF, genes which are transcribed by E-sigma F at intermediate stages of sporulation, included some organisms showing uncompartmentalized fluorescence and others showing compartment-specific fluorescence; the proportion showing compartment-specific fluorescence increased in samples taken later in sporulation. Several possible explanations of the results obtained with gpr and dacF are considered. A plausible interpretation is that sigma F activity is initially not compartmentalized and becomes compartmentalized as sporulation progresses. The progression to compartmentalization does not require the activities of the sporulation-specific factor sigma E or sigma G but may require some product of sigma F activity.
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Affiliation(s)
- J E Bylund
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140
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Smith K, Youngman P. Evidence that the spoIIM gene of Bacillus subtilis is transcribed by RNA polymerase associated with sigma E. J Bacteriol 1993; 175:3618-27. [PMID: 8501065 PMCID: PMC204763 DOI: 10.1128/jb.175.11.3618-3627.1993] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We have investigated the temporal and spatial regulation of spoIIM, a gene of Bacillus subtilis whose product is required for complete septum migration and engulfment of the forespore compartment during sporulation. The spoIIM promoter was found to become active about 2 h after the initiation of sporulation. The effects of mutations on the expression of a spoIIM-lacZ fusion were most consistent with its utilization by sigma-E-associated RNA polymerase (E sigma E). A unique 5' end of the in vivo spoIIM transcript was detected by primer extension analysis and was determined to initiate at the appropriate distance from a sequence conforming very closely to the consensus for genes transcribed by E sigma E. A partially purified preparation of E sigma E produced a transcript in vitro that initiated at the same nucleotide as the primer extension product generated from in vivo RNA. Ectopic induction of sigma E synthesis during growth resulted in the immediate and strong expression of a spoIIM-lacZ fusion, but an identical fusion was completely unresponsive to induced synthesis of either sigma F or sigma G under similar conditions. The results of plasmid integration-excision experiments in which the spoIIM gene was reversibly disrupted by a temperature-sensitive integrational vector suggested that spoIIM expression is required in the forespore compartment, but direct examination of subcellular fractions enriched for mother cell or forespore material indicated that spoIIM expression cannot be confined to the forespore. We conclude that spoIIM is a member of the sigma E regulon and that it may be transcribed exclusively by E sigma E. We discuss the implications of this conclusion for models in which activation of sigma E in the mother cell is proposed to be a part of the mechanism responsible for initiating separate programs of gene activity in the two sporangium compartments.
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Affiliation(s)
- K Smith
- Molecular Biology Graduate Group, University of Pennsylvania School of Medicine, Philadelphia 19104
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Errington J. Bacillus subtilis sporulation: regulation of gene expression and control of morphogenesis. Microbiol Rev 1993; 57:1-33. [PMID: 8464402 PMCID: PMC372899 DOI: 10.1128/mr.57.1.1-33.1993] [Citation(s) in RCA: 332] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Bacillus subtilis sporulation is an adaptive response to nutritional stress and involves the differential development of two cells. In the last 10 years or so, virtually all of the regulatory genes controlling sporulation, and many genes directing the structural and morphological changes that accompany sporulation, have been cloned and characterized. This review describes our current knowledge of the program of gene expression during sporulation and summarizes what is known about the functions of the genes that determine the specialized biochemical and morphological properties of sporulating cells. Most steps in the genetic program are controlled by transcription factors that have been characterized in vitro. Two sporulation-specific sigma factors, sigma E and sigma F, appear to segregate at septation, effectively determining the differential development of the mother cell and prespore. Later, each sigma is replaced by a second cell-specific sigma factor, sigma K in the mother cell and sigma G in the prespore. The synthesis of each sigma factor is tightly regulated at both the transcriptional and posttranslational levels. Usually this regulation involves an intercellular interaction that coordinates the developmental programmes of the two cells. At least two other transcription factors fine tune the timing and levels of expression of genes in the sigma E and sigma K regulons. The controlled synthesis of the sigma factors and other transcription factors leads to a spatially and temporally ordered program of gene expression. The gene products made during each successive stage of sporulation help to bring about a sequence of gross morphological changes and biochemical adaptations. The formation of the asymmetric spore septum, engulfment of the prespore by the mother cell, and formation of the spore core, cortex, and coat are described. The importance of these structures in the development of the resistance, dormancy, and germination properties of the spore is assessed.
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Affiliation(s)
- J Errington
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom
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Nagao T, Mitamura T, Wang XH, Negoro S, Yomo T, Urabe I, Okada H. Cloning, nucleotide sequences, and enzymatic properties of glucose dehydrogenase isozymes from Bacillus megaterium IAM1030. J Bacteriol 1992; 174:5013-20. [PMID: 1629157 PMCID: PMC206315 DOI: 10.1128/jb.174.15.5013-5020.1992] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Bacillus megaterium is known to have several genes that code for isozymes of glucose dehydrogenase. Two of them, gdhI and gdhII, were cloned from B. megaterium IAM1030 in our previous work (T. Mitamura, R. V. Evora, T. Nakai, Y. Makino, S. Negoro, I. Urabe, and H. Okada, J. Ferment. Bioeng. 70:363-369, 1990). In the present study, two new genes, gdhIII and gdhIV, were isolated from the same strain and their nucleotide sequences were identified. Each gene has an open reading frame of 783 bp available to encode a peptide of 261 amino acids. Thus, a total of four glucose dehydrogenase genes have been cloned from B. megaterium IAM1030. In addition, this strain does not seem to have other glucose dehydrogenase genes that can be distinguished from the four cloned genes so far examined by Southern hybridization analysis. The two newly cloned genes were expressed in Escherichia coli cells, and the products, GlcDH-III and GlcDH-IV, were purified and characterized and compared with the other isozymes, GlcDH-I and GlcDH-II, encoded by gdhI and gdhII, respectively. These isozymes showed different mobilities in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (GlcDH-I greater than GlcDH-III = GlcDH-IV greater than GlcDH-II), although they have the same number of amino acid residues. Double-immunodiffusion tests showed that GlcDH-I is immunologically different from the other isozymes and that GlcDH-III and GlcDH-IV are identical to one another but a little different from GlcDH-II. These glucose dehydrogenases were stabilized in the presence of 2 M NaCl. The effect of NaCl was especially large for GlcDH-III, which is most unstable enzyme. Kinetic studies showed that these isozymes are divided into two groups with respect to coenzyme specificity, although they can utilize both NAD and NADP: GlcDH-III and GlcDH-IV prefer NAD, and GlcDH-I and GlcDH-II prefer NADP. The phylogenic relationship of these glucose dehydrogenase genes is also discussed.
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Affiliation(s)
- T Nagao
- Department of Biotechnology, Faculty of Engineering, Osaka University, Japan
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Kemp EH, Sammons RL, Moir A, Sun D, Setlow P. Analysis of transcriptional control of the gerD spore germination gene of Bacillus subtilis 168. J Bacteriol 1991; 173:4646-52. [PMID: 1906867 PMCID: PMC208140 DOI: 10.1128/jb.173.15.4646-4652.1991] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The gerD locus of Bacillus subtilis comprises a single gene whose function is essential for the germination of B. subtilis spores in media containing asparagine, glucose, and fructose. The expression of gerD has been characterized by using a chromosomal lacZ fusion to the gerD promoter. The promoter is switched on at the same time as the synthesis of glucose dehydrogenase, 2.5 h after sporulation has been initiated in the developing forespore. The gerD gene is not expressed in spoIIB or spoIIIA, -IIIB, -EIII, -FIII, or -IIIG mutants, but it is expressed in spoIIIC and -IIID and spoIVA mutant backgrounds. The in vivo transcriptional start point of the gene has been mapped by primer extension analysis, and sequences upstream from the start point show considerable homology with the promoter consensus sequences recognized by RNA polymerase containing the forespore-specific sigma factor sigma G (E sigma G). gerD is transcribed in vitro by E sigma G with a similar if not identical start point to that found in vivo, and expression of the gene can be rapidly induced in vegetative cells following the induction of sigma G synthesis. These results indicate that gerD is another member of the sigma G regulon, which includes a number of genes expressed only in the forespore compartment of sporulating cells of B. subtilis.
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Affiliation(s)
- E H Kemp
- Krebs Institute, Department of Molecular Biology and Biotechnology, Sheffield, United Kingdom
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Fajardo-Cavazos P, Tovar-Rojo F, Setlow P. Effect of promoter mutations and upstream deletions on the expression of genes coding for small, acid-soluble spore proteins of Bacillus subtilis. J Bacteriol 1991; 173:2011-6. [PMID: 1900507 PMCID: PMC207735 DOI: 10.1128/jb.173.6.2011-2016.1991] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The sspB and sspE genes code for major small, acid-soluble proteins of Bacillus subtilis spores and are transcribed during sporulation by RNA polymerase containing sigma G. Analysis of the expression in vivo and the sigma G-dependent transcription in vitro of sspB and sspE genes carrying upstream deletions or point mutations in -10 and -35 promoter regions is consistent with sigma G being the only major transcriptional regulator of these genes. These data also provide information on the residues in -10 and -35 regions which are most important for sigma G recognition.
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Affiliation(s)
- P Fajardo-Cavazos
- Department of Biochemistry, University of Connecticut Health Center, Farmington 06032
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Abstract
The asymmetric targeting of proteins to the Caulobacter predivisional cell poles yields dissimilar progeny. We show that the products of transcriptional reporter gene fusions to a flagellin gene and to the flagellar hook operon are segregated to the progeny swarmer cell. This segregation does not depend on sequences within the mRNA, but on the upstream regulatory region. The subset of developmentally regulated flagellar genes that exhibit mRNA segregation has the same upstream cis-acting elements: an activator-binding site known as the ftr sequence and an IHF-binding site. We propose that these genes are preferentially transcribed from the chromosome in the incipient swarmer cell pole of the predivisional cell.
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Sussman MD, Setlow P. Cloning, nucleotide sequence, and regulation of the Bacillus subtilis gpr gene, which codes for the protease that initiates degradation of small, acid-soluble proteins during spore germination. J Bacteriol 1991; 173:291-300. [PMID: 1840582 PMCID: PMC207186 DOI: 10.1128/jb.173.1.291-300.1991] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The gpr gene, which codes for the protease that initiates degradation of small, acid-soluble proteins during spore germination, has been cloned from Bacillus megaterium and Bacillus subtilis, and its nucleotide sequence has been determined. Use of a translational gpr-lacZ fusion showed that the B. subtilis gpr gene was expressed primarily, if not exclusively, in the forespore compartment of the sporulating cell, with expression taking place approximately 1 h before expression of glucose dehydrogenase and ssp genes. gpr-lacZ expression was abolished in spoIIAC (sigF) and spoIIIE mutants but was reduced only approximately 50% in a spoIIIG (sigG) mutant. However, the kinetics of the initial approximately 50% of gpr-lacZ expression were unaltered in a spoIIIG mutant. The in vivo transcription start site of gpr has been identified and found to be identical to the in vitro start site on this gene with either E sigma F or E sigma G. Induction of sigma G synthesis in vivo turned on gpr-lacZ expression in parallel with synthesis of glucose dehydrogenase. These data are consistent with gpr transcription during sporulation first by E sigma F and then by E sigma G.
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Affiliation(s)
- M D Sussman
- Department of Biochemistry, University of Connecticut Health Center, Farmington 06032
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