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Hao Y, Pan X, You J, Li G, Xu M, Rao Z. Microbial production of branched chain amino acids: Advances and perspectives. BIORESOURCE TECHNOLOGY 2024; 397:130502. [PMID: 38417463 DOI: 10.1016/j.biortech.2024.130502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 02/23/2024] [Accepted: 02/25/2024] [Indexed: 03/01/2024]
Abstract
Branched-chain amino acids (BCAAs) such as L-valine, L-leucine, and L-isoleucine are widely used in food and feed. To comply with sustainable development goals, commercial production of BCAAs has been completely replaced with microbial fermentation. However, the efficient production of BCAAs by microorganisms remains a serious challenge due to their staggered metabolic networks and cell growth. To overcome these difficulties, systemic metabolic engineering has emerged as an effective and feasible strategy for the biosynthesis of BCAA. This review firstly summarizes the research advances in the microbial synthesis of BCAAs and representative engineering strategies. Second, systematic methods, such as high-throughput screening, adaptive laboratory evolution, and omics analysis, can be used to analyses the synthesis of BCAAs at the whole-cell level and further improve the titer of target chemicals. Finally, new tools and engineering strategies that may increase the production output and development direction of the microbial production of BCAAs are discussed.
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Affiliation(s)
- Yanan Hao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Guomin Li
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Meijuan Xu
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
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Zhang H, Ye T, Fengmin L, Zhang X, Wang J, Wei X, Neo YP, Liu H, Fang H. Strategies to Enhance l-Isoleucine Synthesis by Modifying the Threonine Metabolism Pathway in Escherichia coli. ACS OMEGA 2024; 9:10276-10285. [PMID: 38463329 PMCID: PMC10918650 DOI: 10.1021/acsomega.3c07619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/23/2024] [Accepted: 01/30/2024] [Indexed: 03/12/2024]
Abstract
l-threonine as an important precursor substance of l-isoleucine and improving its accumulation in Escherichia coli became an important idea to construct a chassis strain with high l-isoleucine production. Meanwhile, the effect of l-threonine metabolic pathway disruption in E. coli for the improved production of l-isoleucine remains unrevealed. In the present study, a mutant strain of E. coli was engineered by inactivating specific metabolic pathways (e.g., Δtdh, ΔltaE, and ΔyiaY) that were associated with l-threonine metabolism but unrelated to l-isoleucine synthesis. This was done with the aim to reduce the breakdown of l-threonine and, thereby, increase the production of l-isoleucine. The results obtained demonstrated a 72.3% increment in l-isoleucine production from 4.34 to 7.48 g·L-1 in the mutant strain compared with the original strain, with an unexpected 10.3% increment in bacterial growth as measured at OD600. Transcriptome analysis was also conducted on both the mutant strain NXU102 and the original strain NXU101 in the present study to gain a comprehensive understanding of their physiological attributes. The findings revealed a notable disparity in 1294 genes between the two strains, with 658 genes exhibiting up-regulation and 636 genes displaying down-regulation. The activity of tricarboxylic acid (TCA) cycle-related genes was found to decrease, but oxidative phosphorylation-related genes were highly up-regulated, which explained the increased activity of the mutant strain. For instance, l-lysine catabolism-related genes were found to be up-regulated, which reconfigured the carbon flow into the TCA cycle. The augmentation of acetic acid degradation pathway-related genes assisted in the reduction in acetic acid accumulation that could retard cell growth. Notably, substantial up-regulation of the majority of genes within the aspartate pathway could potentially account for the increased production of l-isoleucine in the present study. In this paper, a chassis strain with an l-isoleucine yield of 7.48 g·L-1 was successfully constructed by cutting off the threonine metabolic pathway. Meanwhile, transcriptomic analysis revealed that the cutting off of the threonine metabolic pathway induced perturbation of genes related to the pathways associated with the synthesis of l-isoleucine, such as the tricarboxylic acid cycle, glycolysis, and aspartic acid pathway.
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Affiliation(s)
- HaoJie Zhang
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Tong Ye
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Liu Fengmin
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Xiangjun Zhang
- School of Life Science, Ningxia University, Yinchuan 750021, China
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Jipeng Wang
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Xiaobo Wei
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Yun Ping Neo
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University, Subang Jaya, Selangor 47500, Malaysia
| | - Huiyan Liu
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
| | - Haitian Fang
- Ningxia Key Laboratory for Food Microbial-Applications Technology and Safety Control, School of Food Science and Engineering, Ningxia University, Yinchuan 750021, China
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Kumari K, Sharma PK, Singh RP. Unravelling the transcriptome response of Enterobacter sp. S-33 under varying temperature. Arch Microbiol 2024; 206:81. [PMID: 38294553 DOI: 10.1007/s00203-023-03792-6] [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] [Received: 11/22/2023] [Revised: 11/22/2023] [Accepted: 12/11/2023] [Indexed: 02/01/2024]
Abstract
Enterobacter genus includes the bacteria occupying every aspect of environment, however, their adaptability at varying temperature is not clear. In the present study, we analyzed the transcriptome response of Enterobacter sp. S-33 and their functional genes under various temperatures (30-45 ℃) that were expressed and accumulated in cells under temperature-stress. During a temperature shift from 37 to 45 ℃, 165 genes showed differential expression including 112 up-regulated and 53 down-regulated. In particular, heat-shock genes such as CspA, 16 kDa heat shock protein A/B and transcriptional regulators such as LysR, TetR, and LuxR were differentially expressed, indicating the role of complex molecular mechanism of Enterobacter adapting to temperature stress. Similarly, genes associated to signal transduction, ABC transporters, iron homeostasis, and quorum sensing were also induced. The Gene ontology enrichment analysis of differentially expressed genes (DEGs) were categorized into "transmembrane transport", "tRNA binding", "hydrogen sulfide biosynthetic process" and "sulfate assimilation" terms. In addition, Kyoto Encyclopedia of Genes and Genomes pathways showed that ABC transporter as well as quorum sensing pathways were significantly enriched. Overall, current study has contributed to explore the adaptive molecular mechanisms of Enterobacter spp. upon temperature change, which further opens new avenues for future in-depth functional studies.
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Affiliation(s)
- Kiran Kumari
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
| | - Parva Kumar Sharma
- Department of Plant Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742, USA
| | - Rajnish Prakash Singh
- Department of Biotechnology, Jaypee Institute of Information Technology, Noida, India.
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Wang Y, Bai Y, Zeng Q, Jiang Z, Liu Y, Wang X, Liu X, Liu C, Min W. Recent advances in the metabolic engineering and physiological opportunities for microbial synthesis of L-aspartic acid family amino acids: A review. Int J Biol Macromol 2023; 253:126916. [PMID: 37716660 DOI: 10.1016/j.ijbiomac.2023.126916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/10/2023] [Accepted: 09/13/2023] [Indexed: 09/18/2023]
Abstract
L-aspartic acid, L-threonine, L-isoleucine, l-lysine, and L-methionine constitute the l-aspartate amino acids (AFAAs). Except for L-aspartic acid, these are essential amino acids that cannot be synthesized by humans or animals themselves. E. coli and C. glutamicum are the main model organisms for AFAA production. It is necessary to reconstitute microbial cell factories and the physiological state of industrial fermentation cells for in-depth research into strains with higher AFAA production levels and optimal growth states. Considering that the anabolic pathways of the AFAAs and engineering modifications have rarely been reviewed in the latest progress, this work reviews the central metabolic pathways of two strains and strategies for the metabolic engineering of AFAA synthetic pathways. The challenges posed by microbial physiology in AFAA production and possible strategies to address them, as well as future research directions for constructing strains with high AFAA production levels, are discussed in this review article.
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Affiliation(s)
- Yusheng Wang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Yunlong Bai
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Qi Zeng
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Zeyuan Jiang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Yuzhe Liu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Xiyan Wang
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Xiaoting Liu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China
| | - Chunlei Liu
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China.
| | - Weihong Min
- College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, PR China.
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Guo M, Liu J, Xu Z, Wang J, Li T, Lei H, Duan X, Sun Y, Zhang X, Huang R. 2-Methoxy-1,4-naphthoquinone Induces Metabolic Shifts in Penicillium Digitatum Revealed by High-Dimensional Biological Data. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:9697-9706. [PMID: 32803964 DOI: 10.1021/acs.jafc.0c03396] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Penicillium digitatum is the primary pathogen causing the green mold of citrus. The need for the development of higher effective and lower toxic natural antifungal agents is urgent, owing to the lack of antifungal agents that can successfully combat P. digitatum. Herein, the effects and mechanisms of 2-methoxy-1,4-naphthoquinone (MNQ) as a potential inhibitor of P. digitatumwere studied. First, MNQ showed a significant anti-P. digitatum effect with a minimum inhibitory concentration value of 5.0 μg/mL. Then, transcriptome, proteome, and metabolome profiling were performed on the MNQ-treated P. digitatum. A total of 910 genes, 297 proteins, and 174 metabolites changed significantly. The omics analysis indicated that it could be seen that MNQ mainly inhibits the growth of P. digitatum by affecting the synthesis of branched-chain amino acids and cell walls. These findings will be a great contribution to the further understanding of the possible molecular action of MNQ.
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Affiliation(s)
- Meixia Guo
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Jun Liu
- Laboratory of Pathogenic Biology, Guangdong Medical University, Zhanjiang 524023, China
| | - Zhenlin Xu
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Jie Wang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Taotao Li
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Hongtao Lei
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xuewu Duan
- Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
| | - Yuanming Sun
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiaoyong Zhang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou 510642, China
| | - Riming Huang
- Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University, Guangzhou 510642, China
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Strategy for improving L-isoleucine production efficiency in Corynebacterium glutamicum. Appl Microbiol Biotechnol 2019; 103:2101-2111. [DOI: 10.1007/s00253-019-09632-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 01/06/2019] [Accepted: 01/07/2019] [Indexed: 01/25/2023]
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Metabolically engineered Corynebacterium glutamicum for bio-based production of chemicals, fuels, materials, and healthcare products. Metab Eng 2018; 50:122-141. [DOI: 10.1016/j.ymben.2018.07.008] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 01/15/2023]
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Lee MJ, Kim P. Recombinant Protein Expression System in Corynebacterium glutamicum and Its Application. Front Microbiol 2018; 9:2523. [PMID: 30416490 PMCID: PMC6213972 DOI: 10.3389/fmicb.2018.02523] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/03/2018] [Indexed: 01/01/2023] Open
Abstract
Corynebacterium glutamicum, a soil-derived gram-positive actinobacterium, has been widely used for the production of biochemical molecules such as amino acids (i.e., L-glutamate and L-lysine), nucleic acids, alcohols, and organic acids. The metabolism of the bacterium has been engineered to increase the production of the target biochemical molecule, which requires a cytosolic enzyme expression. As recent demand for new proteinaceous biologics (such as antibodies, growth factors, and hormones) increase, C. glutamicum is attracting industrial interest as a recombinant protein expression host for therapeutic protein production due to the advantages such as low protease activity without endotoxin activity. In this review, we have summarized the recent studies on the heterologous expression of the recombinant protein in C. glutamicum for metabolic engineering, expansion of substrate availability, and recombinant protein secretion. We have also outlined the advances in genetic components such as promoters, surface anchoring systems, and secretory signal sequences in C. glutamicum for effective recombinant protein expression.
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Affiliation(s)
| | - Pil Kim
- Department of Biotechnology, The Catholirc University of Korea, Bucheon, South Korea
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Zhou J, Zhang R, Yang T, Liu Q, Zheng J, Wang F, Liu F, Xu M, Zhang X, Rao Z. Relieving Allosteric Inhibition by Designing Active Inclusion Bodies and Coating of the Inclusion Bodies with Fe3O4 Nanomaterials for Sustainable 2-Oxobutyric Acid Production. ACS Catal 2018. [DOI: 10.1021/acscatal.8b03181] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Junping Zhou
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Rongzhen Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Taowei Yang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Qiaoli Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Junxian Zheng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Fang Wang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Fei Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Meijuan Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Xian Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
| | - Zhiming Rao
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu Province 214122, China
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Glutamine 89 is a key residue in the allosteric modulation of human serine racemase activity by ATP. Sci Rep 2018; 8:9016. [PMID: 29899358 PMCID: PMC5998037 DOI: 10.1038/s41598-018-27227-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/25/2018] [Indexed: 11/17/2022] Open
Abstract
Serine racemase (SR) catalyses two reactions: the reversible racemisation of L-serine and the irreversible dehydration of L- and D-serine to pyruvate and ammonia. SRs are evolutionarily related to serine dehydratases (SDH) and degradative threonine deaminases (TdcB). Most SRs and TdcBs – but not SDHs – are regulated by nucleotides. SR binds ATP cooperatively and the nucleotide allosterically stimulates the serine dehydratase activity of the enzyme. A H-bond network comprising five residues (T52, N86, Q89, E283 and N316) and water molecules connects the active site with the ATP-binding site. Conservation analysis points to Q89 as a key residue for the allosteric communication, since its mutation to either Met or Ala is linked to the loss of control of activity by nucleotides. We verified this hypothesis by introducing the Q89M and Q89A point mutations in the human SR sequence. The allosteric communication between the active site and the allosteric site in both mutants is almost completely abolished. Indeed, the stimulation of the dehydratase activity by ATP is severely diminished and the binding of the nucleotide is no more cooperative. Ancestral state reconstruction suggests that the allosteric control by nucleotides established early in SR evolution and has been maintained in most eukaryotic lineages.
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Metabolic engineering of Corynebacterium glutamicum for fermentative production of chemicals in biorefinery. Appl Microbiol Biotechnol 2018; 102:3915-3937. [DOI: 10.1007/s00253-018-8896-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 01/22/2023]
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Abstract
One of the greatest sources of metabolic and enzymatic diversity are microorganisms. In recent years, emerging recombinant DNA and genomic techniques have facilitated the development of new efficient expression systems, modification of biosynthetic pathways leading to new metabolites by metabolic engineering, and enhancement of catalytic properties of enzymes by directed evolution. Complete sequencing of industrially important microbial genomes is taking place very rapidly, and there are already hundreds of genomes sequenced. Functional genomics and proteomics are major tools used in the search for new molecules and development of higher-producing strains.
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Affiliation(s)
| | - Sergio Sánchez
- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, CDMX, México
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Sharma R, Keshari D, Singh KS, Singh SK. Biochemical and functional characterization of MRA_1571 of Mycobacterium tuberculosis H37Ra and effect of its down-regulation on survival in macrophages. Biochem Biophys Res Commun 2017; 487:892-897. [PMID: 28465237 DOI: 10.1016/j.bbrc.2017.04.149] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 04/29/2017] [Indexed: 12/31/2022]
Abstract
Amino acid biosynthesis has emerged as a source of new drug targets as many bacterial strains auxotrophic for amino acids fail to proliferate under in vivo conditions. Branch chain amino acids (BCAAs) are important for Mycobacterium tuberculosis (Mtb) survival and strains deficient in their biosynthesis were attenuated for growth in mice. Threonine dehydratase (IlvA) is a pyridoxal-5-phosphate (PLP) dependent enzyme that catalyzes the first step in isoleucine biosynthesis. The MRA_1571 of Mycobacterium tuberculosis H37Ra (Mtb-Ra), annotated to be coding for IlvA, was cloned, expressed and purified. Purified protein was subsequently used for developing enzyme assay and to study its biochemical properties. Also, E. coli BL21 (DE3) IlvA knockout (E. coli-ΔilvA) was developed and genetically complemented with Mtb-Ra ilvA expression construct (pET32a-ilvA) to make complemented E. coli strain (E. coli-ΔilvA + pET32a-ilvA). The E. coli-ΔilvA showed growth failure in minimal medium but growth restoration was observed in E. coli-ΔilvA + pET32a-ilvA. E. coli-ΔilvA growth was also restored in the presence of isoleucine. The IlvA localization studies detected its distribution in cell wall and membrane fractions with relatively minor presence in cytosolic fraction. Maximum IlvA expression was observed at 72 h in wild-type (WT) Mtb-Ra infecting macrophages. Also, Mtb-Ra IlvA knockdown (KD) showed reduced survival in macrophages compared to WT and complemented strain (KDC).
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Affiliation(s)
- Rishabh Sharma
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India
| | - Deepa Keshari
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India
| | - Kumar Sachin Singh
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India
| | - Sudheer Kumar Singh
- Microbiology Division, CSIR-Central Drug Research Institute, B.S. 10/1, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow - 226031, India; Academy of Scientific and Industrial Research (AcSIR), New Delhi, India.
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14
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Chai X, Shang X, Zhang Y, Liu S, Liang Y, Zhang Y, Wen T. A novel pyruvate kinase and its application in lactic acid production under oxygen deprivation in Corynebacterium glutamicum. BMC Biotechnol 2016; 16:79. [PMID: 27852252 PMCID: PMC5112673 DOI: 10.1186/s12896-016-0313-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 11/01/2016] [Indexed: 11/18/2022] Open
Abstract
Background Pyruvate kinase (Pyk) catalyzes the generation of pyruvate and ATP in glycolysis and functions as a key switch in the regulation of carbon flux distribution. Both the substrates and products of Pyk are involved in the tricarboxylic acid cycle, anaplerosis and energy anabolism, which places Pyk at a primary metabolic intersection. Pyks are highly conserved in most bacteria and lower eukaryotes. Corynebacterium glutamicum is an industrial workhorse for the production of various amino acids and organic acids. Although C. glutamicum was assumed to possess only one Pyk (pyk1, NCgl2008), NCgl2809 was annotated as a pyruvate kinase with an unknown role. Results Here, we identified that NCgl2809 was a novel pyruvate kinase (pyk2) in C. glutamicum. Complementation of the WTΔpyk1Δpyk2 strain with the pyk2 gene restored its growth on d-ribose, which demonstrated that Pyk2 could substitute for Pyk1 in vivo. Pyk2 was co-dependent on Mn2+ and K+ and had a higher affinity for ADP than phosphoenolpyruvate (PEP). The catalytic activity of Pyk2 was allosterically regulated by fructose 1,6-bisphosphate (FBP) activation and ATP inhibition. Furthermore, pyk2 and ldhA, which encodes l-lactate dehydrogenase, were co-transcribed as a bicistronic mRNA under aerobic conditions and pyk2 deficiency had a slight effect on the intracellular activity of Pyk. However, the mRNA level of pyk2 in the wild-type strain under oxygen deprivation was 14.24-fold higher than that under aerobic conditions. Under oxygen deprivation, pyk1 or pyk2 deficiency decreased the generation of lactic acid, and the overexpression of either pyk1 or pyk2 increased the production of lactic acid as the activity of Pyk increased. Fed-batch fermentation of the pyk2-overexpressing WTΔpyk1 strain produced 60.27 ± 1.40 g/L of lactic acid, which was a 47% increase compared to the parent strain under oxygen deprivation. Conclusions Pyk2 functioned as a pyruvate kinase and contributed to the increased level of Pyk activity under oxygen deprivation. Electronic supplementary material The online version of this article (doi:10.1186/s12896-016-0313-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xin Chai
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Xiuling Shang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yu Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Shuwen Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yong Liang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China
| | - Yun Zhang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
| | - Tingyi Wen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China. .,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
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15
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Dong X, Zhao Y, Hu J, Li Y, Wang X. Attenuating l -lysine production by deletion of ddh and lysE and their effect on l -threonine and l -isoleucine production in Corynebacterium glutamicum. Enzyme Microb Technol 2016; 93-94:70-78. [DOI: 10.1016/j.enzmictec.2016.07.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 07/09/2016] [Accepted: 07/22/2016] [Indexed: 11/25/2022]
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16
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Characterization of aspartate kinase and homoserine dehydrogenase from Corynebacterium glutamicum IWJ001 and systematic investigation of l-isoleucine biosynthesis. ACTA ACUST UNITED AC 2016; 43:873-85. [DOI: 10.1007/s10295-016-1763-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 03/16/2016] [Indexed: 11/24/2022]
Abstract
Abstract
Previously we have characterized a threonine dehydratase mutant TDF383V (encoded by ilvA1) and an acetohydroxy acid synthase mutant AHASP176S, D426E, L575W (encoded by ilvBN1) in Corynebacterium glutamicum IWJ001, one of the best l-isoleucine producing strains. Here, we further characterized an aspartate kinase mutant AKA279T (encoded by lysC1) and a homoserine dehydrogenase mutant HDG378S (encoded by hom1) in IWJ001, and analyzed the consequences of all these mutant enzymes on amino acids production in the wild type background. In vitro enzyme tests confirmed that AKA279T is completely resistant to feed-back inhibition by l-threonine and l-lysine, and that HDG378S is partially resistant to l-threonine with the half maximal inhibitory concentration between 12 and 14 mM. In C. glutamicum ATCC13869, expressing lysC1 alone led to exclusive l-lysine accumulation, co-expressing hom1 and thrB1 with lysC1 shifted partial carbon flux from l-lysine (decreased by 50.1 %) to l-threonine (4.85 g/L) with minor l-isoleucine and no l-homoserine accumulation, further co-expressing ilvA1 completely depleted l-threonine and strongly shifted carbon flux from l-lysine (decreased by 83.0 %) to l-isoleucine (3.53 g/L). The results demonstrated the strongly feed-back resistant TDF383V might be the main driving force for l-isoleucine over-synthesis in this case, and the partially feed-back resistant HDG378S might prevent the accumulation of toxic intermediates. Information exploited from such mutation-bred production strain would be useful for metabolic engineering.
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Yamamoto K, Tsuchisaka A, Yukawa H. Branched-Chain Amino Acids. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 159:103-128. [PMID: 27872960 DOI: 10.1007/10_2016_28] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Branched-chain amino acids (BCAAs), viz., L-isoleucine, L-leucine, and L-valine, are essential amino acids that cannot be synthesized in higher organisms and are important nutrition for humans as well as livestock. They are also valued as synthetic intermediates for pharmaceuticals. Therefore, the demand for BCAAs in the feed and pharmaceutical industries is increasing continuously. Traditional industrial fermentative production of BCAAs was performed using microorganisms isolated by random mutagenesis. A collection of these classical strains was also scientifically useful to clarify the details of the BCAA biosynthetic pathways, which are tightly regulated by feedback inhibition and transcriptional attenuation. Based on this understanding of the metabolism of BCAAs, it is now possible for us to pursue strains with higher BCAA productivity using rational design and advanced molecular biology techniques. Additionally, systems biology approaches using augmented omics information help us to optimize carbon flux toward BCAA production. Here, we describe the biosynthetic pathways of BCAAs and their regulation and then overview the microorganisms developed for BCAA production. Other chemicals, including isobutanol, i.e., a second-generation biofuel, can be synthesized by branching the BCAA biosynthetic pathways, which are also outlined.
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Affiliation(s)
- Keisuke Yamamoto
- Green Earth Institute Co., Ltd, Hongo, Tokyo, Japan
- Green Earth Research Center, Kisarazu, Chiba, Japan
| | - Atsunari Tsuchisaka
- Green Earth Institute Co., Ltd, Hongo, Tokyo, Japan
- Green Earth Research Center, Kisarazu, Chiba, Japan
| | - Hideaki Yukawa
- Green Earth Institute Co., Ltd, Hongo, Tokyo, Japan.
- Green Earth Research Center, Kisarazu, Chiba, Japan.
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18
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Generation of mutant threonine dehydratase and its effects on isoleucine synthesis in Corynebacterium glutamicum. World J Microbiol Biotechnol 2015; 31:1369-77. [DOI: 10.1007/s11274-015-1885-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 06/05/2015] [Indexed: 12/15/2022]
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19
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Liu X, Yang Y, Zhang W, Sun Y, Peng F, Jeffrey L, Harvey L, McNeil B, Bai Z. Expression of recombinant protein using Corynebacterium Glutamicum: progress, challenges and applications. Crit Rev Biotechnol 2015; 36:652-64. [PMID: 25714007 DOI: 10.3109/07388551.2015.1004519] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Corynebacterium glutamicum (C. glutamicum) is a highly promising alternative prokaryotic host for recombinant protein expression, as it possesses several significant advantages over Escherichia coli (E. coli), the currently leading bacterial protein expression system. During the past decades, several experimental techniques and vector components for genetic manipulation of C. glutamicum have been developed and validated, including strong promoters for tightly regulating target gene expression, various types of plasmid vectors, protein secretion systems and methods of genetically modifying the host strain genome to improve protein production potential. This review critically discusses current progress in establishing C. glutamicum as a host for recombinant protein expression, and examines, in depth, some successful case studies of actual application of this expression system. The established "expression tool box" for developing novel constructs based on C. glutamicum as a host are also evaluated. Finally, the existing issues and solutions in process development with C. glutamicum as a host are specifically addressed.
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Affiliation(s)
- Xiuxia Liu
- a National Engineering Laboratory of Cereal Fermentation Technology , School of Biotechnology, JiangNan University , Wuxi , China and
| | - Yankun Yang
- a National Engineering Laboratory of Cereal Fermentation Technology , School of Biotechnology, JiangNan University , Wuxi , China and
| | - Wei Zhang
- a National Engineering Laboratory of Cereal Fermentation Technology , School of Biotechnology, JiangNan University , Wuxi , China and
| | - Yang Sun
- a National Engineering Laboratory of Cereal Fermentation Technology , School of Biotechnology, JiangNan University , Wuxi , China and
| | - Feng Peng
- a National Engineering Laboratory of Cereal Fermentation Technology , School of Biotechnology, JiangNan University , Wuxi , China and
| | - Laura Jeffrey
- b Institute of Pharmacy & Biomedical Sciences, Strathclyde University , Glasgow , UK
| | - Linda Harvey
- b Institute of Pharmacy & Biomedical Sciences, Strathclyde University , Glasgow , UK
| | - Brian McNeil
- b Institute of Pharmacy & Biomedical Sciences, Strathclyde University , Glasgow , UK
| | - Zhonghu Bai
- a National Engineering Laboratory of Cereal Fermentation Technology , School of Biotechnology, JiangNan University , Wuxi , China and
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20
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Overexpression of ribosome elongation factor G and recycling factor increases L-isoleucine production in Corynebacterium glutamicum. Appl Microbiol Biotechnol 2015; 99:4795-805. [PMID: 25707863 DOI: 10.1007/s00253-015-6458-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 02/02/2015] [Accepted: 02/03/2015] [Indexed: 10/24/2022]
Abstract
Ribosome elongation factor G encoded by fusA promotes the translocation step of protein synthesis in bacteria; ribosome recycling factor encoded by frr, together with the elongation factor G, dissociates ribosomes from messenger RNA after the termination of translation. Both factors play important roles during protein synthesis in bacteria. In this study, we found that overexpression of fusA and/or frr led to the increase of L-isoleucine production in Corynebacterium glutamicum IWJ001, an L-isoleucine production strain generated by random mutagenesis. Reverse transcription polymerase chain reaction analysis showed that transcriptional levels of genes lysC, hom, thrB, ilvA, ilvBN, and ilvE encoding the key enzymes in the biosynthetic pathway of L-isoleucine increased in C. glutamicum IWJ001 when fusA and/or frr were overexpressed. Co-overexpression of fusA and frr, together with genes ilvA, ilvB, ilvN, and ppnk in C. glutamicum IWJ001, led to 76.5 % increase of L-isoleucine production in flask cultivation and produced 28.5 g/L L-isoleucine in 72-h fed-batch fermentation. The results demonstrate that overexpressing ribosome elongation factor G and ribosome recycling factor is an efficient approach to enhance L-isoleucine production in C. glutamicum.
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21
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Enhancing the carbon flux and NADPH supply to increase L-isoleucine production in Corynebacterium glutamicum. BIOTECHNOL BIOPROC E 2014. [DOI: 10.1007/s12257-013-0416-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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22
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The role of ACT-like subdomain in bacterial threonine dehydratases. PLoS One 2014; 9:e87550. [PMID: 24475306 PMCID: PMC3901761 DOI: 10.1371/journal.pone.0087550] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/20/2013] [Indexed: 12/04/2022] Open
Abstract
In bacteria, threonine dehydratases could convert L-threonine to 2-ketobutyrate. Some threonine dehydratases contain only a catalytic domain, while others contain an N-terminal catalytic domain and a C-terminal regulatory domain composed of one or two ACT-like subdomains. However, the role of the ACT-like subdomain in threonine dehydratases is not clear. Here, nine different bacterial threonine dehydratases were studied. Three of the nine contain no ACT-like subdomain, four of them contain a single ACT-like subdomain, and two of them contain two ACT-like subdomains. The nine genes encoding these threonine dehydratases were individually overexpressed in E. coli BL21(DE3), and the enzymes were purified to homogeneity. Activities of the purified enzymes were analyzed after incubation at different temperatures and different pHs. The results showed that threonine dehydratases with a single ACT-like subdomain are more stable at higher temperatures and a broad range of pH than those without ACT-like subdomain or with two ACT-like subdomains. Furthermore, the specific activity of threonine dehydratases increases with the increase of the number of ACT-like subdomains they contain. The results suggest that the ACT-like subdomain plays an important role in bacterial threonine dehydratases.
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23
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Yu X, Li Y, Wang X. Molecular evolution of threonine dehydratase in bacteria. PLoS One 2013; 8:e80750. [PMID: 24324624 PMCID: PMC3851459 DOI: 10.1371/journal.pone.0080750] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/06/2013] [Indexed: 11/23/2022] Open
Abstract
Threonine dehydratase converts L-threonine to 2-ketobutyrate. Several threonine dehydratases exist in bacteria, but their origins and evolutionary pathway are unknown. Here we analyzed all the available threonine dehydratases in bacteria and proposed an evolutionary pathway leading to the genes encoding three different threonine dehydratases CTD, BTD1 and BTD2. The ancestral threonine dehydratase might contain only a catalytic domain, but one or two ACT-like subdomains were fused during the evolution, resulting BTD1 and BTD2, respectively. Horizontal gene transfer, gene fusion, gene duplication, and gene deletion may occur during the evolution of this enzyme. The results are important for understanding the functions of various threonine dehydratases found in bacteria.
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Affiliation(s)
- Xuefei Yu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, China
| | - Ye Li
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, China
| | - Xiaoyuan Wang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
- Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, China
- * E-mail:
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24
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Pátek M, Nešvera J. Promoters and Plasmid Vectors of Corynebacterium glutamicum. CORYNEBACTERIUM GLUTAMICUM 2013. [DOI: 10.1007/978-3-642-29857-8_2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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25
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Park JH, Oh JE, Lee KH, Kim JY, Lee SY. Rational design of Escherichia coli for L-isoleucine production. ACS Synth Biol 2012; 1:532-40. [PMID: 23656230 DOI: 10.1021/sb300071a] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabolic engineering of Escherichia coli was performed to construct a 100% rationally engineered strain capable of overproducing L-isoleucine, an important branched-chain amino acid. The thrABC (encoding L-threonine biosynthetic enzymes), ilvA (encoding feedback-resistant threonine dehydratase), ilvIH (encoding feedback-resistant acetohydroxy acid synthase III), and ygaZH (encoding branched-chain amino acid exporter) genes were amplified by plasmid-based overexpression. The ilvCED (encoding L-isoleucine biosynthetic enzymes) and lrp (encoding global regulator Lrp) genes were also amplified by chromosomal promoter replacement in order to further increase the flux toward L-isoleucine. The final engineered E. coli strain was able to produce 9.46 g/L of L-isoleucine with a yield of 0.14 g/g of glucose by fed-batch culture. The overall design principles described here for the production of highly regulated product should be useful in designing strains for the production of other similar bioproducts.
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Affiliation(s)
- Jin Hwan Park
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Jae Eun Oh
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Kwang Ho Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Ji Young Kim
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
| | - Sang Yup Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Program), Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea
- BioInformatics Research Center and BioProcess Engineering Research Center, KAIST, Daejeon 305-701, Republic of Korea
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26
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Improved production of L-threonine in Escherichia coli by use of a DNA scaffold system. Appl Environ Microbiol 2012; 79:774-82. [PMID: 23160128 DOI: 10.1128/aem.02578-12] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Despite numerous approaches for the development of l-threonine-producing strains, strain development is still hampered by the intrinsic inefficiency of metabolic reactions caused by simple diffusion and random collisions of enzymes and metabolites. A scaffold system, which can promote the proximity of metabolic enzymes and increase the local concentration of intermediates, was reported to be one of the most promising solutions. Here, we report an improvement in l-threonine production in Escherichia coli using a DNA scaffold system, in which a zinc finger protein serves as an adapter for the site-specific binding of each enzyme involved in l-threonine production to a precisely ordered location on a DNA double helix to increase the proximity of enzymes and the local concentration of metabolites to maximize production. The optimized DNA scaffold system for l-threonine production significantly increased the efficiency of the threonine biosynthetic pathway in E. coli, substantially reducing the production time for l-threonine (by over 50%). In addition, this DNA scaffold system enhanced the growth rate of the host strain by reducing the intracellular concentration of toxic intermediates, such as homoserine. Our DNA scaffold system can be used as a platform technology for the construction and optimization of artificial metabolic pathways as well as for the production of many useful biomaterials.
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27
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Abstract
Microorganisms are one of the greatest sources of metabolic and enzymatic diversity. In recent years, emerging recombinant DNA and genomic techniques have facilitated the development of new efficient expression systems, modification of biosynthetic pathways leading to new metabolites by metabolic engineering, and enhancement of catalytic properties of enzymes by directed evolution. Complete sequencing of industrially important microbial genomes is taking place very rapidly and there are already hundreds of genomes sequenced. Functional genomics and proteomics are major tools used in the search for new molecules and development of higher-producing strains.
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28
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Co-expression of feedback-resistant threonine dehydratase and acetohydroxy acid synthase increase L-isoleucine production in Corynebacterium glutamicum. Metab Eng 2012; 14:542-50. [PMID: 22771937 DOI: 10.1016/j.ymben.2012.06.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/19/2012] [Accepted: 06/26/2012] [Indexed: 11/24/2022]
Abstract
Threonine dehydratase and acetohydroxy acid synthase are critical enzymes in the L-isoleucine biosynthesis pathway of Corynebacterium glutamicum, but their activities are usually feedback-inhibited. In this study, we characterized a feedback-resistant threonine dehydratase and an acetohydroxy acid synthase from an L-isoleucine producing strain C. glutamicum JHI3-156. Sequence analysis showed that there was only a single amino acid substitution (Phe383Val) in the feedback-resistant threonine dehydratase, and there were three mutated amino acids (Pro176Ser, Asp426Glu, and Leu575Trp) in the big subunit of feedback-resistant acetohydroxy acid synthase. The mutated threonine dehydratase over-expressed in E. coli not only showed completely resistance to L-isoleucine inhibition, but also showed enhanced activity. The mutated acetohydroxy acid synthase over-expressed in E. coli showed more resistance to L-isoleucine inhibition than the wild type. Over-expression of the feedback-resistant threonine dehydratase or acetohydroxy acid synthase in C. glutamicum JHI3-156 led to increase of L-isoleucine production; co-expression of them in C. glutamicum JHI3-156 led to 131.7% increase in flask cultivation, and could produce 30.7g/L L-isoleucine in 72-h fed-batch fermentation. These results would be useful to enhance L-isoleucine production in C. glutamicum.
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29
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Chen L, Chen Z, Zheng P, Sun J, Zeng AP. Study and reengineering of the binding sites and allosteric regulation of biosynthetic threonine deaminase by isoleucine and valine in Escherichia coli. Appl Microbiol Biotechnol 2012; 97:2939-49. [PMID: 22669632 DOI: 10.1007/s00253-012-4176-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2012] [Revised: 05/10/2012] [Accepted: 05/13/2012] [Indexed: 11/26/2022]
Abstract
Biosynthetic threonine deaminase (TD) is a key enzyme for the synthesis of isoleucine which is allosterically inhibited and activated by Ile and Val, respectively. The binding sites of Ile and Val and the mechanism of their regulations in TD are not clear, but essential for a rational design of efficient productive strain(s) for Ile and related amino acids. In this study, structure-based computational approach and site-directed mutagenesis were combined to identify the potential binding sites of Ile and Val in Escherichia coli TD. Our results demonstrated that each regulatory domain of the TD monomer possesses two nonequivalent effector-binding sites. The residues R362, E442, G445, A446, Y369, I460, and S461 only interact with Ile while E347, G350, and F352 are involved not only in the Ile binding but also in the Val binding. By further considering enzyme kinetic data, we propose a concentration-dependent mechanism of the allosteric regulation of TD by Ile and Val. For the construction of Ile overproducing strain, a novel TD mutant with double mutation of F352A/R362F was also created, which showed both higher activity and much stronger resistance to Ile inhibition comparing to those of wild-type enzyme. Overexpression of this mutant TD in E. coli JW3591 significantly increased the production of ketobutyrate and Ile in comparison to the reference strains overexpressing wild-type TD or the catabolic threonine deaminase (TdcB). This work builds a solid basis for the reengineering of TD and related microorganisms for Ile production.
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Affiliation(s)
- Lin Chen
- Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China
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30
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Removal of l-alanine from the production of l-2-aminobutyric acid by introduction of alanine racemase and d-amino acid oxidase. Appl Microbiol Biotechnol 2011; 90:903-10. [DOI: 10.1007/s00253-011-3127-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 01/10/2011] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
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31
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Cheraghi S, Akbarzade A, Farhangi A, Chiani M, Saffari Z, Ghassemi S, Rastegari H, Mehrabi MR. Improved production of L-lysine by over-expression of Meso-diaminopimelate decarboxylase enzyme of Corynebacterium glutamicum in Escherichia coli. Pak J Biol Sci 2010; 13:504-508. [PMID: 21848075 DOI: 10.3923/pjbs.2010.504.508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim of this study is over-expression of Meso-diaminopimelate decarboxylase enzyme (EC 4.1.1.20) and enhancement of L-lysine production rate. The C. glutamicum LysA gene which encodes a Meso-diaminopimelate decarboxylase was cloned in E. coli. The cloned gene was sequenced; it encodes a 445 amino acids protein with molecular weight of 47 kD. Expression of the LysA gene in E. coli resulted in an increase in Meso-diaminopimelate decarboxylase activity, correlated with the presence in sodium dodecyl sulfate-polyacrylamid gels of a clear protein band that corresponds to this enzyme. The induction of cloned gene by IPTG has been shown to have an inhibitory effect on cell growth due to over-expression of the cloned gene. A two fold increase in lysine production rate was observed after introduction of the cloned gene into E. coli.
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Affiliation(s)
- S Cheraghi
- Department of Biochemistry, Payam-E-Noor University, Tehran, Iran
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32
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Adrio JL, Demain AL. Recombinant organisms for production of industrial products. Bioeng Bugs 2009; 1:116-31. [PMID: 21326937 DOI: 10.4161/bbug.1.2.10484] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 10/30/2009] [Accepted: 11/02/2009] [Indexed: 11/19/2022] Open
Abstract
A revolution in industrial microbiology was sparked by the discoveries of ther double-stranded structure of DNA and the development of recombinant DNA technology. Traditional industrial microbiology was merged with molecular biology to yield improved recombinant processes for the industrial production of primary and secondary metabolites, protein biopharmaceuticals and industrial enzymes. Novel genetic techniques such as metabolic engineering, combinatorial biosynthesis and molecular breeding techniques and their modifications are contributing greatly to the development of improved industrial processes. In addition, functional genomics, proteomics and metabolomics are being exploited for the discovery of novel valuable small molecules for medicine as well as enzymes for catalysis. The sequencing of industrial microbal genomes is being carried out which bodes well for future process improvement and discovery of new industrial products.
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Affiliation(s)
- Jose-Luis Adrio
- NeuronBioPharma, S.A., Parque Tecnologico de Ciencias de la Salud, Edificio BIC, Armilla, Granada, Spain
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33
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Tang KH, Feng X, Tang YJ, Blankenship RE. Carbohydrate metabolism and carbon fixation in Roseobacter denitrificans OCh114. PLoS One 2009; 4:e7233. [PMID: 19794911 PMCID: PMC2749216 DOI: 10.1371/journal.pone.0007233] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2009] [Accepted: 09/04/2009] [Indexed: 11/30/2022] Open
Abstract
The Roseobacter clade of aerobic marine proteobacteria, which compose 10–25% of the total marine bacterial community, has been reported to fix CO2, although it has not been determined what pathway is involved. In this study, we report the first metabolic studies on carbohydrate utilization, CO2 assimilation, and amino acid biosynthesis in the phototrophic Roseobacter clade bacterium Roseobacter denitrificans OCh114. We develop a new minimal medium containing defined carbon source(s), in which the requirements of yeast extract reported previously for the growth of R. denitrificans can be replaced by vitamin B12 (cyanocobalamin). Tracer experiments were carried out in R. denitrificans grown in a newly developed minimal medium containing isotopically labeled pyruvate, glucose or bicarbonate as a single carbon source or in combination. Through measurements of 13C-isotopomer labeling patterns in protein-derived amino acids, gene expression profiles, and enzymatic activity assays, we report that: (1) R. denitrificans uses the anaplerotic pathways mainly via the malic enzyme to fix 10–15% of protein carbon from CO2; (2) R. denitrificans employs the Entner-Doudoroff (ED) pathway for carbohydrate metabolism and the non-oxidative pentose phosphate pathway for the biosynthesis of histidine, ATP, and coenzymes; (3) the Embden-Meyerhof-Parnas (EMP, glycolysis) pathway is not active and the enzymatic activity of 6-phosphofructokinase (PFK) cannot be detected in R. denitrificans; and (4) isoleucine can be synthesized from both threonine-dependent (20% total flux) and citramalate-dependent (80% total flux) pathways using pyruvate as the sole carbon source.
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Affiliation(s)
- Kuo-Hsiang Tang
- Departments of Biology and Chemistry, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Xueyang Feng
- Department of Energy, Environment and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Yinjie J. Tang
- Department of Energy, Environment and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Robert E. Blankenship
- Departments of Biology and Chemistry, Washington University in St. Louis, St. Louis, Missouri, United States of America
- * E-mail:
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34
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Citrate utilization by Corynebacterium glutamicum is controlled by the CitAB two-component system through positive regulation of the citrate transport genes citH and tctCBA. J Bacteriol 2009; 191:3869-80. [PMID: 19376865 DOI: 10.1128/jb.00113-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this work, the molecular basis of aerobic citrate utilization by the gram-positive bacterium Corynebacterium glutamicum was studied. Genome analysis revealed the presence of two putative citrate transport systems. The permease encoded by citH belongs to the citrate-Mg(2+):H(+)/citrate-Ca(2+):H(+) symporter family, whereas the permease encoded by the tctCBA operon is a member of the tripartite tricarboxylate transporter family. The expression of citH or tctCBA in Escherichia coli enabled this species to utilize citrate aerobically, indicating that both CitH and TctABC are functional citrate transporters. Growth tests with the recombinant E. coli strains indicated that CitH is active with Ca(2+) or Sr(2+) but not with Mg(2+) and that TctABC is active with Ca(2+) or Mg(2+) but not with Sr(2+). We could subsequently show that, with 50 mM citrate as the sole carbon and energy source, the C. glutamicum wild type grew best when the minimal medium was supplemented with CaCl(2) but that MgCl(2) and SrCl(2) also supported growth. Each of the two transporters alone was sufficient for growth on citrate. The expression of citH and tctCBA was activated by citrate in the growth medium, independent of the presence or absence of glucose. This activation was dependent on the two-component signal transduction system CitAB, composed of the sensor kinase CitA and the response regulator CitB. CitAB belongs to the CitAB/DcuSR family of two-component systems, whose members control the expression of genes that are involved in the transport and catabolism of tricarboxylates or dicarboxylates. C. glutamicum CitAB is the first member of this family studied in Actinobacteria.
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Cann AF, Liao JC. Production of 2-methyl-1-butanol in engineered Escherichia coli. Appl Microbiol Biotechnol 2008; 81:89-98. [PMID: 18758769 PMCID: PMC7419481 DOI: 10.1007/s00253-008-1631-y] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 07/18/2008] [Accepted: 07/24/2008] [Indexed: 11/04/2022]
Abstract
Recent progress has been made in the production of higher alcohols by harnessing the power of natural amino acid biosynthetic pathways. Here, we describe the first strain of Escherichia coli developed to produce the higher alcohol and potential new biofuel 2-methyl-1-butanol (2MB). To accomplish this, we explored the biodiversity of enzymes catalyzing key parts of the isoleucine biosynthetic pathway, finding that AHAS II (ilvGM) from Salmonella typhimurium and threonine deaminase (ilvA) from Corynebacterium glutamicum improve 2MB production the most. Overexpression of the native threonine biosynthetic operon (thrABC) on plasmid without the native transcription regulation also improved 2MB production in E. coli. Finally, we knocked out competing pathways upstream of threonine production (ΔmetA, Δtdh) to increase its availability for further improvement of 2MB production. This work led to a strain of E. coli that produces 1.25 g/L 2MB in 24 h, a total alcohol content of 3 g/L, and with yields of up to 0.17 g 2MB/g glucose.
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Affiliation(s)
- Anthony F Cann
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
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36
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Metabolic engineering of Escherichia coli for 1-butanol and 1-propanol production via the keto-acid pathways. Metab Eng 2008; 10:312-20. [PMID: 18775501 DOI: 10.1016/j.ymben.2008.08.001] [Citation(s) in RCA: 310] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Accepted: 08/10/2008] [Indexed: 11/24/2022]
Abstract
Production of higher alcohols via the keto-acid intermediates found in microorganism's native amino-acid pathways has recently shown promising results. In this work, an Escherichia coli strain that produces 1-butanol and 1-propanol from glucose was constructed. The strain first converts glucose to 2-ketobutyrate, a common keto-acid intermediate for isoleucine biosynthesis. Then, 2-ketobutyrate is converted to 1-propanol through reactions catalyzed by the heterologous decarboxylase and dehydrogenase, or to 1-butanol via the chemistry involved in the synthesis of the unnatural amino acid norvaline. We systematically improved the synthesis of 1-propanol and 1-butanol through deregulation of amino-acid biosynthesis and elimination of competing pathways. The final strain demonstrated a production titer of 2 g/L with nearly 1:1 ratio of butanol and propanol.
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Simanshu DK, Savithri HS, Murthy MRN. Crystal structures of Salmonella typhimurium biodegradative threonine deaminase and its complex with CMP provide structural insights into ligand-induced oligomerization and enzyme activation. J Biol Chem 2006; 281:39630-41. [PMID: 17046821 DOI: 10.1074/jbc.m605721200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two different pyridoxal 5'-phosphate-containing l-threonine deaminases (EC 4.3.1.19), biosynthetic and biodegradative, which catalyze the deamination of l-threonine to alpha-ketobutyrate, are present in Escherichia coli and Salmonella typhimurium. Biodegradative threonine deaminase (TdcB) catalyzes the first reaction in the anaerobic breakdown of l-threonine to propionate. TdcB, unlike the biosynthetic threonine deaminase, is insensitive to l-isoleucine and is activated by AMP. In the present study, TdcB from S. typhimurium was cloned and overexpressed in E. coli. In the presence of AMP or CMP, the recombinant enzyme was converted to the tetrameric form accompanied by significant enzyme activation. To provide insights into ligand-mediated oligomerization and enzyme activation, crystal structures of S. typhimurium TdcB and its complex with CMP were determined. In the native structure, TdcB is in a dimeric form, whereas in the TdcB.CMP complex, it exists in a tetrameric form with 222 symmetry and appears as a dimer of dimers. Tetrameric TdcB binds to four molecules of CMP, two at each of the dimer interfaces. Comparison of the dimer structure in the ligand (CMP)-free and -bound forms suggests that the changes induced by ligand binding at the dimer interface are essential for tetramerization. The differences observed in the tertiary and quaternary structures of TdcB in the absence and presence of CMP appear to account for enzyme activation and increased binding affinity for l-threonine. Comparison of TdcB with related pyridoxal 5'-phosphate-dependent enzymes points to structural and mechanistic similarities.
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Abstract
Although microorganisms are extremely good in presenting us with an amazing array of valuable products, they usually produce them only in amounts that they need for their own benefit; thus, they tend not to overproduce their metabolites. In strain improvement programs, a strain producing a high titer is usually the desired goal. Genetics has had a long history of contributing to the production of microbial products. The tremendous increases in fermentation productivity and the resulting decreases in costs have come about mainly by mutagenesis and screening/selection for higher producing microbial strains and the application of recombinant DNA technology.
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Affiliation(s)
- Jose L Adrio
- Department of Biotechnology, Puleva Biotech, S.A., Granada, Spain.
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Demain AL. From natural products discovery to commercialization: a success story. J Ind Microbiol Biotechnol 2006; 33:486-95. [PMID: 16402247 DOI: 10.1007/s10295-005-0076-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2005] [Accepted: 12/24/2005] [Indexed: 10/25/2022]
Abstract
In order for a natural product to become a commercial reality, laboratory improvement of its production process is a necessity since titers produced by wild strains could never compete with the power of synthetic chemistry. Strain improvement by mutagenesis has been a major success. It has mainly been carried out by "brute force" screening or selection, but modern genetic technologies have entered the scene in recent years. For every new strain developed genetically, there is further opportunity to raise titers by medium modifications. Of major interest has been the nutritional control by induction, as well as inhibition and repression by sources of carbon, nitrogen, phosphate and end products. Both strain improvement and nutritional modification contribute to the new process, which is then scaled up by biochemical engineers into pilot scale and later into factory size fermentors.
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Affiliation(s)
- Arnold L Demain
- Research Institute for Scientists Emeriti (R.I.S.E), Drew University, Madison, NJ 07940, USA.
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40
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Garcia EL, Mourad GS. A site-directed mutagenesis interrogation of the carboxy-terminal end of Arabidopsis thaliana threonine dehydratase/deaminase reveals a synergistic interaction between two effector-binding sites and contributes to the development of a novel selectable marker. PLANT MOLECULAR BIOLOGY 2004; 55:121-134. [PMID: 15604669 DOI: 10.1007/s11103-004-0500-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We fused four mutant omr1 alleles, encoding feedback-insensitive forms of Arabidopsis thaliana biosynthetic threonine dehydratase/deaminase (TD), to the CaMV 35S promoter and transformed these constructs into A. thaliana Columbia wild type plants. The mutant TD forms consisted of our previously isolated double mutant, omr1-1 , and three new site-directed mutants, omr1-5 , omr1-7 , and omr1-8 with single point mutations. We employed site-directed mutagenesis to assay the effects of amino acid substitutions in separate regulatory regions within the carboxy-terminal (C-term) allosteric end. TD assays and growth resistance to the isoleucine (Ile) toxic analog -O-methylthreonine (OMT) confirmed the desensitization to feedback inhibition and the viability of these mutant omr1 alleles as selectable markers, respectively. Two of the site-directed mutants, omr1-5 and omr1-7 , appeared to influence one of the two separate Ile-binding sites and had a notable 13-fold and 15-fold increase in free Ile, respectively. The omr1-8 appeared to influence the other Ile-binding site and resulted in a 2-fold increase in free Ile. The transgenic omr1-1 double mutant affecting both Ile-binding sites, however, displayed a 106-fold increase in free Ile revealing a profound synergistic interplay between these separate Ile-binding sites. While all of the four omr1 alleles conferred resistance to elevated concentrations of OMT, the progeny of omr1-1 initial transformants exhibited a bushy phenotype at the rosette stage. On the other hand, progeny of transformants omr1-5 , omr1-7 , and omr1-8 had a normal phenotype, undistinguishable from wild type. Therefore, alleles omr1-5 , omr1-7 , and omr1-8 , proved to be ideal as environmentally-friendly, dominant, selectable markers for plant transformation.
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Affiliation(s)
- Eric L Garcia
- Department of Biology, Indiana-Purdue University, 2101 East Coliseum Blvd, IN, USA
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41
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Ganesan B, Weimer BC. Role of aminotransferase IlvE in production of branched-chain fatty acids by Lactococcus lactis subsp. lactis. Appl Environ Microbiol 2004; 70:638-41. [PMID: 14711703 PMCID: PMC321303 DOI: 10.1128/aem.70.1.638-641.2004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The objective of this study was to determine the role of a lactococcal branched-chain amino acid aminotransferase gene, ilvE, in the production of branched-chain fatty acids. Lactococcus lactis subsp. lactis LM0230 and an ilvE deletion mutant, JLS450, produced branched-chain fatty acids from amino and alpha-keto acids at levels above alpha-keto acid spontaneous degradation and the fatty acids' flavor thresholds. The deletion mutant produced the same amounts of branched-chain fatty acids from precursor amino acids as did the parent. This was not the case, however, for the production of branched-chain fatty acids from the corresponding precursor alpha-keto acids. The deletion mutant produced a set of fatty acids different from that produced by the parent. We concluded from these observations that ilvE plays a role in the specific type of fatty acids produced but has little influence on the total amount of fatty acids produced by lactococci.
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Affiliation(s)
- Balasubramanian Ganesan
- Western Dairy Center, Center for Microbe Detection and Physiology, Center for Integrated BioSystems, and Department of Nutrition and Food Sciences, Utah State University, Logan, Utah 84322-8700, USA
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Ganesan B, Seefeldt K, Koka RC, Dias B, Weimer BC. Monocarboxylic acid production by lactococci and lactobacilli. Int Dairy J 2004. [DOI: 10.1016/j.idairyj.2003.07.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Padilla L, Krämer R, Stephanopoulos G, Agosin E. Overproduction of trehalose: heterologous expression of Escherichia coli trehalose-6-phosphate synthase and trehalose-6-phosphate phosphatase in Corynebacterium glutamicum. Appl Environ Microbiol 2004; 70:370-6. [PMID: 14711665 PMCID: PMC321289 DOI: 10.1128/aem.70.1.370-376.2004] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Accepted: 10/10/2003] [Indexed: 11/20/2022] Open
Abstract
Trehalose is a disaccharide with potential applications in the biotechnology and food industries. We propose a method for industrial production of trehalose, based on improved strains of Corynebacterium glutamicum. This paper describes the heterologous expression of Escherichia coli trehalose-synthesizing enzymes trehalose-6-phosphate synthase (OtsA) and trehalose-6-phosphate phosphatase (OtsB) in C. glutamicum, as well as its impact on the trehalose biosynthetic rate and metabolic-flux distributions, during growth in a defined culture medium. The new recombinant strain showed a five- to sixfold increase in the activity of OtsAB pathway enzymes, compared to a control strain, as well as an almost fourfold increase in the trehalose excretion rate during the exponential growth phase and a twofold increase in the final titer of trehalose. The heterologous expression described resulted in a reduced specific glucose uptake rate and Krebs cycle flux, as well as reduced pentose pathway flux, a consequence of downregulated glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. The results proved the suitability of using the heterologous expression of Ots proteins in C. glutamicum to increase the trehalose biosynthetic rate and yield and suggest critical points for further improvement of trehalose overproduction in C. glutamicum.
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Affiliation(s)
- Leandro Padilla
- Departmento de Ingeniería Química y Bioprocesos, Escuela de Ingeniería, Pontificia Universidad Católica de Chile, Santiago, Chile
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Kirchner O, Tauch A. Tools for genetic engineering in the amino acid-producing bacterium Corynebacterium glutamicum. J Biotechnol 2003; 104:287-99. [PMID: 12948646 DOI: 10.1016/s0168-1656(03)00148-2] [Citation(s) in RCA: 234] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During the last decades, the gram-positive soil bacterium Corynebacterium glutamicum has been shown to be a very versatile microorganism for the large-scale fermentative production of L-amino acids. Up to now, a vast amount of techniques and tools for genetic engineering and amplification of relevant structural genes have been developed. The objectives of this study are to summarize the published literature on tools for genetic engineering in C. glutamicum and to focus on new sophisticated and highly efficient methods in the fields of DNA transfer techniques, cloning vectors, integrative genetic tools, and antibiotic-free self-cloning. This repertoire of C. glutamicum methodology provides an experimental basis for efficient genetic analyses of the recently completed genome sequence.
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Affiliation(s)
- Oliver Kirchner
- Lehrstuhl für Gentechnologie/Mikrobiologie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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Glanemann C, Loos A, Gorret N, Willis LB, O'Brien XM, Lessard PA, Sinskey AJ. Disparity between changes in mRNA abundance and enzyme activity in Corynebacterium glutamicum: implications for DNA microarray analysis. Appl Microbiol Biotechnol 2003; 61:61-8. [PMID: 12658516 DOI: 10.1007/s00253-002-1191-5] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2002] [Revised: 10/25/2002] [Accepted: 11/08/2002] [Indexed: 10/25/2022]
Abstract
The relationship between changes in mRNA abundance and enzyme activity was determined for three genes over a span of nearly 3 h during amino acid production in Corynebacterium glutamicum. Gene expression changes during C. glutamicum fermentations were examined by complementary DNA (cDNA) microarrays and by a second method for quantitating RNA levels, competitive reverse transcriptase-PCR (RT-PCR). The results obtained independently by both methods were compared and found to be in agreement, thus validating the quantitative potential of DNA microarrays for gene expression profiling. Evidence of a disparity between mRNA abundance and enzyme activity is presented and supports our belief that it is difficult to generally predict protein activity from quantitative transcriptome data. Homoserine dehydrogenase, threonine dehydratase, and homoserine kinase are enzymes involved in the biosynthesis of l-isoleucine and other aspartate-derived amino acids in C. glutamicum. Our data suggest that different underlying regulatory mechanisms may be connected with the expression of the genes encoding each of these three enzymes. Indeed, whereas in one case the increases in enzyme activity exceeded those in the corresponding mRNA abundance, in another case large increases in the levels of gene expression were not congruent with changes in enzyme activity.
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Affiliation(s)
- C Glanemann
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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46
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Abstract
With the exploitation of new uses and the growing markets of amino acids, amino acid production technology has made large progress during the latter half of the 20th century. Fermentation technology has played crucial roles in this progress, and currently the fermented amino acids represent chief products of biotechnology in both volume and value. This area is highly competitive in the world market and process economics are of primary importance. For cost-effective production, many technologies have been developed to establish high-productive fermentation and recovery processes. The producer organisms used in large-scale, well-established processes have been developed to a high level of production efficiency. The tools of genetic engineering of amino acid-producing organisms have been well developed and are now being applied for enlargement of biosynthetic and transport capacity, which is beginning to have a great impact on the amino acid industry. Furthermore, the rapid strides in genome analysis are bound to revolutionize the strain improvement methodology.
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Affiliation(s)
- Masato Ikeda
- Tokyo Research Laboratories, Kyowa Hakko Kogyo Co., Ltd, 3-6-6, Asahi-machi, Machida, Tokyo 194-8533, Japan.
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47
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Abstract
L-Threonine is an essential amino acid which has recently been brought into agricultural industry for balancing the livestock feed. L-Threonine is produced by microbial synthesis using glucose or sucrose as substrates. For the process to be cost-effective, the microbial strain must be capable of threonine overproduction. This paper reviews the biochemical pathways of L-threonine synthesis in bacteria and the regulation of these pathways, the principles and the techniques of constructing high-producing strains, and the most efficient strains thus developed.
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Affiliation(s)
- Vladimir G Debabov
- State Research Institute of Genetics and Selection of Industrial Microorganisms, 1st Dorozhnyi proezd, Moscow 113545, Russia.
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48
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Jenkins C, Kedar V, Fuerst JA. Gene discovery within the planctomycete division of the domain Bacteria using sequence tags from genomic DNA libraries. Genome Biol 2002; 3:RESEARCH0031. [PMID: 12093378 PMCID: PMC116728 DOI: 10.1186/gb-2002-3-6-research0031] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2002] [Revised: 04/15/2002] [Accepted: 04/17/2002] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The planctomycetes comprise a distinct group of the domain Bacteria, forming a separate division by phylogenetic analysis. The organization of their cells into membrane-defined compartments including membrane-bounded nucleoids, their budding reproduction and complete absence of peptidoglycan distinguish them from most other Bacteria. A random sequencing approach was applied to the genomes of two planctomycete species, Gemmata obscuriglobus and Pirellula marina, to discover genes relevant to their cell biology and physiology. RESULTS Genes with a wide variety of functions were identified in G. obscuriglobus and Pi. marina, including those of metabolism and biosynthesis, transport, regulation, translation and DNA replication, consistent with established phenotypic characters for these species. The genes sequenced were predominantly homologous to those in members of other divisions of the Bacteria, but there were also matches with nuclear genomic genes of the domain Eukarya, genes that may have appeared in the planctomycetes via horizontal gene transfer events. Significant among these matches are those with two genes atypical for Bacteria and with significant cell-biology implications - integrin alpha-V and inter-alpha-trypsin inhibitor protein - with homologs in G. obscuriglobus and Pi. marina respectively. CONCLUSIONS The random-sequence-tag approach applied here to G. obscuriglobus and Pi. marina is the first report of gene recovery and analysis from members of the planctomycetes using genome-based methods. Gene homologs identified were predominantly similar to genes of Bacteria, but some significant best matches to genes from Eukarya suggest that lateral gene transfer events between domains may have involved this division at some time during its evolution.
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Affiliation(s)
- Cheryl Jenkins
- Department of Microbiology and Parasitology, School of Molecular and Microbial Sciences, University of Queensland, Brisbane, Queensland 4072, Australia.
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Rohlin L, Oh MK, Liao JC. Microbial pathway engineering for industrial processes: evolution, combinatorial biosynthesis and rational design. Curr Opin Microbiol 2001; 4:330-5. [PMID: 11378488 DOI: 10.1016/s1369-5274(00)00213-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Microbial pathway engineering has made significant progress in multiple areas. Many examples of successful pathway engineering for specialty and fine chemicals have been reported in the past two years. Novel carotenoids and polyketides have been synthesized using molecular evolution and combinatorial strategies. In addition, rational design approaches based on metabolic control have been reported to increase metabolic flux to specific products. Experimental and computational tools have been developed to aid in design, reconstruction and analysis of non-native pathways. It is expected that a hybrid of evolutionary, combinatorial and rational design approaches will yield significant advances in the near future.
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Affiliation(s)
- L Rohlin
- Department of Chemical Engineering, 405 Hilgard Avenue, University of California, Los Angeles, California 90095, USA
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50
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Loos A, Glanemann C, Willis LB, O'Brien XM, Lessard PA, Gerstmeir R, Guillouet S, Sinskey AJ. Development and validation of corynebacterium DNA microarrays. Appl Environ Microbiol 2001; 67:2310-8. [PMID: 11319117 PMCID: PMC92872 DOI: 10.1128/aem.67.5.2310-2318.2001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We have developed DNA microarray techniques for studying Corynebacterium glutamicum. A set of 52 C. glutamicum genes encoding enzymes from primary metabolism was amplified by PCR and printed in triplicate onto glass slides. Total RNA was extracted from cells harvested during the exponential-growth and lysine production phases of a C. glutamicum fermentation. Fluorescently labeled cDNAs were prepared by reverse transcription using random hexamer primers and hybridized to the microarrays. To establish a set of benchmark metrics for this technique, we compared the variability between replicate spots on the same slide, between slides hybridized with cDNAs from the same labeling reaction, and between slides hybridized with cDNAs prepared in separate labeling reactions. We found that the results were both robust and statistically reproducible. Spot-to-spot variability was 3.8% between replicate spots on a given slide, 5.0% between spots on separate slides (though hybridized with identical, labeled cDNA), and 8.1% between spots from separate slides hybridized with samples from separate reverse transcription reactions yielding an average spot to spot variability of 7.1% across all conditions. Furthermore, when we examined the changes in gene expression that occurred between the two phases of the fermentation, we found that results for the majority of the genes agreed with observations made using other methods. These procedures will be a valuable addition to the metabolic engineering toolbox for the improvement of C. glutamicum amino acid-producing strains.
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Affiliation(s)
- A Loos
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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