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Xiao F, Zhang Y, Zhang L, Ding Z, Shi G, Li Y. Construction of the genetic switches in response to mannitol based on artificial MtlR box. BIORESOUR BIOPROCESS 2023; 10:9. [PMID: 38647829 PMCID: PMC10992428 DOI: 10.1186/s40643-023-00634-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/19/2023] [Indexed: 01/31/2023] Open
Abstract
Synthetic biology has rapidly advanced from the setup of native genetic devices to the design of artificial elements able to provide organisms with highly controllable functions. In particular, genetic switches are crucial for deploying new layers of regulation into the engineered organisms. While the assembly and mutagenesis of native elements have been extensively studied, limited progress has been made in rational design of genetic switches due to a lack of understanding of the molecular mechanism by which a specific transcription factor interacts with its target gene. Here, a reliable workflow is presented for designing two categories of genetic elements, one is the switch element-MtlR box and the other is the transcriptional regulatory element- catabolite control protein A (CcpA) box. The MtlR box was designed for ON/OFF-state selection and is controlled by mannitol. The rational design of MtlR box-based molecular structures can flexibly tuned the selection of both ON and OFF states with different output switchability in response to varied kind effectors. Different types of CcpA boxes made the switches with more markedly inducer sensitivities. Ultimately, the OFF-state value was reduced by 90.69%, and the maximum change range in the presence of two boxes was 15.31-fold. This study presents a specific design of the switch, in a plug-and-play manner, which has great potential for controlling the flow of the metabolic pathway in synthetic biology.
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Affiliation(s)
- Fengxu Xiao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, People's Republic of China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Yupeng Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, People's Republic of China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Liang Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, People's Republic of China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Zhongyang Ding
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, People's Republic of China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Guiyang Shi
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, People's Republic of China
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Youran Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.
- National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu, People's Republic of China.
- Jiangsu Provincial Engineering Research Center for Bioactive Product Processing, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
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Deciphering the Regulation of the Mannitol Operon Paves the Way for Efficient Production of Mannitol in Lactococcus lactis. Appl Environ Microbiol 2021; 87:e0077921. [PMID: 34105983 DOI: 10.1128/aem.00779-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lactococcus lactis has great potential for high-yield production of mannitol, which has not yet been fully realized. In this study, we characterize how the mannitol genes in L. lactis are organized and regulated and use this information to establish efficient mannitol production. Although the organization of the mannitol genes in L. lactis was similar to that in other Gram-positive bacteria, mtlF and mtlD, encoding the enzyme IIA component (EIIAmtl) of the mannitol phosphotransferase system (PTS) and the mannitol-1-phosphate dehydrogenase, respectively, were separated by a transcriptional terminator, and the mannitol genes were found to be organized in two transcriptional units: an operon comprising mtlA, encoding the enzyme IIBC component (EIIBCmtl) of the mannitol PTS, mtlR, encoding a transcriptional activator, and mtlF, as well as a separately expressed mtlD gene. The promoters driving expression of the two transcriptional units were somewhat similar, and both contained predicted catabolite responsive element (cre) genes. The presence of carbon catabolite repression was demonstrated and was shown to be relieved in stationary-phase cells. The transcriptional activator MtlR (mtlR), in some Gram-positive bacteria, is repressed by phosphorylation by EIIAmtl, and when we knocked out mtlF, we indeed observed enhanced expression from the two promoters, which indicated that this mechanism was in place. Finally, by overexpressing the mtlD gene and using stationary-phase cells as biocatalysts, we attained 10.1 g/liter mannitol with a 55% yield, which, to the best of our knowledge, is the highest titer ever reported for L. lactis. Summing up, the results of our study should be useful for improving the mannitol-producing capacity of this important industrial organism. IMPORTANCE Lactococcus lactis is the most studied species of the lactic acid bacteria, and it is widely used in various food fermentations. To date, there have been several attempts to persuade L. lactis to produce mannitol, a sugar alcohol with important therapeutic and food applications. Until now, to achieve mannitol production in L. lactis with significant titer and yield, it has been necessary to introduce and express foreign genes, which precludes the use of such strains in foods, due to their recombinant status. In this study, we systematically characterize how the mannitol genes in L. lactis are regulated and demonstrate how this impacts mannitol production capability. We harnessed this information and managed to establish efficient mannitol production without introducing foreign genes.
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Bechtner J, Ludwig C, Kiening M, Jakob F, Vogel RF. Living the Sweet Life: How Liquorilactobacillus hordei TMW 1.1822 Changes Its Behavior in the Presence of Sucrose in Comparison to Glucose. Foods 2020; 9:foods9091150. [PMID: 32825547 PMCID: PMC7555045 DOI: 10.3390/foods9091150] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 12/12/2022] Open
Abstract
Liquorilactobacillus (L.) hordei (formerly Lactobacillus hordei) is one of the dominating lactic acid bacteria within the water kefir consortium, being highly adapted to survive in this environment, while producing high molecular weight dextrans from sucrose. In this work, we extensively studied the physiological response of L. hordei TMW 1.1822 to sucrose compared to glucose, applying label-free, quantitative proteomics of cell lysates and exoproteomes. This revealed the differential expression of 53 proteins within cellular proteomes, mostly associated with carbohydrate uptake and metabolism. Supported by growth experiments, this suggests that L. hordei TMW 1.1822 favors fructose over other sugars. The dextransucrase was expressed irrespectively of the present carbon source, while it was significantly more released in the presence of sucrose (log2FC = 3.09), being among the most abundant proteins within exoproteomes of sucrose-treated cells. Still, L. hordei TMW 1.1822 expressed other sucrose active enzymes, predictively competing with the dextransucrase reaction. While osmolysis appeared to be unlikely, sucrose led to increased release of a multitude of cytoplasmic proteins, suggesting that biofilm formation in L. hordei is not only composed of a polysaccharide matrix but is also of proteinaceous nature. Therefore, our study highlights the intrinsic adaptation of water kefir-borne L. hordei to sucrose-rich habitats and provides fundamental knowledge for its use as a starter culture in plant-based food fermentations with in situ dextran formation.
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Affiliation(s)
- Julia Bechtner
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München (TUM), 85354 Freising, Germany; (J.B.); (F.J.)
| | - Christina Ludwig
- Bavarian Center for Biomolecular Mass Spectrometry (BayBioMS), 85354 Freising, Germany;
| | - Michael Kiening
- Lehrstuhl für Genomorientierte Bioinformatik, Technische Universität München (TUM), 85354 Freising, Germany;
| | - Frank Jakob
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München (TUM), 85354 Freising, Germany; (J.B.); (F.J.)
| | - Rudi F. Vogel
- Lehrstuhl für Technische Mikrobiologie, Technische Universität München (TUM), 85354 Freising, Germany; (J.B.); (F.J.)
- Correspondence:
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Xiao F, Li Y, Zhang Y, Wang H, Zhang L, Ding Z, Gu Z, Xu S, Shi G. Construction of a novel sugar alcohol-inducible expression system in Bacillus licheniformis. Appl Microbiol Biotechnol 2020; 104:5409-5425. [PMID: 32333054 DOI: 10.1007/s00253-020-10618-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 03/31/2020] [Accepted: 04/09/2020] [Indexed: 12/13/2022]
Abstract
Bacillus licheniformis is an important industrial microorganism that can utilize a wide range of biomass. However, the lack of expression elements in B. licheniformis, especially regulated promoters, significantly restricts its applications. In this study, two promoters involved in the sugar alcohol uptake pathway, PmtlA and PmtlR, were characterized and developed as regulated promoters for expression. The results showed that mannitol, mannose, sorbitol, sorbose, and arabinose can act as inducers to activate expression from PmtlA at different levels. The induction by sorbitol was the strongest, and the optimal induction conditions were 15 g/L sorbitol during mid-logarithmic growth at 28 °C. In this work, the palindrome-like sequence 'TTGTCA-cacggctcc-TGCCAA' in PmtlA was identified as the binding site of the MtlR protein. This study helps to enrich the known inducible expression systems in B. licheniformis.
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Affiliation(s)
- Fengxu Xiao
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Youran Li
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Yupeng Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Hanrong Wang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Liang Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Zhongyang Ding
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Zhenghua Gu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Sha Xu
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China.,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Guiyang Shi
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, People's Republic of China. .,National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, Jiangsu Province, People's Republic of China. .,Jiangsu Provincial Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.
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Nguyen T, Kim T, Ta HM, Yeo WS, Choi J, Mizar P, Lee SS, Bae T, Chaurasia AK, Kim KK. Targeting Mannitol Metabolism as an Alternative Antimicrobial Strategy Based on the Structure-Function Study of Mannitol-1-Phosphate Dehydrogenase in Staphylococcus aureus. mBio 2019; 10:e02660-18. [PMID: 31289190 PMCID: PMC6623548 DOI: 10.1128/mbio.02660-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 06/05/2019] [Indexed: 11/22/2022] Open
Abstract
Mannitol-1-phosphate dehydrogenase (M1PDH) is a key enzyme in Staphylococcus aureus mannitol metabolism, but its roles in pathophysiological settings have not been established. We performed comprehensive structure-function analysis of M1PDH from S. aureus USA300, a strain of community-associated methicillin-resistant S. aureus, to evaluate its roles in cell viability and virulence under pathophysiological conditions. On the basis of our results, we propose M1PDH as a potential antibacterial target. In vitro cell viability assessment of ΔmtlD knockout and complemented strains confirmed that M1PDH is essential to endure pH, high-salt, and oxidative stress and thus that M1PDH is required for preventing osmotic burst by regulating pressure potential imposed by mannitol. The mouse infection model also verified that M1PDH is essential for bacterial survival during infection. To further support the use of M1PDH as an antibacterial target, we identified dihydrocelastrol (DHCL) as a competitive inhibitor of S. aureus M1PDH (SaM1PDH) and confirmed that DHCL effectively reduces bacterial cell viability during host infection. To explain physiological functions of SaM1PDH at the atomic level, the crystal structure of SaM1PDH was determined at 1.7-Å resolution. Structure-based mutation analyses and DHCL molecular docking to the SaM1PDH active site followed by functional assay identified key residues in the active site and provided the action mechanism of DHCL. Collectively, we propose SaM1PDH as a target for antibiotic development based on its physiological roles with the goals of expanding the repertory of antibiotic targets to fight antimicrobial resistance and providing essential knowledge for developing potent inhibitors of SaM1PDH based on structure-function studies.IMPORTANCE Due to the shortage of effective antibiotics against drug-resistant Staphylococcus aureus, new targets are urgently required to develop next-generation antibiotics. We investigated mannitol-1-phosphate dehydrogenase of S. aureus USA300 (SaM1PDH), a key enzyme regulating intracellular mannitol levels, and explored the possibility of using SaM1PDH as a target for developing antibiotic. Since mannitol is necessary for maintaining the cellular redox and osmotic potential, the homeostatic imbalance caused by treatment with a SaM1PDH inhibitor or knockout of the gene encoding SaM1PDH results in bacterial cell death through oxidative and/or mannitol-dependent cytolysis. We elucidated the molecular mechanism of SaM1PDH and the structural basis of substrate and inhibitor recognition by enzymatic and structural analyses of SaM1PDH. Our results strongly support the concept that targeting of SaM1PDH represents an alternative strategy for developing a new class of antibiotics that cause bacterial cell death not by blocking key cellular machinery but by inducing cytolysis and reducing stress tolerance through inhibition of the mannitol pathway.
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Affiliation(s)
- Thanh Nguyen
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Truc Kim
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Hai Minh Ta
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Won Sik Yeo
- Department of Microbiology and Immunology, Indiana University School of Medicine Northwest, Gary, Indiana, USA
| | - Jongkeun Choi
- Department of Chemical Engineering, Chungwoon University, Incheon, South Korea
| | - Pushpak Mizar
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Seung Seo Lee
- School of Chemistry, University of Southampton, Southampton, United Kingdom
| | - Taeok Bae
- Department of Microbiology and Immunology, Indiana University School of Medicine Northwest, Gary, Indiana, USA
| | - Akhilesh Kumar Chaurasia
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, Institute for Antimicrobial Research and Therapeutics, Sungkyunkwan University School of Medicine, Suwon, South Korea
- Samsung Biomedical Research Institute, Samsung Advanced Institute for Health Sciences and Technology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
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Establishment and application of CRISPR interference to affect sporulation, hydrogen peroxide detoxification, and mannitol catabolism in the methylotrophic thermophile Bacillus methanolicus. Appl Microbiol Biotechnol 2019; 103:5879-5889. [DOI: 10.1007/s00253-019-09907-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 11/30/2022]
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7
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Pagano GJ, Arsenault RJ. Advances, challenges and tools in characterizing bacterial serine, threonine and tyrosine kinases and phosphorylation target sites. Expert Rev Proteomics 2019; 16:431-441. [DOI: 10.1080/14789450.2019.1601015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Giovanni J. Pagano
- Center for Bioinformatics & Computational Biology, University of Delaware, Newark, DE, USA
| | - Ryan J. Arsenault
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, USA
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Galinier A, Deutscher J. Sophisticated Regulation of Transcriptional Factors by the Bacterial Phosphoenolpyruvate: Sugar Phosphotransferase System. J Mol Biol 2017; 429:773-789. [PMID: 28202392 DOI: 10.1016/j.jmb.2017.02.006] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/01/2017] [Accepted: 02/04/2017] [Indexed: 11/16/2022]
Abstract
The phosphoenolpyruvate:sugar phosphotransferase system (PTS) is a carbohydrate transport and phosphorylation system present in bacteria of all different phyla and in archaea. It is usually composed of three proteins or protein complexes, enzyme I, HPr, and enzyme II, which are phosphorylated at histidine or cysteine residues. However, in many bacteria, HPr can also be phosphorylated at a serine residue. The PTS not only functions as a carbohydrate transporter but also regulates numerous cellular processes either by phosphorylating its target proteins or by interacting with them in a phosphorylation-dependent manner. The target proteins can be catabolic enzymes, transporters, and signal transduction proteins but are most frequently transcriptional regulators. In this review, we will describe how PTS components interact with or phosphorylate proteins to regulate directly or indirectly the activity of transcriptional repressors, activators, or antiterminators. We will briefly summarize the well-studied mechanism of carbon catabolite repression in firmicutes, where the transcriptional regulator catabolite control protein A needs to interact with seryl-phosphorylated HPr in order to be functional. We will present new results related to transcriptional activators and antiterminators containing specific PTS regulation domains, which are the phosphorylation targets for three different types of PTS components. Moreover, we will discuss how the phosphorylation level of the PTS components precisely regulates the activity of target transcriptional regulators or antiterminators, with or without PTS regulation domain, and how the availability of PTS substrates and thus the metabolic status of the cell are connected with various cellular processes, such as biofilm formation or virulence of certain pathogens.
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Affiliation(s)
- Anne Galinier
- Laboratoire de Chimie Bactérienne, UPR 9043, CNRS, Aix Marseille Université, IMM, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
| | - Josef Deutscher
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France; Centre National de la Recherche Scientifique, UMR8261 (affiliated with the Univ. Paris Diderot, Sorbonne, Paris Cité), Expression Génétique Microbienne, Institut de Biologie Physico-Chimique, 75005 Paris, France.
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Joyet P, Derkaoui M, Bouraoui H, Deutscher J. PTS-Mediated Regulation of the Transcription Activator MtlR from Different Species: Surprising Differences despite Strong Sequence Conservation. J Mol Microbiol Biotechnol 2015; 25:94-105. [PMID: 26159071 DOI: 10.1159/000369619] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The hexitol D-mannitol is transported by many bacteria via a phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS). In most Firmicutes, the transcription activator MtlR controls the expression of the genes encoding the D-mannitol-specific PTS components and D-mannitol-1-P dehydrogenase. MtlR contains an N-terminal helix-turn-helix motif followed by an Mga-like domain, two PTS regulation domains (PRDs), an EIIB(Gat)- and an EIIA(Mtl)-like domain. The four regulatory domains are the target of phosphorylation by PTS components. Despite strong sequence conservation, the mechanisms controlling the activity of MtlR from Lactobacillus casei, Bacillus subtilis and Geobacillus stearothermophilus are quite different. Owing to the presence of a tyrosine in place of the second conserved histidine (His) in PRD2, L. casei MtlR is not phosphorylated by Enzyme I (EI) and HPr. When the corresponding His in PRD2 of MtlR from B. subtilis and G. stearothermophilus was replaced with alanine, the transcription regulator was no longer phosphorylated and remained inactive. Surprisingly, L. casei MtlR functions without phosphorylation in PRD2 because in a ptsI (EI) mutant MtlR is constitutively active. EI inactivation prevents not only phosphorylation of HPr, but also of the PTS(Mtl) components, which inactivate MtlR by phosphorylating its EIIB(Gat)- or EIIA(Mtl)-like domain. This explains the constitutive phenotype of the ptsI mutant. The absence of EIIB(Mtl)-mediated phosphorylation leads to induction of the L. caseimtl operon. This mechanism resembles mtlARFD induction in G. stearothermophilus, but differs from EIIA(Mtl)-mediated induction in B. subtilis. In contrast to B. subtilis MtlR, L. casei MtlR activation does not require sequestration to the membrane via the unphosphorylated EIIB(Mtl) domain.
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Affiliation(s)
- Philippe Joyet
- INRA, Microbiologie de l'alimentation au service de la santé humaine (MICALIS), UMR1319, Jouy en Josas, France
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The bacterial phosphoenolpyruvate:carbohydrate phosphotransferase system: regulation by protein phosphorylation and phosphorylation-dependent protein-protein interactions. Microbiol Mol Biol Rev 2015; 78:231-56. [PMID: 24847021 DOI: 10.1128/mmbr.00001-14] [Citation(s) in RCA: 277] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The bacterial phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) carries out both catalytic and regulatory functions. It catalyzes the transport and phosphorylation of a variety of sugars and sugar derivatives but also carries out numerous regulatory functions related to carbon, nitrogen, and phosphate metabolism, to chemotaxis, to potassium transport, and to the virulence of certain pathogens. For these different regulatory processes, the signal is provided by the phosphorylation state of the PTS components, which varies according to the availability of PTS substrates and the metabolic state of the cell. PEP acts as phosphoryl donor for enzyme I (EI), which, together with HPr and one of several EIIA and EIIB pairs, forms a phosphorylation cascade which allows phosphorylation of the cognate carbohydrate bound to the membrane-spanning EIIC. HPr of firmicutes and numerous proteobacteria is also phosphorylated in an ATP-dependent reaction catalyzed by the bifunctional HPr kinase/phosphorylase. PTS-mediated regulatory mechanisms are based either on direct phosphorylation of the target protein or on phosphorylation-dependent interactions. For regulation by PTS-mediated phosphorylation, the target proteins either acquired a PTS domain by fusing it to their N or C termini or integrated a specific, conserved PTS regulation domain (PRD) or, alternatively, developed their own specific sites for PTS-mediated phosphorylation. Protein-protein interactions can occur with either phosphorylated or unphosphorylated PTS components and can either stimulate or inhibit the function of the target proteins. This large variety of signal transduction mechanisms allows the PTS to regulate numerous proteins and to form a vast regulatory network responding to the phosphorylation state of various PTS components.
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11
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Interaction with enzyme IIBMpo (EIIBMpo) and phosphorylation by phosphorylated EIIBMpo exert antagonistic effects on the transcriptional activator ManR of Listeria monocytogenes. J Bacteriol 2015; 197:1559-72. [PMID: 25691525 DOI: 10.1128/jb.02522-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/06/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Listeriae take up glucose and mannose predominantly through a mannose class phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS(Man)), whose three components are encoded by the manLMN genes. The expression of these genes is controlled by ManR, a LevR-type transcription activator containing two PTS regulation domains (PRDs) and two PTS-like domains (enzyme IIA(Man) [EIIA(Man)]- and EIIB(Gat)-like). We demonstrate here that in Listeria monocytogenes, ManR is activated via the phosphorylation of His585 in the EIIA(Man)-like domain by the general PTS components enzyme I and HPr. We also show that ManR is regulated by the PTS(Mpo) and that EIIB(Mpo) plays a dual role in ManR regulation. First, yeast two-hybrid experiments revealed that unphosphorylated EIIB(Mpo) interacts with the two C-terminal domains of ManR (EIIB(Gat)-like and PRD2) and that this interaction is required for ManR activity. Second, in the absence of glucose/mannose, phosphorylated EIIB(Mpo) (P∼EIIB(Mpo)) inhibits ManR activity by phosphorylating His871 in PRD2. The presence of glucose/mannose causes the dephosphorylation of P∼EIIB(Mpo) and P∼PRD2 of ManR, which together lead to the induction of the manLMN operon. Complementation of a ΔmanR mutant with various manR alleles confirmed the antagonistic effects of PTS-catalyzed phosphorylation at the two different histidine residues of ManR. Deletion of manR prevented not only the expression of the manLMN operon but also glucose-mediated repression of virulence gene expression; however, repression by other carbohydrates was unaffected. Interestingly, the expression of manLMN in Listeria innocua was reported to require not only ManR but also the Crp-like transcription activator Lin0142. Unlike Lin0142, the L. monocytogenes homologue, Lmo0095, is not required for manLMN expression; its absence rather stimulates man expression. IMPORTANCE Listeria monocytogenes is a human pathogen causing the foodborne disease listeriosis. The expression of most virulence genes is controlled by the transcription activator PrfA. Its activity is strongly repressed by carbohydrates, including glucose, which is transported into L. monocytogenes mainly via a mannose/glucose-specific phosphotransferase system (PTS(Man)). Expression of the man operon is regulated by the transcription activator ManR, the activity of which is controlled by a second, low-efficiency PTS of the mannose family, which functions as glucose sensor. Here we demonstrate that the EIIB(Mpo) component plays a dual role in ManR regulation: it inactivates ManR by phosphorylating its His871 residue and stimulates ManR by interacting with its two C-terminal domains.
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Moye ZD, Zeng L, Burne RA. Fueling the caries process: carbohydrate metabolism and gene regulation by Streptococcus mutans. J Oral Microbiol 2014; 6:24878. [PMID: 25317251 PMCID: PMC4157138 DOI: 10.3402/jom.v6.24878] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 11/17/2022] Open
Abstract
The nature of the oral cavity and host behaviors has mandated that the oral microbiota evolve mechanisms for coping with environmental fluctuations, especially changes in the type and availability of carbohydrates. In the case of human dental caries, the presence of excess carbohydrates is often responsible for altering the local environment to be more favorable for species associated with the initiation and progression of disease, including Streptococcus mutans. Some of the earliest endeavors to understand how cariogenic species respond to environmental perturbations were carried out using chemostat cultivation, which provides fine control over culture conditions and bacterial behaviors. The development of genome-scale methodologies has allowed for the combination of sophisticated cultivation technologies with genome-level analysis to more thoroughly probe how bacterial pathogens respond to environmental stimuli. Recent investigations in S. mutans and other closely related streptococci have begun to reveal that carbohydrate metabolism can drastically impact pathogenic potential and highlight the important influence that nutrient acquisition has on the success of pathogens; inside and outside of the oral cavity. Collectively, research into pathogenic streptococci, which have evolved in close association with the human host, has begun to unveil the essential nature of careful orchestration of carbohydrate acquisition and catabolism to allow the organisms to persist and, when conditions allow, initiate or worsen disease.
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Affiliation(s)
- Zachary D Moye
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Lin Zeng
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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Anantharaman V, Makarova KS, Burroughs AM, Koonin EV, Aravind L. Comprehensive analysis of the HEPN superfamily: identification of novel roles in intra-genomic conflicts, defense, pathogenesis and RNA processing. Biol Direct 2013; 8:15. [PMID: 23768067 PMCID: PMC3710099 DOI: 10.1186/1745-6150-8-15] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 05/09/2013] [Indexed: 12/20/2022] Open
Abstract
Background The major role of enzymatic toxins that target nucleic acids in biological conflicts at all levels has become increasingly apparent thanks in large part to the advances of comparative genomics. Typically, toxins evolve rapidly hampering the identification of these proteins by sequence analysis. Here we analyze an unexpectedly widespread superfamily of toxin domains most of which possess RNase activity. Results The HEPN superfamily is comprised of all α-helical domains that were first identified as being associated with DNA polymerase β-type nucleotidyltransferases in prokaryotes and animal Sacsin proteins. Using sensitive sequence and structure comparison methods, we vastly extend the HEPN superfamily by identifying numerous novel families and by detecting diverged HEPN domains in several known protein families. The new HEPN families include the RNase LS and LsoA catalytic domains, KEN domains (e.g. RNaseL and Ire1) and the RNase domains of RloC and PrrC. The majority of HEPN domains contain conserved motifs that constitute a metal-independent endoRNase active site. Some HEPN domains lacking this motif probably function as non-catalytic RNA-binding domains, such as in the case of the mannitol repressor MtlR. Our analysis shows that HEPN domains function as toxins that are shared by numerous systems implicated in intra-genomic, inter-genomic and intra-organismal conflicts across the three domains of cellular life. In prokaryotes HEPN domains are essential components of numerous toxin-antitoxin (TA) and abortive infection (Abi) systems and in addition are tightly associated with many restriction-modification (R-M) and CRISPR-Cas systems, and occasionally with other defense systems such as Pgl and Ter. We present evidence of multiple modes of action of HEPN domains in these systems, which include direct attack on viral RNAs (e.g. LsoA and RNase LS) in conjunction with other RNase domains (e.g. a novel RNase H fold domain, NamA), suicidal or dormancy-inducing attack on self RNAs (RM systems and possibly CRISPR-Cas systems), and suicidal attack coupled with direct interaction with phage components (Abi systems). These findings are compatible with the hypothesis on coupling of pathogen-targeting (immunity) and self-directed (programmed cell death and dormancy induction) responses in the evolution of robust antiviral strategies. We propose that altruistic cell suicide mediated by HEPN domains and other functionally similar RNases was essential for the evolution of kin and group selection and cell cooperation. HEPN domains were repeatedly acquired by eukaryotes and incorporated into several core functions such as endonucleolytic processing of the 5.8S-25S/28S rRNA precursor (Las1), a novel ER membrane-associated RNA degradation system (C6orf70), sensing of unprocessed transcripts at the nuclear periphery (Swt1). Multiple lines of evidence suggest that, similar to prokaryotes, HEPN proteins were recruited to antiviral, antitransposon, apoptotic systems or RNA-level response to unfolded proteins (Sacsin and KEN domains) in several groups of eukaryotes. Conclusions Extensive sequence and structure comparisons reveal unexpectedly broad presence of the HEPN domain in an enormous variety of defense and stress response systems across the tree of life. In addition, HEPN domains have been recruited to perform essential functions, in particular in eukaryotic rRNA processing. These findings are expected to stimulate experiments that could shed light on diverse cellular processes across the three domains of life. Reviewers This article was reviewed by Martijn Huynen, Igor Zhulin and Nick Grishin
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Affiliation(s)
- Vivek Anantharaman
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA
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Wenzel M, Altenbuchner J. The Bacillus subtilis mannose regulator, ManR, a DNA-binding protein regulated by HPr and its cognate PTS transporter ManP. Mol Microbiol 2013; 88:562-76. [PMID: 23551403 DOI: 10.1111/mmi.12209] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 11/28/2022]
Abstract
The transcriptional activator ManR of the Bacillus subtilis mannose utilization operon is composed of an N-terminal DNA-binding domain, two phosphotransferase system (PTS) regulation domains (PRDs), an EIIB(Bgl) - and an EIIA(Fru) -like domain. Site-specific mutagenesis of ManR revealed the role of conserved amino acids representing potential phosphorylation sites. This was investigated by β-galactosidase activity tests and by mobility shift assays after incubation with the PTS components HPr and EI. In analogy to other PRD-containing regulators we propose stimulation of ManR activity by phosphorylation. Mutations in PRD1 lowered ManR activity, whereas mutations in PRD2 abolished ManR activity completely. The Cys415Ala (EIIB(Bgl)) and the His570Ala mutations (EIIA(Fru)) provoked constitutive activities to different degrees, whereas the latter had the greater influence. Addition of EIIBA(Man) reduced the binding capability significantly in a wild-type and a Cys415Ala background, but had no effect on a His570Ala mutant. The different expression levels originating from the two promoters PmanR and PmanP could be ascribed to different 5'-untranslated mRNA regions. Sequences of 44 bp were identified and confirmed as the ManR binding sites by DNase I footprinting. The binding properties of ManR, in particular the equilibrium dissociation constant KD and the dissociation rate kdiss, were determined for both promoter regions.
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Affiliation(s)
- Marian Wenzel
- Institut für Industrielle Genetik, Universität Stuttgart, Allmandring 31, 70569, Stuttgart, Germany
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Bouraoui H, Ventroux M, Noirot-Gros MF, Deutscher J, Joyet P. Membrane sequestration by the EIIB domain of the mannitol permease MtlA activates the Bacillus subtilis mtl operon regulator MtlR. Mol Microbiol 2013; 87:789-801. [PMID: 23279188 DOI: 10.1111/mmi.12131] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/15/2012] [Indexed: 11/29/2022]
Abstract
In most firmicutes expression of the mannitol operon is regulated by MtlR. This transcription activator is controlled via phosphorylation of its regulatory domains by components of the phosphoenolpyruvate : carbohydrate phosphotransferase system (PTS). We found that activation of Bacillus subtilis MtlR also requires an interaction with the EIIB(Mtl) domain of the mannitol permease MtlA (EIICB(Mtl) ). The constitutive expression of the mtlAFD operon in an mtlF mutant was prevented when entire mtlA or only its 3' part (EIIB(Mtl) ) were deleted. Yeast two-hybrid experiments revealed a direct interaction of the EIIB(Mtl) domain with the two C-terminal domains of MtlR. Complementation of the Δ3'-mtlA ΔmtlF or ΔmtlAFD mutants with mtlA restored constitutive MtlR activity, whereas complementation with only 3'-mtlA had no effect. Moreover, synthesis of EIIB(Mtl) in strains producing constitutively active MtlR caused MtlR inactivation. Interestingly, EIIB(Mtl) fused to the trans-membrane protein YwqC restored constitutive MtlR activity in the above mutants. Replacing the phosphorylatable Cys with Asp in MtlA or soluble EIIB(Mtl) lowered MtlR activation, indicating that MtlR does not interact with phosphorylatyed EIIB(Mtl) . Induction of the B. subtilis mtl operon therefore follows a novel regulation mechanism where the transcription activator needs to be sequestered to the membrane by unphosphorylated EIICB(Mtl) in order to be functional.
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Affiliation(s)
- Houda Bouraoui
- Institut de la Recherche Agronomique, UMR1319 Microbiologie de l'alimentation au service de la santé humaine Micalis, F-78350 Jouy-en-Josas, France
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Bhatt SM, Mohan A, Srivastava SK. Challenges in enzymatic route of mannitol production. ISRN BIOTECHNOLOGY 2013; 2013:914187. [PMID: 25969783 PMCID: PMC4403613 DOI: 10.5402/2013/914187] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 08/10/2012] [Indexed: 11/23/2022]
Abstract
Mannitol is an important biochemical often used as medicine and in food sector, yet its biotechnological is not preffered in Industry for large scale production, which may be due to the multistep mechanism involved in hydrogenation and reduction. This paper is a comparative preview covering present chemical and biotechnological approaches existing today for mannitol production at industrial scale. Biotechnological routes are suitable for adaptation at industrial level for mannitol production, and whatever concerns are there had been discussed in detail, namely, raw materials, broad range of enzymes with high activity at elevated temperature suitable for use in reactor, cofactor limitation, reduced by-product formation, end product inhibition, and reduced utilization of mannitol for enhancing the yield with maximum volumetric productivity.
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Affiliation(s)
| | - Anand Mohan
- Biotechnology Department, Lovely Professional University, Punjab 144 401, India
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Heravi KM, Wenzel M, Altenbuchner J. Regulation of mtl operon promoter of Bacillus subtilis: requirements of its use in expression vectors. Microb Cell Fact 2011; 10:83. [PMID: 22014119 PMCID: PMC3217849 DOI: 10.1186/1475-2859-10-83] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Accepted: 10/20/2011] [Indexed: 11/10/2022] Open
Abstract
Background Several vector systems have been developed to express any gene desired to be studied in Bacillus subtilis. Among them, the transcriptionally regulated promoters involved in carbohydrate utilization are a research priority. Expression systems based on Bacillus promoters for xylose, maltose, and mannose utilization, as well as on the heterologous E. coli lactose promoter, have been successfully constructed. The promoter of the mtlAFD operon for utilization of mannitol is another promising candidate for its use in expression vectors. In this study, we investigated the regulation of the mtl genes in order to identify the elements needed to construct a strong mannitol inducible expression system in B. subtilis. Results Regulation of the promoters of mtlAFD operon (PmtlA) and mtlR (PmtlR) encoding the activator were investigated by fusion to lacZ. Identification of the PmtlA and PmtlR transcription start sites revealed the σA like promoter structures. Also, the operator of PmtlA was determined by shortening, nucleotide exchange, and alignment of PmtlA and PmtlR operator regions. Deletion of the mannitol-specific PTS genes (mtlAF) resulted in PmtlA constitutive expression demonstrating the inhibitory effect of EIICBMtl and EIIAMtl on MtlR in the absence of mannitol. Disruption of mtlD made the cells sensitive to mannitol and glucitol. Both PmtlA and PmtlR were influenced by carbon catabolite repression (CCR). However, a CcpA deficient mutant showed only a slight reduction in PmtlR catabolite repression. Similarly, using PgroE as a constitutive promoter, putative cre sites of PmtlA and PmtlR slightly reduced the promoter activity in the presence of glucose. In contrast, glucose repression of PmtlA and PmtlR was completely abolished in a ΔptsG mutant and significantly reduced in a MtlR (H342D) mutant. Conclusions The mtl operon promoter (PmtlA) is a strong promoter that reached a maximum of 13,000 Miller units with lacZ as a reporter on low copy plasmids. It is tightly regulated by just one copy of the mtlR gene on the chromosome and subject to CCR. CCR can be switched off by mutations in MtlR and the glucose transporter. These properties and the low costs of the inducers, i.e. mannitol and glucitol, make the promoter ideal for designing regulated expression systems.
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Hammerstrom TG, Roh JH, Nikonowicz EP, Koehler TM. Bacillus anthracis virulence regulator AtxA: oligomeric state, function and CO(2) -signalling. Mol Microbiol 2011; 82:634-47. [PMID: 21923765 DOI: 10.1111/j.1365-2958.2011.07843.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
AtxA, a unique regulatory protein of unknown molecular function, positively controls expression of the major virulence genes of Bacillus anthracis. The 475 amino acid sequence of AtxA reveals DNA binding motifs and regions similar to proteins associated with the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS). We used strains producing native and functional epitope-tagged AtxA proteins to examine protein-protein interactions in cell lysates and in solutions of purified protein. Co-affinity purification, non-denaturing polyacrylamide gel electrophoresis and bis(maleimido)hexane (BMH) cross-linking experiments revealed AtxA homo-multimers. Dimers were the most abundant species. BMH cross-links available cysteines within 13 Å. To localize interaction sites, six AtxA mutants containing distinct Cys→Ser substitutions were tested for multimerization and cross-linking. All mutants multimerized, but one mutation, C402S, prevented cross-linking. Thus, BMH uses C402 to make the inter-molecular bond between AtxA proteins, but C402 is not required for protein-protein interaction. C402 is in a region bearing amino acid similarity to Enzyme IIB proteins of the PTS. The AtxA EIIB motif may function in protein oligomerization. Finally, cultures grown with elevated CO(2) /bicarbonate exhibited increased AtxA dimer/monomer ratios and increased AtxA activity, relative to cultures grown without added CO(2) /bicarbonate, suggesting that this host-associated signal enhances AtxA function by shifting the dimer/monomer equilibrium towards the dimeric state.
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Affiliation(s)
- Troy G Hammerstrom
- Department of Microbiology and Molecular Genetics, The University of Texas - Houston Health Science Center, Medical School, Houston, TX, USA
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Self-inducible Bacillus subtilis expression system for reliable and inexpensive protein production by high-cell-density fermentation. Appl Environ Microbiol 2011; 77:6419-25. [PMID: 21803899 DOI: 10.1128/aem.05219-11] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel technically compliant expression system was developed for heterologous protein production in Bacillus subtilis with the aim of increasing product yields at the same time as decreasing production costs. Standard systems involve the positively regulated manP promoter of the mannose operon, which led to relatively high product yields of 5.3% (5.3 g enhanced green fluorescent protein [eGFP] per 100 g cell dry weight [CDW]) but required large quantities of mannose to induce the reactions, thus rendering the system's technical application rather expensive. To improve this situation, mutant B. subtilis strains were used: the ΔmanA (mannose metabolism) strain TQ281 and the ΔmanP (mannose uptake) strain TQ356. The total amount of inducer could be reduced with TQ281, which, however, displayed sensitivity to mannose. An inducer-independent self-induction system was developed with TQ356 to further improve the cost efficiency and product yield of the system, in which glucose prevents induction by carbon catabolite repression. To create optimal self-induction conditions, a glucose-limited process strategy, namely, a fed-batch process, was utilized as follows. The initiation of self-induction at the beginning of the glucose-restricted transition phase between the batch and fed-batch phase of fermentation and its maintenance throughout the glucose-limiting fed-batch phase led to a nearly 3-fold increase of product yield, to 14.6%. The novel B. subtilis self-induction system thus makes a considerable contribution to improving product yield and reducing the costs associated with its technical application.
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Michel E, Stephan R, Tasara T. The lmo0501 gene coding for a putative transcription activator protein in Listeria monocytogenes promotes growth under cold, osmotic and acid stress conditions. Food Microbiol 2011; 28:1261-5. [PMID: 21839374 DOI: 10.1016/j.fm.2011.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 03/16/2011] [Accepted: 05/06/2011] [Indexed: 10/18/2022]
Abstract
In Listeria monocytogenes EGDe, the lmo0501 gene locus encodes a protein similar to the mannitol transcription regulator (MltR) protein in Bacillus subtilis and Bacillus stearothermophilus. In this study we investigated its functional role in L. monocytogenes EGDe cells in view of growth under different stress conditions. Increased lmo0501 gene expression at mRNA level was detected in response to cold, osmotic and organic acid stress exposure. An EGDe Δlmo0501 mutant strain was diminished in growth compared to the wild type strain in minimal defined medium containing either glucose or fructose, as carbon sources. Growth of the lmo0501 null mutant was retarded growth under cold (4 °C), salt (NaCl) and organic acid stress conditions relative to the parental wild type strain. Our results confirm the role of the lmo0501 gene in adaptation of L. monocytogenes cells to food preservation stress conditions as well as to the efficient utilization of glucose and fructose as carbon sources.
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Affiliation(s)
- Evelyne Michel
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich, Winterthurerstr. 272, CH-8057 Zurich, Switzerland
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Joyet P, Derkaoui M, Poncet S, Deutscher J. Control of Bacillus subtilis mtl operon expression by complex phosphorylation-dependent regulation of the transcriptional activator MtlR. Mol Microbiol 2010; 76:1279-94. [PMID: 20444094 DOI: 10.1111/j.1365-2958.2010.07175.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many bacteria transport mannitol via the mtlAF-encoded phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS). In most firmicutes the transcriptional activator MtlR controls expression of the mtl operon. MtlR possesses an N-terminal DNA binding domain, two PTS regulation domains (PRDs), an EIIB(Gat)- and EIIA(Mtl)-like domain. These four regulatory domains contain one or two potential PTS phosphorylation sites. Replacement of His-342 or His-399 in PRD2 with Ala prevented the phosphorylation of Bacillus subtilis MtlR by PEP, EI and HPr. These mutations as well as EI inactivation caused a loss of MtlR function in vivo. In contrast, phosphomimetic replacement of His-342 with Asp rendered MtlR constitutively active. The absence of phosphorylation in PRD2 serves as catabolite repression mechanism. When EIIA(Mtl) and the soluble EIIB(Mtl) domain of the EIICB(Mtl) permease were included in the phosphorylation mixture, His-599 in the EIIA-like domain of MtlR also became phosphorylated. Replacement of His-599 with Asp rendered MtlR inactive, while His599Ala replacement caused slightly constitutive, glucose-repressible MtlR activity. Doubly mutated His342Ala/His599Ala MtlR was still phosphorylated by EI, HPr and EIIA(Mtl) at Cys-419 in the EIIB(Gat)-like domain. Cys419Ala replacement and deletion of EIIA(Mtl) caused strong constitutive glucose-repressible MtlR activity. This is the first report that Cys phosphorylation controls PRD-containing transcriptional activators.
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Affiliation(s)
- Philippe Joyet
- Laboratoire de Microbiologie et Génétique Moléculaire, INRA-CNRS-AgroParisTech UMR2585, 78850 Thiverval-Grignon, France
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Abstract
The mannose operon of Bacillus subtilis consists of three genes, manP, manA, and yjdF, which are responsible for the transport and utilization of mannose. Upstream and in the same orientation as the mannose operon a regulatory gene, manR, codes for a transcription activator of the mannose operon, as shown in this study. Both mannose operon transcription and manR transcription are inducible by mannose. The presence of mannose resulted in a 4- to 7-fold increase in expression of lacZ from the manP promoter (P(manP)) and in a 3-fold increase in expression of lacZ from the manR promoter (P(manR)). The transcription start sites of manPA-yjdF and manR were determined to be a single A residue and a single G residue, respectively, preceded by -10 and -35 boxes resembling a vegetative sigma(A) promoter structure. Through deletion analysis the target sequences of ManR upstream of P(manP) and P(manR) were identified between bp -80 and -35 with respect to the transcriptional start site of both promoters. Deletion of manP (mannose transporter) resulted in constitutive expression from both the P(manP) and P(manR) promoters, indicating that the phosphotransferase system (PTS) component EII(Man) has a negative effect on regulation of the mannose operon and manR. Moreover, both P(manP) and P(manR) are subject to carbon catabolite repression (CCR). By constructing protein sequence alignments a DNA binding motif at the N-terminal end, two PTS regulation domains (PRDs), and an EIIA- and EIIB-like domain were identified in the ManR sequence, indicating that ManR is a PRD-containing transcription activator. Like findings for other PRD regulators, the phosphoenolpyruvate (PEP)-dependent phosphorylation by the histidine protein HPr via His15 plays an essential role in transcriptional activation of P(manP) and P(manR). Phosphorylation of Ser46 of HPr or of the homologous Crh protein by HPr kinase and formation of a repressor complex with CcpA are parts of the B. subtilis CCR system. Only in the double mutant with an HPr Ser46Ala mutation and a crh knockout mutation was CCR strongly reduced. In contrast, P(manR) and P(manP) were not inducible in a ccpA deletion mutant.
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Tan K, Clancy S, Borovilos M, Zhou M, Hörer S, Moy S, Volkart LL, Sassoon J, Baumann U, Joachimiak A. The mannitol operon repressor MtlR belongs to a new class of transcription regulators in bacteria. J Biol Chem 2009; 284:36670-36679. [PMID: 19840941 DOI: 10.1074/jbc.m109.062679] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many bacteria express phosphoenolpyruvate-dependent phosphotransferase systems (PTS). The mannitol-specific PTS catalyze the uptake and phosphorylation of d-mannitol. The uptake system comprises several genes encoded in the single operon. The expression of the mannitol operon is regulated by a proposed transcriptional factor, mannitol operon repressor (MtlR) that was first studied in Escherichia coli. Here we report the first crystal structures of MtlR from Vibrio parahemeolyticus (Vp-MtlR) and its homolog YggD protein from Shigella flexneri (Sf-YggD). MtlR and YggD belong to the same protein family (Pfam05068). Although Vp-MtlR and Sf-YggD share low sequence identity (22%), their overall structures are very similar, representing a novel all alpha-helical fold, and indicate similar function. However, their lack of any known DNA-binding structural motifs and their unfavorable electrostatic properties imply that MtlR/YggD are unlikely to bind a specific DNA operator directly as proposed earlier. This structural observation is further corroborated by in vitro DNA-binding studies of E. coli MtlR (Ec-MtlR), which detected no interaction of Ec-MtlR with the well characterized mannitol operator/promoter region. Therefore, MtlR/YggD belongs to a new class of transcription factors in bacteria that may regulate gene expression indirectly as a part of a larger transcriptional complex.
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Affiliation(s)
- Kemin Tan
- Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Shonda Clancy
- Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Maria Borovilos
- Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Min Zhou
- Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Stefan Hörer
- Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, 3012 Berne, Switzerland
| | - Shiu Moy
- Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Lour L Volkart
- Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Judyth Sassoon
- Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, 3012 Berne, Switzerland
| | - Ulrich Baumann
- Department of Chemistry and Biochemistry, University of Berne, Freiestrasse 3, 3012 Berne, Switzerland
| | - Andrzej Joachimiak
- Midwest Center for Structural Genomics and Structural Biology Center, Biosciences Division, Argonne National Laboratory, Argonne, Illinois 60439.
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Transcriptional regulation of the cellobiose operon of Streptococcus mutans. J Bacteriol 2009; 191:2153-62. [PMID: 19168613 DOI: 10.1128/jb.01641-08] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ability of Streptococcus mutans to catabolize cellobiose, a beta-linked glucoside generated during the hydrolysis of cellulose, is shown to be regulated by a transcriptional regulator, CelR, which is encoded by an operon with a phospho-beta-glucosidase (CelA) and a cellobiose-specific sugar phosphotransferase system (PTS) permease (EII(Cel)). The roles of CelR, EII(Cel) components, and certain fructose/mannose-PTS permeases in the transcriptional regulation of the cel locus were analyzed. The results revealed that (i) the celA and celB (EIIB(Cel)) gene promoters require CelR for transcriptional activation in response to cellobiose, but read-through from the celA promoter contributes to expression of the EII(Cel) genes; (ii) the EII(Cel) subunits were required for growth on cellobiose and for transcriptional activation of the cel genes; (iii) CcpA plays little direct role in catabolite repression of the cel regulon, but loss of specific PTS permeases alleviated repression of cel genes in the presence of preferred carbohydrates; and (iv) glucose could induce transcription of the cel regulon when transported by EII(Cel). CelR derivatives containing amino acid substitutions for five conserved histidine residues in two PTS regulatory domains and an EIIA-like domain also provided important insights regarding the function of this regulator. Based on these data, a model for the involvement of PTS permeases and the general PTS proteins enzyme I and HPr was developed that reveals a critical role for the PTS in CcpA-independent catabolite repression and induction of cel gene expression in S. mutans.
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Deutscher J, Francke C, Postma PW. How phosphotransferase system-related protein phosphorylation regulates carbohydrate metabolism in bacteria. Microbiol Mol Biol Rev 2007; 70:939-1031. [PMID: 17158705 PMCID: PMC1698508 DOI: 10.1128/mmbr.00024-06] [Citation(s) in RCA: 987] [Impact Index Per Article: 58.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The phosphoenolpyruvate(PEP):carbohydrate phosphotransferase system (PTS) is found only in bacteria, where it catalyzes the transport and phosphorylation of numerous monosaccharides, disaccharides, amino sugars, polyols, and other sugar derivatives. To carry out its catalytic function in sugar transport and phosphorylation, the PTS uses PEP as an energy source and phosphoryl donor. The phosphoryl group of PEP is usually transferred via four distinct proteins (domains) to the transported sugar bound to the respective membrane component(s) (EIIC and EIID) of the PTS. The organization of the PTS as a four-step phosphoryl transfer system, in which all P derivatives exhibit similar energy (phosphorylation occurs at histidyl or cysteyl residues), is surprising, as a single protein (or domain) coupling energy transfer and sugar phosphorylation would be sufficient for PTS function. A possible explanation for the complexity of the PTS was provided by the discovery that the PTS also carries out numerous regulatory functions. Depending on their phosphorylation state, the four proteins (domains) forming the PTS phosphorylation cascade (EI, HPr, EIIA, and EIIB) can phosphorylate or interact with numerous non-PTS proteins and thereby regulate their activity. In addition, in certain bacteria, one of the PTS components (HPr) is phosphorylated by ATP at a seryl residue, which increases the complexity of PTS-mediated regulation. In this review, we try to summarize the known protein phosphorylation-related regulatory functions of the PTS. As we shall see, the PTS regulation network not only controls carbohydrate uptake and metabolism but also interferes with the utilization of nitrogen and phosphorus and the virulence of certain pathogens.
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Affiliation(s)
- Josef Deutscher
- Microbiologie et Génétique Moléculaire, INRA-CNRS-INA PG UMR 2585, Thiverval-Grignon, France.
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Tsvetanova B, Wilson AC, Bongiorni C, Chiang C, Hoch JA, Perego M. Opposing effects of histidine phosphorylation regulate the AtxA virulence transcription factor in Bacillus anthracis. Mol Microbiol 2007; 63:644-55. [PMID: 17302798 DOI: 10.1111/j.1365-2958.2006.05543.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Expression of genes for Bacillus anthracis toxin and capsule virulence factors are dependent upon the AtxA transcription factor. The mechanism by which AtxA regulates the transcription of its target genes is unknown. Here we report that bioinformatic analyses suggested the presence in AtxA of two PTS (phosphenolpyruvate : sugar phosphotransferase system) regulation domains (PRD) generally regulated by phosphorylation/dephosphorylation at conserved histidine residues. By means of amino acid substitutions that mimic the phosphorylated (H to D) or the unphosphorylated (H to A) state of the protein, we showed that phosphorylation of H199 of PRD1 is likely to be necessary for AtxA activation while phosphorylation of H379 in PRD2 is inhibitory to toxin gene transcription. In vivo labelling experiments with radioactive phosphate allowed us to propose that H199 and H379 are AtxA residues subject to regulated phosphorylation. In support to these notions, we also show that deletion of ptsHI, encoding the HPr intermediate and the EI enzymes of PTS, or growth in the presence of glucose affect positively and negatively, respectively, the activity of AtxA. Our results link virulence factor production in B. anthracis to carbohydrate metabolism and, for the first time, provide a mechanistic explanation for AtxA transcriptional activity.
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Affiliation(s)
- Billyana Tsvetanova
- The Scripps Research Institute, Department of Molecular and Experimental Medicine, Division of Cellular Biology, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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Monedero V, Mazé A, Boël G, Zúñiga M, Beaufils S, Hartke A, Deutscher J. The Phosphotransferase System of Lactobacillus casei: Regulation of Carbon Metabolism and Connection to Cold Shock Response. J Mol Microbiol Biotechnol 2006; 12:20-32. [PMID: 17183208 DOI: 10.1159/000096456] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Genome sequencing of two different Lactobacillus casei strains (ATCC334 and BL23) is presently going on and preliminary data revealed that this lactic acid bacterium possesses numerous carbohydrate transport systems probably reflecting its capacity to proliferate under varying environmental conditions. Many carbohydrate transporters belong to the phosphoenolpyruvate:sugar phosphotransferase system (PTS), but all different kinds of non-PTS transporters are present as well and their substrates are known in a few cases. In L. casei regulation of carbohydrate transport and carbon metabolism is mainly achieved by PTS proteins. Carbon catabolite repression (CCR) is mediated via several mechanisms, including the major P-Ser-HPr/catabolite control protein A (CcpA)-dependent mechanism. Catabolite response elements, the target sites for the P-Ser-HPr/CcpA complex, precede numerous genes and operons. PTS regulation domain-containing antiterminators and transcription activators are also present in both L. casei strains. Their activity is usually controlled by two PTS-mediated phosphorylation reactions exerting antagonistic effects on the transcription regulators: P~EIIB-dependent phosphorylation regulates induction of the corresponding genes and P~His-HPr-mediated phosphorylation plays a role in CCR. Carbohydrate transport of L. casei is also regulated via inducer exclusion and inducer expulsion. The presence of glucose, fructose, etc. leads to inhibition of the transport or metabolism of less favorable carbon sources (inducer exclusion) or to the export of accumulated non-metabolizable carbon sources (inducer expulsion). While P-Ser-HPr is essential for inducer exclusion of maltose, it is not necessary for the expulsion of accumulated thio-methyl-beta-D-galactopyranoside. Surprisingly, recent evidence suggests that the PTS of L. casei also plays a role in cold shock response.
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Affiliation(s)
- Vicente Monedero
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Burjassot, Spain
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Wisselink HW, Mars AE, van der Meer P, Eggink G, Hugenholtz J. Metabolic engineering of mannitol production in Lactococcus lactis: influence of overexpression of mannitol 1-phosphate dehydrogenase in different genetic backgrounds. Appl Environ Microbiol 2004; 70:4286-92. [PMID: 15240312 PMCID: PMC444806 DOI: 10.1128/aem.70.7.4286-4292.2004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To obtain a mannitol-producing Lactococcus lactis strain, the mannitol 1-phosphate dehydrogenase gene (mtlD) from Lactobacillus plantarum was overexpressed in a wild-type strain, a lactate dehydrogenase(LDH)-deficient strain, and a strain with reduced phosphofructokinase activity. High-performance liquid chromatography and (13)C nuclear magnetic resonance analysis revealed that small amounts (<1%) of mannitol were formed by growing cells of mtlD-overexpressing LDH-deficient and phosphofructokinase-reduced strains, whereas resting cells of the LDH-deficient transformant converted 25% of glucose into mannitol. Moreover, the formed mannitol was not reutilized upon glucose depletion. Of the metabolic-engineering strategies investigated in this work, mtlD-overexpressing LDH-deficient L. lactis seemed to be the most promising strain for mannitol production.
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Affiliation(s)
- H Wouter Wisselink
- Wageningen Centre for Food Sciences, Wageningen University and Research Centre-Agrotechnology and Food Innovations, Ede, The Netherlands
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Watanabe S, Hamano M, Kakeshita H, Bunai K, Tojo S, Yamaguchi H, Fujita Y, Wong SL, Yamane K. Mannitol-1-phosphate dehydrogenase (MtlD) is required for mannitol and glucitol assimilation in Bacillus subtilis: possible cooperation of mtl and gut operons. J Bacteriol 2003; 185:4816-24. [PMID: 12897001 PMCID: PMC166460 DOI: 10.1128/jb.185.16.4816-4824.2003] [Citation(s) in RCA: 28] [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
We found that mannitol-1-phosphate dehydrogenase (MtlD), a component of the mannitol-specific phosphotransferase system, is required for glucitol assimilation in addition to GutR, GutB, and GutP in Bacillus subtilis. Northern hybridization of total RNA and microarray studies of RNA from cells cultured on glucose, mannitol, and glucitol indicated that mannitol as the sole carbon source induced hyperexpression of the mtl operon, whereas glucitol induced both mtl and gut operons. The B. subtilis mtl operon consists of mtlA (encoding enzyme IICBA(mt1)) and mtlD, and its transcriptional regulator gene, mtlR, is located 14.4 kb downstream from the mtl operon on the chromosome. The mtlA, mtlD, and mtlR mutants disrupted by the introduction of the pMUTin derivatives MTLAd, MTLDd, and MTLRd, respectively, could not grow normally on either mannitol or glucitol. However, the growth of MTLAd on glucitol was enhanced by IPTG (isopropyl-beta-D-thiogalactopyranoside). This mutant has an IPTG-inducible promoter (Pspac promoter) located in mtlA, and this site corresponds to the upstream region of mtlD. Insertion mutants of mtlD harboring the chloramphenicol resistance gene also could not grow on either mannitol or glucitol. In contrast, an insertion mutant of mtlA could grow on glucitol but not on mannitol in the presence or absence of IPTG. MtlR bound to the promoter region of the mtl operon but not to a DNA fragment containing the gut promoter region.
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Affiliation(s)
- Shouji Watanabe
- Institute of Biological Sciences, University of Tsukuba, Tsukuba-shi, Ibaraki 305-8572, Japan
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Declerck N, Dutartre H, Receveur V, Dubois V, Royer C, Aymerich S, van Tilbeurgh H. Dimer stabilization upon activation of the transcriptional antiterminator LicT. J Mol Biol 2001; 314:671-81. [PMID: 11733988 DOI: 10.1006/jmbi.2001.5185] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
LicT belongs to the BglG/SacY family of transcriptional antiterminators that induce the expression of sugar metabolizing operons in Gram positive and Gram negative bacteria. These proteins contain a N-terminal RNA-binding domain and a regulatory domain called PRD which is phosphorylated on conserved histidine residues by components of the phosphoenolpyruvate:sugar phosphotransferase system (PTS). Although it is now well established that phosphorylation of PRD-containing transcriptional regulators tunes their functional response, the molecular and structural basis of the regulation mechanism remain largely unknown.A constitutively active LicT variant has been obtained by introducing aspartic acid in replacement of His207 and His269, the two phosphorylatable residues of the PRD2 regulatory sub-domain. Here, the functional and structural consequences of these activating mutations have been evaluated in vitro using various techniques including surface plasmon resonance, limited proteolysis, analytical centrifugation and X-ray scattering. Comparison with the native, unphosphorylated form shows that the activating mutations enhance the RNA-binding activity and induce tertiary and quaternary structural changes. Both mutant and native LicT form dimers in solution but the native dimer exhibits a less stable and more open conformation than the activated mutant form. Examination of the recently determined crystal structure of mutant LicT regulatory domain suggests that dimer stabilization is accomplished through salt-bridge formation at the PRD2:PRD2 interface, resulting in domain motion and dimer closure propagating the stabilizing effect from the protein C-terminal end to the N-terminal effector domain. These results suggest that LicT activation arises from a conformational switch inducing long range rearrangement of the dimer interaction surface, rather than from an oligomerization switch converting an inactive monomer into an active dimer.
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Affiliation(s)
- N Declerck
- Génétique Moléculaire et Cellulaire, INRA-UMR216 CNRS-URA1925, and INAPG, Thiverval-Grignon, F-78850, France.
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Görke B, Rak B. Efficient transcriptional antitermination from the Escherichia coli cytoplasmic membrane. J Mol Biol 2001; 308:131-45. [PMID: 11327758 DOI: 10.1006/jmbi.2001.4590] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The BglG protein is a transcriptional antiterminator acting within the beta-glucoside operon of Escherichia coli by binding to a specific sequence motif in the growing mRNA. Binding of BglG prevents formation of the terminator stem-loop structure, thereby causing the RNA polymerase to continue transcription. Activity of BglG is modulated in a complex way by antagonistically acting phosphorylations in response to the availability of beta-glucosidic substrates and to the catabolic state of the cell. The enzymes responsible for these phosphorylations are members of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) that represents a central carbohydrate uptake and signal transduction system. As these enzymes are believed to all form higher-order complexes associated with the cytoplasmic membrane, we tested whether or not BglG would remain active when artificially anchored to its presumptive site of regulation, the inner membrane. We show that the membrane-anchored protein indeed efficiently catalyzes transcriptional antitermination. Moreover, the membrane-attached BglG remains regulated by the PTS. Thus, a membrane-bound regulatory RNA binding protein can potentially interact fast enough with its target within the nascent transcript and cause the transcriptional machinery to proceed, before transcriptional termination would occur. Consequently, there is no principal necessity for an RNA-binding transcriptional regulator like BglG to leave the inner membrane, a potential regulatory site, and migrate to the site of transcription, the nucleoid.
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Affiliation(s)
- B Görke
- Institut für Biologie III, Universität, Schänzlestr. 1, D-79104 Freiburg, Germany
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Abstract
The gram-positive bacterium Bacillus subtilisis capable of using numerous carbohydrates as single sources of carbon and energy. In this review, we discuss the mechanisms of carbon catabolism and its regulation. Like many other bacteria, B. subtilis uses glucose as the most preferred source of carbon and energy. Expression of genes involved in catabolism of many other substrates depends on their presence (induction) and the absence of carbon sources that can be well metabolized (catabolite repression). Induction is achieved by different mechanisms, with antitermination apparently more common in B. subtilis than in other bacteria. Catabolite repression is regulated in a completely different way than in enteric bacteria. The components mediating carbon catabolite repression in B. subtilis are also found in many other gram-positive bacteria of low GC content.
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Affiliation(s)
- J Stülke
- Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie, Biochemie und Genetik der Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Behrens S, Mitchell W, Bahl H. Molecular analysis of the mannitol operon of Clostridium acetobutylicum encoding a phosphotransferase system and a putative PTS-modulated regulator. MICROBIOLOGY (READING, ENGLAND) 2001; 147:75-86. [PMID: 11160802 DOI: 10.1099/00221287-147-1-75] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Clostridium acetobutylicum DSM 792 accumulates and phosphorylates mannitol via a phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS). PEP-dependent mannitol phosphorylation by extracts of cells grown on mannitol required both soluble and membrane fractions. Neither the soluble nor the membrane fraction could be complemented by the opposite fraction prepared from glucose-grown cells, indicating that the mannitol-specific PTS consists of both a soluble (IIA) and a membrane-bound (IICB) component. The mannitol (mtl) operon of C. acetobutylicum DSM 792 comprises four genes in the order mtlARFD. Sequence analysis of deduced protein products indicated that the mtlA and mtlF genes respectively encode the IICB and IIA components of the mannitol PTS, which is a member of the fructose-mannitol (Fru) family. The mtlD gene product is a mannitol-1-phosphate dehydrogenase, while mtlR encodes a putative transcriptional regulator. MtlR contains two PTS regulatory domains (PRDs), which have been found in a number of DNA-binding transcriptional regulators and in transcriptional antiterminators of the Escherichia coli BglG family. Also, near the C-terminus is a well-conserved signature motif characteristic of members of the IIA(Fru)/IIA(Mtl)/IIA(Ntr) PTS protein family. These regions are probably the sites of PTS-dependent phosphorylation to regulate the activity of the protein. A helix-turn-helix DNA-binding motif was not found in MtlR. Transcriptional analysis of the mtl genes by Northern blotting indicated that the genes were transcribed as a polycistronic operon, expression of which was induced by mannitol and repressed by glucose. Primer extension experiments identified a transcriptional start point 42 bp upstream of the mtlA start codon. Two catabolite-responsive elements (CREs), one of which overlapped the putative -35 region of the promoter, were located within the 100 bp upstream of the start codon. These sequences may be involved in regulation of expression of the operon.
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Affiliation(s)
- S Behrens
- Institut für Mikrobiologie, Georg-August-Universität Göttingen, Grisebachstrasse 8, D-37077 Göttingen, Germany
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Kotrba P, Inui M, Yukawa H. Bacterial phosphotransferase system (PTS) in carbohydrate uptake and control of carbon metabolism. J Biosci Bioeng 2001. [DOI: 10.1016/s1389-1723(01)80308-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Honeyman AL, Curtiss R. The mannitol-specific enzyme II (mtlA) gene and the mtlR gene of the PTS of Streptococcus mutans. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 7):1565-1572. [PMID: 10878121 DOI: 10.1099/00221287-146-7-1565] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The phosphoenolpyruvate-dependent phosphotransferase system (PTS) is widely found among Gram-positive bacteria. It is the major source of carbohydrate transport in the dental pathogen Streptococcus mutans. The transported carbohydrates are fermented to produce large amounts of lactic acid which initiates dental caries. The authors have isolated the S. mutans gene for the mannitol-specific Enzyme II (EII) component of the PTS, mtlA, and the adjacent mtlR gene, which is located in the same operon. The mtlR gene is located between mtlA and the genes mtlF and mtlD. The nucleotide sequence of the mtlA and mtlR loci has been determined. The deduced mtlA gene product of S. mutans consists of 589 amino acids with a molecular mass of 62.0 kDa. It exhibits similarity with the mtlA gene products from other organisms. However, the similarity between these proteins is generally restricted to the 470 amino-terminal residues of the S. mutans protein. This region would correspond to the EIICB domains of the PTS. The authors have previously shown that the S. mutans mtlF gene product exhibits 76.6% similarity to the carboxyl-terminal 143 amino acids of the Escherichia coli mtlA product and that the mtlF gene encodes the EIIA domain of the PTS. Thus, the genes that encode the EIICB and the EIIA domains are separated by approximately 2250 bp. In many organisms, all of the EII domains may be fused together to form one molecule. The fact that these domains are separated by this distance in S. mutans supports the hypothesis that various functional domains of the PTS have been rearranged during evolution. The sequence of the 119 carboxyl-terminal amino acids of the S. mutans mtlA gene product also displays homology to the carboxyl-terminal end of the EIIB domain of various mannitol PTSs. Thus, this domain may have been duplicated in S. mutans during evolution of the operon. The mtlR gene is located in the same operon structure as mtlA but these loci are separated by an intragenic space. The precise 5' end of the mtlR locus cannot be determined either by in vitro transcription-translation assays or based upon nucleotide sequence analysis because of the apparent lack of a ribosome-binding site preceding the gene. The deduced mtlR gene product, which consists of approximately 650 amino acids with a molecular mass of 75.3 kDa, exhibits limited similarity to several potential transcriptional regulators. However, the exact function of this locus is currently unknown.
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Affiliation(s)
- Allen L Honeyman
- Department of Medical Microbiology and Immunology, University of South Florida College of Medicine, 12901 Bruce B. Downs Boulevard, Tampa, FL 33612, USA2
- Department of Biology, Washington University, St Louis, MO 63130, USA1
| | - Roy Curtiss
- Department of Biology, Washington University, St Louis, MO 63130, USA1
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Henstra SA, Duurkens RH, Robillard GT. Multiple phosphorylation events regulate the activity of the mannitol transcriptional regulator MtlR of the Bacillus stearothermophilus phosphoenolpyruvate-dependent mannitol phosphotransferase system. J Biol Chem 2000; 275:7037-44. [PMID: 10702268 DOI: 10.1074/jbc.275.10.7037] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
D-mannitol is taken up by Bacillus stearothermophilus and phosphorylated via a phosphoenolpyruvate-dependent phosphotransferase system (PTS). Transcription of the genes involved in mannitol uptake in this bacterium is regulated by the transcriptional regulator MtlR, a DNA-binding protein whose affinity for DNA is controlled by phosphorylation by the PTS proteins HPr and IICB(mtl). The mutational and biochemical studies presented in this report reveal that two domains of MtlR, PTS regulation domain (PRD)-I and PRD-II, are phosphorylated by HPr, whereas a third IIA-like domain is phosphorylated by IICB(mtl). An involvement of PRD-I and the IIA-like domain in a decrease in affinity of MtlR for DNA and of PRD-II in an increase in affinity is demonstrated by DNA footprint experiments using MtlR mutants. Since both PRD-I and PRD-II are phosphorylated by HPr, PRD-I needs to be dephosphorylated by IICB(mtl) and mannitol to obtain maximal affinity for DNA. This implies that a phosphoryl group can be transferred from HPr to IICB(mtl) via MtlR. Indeed, this transfer could be demonstrated by the phosphoenolpyruvate-dependent formation of [(3)H]mannitol phosphate in the absence of IIA(mtl). Phosphoryl transfer experiments using MtlR mutants revealed that PRD-I and PRD-II are dephosphorylated via the IIA-like domain. Complementation experiments using two mutants with no or low phosphoryl transfer activity showed that phosphoryl transfer between MtlR molecules is possible, indicating that MtlR-MtlR interactions take place. Phosphorylation of the same site by HPr and dephosphorylation by IICB(mtl) have not been described before; they could also play a role in other PRD-containing proteins.
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Affiliation(s)
- S A Henstra
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Reizer J, Bachem S, Reizer A, Arnaud M, Saier MH, Stülke J. Novel phosphotransferase system genes revealed by genome analysis - the complete complement of PTS proteins encoded within the genome of Bacillus subtilis. MICROBIOLOGY (READING, ENGLAND) 1999; 145 ( Pt 12):3419-3429. [PMID: 10627040 DOI: 10.1099/00221287-145-12-3419] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Bacillus subtilis can utilize several sugars as single sources of carbon and energy. Many of these sugars are transported and concomitantly phosphorylated by the phosphoenolpyruvate:sugar phosphotransferase system (PTS). In addition to its role in sugar uptake, the PTS is one of the major signal transduction systems in B. subtilis. In this study, an analysis of the complete set of PTS proteins encoded within the B. subtilis genome is presented. Fifteen sugar-specific PTS permeases were found to be present and the functions of novel PTS permeases were studied based on homology to previously characterized permeases, analysis of the structure of the gene clusters in which the permease encoding genes are located and biochemical analysis of relevant mutants. Members of the glucose, sucrose, lactose, mannose and fructose/mannitol families of PTS permeases were identified. Interestingly, nine pairs of IIB and IIC domains belonging to the glucose and sucrose permease families are present in B. subtilis; by contrast only five Enzyme IIA(Glc)-like proteins or domains are encoded within the B. subtilis genome. Consequently, some of the EIIA(Glc)-like proteins must function in phosphoryl transfer to more than one IIB domain of the glucose and sucrose families. In addition, 13 PTS-associated proteins are encoded within the B. subtilis genome. These proteins include metabolic enzymes, a bifunctional protein kinase/phosphatase, a transcriptional cofactor and transcriptional regulators that are involved in PTS-dependent signal transduction. The PTS proteins and the auxiliary PTS proteins represent a highly integrated network that catalyses and simultaneously modulates carbohydrate utilization in this bacterium.
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Affiliation(s)
- Jonathan Reizer
- Department of Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA1
| | - Steffi Bachem
- Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie, Biochemie und Genetik der Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, Germany2
| | - Aiala Reizer
- Department of Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA1
| | - Maryvonne Arnaud
- Unité de Biochimie Microbienne, D épartement des Biotechnologies, Institut Pasteur, 25 rue du Dr Roux, F-75724 Paris Cedex 15, France 3
| | - Milton H Saier
- Department of Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA1
| | - Jörg Stülke
- Lehrstuhl für Mikrobiologie, Institut für Mikrobiologie, Biochemie und Genetik der Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstr. 5, D-91058 Erlangen, Germany2
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