1
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Tharmasothirajan A, Melcr J, Linney J, Gensch T, Krumbach K, Ernst KM, Brasnett C, Poggi P, Pitt AR, Goddard AD, Chatgilialoglu A, Marrink SJ, Marienhagen J. Membrane manipulation by free fatty acids improves microbial plant polyphenol synthesis. Nat Commun 2023; 14:5619. [PMID: 37699874 PMCID: PMC10497605 DOI: 10.1038/s41467-023-40947-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 08/16/2023] [Indexed: 09/14/2023] Open
Abstract
Microbial synthesis of nutraceutically and pharmaceutically interesting plant polyphenols represents a more environmentally friendly alternative to chemical synthesis or plant extraction. However, most polyphenols are cytotoxic for microorganisms as they are believed to negatively affect cell integrity and transport processes. To increase the production performance of engineered cell factories, strategies have to be developed to mitigate these detrimental effects. Here, we examine the accumulation of the stilbenoid resveratrol in the cell membrane and cell wall during its production using Corynebacterium glutamicum and uncover the membrane rigidifying effect of this stilbenoid experimentally and with molecular dynamics simulations. A screen of free fatty acid supplements identifies palmitelaidic acid and linoleic acid as suitable additives to attenuate resveratrol's cytotoxic effects resulting in a three-fold higher product titer. This cost-effective approach to counteract membrane-damaging effects of product accumulation is transferable to the microbial production of other polyphenols and may represent an engineering target for other membrane-active bioproducts.
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Affiliation(s)
- Apilaasha Tharmasothirajan
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425, Jülich, Germany
- Institute of Biotechnology, RWTH Aachen University, Worringer Weg 3, 52074, Aachen, Germany
| | - Josef Melcr
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - John Linney
- College of Health and Life Sciences, Aston University, Birmingham, B4 7ET, UK
| | - Thomas Gensch
- Institute for Information Processing, IBI-1: Molecular and Cellular Physiology, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Karin Krumbach
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Karla Marlen Ernst
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Christopher Brasnett
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Paola Poggi
- Remembrane Srl, via San Francesco 40, 40026, Imola, Italy
| | - Andrew R Pitt
- College of Health and Life Sciences, Aston University, Birmingham, B4 7ET, UK
- Manchester Institute of Biotechnology and Department of Chemistry, University of Manchester, Manchester, UK
| | - Alan D Goddard
- College of Health and Life Sciences, Aston University, Birmingham, B4 7ET, UK
| | | | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Jan Marienhagen
- Institute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich, 52425, Jülich, Germany.
- Institute of Biotechnology, RWTH Aachen University, Worringer Weg 3, 52074, Aachen, Germany.
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2
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Lin K, Zhao N, Cai Y, Lin Y, Han S, Zheng S. Genome-Scale Mining of Novel Anchor Proteins of Corynebacterium glutamicum. Front Microbiol 2022; 12:677702. [PMID: 35185806 PMCID: PMC8854784 DOI: 10.3389/fmicb.2021.677702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 12/17/2021] [Indexed: 11/26/2022] Open
Abstract
The display of recombinant proteins on the surfaces of bacteria is a research topic with many possible biotechnology applications—among which, the choice of host cell and anchoring motif is the key for efficient display. Corynebacterium glutamicum is a promising host for surface display due to its natural advantages, while single screening methods and fewer anchor proteins restrict its application. In this study, the subcellular localization (SCL) predictor LocateP and tied-mixture hidden Markov models were used to analyze all five known endogenous anchor proteins of C. glutamicum and test the accuracy of the predictions. Using these two tools, the SCLs of all proteins encoded by the genome of C. glutamicum 13032 were predicted, and 14 potential anchor proteins were screened. Compared with the positive controls NCgl1221 and NCgl1337, three anchoring proteins—NCgl1307, NCgl2775, and NCgl0717—performed better. This study also discussed the applicability of the anchor protein screening method used in this experiment to other bacteria.
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Affiliation(s)
- Kerui Lin
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Nannan Zhao
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Youhua Cai
- Star Lake Bioscience Co. Inc., Zhaoqing Guangdong, Zhaoqing, China
| | - Ying Lin
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shuangyan Han
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Shuangyan Han,
| | - Suiping Zheng
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- *Correspondence: Suiping Zheng,
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3
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Lin K, Han S, Zheng S. Application of Corynebacterium glutamicum engineering display system in three generations of biorefinery. Microb Cell Fact 2022; 21:14. [PMID: 35090458 PMCID: PMC8796525 DOI: 10.1186/s12934-022-01741-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/09/2022] [Indexed: 11/29/2022] Open
Abstract
The fermentation production of platform chemicals in biorefineries is a sustainable alternative to the current petroleum refining process. The natural advantages of Corynebacterium glutamicum in carbon metabolism have led to C. glutamicum being used as a microbial cell factory that can use various biomass to produce value-added platform chemicals and polymers. In this review, we discussed the use of C. glutamicum surface display engineering bacteria in the three generations of biorefinery resources, and analyzed the C. glutamicum engineering display system in degradation, transport, and metabolic network reconstruction models. These engineering modifications show that the C. glutamicum engineering display system has great potential to become a cell refining factory based on sustainable biomass, and further optimizes the inherent properties of C. glutamicum as a whole-cell biocatalyst. This review will also provide a reference for the direction of future engineering transformation.
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Affiliation(s)
- Kerui Lin
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China.,Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China
| | - Shuangyan Han
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China.,Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China
| | - Suiping Zheng
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China. .,Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China.
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4
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Li H, Xu D, Liu Y, Tan X, Qiao J, Li Z, Qi B, Hu X, Wang X. Preventing mycolic acid reduction in Corynebacterium glutamicum can efficiently increase L-glutamate production. Biochem Eng J 2022. [DOI: 10.1016/j.bej.2021.108255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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5
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Nie Z, Liu P, Wang Y, Guo X, Tan Z, Shen J, Tang Z, Lin J, Sun J, Zheng P, Zhu L. Directed Evolution and Rational Design of Mechanosensitive Channel MscCG2 for Improved Glutamate Excretion Efficiency. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:15660-15669. [PMID: 34928605 DOI: 10.1021/acs.jafc.1c07086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Mechanosensitive amino acid exporters have drawn increasing attention due to their important roles in extracellular accumulation of the target amino acids. Protein engineering is a powerful approach to tailor the properties of amino acid exporters and illustrate structure-function relationships. Here we report the first protein engineering effort on the mechanosensitive glutamate exporter MscCG2 from Corynebacterium glutamicum for improved excretion efficiency of glutamate and understanding of the structure-function relationship. MscCG2 was engineered through directed evolution and computer-assisted design with a coupled assay in microtiter plate format. Improved MscCG2 variants were identified with up to 2.5-fold increase in the level of glutamate excretion in the early stage of fermentation and 1.5-fold in the late stage of fermentation under experimental conditions. Furthermore, the identified variants exhibited enhanced efflux of 4-fluoroglutamate (4-FG), an analog of glutamate. Structure analysis employing homology modeling and molecular dynamics (MD) simulation reveal that identified amino acid substitutions enlarge the size of the seven portals on the equator of MscCG2 and expand the narrowest rim of its inner channel, respectively. This study demonstrates the great potential of protein engineering in improving the secretion efficiency of exporters for enhanced bioproduction.
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Affiliation(s)
- Zhihua Nie
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Pi Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Yu Wang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Xuan Guo
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Zijian Tan
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Jie Shen
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Zijing Tang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Jianping Lin
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Jibin Sun
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Ping Zheng
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
| | - Leilei Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Technology Innovation Center of Synthetic Biology, Tianjin 300308, China
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6
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Kataoka N, Matsutani M, Murata R, Koga R, Nantapong N, Yakushi T, Matsushita K. Potassium ion leakage impairs thermotolerance in Corynebacterium glutamicum. J Biosci Bioeng 2021; 133:119-125. [PMID: 34789412 DOI: 10.1016/j.jbiosc.2021.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/21/2021] [Accepted: 10/19/2021] [Indexed: 12/30/2022]
Abstract
Corynebacterium glutamicum, a gram-positive bacterium, can produce amino acids such as glutamic acid and lysine. The heat generated during cell growth and/or glutamate fermentation disturbs both the cell growth and fermentation. To overcome such a negative effect of the fermentation heat, we have tried to establish a high temperature fermentation. One of the approach is to create a thermotolerant strains, while the other is to create an optimum culture conditions able for the strain to grow at higher temperatures. In this study, we focused on the latter approach, where we examined the effect of potassium ion on cell growth at high growth temperatures of C. glutamicum. The supplementation of high concentrations of potassium chloride (300 mM) (or sorbitol, an osmolyte) mitigated the repressed cell growth induced by high temperature at 39 °C or 40 °C. The intracellular potassium concentration declines from 300 mM to ∼150 mM by increasing the growth temperature but not by supplementing potassium chloride or sorbitol. Furthermore, in vitro experiments revealed that the potassium ion leakage occurs at high temperatures, which was mitigated in the presence of high concentrations of extracellular potassium chloride. This suggested that the presence of high osmolyte in the culture medium could inhibit the potassium ion leakage induced by high temperature and subsequently support cell growth at high temperatures.
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Affiliation(s)
- Naoya Kataoka
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; Graduate School of Science and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan; Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Minenosuke Matsutani
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; NODAI Genome Research Center, Tokyo University of Agriculture, Tokyo 156-8502, Japan
| | - Ryutarou Murata
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Ryo Koga
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Nawarat Nantapong
- School of Preclinical Sciences, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 3000, Thailand
| | - Toshiharu Yakushi
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; Graduate School of Science and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan; Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8515, Japan
| | - Kazunobu Matsushita
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan; Graduate School of Science and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8515, Japan; Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi 753-8515, Japan.
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7
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Soares-Silva I, Ribas D, Sousa-Silva M, Azevedo-Silva J, Rendulić T, Casal M. Membrane transporters in the bioproduction of organic acids: state of the art and future perspectives for industrial applications. FEMS Microbiol Lett 2021; 367:5873408. [PMID: 32681640 PMCID: PMC7419537 DOI: 10.1093/femsle/fnaa118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 07/17/2020] [Indexed: 12/16/2022] Open
Abstract
Organic acids such as monocarboxylic acids, dicarboxylic acids or even more complex molecules such as sugar acids, have displayed great applicability in the industry as these compounds are used as platform chemicals for polymer, food, agricultural and pharmaceutical sectors. Chemical synthesis of these compounds from petroleum derivatives is currently their major source of production. However, increasing environmental concerns have prompted the production of organic acids by microorganisms. The current trend is the exploitation of industrial biowastes to sustain microbial cell growth and valorize biomass conversion into organic acids. One of the major bottlenecks for the efficient and cost-effective bioproduction is the export of organic acids through the microbial plasma membrane. Membrane transporter proteins are crucial elements for the optimization of substrate import and final product export. Several transporters have been expressed in organic acid-producing species, resulting in increased final product titers in the extracellular medium and higher productivity levels. In this review, the state of the art of plasma membrane transport of organic acids is presented, along with the implications for industrial biotechnology.
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Affiliation(s)
- I Soares-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - D Ribas
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - M Sousa-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - J Azevedo-Silva
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - T Rendulić
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
| | - M Casal
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, Braga 4710-057, Portugal.,Institute of Science and Innovation for Bio-Sustainability (IB-S), University of Minho, Campus de Gualtar, Braga 4710-057, Portugal
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8
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Nakayama Y. Corynebacterium glutamicum Mechanosensing: From Osmoregulation to L-Glutamate Secretion for the Avian Microbiota-Gut-Brain Axis. Microorganisms 2021; 9:201. [PMID: 33478007 PMCID: PMC7835871 DOI: 10.3390/microorganisms9010201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/15/2021] [Accepted: 01/18/2021] [Indexed: 12/18/2022] Open
Abstract
After the discovery of Corynebacterium glutamicum from avian feces-contaminated soil, its enigmatic L-glutamate secretion by corynebacterial MscCG-type mechanosensitive channels has been utilized for industrial monosodium glutamate production. Bacterial mechanosensitive channels are activated directly by increased membrane tension upon hypoosmotic downshock; thus; the physiological significance of the corynebacterial L-glutamate secretion has been considered as adjusting turgor pressure by releasing cytoplasmic solutes. In this review, we present information that corynebacterial mechanosensitive channels have been evolutionally specialized as carriers to secrete L-glutamate into the surrounding environment in their habitats rather than osmotic safety valves. The lipid modulation activation of MscCG channels in L-glutamate production can be explained by the "Force-From-Lipids" and "Force-From-Tethers" mechanosensing paradigms and differs significantly from mechanical activation upon hypoosmotic shock. The review also provides information on the search for evidence that C. glutamicum was originally a gut bacterium in the avian host with the aim of understanding the physiological roles of corynebacterial mechanosensing. C. glutamicum is able to secrete L-glutamate by mechanosensitive channels in the gut microbiota and help the host brain function via the microbiota-gut-brain axis.
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Affiliation(s)
- Yoshitaka Nakayama
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; ; Tel.: +61-2-9295-8744
- St Vincent’s Clinical School, Faculty of Medicine, The University of New South Wales, Darlinghurst, NSW 2010, Australia
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9
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Krüger L, Herzberg C, Rath H, Pedreira T, Ischebeck T, Poehlein A, Gundlach J, Daniel R, Völker U, Mäder U, Stülke J. Essentiality of c-di-AMP in Bacillus subtilis: Bypassing mutations converge in potassium and glutamate homeostasis. PLoS Genet 2021; 17:e1009092. [PMID: 33481774 PMCID: PMC7857571 DOI: 10.1371/journal.pgen.1009092] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 02/03/2021] [Accepted: 12/14/2020] [Indexed: 12/14/2022] Open
Abstract
In order to adjust to changing environmental conditions, bacteria use nucleotide second messengers to transduce external signals and translate them into a specific cellular response. Cyclic di-adenosine monophosphate (c-di-AMP) is the only known essential nucleotide second messenger. In addition to the well-established role of this second messenger in the control of potassium homeostasis, we observed that glutamate is as toxic as potassium for a c-di-AMP-free strain of the Gram-positive model bacterium Bacillus subtilis. In this work, we isolated suppressor mutants that allow growth of a c-di-AMP-free strain under these toxic conditions. Characterization of glutamate resistant suppressors revealed that they contain pairs of mutations, in most cases affecting glutamate and potassium homeostasis. Among these mutations, several independent mutations affected a novel glutamate transporter, AimA (Amino acid importer A, formerly YbeC). This protein is the major transporter for glutamate and serine in B. subtilis. Unexpectedly, some of the isolated suppressor mutants could suppress glutamate toxicity by a combination of mutations that affect phospholipid biosynthesis and a specific gain-of-function mutation of a mechanosensitive channel of small conductance (YfkC) resulting in the acquisition of a device for glutamate export. Cultivation of the c-di-AMP-free strain on complex medium was an even greater challenge because the amounts of potassium, glutamate, and other osmolytes are substantially higher than in minimal medium. Suppressor mutants viable on complex medium could only be isolated under anaerobic conditions if one of the two c-di-AMP receptor proteins, DarA or DarB, was absent. Also on complex medium, potassium and osmolyte toxicity are the major bottlenecks for the growth of B. subtilis in the absence of c-di-AMP. Our results indicate that the essentiality of c-di-AMP in B. subtilis is caused by the global impact of the second messenger nucleotide on different aspects of cellular physiology.
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Affiliation(s)
- Larissa Krüger
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Christina Herzberg
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Hermann Rath
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Tiago Pedreira
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Till Ischebeck
- Department of Plant Biochemistry, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Jan Gundlach
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
| | - Uwe Völker
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Ulrike Mäder
- Interfaculty Institute for Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Jörg Stülke
- Department of General Microbiology, GZMB, Georg-August-University Göttingen, Göttingen, Germany
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10
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Kawasaki H, Martinac B. Mechanosensitive channels of Corynebacterium glutamicum functioning as exporters of l-glutamate and other valuable metabolites. Curr Opin Chem Biol 2020; 59:77-83. [DOI: 10.1016/j.cbpa.2020.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/09/2020] [Accepted: 05/17/2020] [Indexed: 01/06/2023]
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11
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Contribution of mechanosensitive channels to osmoadaptation and ectoine excretion in Halomonas elongata. Extremophiles 2020; 24:421-432. [PMID: 32266565 PMCID: PMC7174268 DOI: 10.1007/s00792-020-01168-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 03/24/2020] [Indexed: 12/05/2022]
Abstract
For osmoadaptation the halophilic bacterium Halomonas elongata synthesizes as its main compatible solute the aspartate derivative ectoine. H. elongata does not rely entirely on synthesis but can accumulate ectoine by uptake from the surrounding environment with the help of the osmoregulated transporter TeaABC. Disruption of the TeaABC-mediated ectoine uptake creates a strain that is constantly losing ectoine to the medium. However, the efflux mechanism of ectoine in H. elongata is not yet understood. H. elongata possesses four genes encoding mechanosensitive channels all of which belong to the small conductance type (MscS). Analysis by qRT-PCR revealed a reduction in transcription of the mscS genes with increasing salinity. The response of H. elongata to hypo- and hyperosmotic shock never resulted in up-regulation but rather in down-regulation of mscS transcription. Deletion of all four mscS genes created a mutant that was unable to cope with hypoosmotic shock. However, the knockout mutant grew significantly faster than the wildtype at high salinity of 2 M NaCl, and most importantly, still exported 80% of the ectoine compared to the wildtype. We thus conclude that a yet unknown system, which is independent of mechanosensitive channels, is the major export route for ectoine in H. elongata.
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12
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Battle AR, Norton RS, Böcking T, Noji H, Kim KK, Nagayama K. Editorial: Special issue of Biophysical Reviews dedicated to the joint 10th Asian Biophysics Association Symposium and 42nd Australian Society for Biophysics Meeting, Melbourne, Australia, December 2-6, 2018. Biophys Rev 2019; 11:245-247. [PMID: 31115863 PMCID: PMC6557946 DOI: 10.1007/s12551-019-00553-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 05/07/2019] [Indexed: 12/15/2022] Open
Affiliation(s)
- Andrew R Battle
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, 4000, Australia.
- Translational Research Institute and Institute for Biomedical Innovation (QUT), 37 Kent Street, Woolloongabba, 4102, Australia.
- The University of Queensland Diamantina Institute, Faculty of Medicine, The University of Queensland, Brisbane, 4102, Australia.
| | - Raymond S Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 381 Royal Parade, Parkville, VIC, 3052, Australia
| | - Till Böcking
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Hiroyuki Noji
- Department of Applied Chemistry, School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Kyeong Kyu Kim
- Department of Molecular Cell Biology, School of Medicine, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Kuniaki Nagayama
- National Institute for Physiological Sciences, Myodaiji-cho, Okazaki, 444-8585, Japan
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