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Wang ZQ, Yang Y, Zhang JY, Zeng X, Zhang CC. Global translational control by the transcriptional repressor TrcR in the filamentous cyanobacterium Anabaena sp. PCC 7120. Commun Biol 2023; 6:643. [PMID: 37322092 PMCID: PMC10272220 DOI: 10.1038/s42003-023-05012-9] [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: 02/03/2023] [Accepted: 06/02/2023] [Indexed: 06/17/2023] Open
Abstract
Transcriptional and translational regulations are important mechanisms for cell adaptation to environmental conditions. In addition to house-keeping tRNAs, the genome of the filamentous cyanobacterium Anabaena sp. strain PCC 7120 (Anabaena) has a long tRNA operon (trn operon) consisting of 26 genes present on a megaplasmid. The trn operon is repressed under standard culture conditions, but is activated under translational stress in the presence of antibiotics targeting translation. Using the toxic amino acid analog β-N-methylamino-L-alanine (BMAA) as a tool, we isolated and characterized several BMAA-resistance mutants from Anabaena, and identified one gene of unknown function, all0854, named as trcR, encoding a transcription factor belonging to the ribbon-helix-helix (RHH) family. We provide evidence that TrcR represses the expression of the trn operon and is thus the missing link between the trn operon and translational stress response. TrcR represses the expression of several other genes involved in translational control, and is required for maintaining translational fidelity. TrcR, as well as its binding sites, are highly conserved in cyanobacteria, and its functions represent an important mechanism for the coupling of the transcriptional and translational regulations in cyanobacteria.
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Affiliation(s)
- Zi-Qian Wang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China.
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
| | - Yiling Yang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China
| | - Ju-Yuan Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China
| | - Xiaoli Zeng
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China
| | - Cheng-Cai Zhang
- State Key Laboratory of Freshwater Ecology and Biotechnology and Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, People's Republic of China.
- Institute AMU-WUT, Aix-Marseille Université and Wuhan University of Technology, Wuhan, Hubei, People's Republic of China.
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Unveiling the Effect of NCgl0580 Gene Deletion on 5-Aminolevulinic Acid Biosynthesis in Corynebacterium glutamicum. FERMENTATION-BASEL 2023. [DOI: 10.3390/fermentation9030213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
Abstract
5-Aminolevulinic acid (5-ALA) has recently received much attention for its wide applications in medicine and agriculture. In this study, we investigated the effect of NCgl0580 in Corynebacterium glutamicum on 5-ALA biosynthesis as well as its possible mechanism. It was found that the overexpression of NCgl0580 increased 5-ALA production by approximately 53.3%. Interestingly, the knockout of this gene led to an even more significant 2.49-fold increase in 5-ALA production. According to transcriptome analysis and functional validation of phenotype-related targets, the deletion of NCgl0580 brought about considerable changes in the transcript levels of genes involved in central carbon metabolism, leading to fluxes redistribution toward the 5-ALA precursor succinyl-CoA as well as ATP-binding cassette (ABC) transporters affecting 5-ALA biosynthesis. In particular, the positive effects of enhanced sugar transport (by overexpressing NCgl1445 and iolT1), glycolysis (by overexpressing pyk2), iron uptake (by overexpressing afuABC), and phosphate uptake (by overexpressing pstSCAB and ugpQ) on 5-ALA biosynthesis were demonstrated for the first time. Thus, the transcriptional mechanism underlying the effect of NCgl0580 deletion on 5-ALA biosynthesis was elucidated, providing new strategies to regulate the metabolic network of C. glutamicum to achieve a further increase in 5-ALA production.
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Liu S, Xu JZ, Zhang WG. Advances and prospects in metabolic engineering of Escherichia coli for L-tryptophan production. World J Microbiol Biotechnol 2022; 38:22. [PMID: 34989926 DOI: 10.1007/s11274-021-03212-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/15/2021] [Indexed: 10/19/2022]
Abstract
As an important raw material for pharmaceutical, food and feed industry, highly efficient production of L-tryptophan by Escherichia coli has attracted a considerable attention. However, there are complicated and multiple layers of regulation networks in L-tryptophan biosynthetic pathway and thus have difficulty to rewrite the biosynthetic pathway for producing L-tryptophan with high efficiency in E. coli. This review summarizes the biosynthetic pathway of L-tryptophan and highlights the main regulatory mechanisms in E. coli. In addition, we discussed the latest metabolic engineering strategies achieved in E. coli to reconstruct the L-tryptophan biosynthetic pathway. Moreover, we also review a few strategies that can be used in E. coli to improve robustness and streamline of L-tryptophan high-producing strains. Lastly, we also propose the potential strategies to further increase L-tryptophan production by systematic metabolic engineering and synthetic biology techniques.
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Affiliation(s)
- Shuai Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China
| | - Jian-Zhong Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
| | - Wei-Guo Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
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Mohany NAM, Totti A, Naylor KR, Janovjak H. Microbial methionine transporters and biotechnological applications. Appl Microbiol Biotechnol 2021; 105:3919-3929. [PMID: 33929594 PMCID: PMC8140960 DOI: 10.1007/s00253-021-11307-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/13/2021] [Accepted: 04/18/2021] [Indexed: 11/07/2022]
Abstract
Methionine (Met) is an essential amino acid with commercial value in animal feed, human nutrition, and as a chemical precursor. Microbial production of Met has seen intensive investigation towards a more sustainable alternative to the chemical synthesis that currently meets the global Met demand. Indeed, efficient Met biosynthesis has been achieved in genetically modified bacteria that harbor engineered enzymes and streamlined metabolic pathways. Very recently, the export of Met as the final step during its fermentative production has been studied and optimized, primarily through identification and expression of microbial Met efflux transporters. In this mini-review, we summarize the current knowledge on four families of Met export and import transporters that have been harnessed for the production of Met and other valuable biomolecules. These families are discussed with respect to their function, gene regulation, and biotechnological applications. We cover methods for identification and characterization of Met transporters as the basis for the further engineering of these proteins and for exploration of other solute carrier families. The available arsenal of Met transporters from different species and protein families provides blueprints not only for fermentative production but also synthetic biology systems, such as molecular sensors and cell-cell communication systems. KEY POINTS: • Sustainable production of methionine (Met) using microbes is actively explored. • Met transporters of four families increase production yield and specificity. • Further applications include other biosynthetic pathways and synthetic biology.
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Affiliation(s)
- Nurul Amira Mohammad Mohany
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Clayton, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, Melbourne, Clayton, Australia
| | - Alessandra Totti
- Department of Pharmacy and Biotechnology FaBiT, University of Bologna, Bologna, Italy
| | - Keith R Naylor
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Clayton, Australia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, Melbourne, Clayton, Australia
| | - Harald Janovjak
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Clayton, Australia.
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash University, Melbourne, Clayton, Australia.
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Production and Excretion of Polyamines To Tolerate High Ammonia, a Case Study on Soil Ammonia-Oxidizing Archaeon " Candidatus Nitrosocosmicus agrestis". mSystems 2021; 6:6/1/e01003-20. [PMID: 33594004 PMCID: PMC8573960 DOI: 10.1128/msystems.01003-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Ammonia tolerance is a universal characteristic among the ammonia-oxidizing bacteria (AOB); in contrast, the known species of ammonia-oxidizing archaea (AOA) have been regarded as ammonia sensitive, until the identification of the genus “Candidatus Nitrosocosmicus.” However, the mechanism of its ammonia tolerance has not been reported. In this study, the AOA species “Candidatus Nitrosocosmicus agrestis,” obtained from agricultural soil, was determined to be able to tolerate high concentrations of NH3 (>1,500 μM). In the genome of this strain, which was recovered from metagenomic data, a full set of genes for the pathways of polysaccharide metabolism, urea hydrolysis, arginine synthesis, and polyamine synthesis was identified. Among them, the genes encoding cytoplasmic carbonic anhydrase (CA) and a potential polyamine transporter (drug/metabolite exporter [DME]) were found to be unique to the genus “Ca. Nitrosocosmicus.” When “Ca. Nitrosocosmicus agrestis” was grown with high levels of ammonia, the genes that participate in CO2/HCO3− conversion, glutamate/glutamine syntheses, arginine synthesis, polyamine synthesis, and polyamine excretion were significantly upregulated, and the polyamines, including putrescine and spermidine, had significant levels of production. Based on genome analysis, gene expression quantification, and polyamine determination, we propose that the production and excretion of polyamines is probably one of the reasons for the ammonia tolerance of “Ca. Nitrosocosmicus agrestis,” and even of the genus “Ca. Nitrosocosmicus.” IMPORTANCE Ammonia tolerance of AOA is usually much lower than that of the AOB, which makes the AOB rather than AOA a predominant ammonia oxidizer in agricultural soils, contributing to global N2O emission. Recently, some AOA species from the genus “Ca. Nitrosocosmicus” were also found to have high ammonia tolerance. However, the reported mechanism for the ammonia tolerance is very rare and indeterminate for AOB and for AOA species. In this study, an ammonia-tolerant AOA strain of the species “Ca. Nitrosocosmicus agrestis” was identified and its potential mechanisms for ammonia tolerance were explored. This study will be of benefit for determining more of the ecological role of AOA in agricultural soils or other environments.
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Exporters for Production of Amino Acids and Other Small Molecules. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 159:199-225. [PMID: 27832297 DOI: 10.1007/10_2016_32] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Microbes are talented catalysts to synthesize valuable small molecules in their cytosol. However, to make full use of their skills - and that of metabolic engineers - the export of intracellularly synthesized molecules to the culture medium has to be considered. This step is as essential as is each step for the synthesis of the favorite molecule of the metabolic engineer, but is frequently not taken into account. To export small molecules via the microbial cell envelope, a range of different types of carrier proteins is recognized to be involved, which are primary active carriers, secondary active carriers, or proteins increasing diffusion. Relevant export may require just one carrier as is the case with L-lysine export by Corynebacterium glutamicum or involve up to four carriers as known for L-cysteine excretion by Escherichia coli. Meanwhile carriers for a number of small molecules of biotechnological interest are recognized, like for production of peptides, nucleosides, diamines, organic acids, or biofuels. In addition to carriers involved in amino acid excretion, such carriers and their impact on product formation are described, as well as the relatedness of export carriers which may serve as a hint to identify further carriers required to improve product formation by engineering export.
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Dudnik A, Dudler R. Genomics-Based Exploration of Virulence Determinants and Host-Specific Adaptations of Pseudomonas syringae Strains Isolated from Grasses. Pathogens 2014; 3:121-48. [PMID: 25437611 PMCID: PMC4235733 DOI: 10.3390/pathogens3010121] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/20/2014] [Accepted: 01/22/2014] [Indexed: 12/14/2022] Open
Abstract
The Pseudomonas syringae species complex has recently been named the number one plant pathogen, due to its economic and environmental impacts, as well as for its role in scientific research. The bacterium has been repeatedly reported to cause outbreaks on bean, cucumber, stone fruit, kiwi and olive tree, as well as on other crop and non-crop plants. It also serves as a model organism for research on the Type III secretion system (T3SS) and plant-pathogen interactions. While most of the current work on this pathogen is either carried out on one of three model strains found on dicot plants with completely sequenced genomes or on isolates obtained from recent outbreaks, not much is known about strains isolated from grasses (Poaceae). Here, we use comparative genomics in order to identify putative virulence-associated genes and other Poaceae-specific adaptations in several newly available genome sequences of strains isolated from grass species. All strains possess only a small number of known Type III effectors, therefore pointing to the importance of non-Type III secreted virulence factors. The implications of this finding are discussed.
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Affiliation(s)
- Alexey Dudnik
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
| | - Robert Dudler
- Institute of Plant Biology, University of Zurich, Zollikerstrasse 107, 8008 Zurich, Switzerland.
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Yuzbashev TV, Vybornaya TV, Larina AS, Gvilava IT, Voyushina NE, Mokrova SS, Yuzbasheva EY, Manukhov IV, Sineoky SP, Debabov VG. Directed modification of Escherichia coli metabolism for the design of threonine-producing strains. APPL BIOCHEM MICRO+ 2013. [DOI: 10.1134/s0003683813090056] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Recruitment of genes and enzymes conferring resistance to the nonnatural toxin bromoacetate. Proc Natl Acad Sci U S A 2010; 107:17968-73. [PMID: 20921376 DOI: 10.1073/pnas.1007559107] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microbial niches contain toxic chemicals capable of forcing organisms into periods of intense natural selection to afford survival. Elucidating the mechanisms by which microbes evade environmental threats has direct relevance for understanding and combating the rise of antibiotic resistance. In this study we used a toxic small-molecule, bromoacetate, to model the selective pressures imposed by antibiotics and anthropogenic toxins. We report the results of genetic selection experiments that identify nine genes from Escherichia coli whose overexpression affords survival in the presence of a normally lethal concentration of bromoacetate. Eight of these genes encode putative transporters or transmembrane proteins, while one encodes the essential peptidoglycan biosynthetic enzyme, UDP-N-acetylglucosamine enolpyruvoyl transferase (MurA). Biochemical studies demonstrate that the primary physiological target of bromoacetate is MurA, which becomes irreversibly inactivated via alkylation of a critical active-site cysteine. We also screened a comprehensive library of E. coli single-gene deletion mutants and identified 63 strains displaying increased susceptibility to bromoacetate. One hypersensitive bacterium lacks yliJ, a gene encoding a predicted glutathione transferase. Herein, YliJ is shown to catalyze the glutathione-dependent dehalogenation of bromoacetate with a k(cat)/K(m) value of 5.4 × 10(3) M(-1) s(-1). YliJ displays exceptional substrate specificity and produces a rate enhancement exceeding 5 orders of magnitude, remarkable characteristics for reactivity with a nonnatural molecule. This study illustrates the wealth of intrinsic survival mechanisms that can be exploited by bacteria when they are challenged with toxins.
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Van Dyk TK. Bacterial Efflux Transport in Biotechnology. ADVANCES IN APPLIED MICROBIOLOGY 2008; 63:231-47. [DOI: 10.1016/s0065-2164(07)00006-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Doroshenko V, Airich L, Vitushkina M, Kolokolova A, Livshits V, Mashko S. YddG from Escherichia coli promotes export of aromatic amino acids. FEMS Microbiol Lett 2007; 275:312-8. [PMID: 17784858 DOI: 10.1111/j.1574-6968.2007.00894.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The inner membrane protein YddG of Escherichia coli is a homologue of the known amino acid exporters RhtA and YdeD. It was found that the yddG gene overexpression conferred resistance upon E. coli cells to the inhibiting concentrations of l-phenylalanine and aromatic amino acid analogues, dl-p-fluorophenylalanine, dl-o-fluorophenylalanine and dl-5-fluorotryptophan. In addition, yddG overexpression enhanced the production of l-phenylalanine, l-tyrosine or l-tryptophan by the respective E. coli-producing strains. On the other hand, the inactivation of yddG decreased the aromatic amino acid accumulation by these strains. The cells of the E. colil-phenylalanine-producing strain containing overexpressed yddG accumulated less l-phenylalanine inside and exported the amino acid at a higher rate than the cells of the isogenic strain containing wild-type yddG. Taken together, these results indicate that YddG functions as an aromatic amino acid exporter.
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Affiliation(s)
- Vera Doroshenko
- Ajinomoto-Genetika Research Institute, Moscow, Russian Federation
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