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Zhang J, Zhao Y, Peng Z, Yang M, Zou W, Wu X, Wang C, Si M, Chen C. The role of the transcriptional repressor CssR in Corynebacterium glutamicum in response to phenolic compounds. Heliyon 2024; 10:e27929. [PMID: 38509974 PMCID: PMC10950717 DOI: 10.1016/j.heliyon.2024.e27929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 03/05/2024] [Accepted: 03/08/2024] [Indexed: 03/22/2024] Open
Abstract
The cssR gene (ncgl1578) of Corynebacterium glutamicum encodes a repressor of the TetR (tetracycline regulator) family. Its role in the stress response to antibiotics/heavy metals has been investigated, but how CssR functions in response to phenolic compounds in C. glutamicum has been rarely studied. In this study, we applied transcriptomic analysis, β-galactosidase analysis, qRT-PCR, and EMSAs to analyze the target genes and functions of CssR in response to phenolic compounds. Consistent with the upregulation of genes involved in the degradation of phenolic compounds, the ΔcssR mutant was more resistant to various phenolic compounds than was the wild-type strain. Furthermore, the addition of phenolic compounds induced the expression of corresponding genes (ncgl0283, ncgl1032, ncgl1111, ncgl2920, ncgl2923, and ncgl2952) in vivo. However, the DNA binding activity of CssR to the promoter of phenolic compound-degrading genes was undetected in vitro. Additionally, we also found that CssR indirectly negatively regulates the expression of cell wall/membrane/envelope biogenesis-related genes, which may enhance resistance to stress caused by phenolic compounds. Together, our findings demonstrate that CssR is a key regulator that copes with stress conditions induced by phenolic compounds, thus greatly expanding our understanding of the functions of TetR family transcription factors.
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Affiliation(s)
- Ju Zhang
- Key Laboratory of Plant Genetics and Molecular Breeding, Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan, China
- College of Horticulture, Agricultural University of Hebei/Key Laboratory for Vegetable Germplasm Enhancement and Utilization of Hebei/Collaborative Innovation Center of Vegetable Industry in Hebei, Baoding, 071001, China
| | - Yuying Zhao
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Zhaoxin Peng
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - MingFei Yang
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Wenyu Zou
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Xinyu Wu
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Chenghui Wang
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Meiru Si
- College of Life Sciences, Qufu Normal University, Qufu, 273165, Shandong, China
| | - Can Chen
- Key Laboratory of Plant Genetics and Molecular Breeding, Henan Key Laboratory of Crop Molecular Breeding & Bioreactor, College of Life Science and Agronomy, Zhoukou Normal University, Zhoukou, 466001, Henan, China
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Nasr M, Timmins LR, Martin VJJ, Kwan DH. A Versatile Transcription Factor Biosensor System Responsive to Multiple Aromatic and Indole Inducers. ACS Synth Biol 2022; 11:1692-1698. [PMID: 35316041 PMCID: PMC9017570 DOI: 10.1021/acssynbio.2c00063] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Allosteric transcription factor (aTF) biosensors are valuable tools for engineering microbes toward a multitude of applications in metabolic engineering, biotechnology, and synthetic biology. One of the challenges toward constructing functional and diverse biosensors in engineered microbes is the limited toolbox of identified and characterized aTFs. To overcome this, extensive bioprospecting of aTFs from sequencing databases, as well as aTF ligand-specificity engineering are essential in order to realize their full potential as biosensors for novel applications. In this work, using the TetR-family repressor CmeR from Campylobacter jejuni, we construct aTF genetic circuits that function as salicylate biosensors in the model organisms Escherichia coli and Saccharomyces cerevisiae. In addition to salicylate, we demonstrate the responsiveness of CmeR-regulated promoters to multiple aromatic and indole inducers. This relaxed ligand specificity of CmeR makes it a useful tool for detecting molecules in many metabolic engineering applications, as well as a good target for directed evolution to engineer proteins that are able to detect new and diverse chemistries.
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Affiliation(s)
- Mohamed
A. Nasr
- Department
of Biology, Centre for Applied Synthetic Biology, and Centre for Structural
and Functional Genomics, Concordia University, Montréal, Quebec H4B 1R6, Canada
- PROTEO,
Quebec Network for Research on Protein Function, Structure, and Engineering, Québec City, Quebec G1 V 0A6, Canada
| | - Logan R. Timmins
- Department
of Biology, Centre for Applied Synthetic Biology, and Centre for Structural
and Functional Genomics, Concordia University, Montréal, Quebec H4B 1R6, Canada
- PROTEO,
Quebec Network for Research on Protein Function, Structure, and Engineering, Québec City, Quebec G1 V 0A6, Canada
| | - Vincent J. J. Martin
- Department
of Biology, Centre for Applied Synthetic Biology, and Centre for Structural
and Functional Genomics, Concordia University, Montréal, Quebec H4B 1R6, Canada
| | - David H. Kwan
- Department
of Biology, Centre for Applied Synthetic Biology, and Centre for Structural
and Functional Genomics, Concordia University, Montréal, Quebec H4B 1R6, Canada
- PROTEO,
Quebec Network for Research on Protein Function, Structure, and Engineering, Québec City, Quebec G1 V 0A6, Canada
- Department
of Chemistry and Biochemistry, Concordia
University, Montréal, Quebec H4B 1R6, Canada
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Kraxner KJ, Polen T, Baumgart M, Bott M. The conserved actinobacterial transcriptional regulator FtsR controls expression of ftsZ and further target genes and influences growth and cell division in Corynebacterium glutamicum. BMC Microbiol 2019; 19:179. [PMID: 31382874 PMCID: PMC6683498 DOI: 10.1186/s12866-019-1553-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/24/2019] [Indexed: 01/11/2023] Open
Abstract
Background Key mechanisms of cell division and its regulation are well understood in model bacteria such as Escherichia coli and Bacillus subtilis. In contrast, current knowledge on the regulation of cell division in Actinobacteria is rather limited. FtsZ is one of the key players in this process, but nothing is known about its transcriptional regulation in Corynebacterium glutamicum, a model organism of the Corynebacteriales. Results In this study, we used DNA affinity chromatography to search for transcriptional regulators of ftsZ in C. glutamicum and identified the Cg1631 protein as candidate, which was named FtsR. Both deletion and overexpression of ftsR caused growth defects and an altered cell morphology. Plasmid-based expression of native ftsR or of homologs of the pathogenic relatives Corynebacterium diphtheriae and Mycobacterium tuberculosis in the ΔftsR mutant could at least partially reverse the mutant phenotype. Absence of ftsR caused decreased expression of ftsZ, in line with an activator function of FtsR. In vivo crosslinking followed by affinity purification of FtsR and next generation sequencing of the enriched DNA fragments confirmed the ftsZ promoter as in vivo binding site of FtsR and revealed additional potential target genes and a DNA-binding motif. Analysis of strains expressing ftsZ under control of the gluconate-inducible gntK promoter revealed that the phenotype of the ΔftsR mutant is not solely caused by reduced ftsZ expression, but involves further targets. Conclusions In this study, we identified and characterized FtsR as the first transcriptional regulator of FtsZ described for C. glutamicum. Both the absence and the overproduction of FtsR had severe effects on growth and cell morphology, underlining the importance of this regulatory protein. FtsR and its DNA-binding site in the promoter region of ftsZ are highly conserved in Actinobacteria, which suggests that this regulatory mechanism is also relevant for the control of cell division in related Actinobacteria. Electronic supplementary material The online version of this article (10.1186/s12866-019-1553-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kim Julia Kraxner
- IBG-1: Biotechnology, Institute for Bio- und Geosciences, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Tino Polen
- IBG-1: Biotechnology, Institute for Bio- und Geosciences, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Meike Baumgart
- IBG-1: Biotechnology, Institute for Bio- und Geosciences, Forschungszentrum Jülich, 52425, Jülich, Germany.
| | - Michael Bott
- IBG-1: Biotechnology, Institute for Bio- und Geosciences, Forschungszentrum Jülich, 52425, Jülich, Germany.
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Ferraro G, Giorgio A, Mansour AM, Merlino A. Protein-mediated disproportionation of Au(i): insights from the structures of adducts of Au(iii) compounds bearingN,N-pyridylbenzimidazole derivatives with lysozyme. Dalton Trans 2019; 48:14027-14035. [DOI: 10.1039/c9dt02729g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Structural data of protein/gold adducts suggest protein-mediated reduction of Au(iii) into Au(i) and disproportionation of Au(i) into Au(iii) and Au(0).
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Affiliation(s)
- Giarita Ferraro
- Department of Chemistry “Ugo Schiff”
- University of Florence
- Sesto Fiorentino
- Italy
| | - Anna Giorgio
- Department of Chemical Sciences
- University of Naples Federico II
- Complesso Universitario di Monte Sant'Angelo
- Naples
- Italy
| | | | - Antonello Merlino
- Department of Chemical Sciences
- University of Naples Federico II
- Complesso Universitario di Monte Sant'Angelo
- Naples
- Italy
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Mycobacterium tuberculosis Rv1474c is a TetR-like transcriptional repressor that regulates aconitase, an essential enzyme and RNA-binding protein, in an iron-responsive manner. Tuberculosis (Edinb) 2017; 103:71-82. [PMID: 28237036 DOI: 10.1016/j.tube.2017.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 01/04/2017] [Accepted: 01/15/2017] [Indexed: 11/21/2022]
Abstract
Mycobacterium tuberculosis (M.tb), tuberculosis (TB) causing bacteria, employs several mechanisms to maintain iron homeostasis which is critical for its survival and pathogenesis. M.tb aconitase (Acn), a [4Fe-4S] cluster-containing essential protein, apart from participating in energy cycle, also binds to predicted iron-responsive RNA elements. In this study, we identified Rv1474c as a regulator of its operonic partner acn and carried out its biochemical and functional characterization. The binding motif for Rv1474c in the upstream region of acn (Rv1475c)-Rv1474c operon was verified by gel-shift assays. Reporter assays in E. coli followed by over-expression studies in mycobacteria, using both wild type and a DNA-binding defective mutant, demonstrated Rv1474c as a Tet-R like repressor of acn. Rv1474c, besides binding tetracycline, could also bind iron which negatively influenced its DNA binding activity. Further, a consistent decrease in the relative transcript levels of acn when M.tb was grown in iron-deficient conditions as compared to either normal or other stress conditions, indicated regulation of acn by Rv1474c in an iron-responsive manner in vivo. The absence of homologs in the human host and its association with indispensable iron homeostasis makes Rv1474c an attractive target for designing novel anti-mycobacterials.
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6
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Blancato VS, Pagliai FA, Magni C, Gonzalez CF, Lorca GL. Functional Analysis of the Citrate Activator CitO from Enterococcus faecalis Implicates a Divalent Metal in Ligand Binding. Front Microbiol 2016; 7:101. [PMID: 26903980 PMCID: PMC4746285 DOI: 10.3389/fmicb.2016.00101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 01/19/2016] [Indexed: 02/04/2023] Open
Abstract
The regulator of citrate metabolism, CitO, from Enterococcus faecalis belongs to the FCD family within the GntR superfamily. In the presence of citrate, CitO binds to cis-acting sequences located upstream of the cit promoters inducing the expression of genes involved in citrate utilization. The quantification of the molecular binding affinities, performed by isothermal titration calorimetry (ITC), indicated that CitO has a high affinity for citrate (KD = 1.2 ± 0.2 μM), while it did not recognize other metabolic intermediates. Based on a structural model of CitO where a putative small molecule and a metal binding site were identified, it was hypothesized that the metal ion is required for citrate binding. In agreement with this model, citrate binding to CitO sharply decreased when the protein was incubated with EDTA. This effect was reverted by the addition of Ni2+, and Zn2+ to a lesser extent. Structure-based site-directed mutagenesis was conducted and it was found that changes to alanine in residues Arg97 and His191 resulted in decreased binding affinities for citrate, as determined by EMSA and ITC. Further assays using lacZ fusions confirmed that these residues in CitO are involved in sensing citrate in vivo. These results indicate that the molecular modifications induced by a ligand and a metal binding in the C-terminal domain of CitO are required for optimal DNA binding activity, and consequently, transcriptional activation.
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Affiliation(s)
- Víctor S Blancato
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular de Rosario, Consejo Nacional de Investigaciones Científicas y TécnicasRosario, Argentina; Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Science, University of FloridaGainesville, FL, USA
| | - Fernando A Pagliai
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Science, University of Florida Gainesville, FL, USA
| | - Christian Magni
- Laboratorio de Fisiología y Genética de Bacterias Lácticas, Instituto de Biología Molecular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas Rosario, Argentina
| | - Claudio F Gonzalez
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Science, University of Florida Gainesville, FL, USA
| | - Graciela L Lorca
- Department of Microbiology and Cell Science, Genetics Institute, Institute of Food and Agricultural Science, University of Florida Gainesville, FL, USA
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7
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Otten A, Brocker M, Bott M. Metabolic engineering of Corynebacterium glutamicum for the production of itaconate. Metab Eng 2015; 30:156-165. [DOI: 10.1016/j.ymben.2015.06.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/23/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
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8
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Chopra T, Hamelin R, Armand F, Chiappe D, Moniatte M, McKinney JD. Quantitative mass spectrometry reveals plasticity of metabolic networks in Mycobacterium smegmatis. Mol Cell Proteomics 2014; 13:3014-28. [PMID: 24997995 DOI: 10.1074/mcp.m113.034082] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Mycobacterium tuberculosis has a remarkable ability to persist within the human host as a clinically inapparent or chronically active infection. Fatty acids are thought to be an important carbon source used by the bacteria during long term infection. Catabolism of fatty acids requires reprogramming of metabolic networks, and enzymes central to this reprogramming have been targeted for drug discovery. Mycobacterium smegmatis, a nonpathogenic relative of M. tuberculosis, is often used as a model system because of the similarity of basic cellular processes in these two species. Here, we take a quantitative proteomics-based approach to achieve a global view of how the M. smegmatis metabolic network adjusts to utilization of fatty acids as a carbon source. Two-dimensional liquid chromatography and mass spectrometry of isotopically labeled proteins identified a total of 3,067 proteins with high confidence. This number corresponds to 44% of the predicted M. smegmatis proteome and includes most of the predicted metabolic enzymes. Compared with glucose-grown cells, 162 proteins showed differential abundance in acetate- or propionate-grown cells. Among these, acetate-grown cells showed a higher abundance of proteins that could constitute a functional glycerate pathway. Gene inactivation experiments confirmed that both the glyoxylate shunt and the glycerate pathway are operational in M. smegmatis. In addition to proteins with annotated functions, we demonstrate carbon source-dependent differential abundance of proteins that have not been functionally characterized. These proteins might play as-yet-unidentified roles in mycobacterial carbon metabolism. This study reveals several novel features of carbon assimilation in M. smegmatis, which suggests significant functional plasticity of metabolic networks in this organism.
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Affiliation(s)
| | - Romain Hamelin
- ¶Proteomics Core Facility, Swiss Federal Institute of Technology in Lausanne, 1015 Lausanne, Switzerland
| | - Florence Armand
- ¶Proteomics Core Facility, Swiss Federal Institute of Technology in Lausanne, 1015 Lausanne, Switzerland
| | - Diego Chiappe
- ¶Proteomics Core Facility, Swiss Federal Institute of Technology in Lausanne, 1015 Lausanne, Switzerland
| | - Marc Moniatte
- ¶Proteomics Core Facility, Swiss Federal Institute of Technology in Lausanne, 1015 Lausanne, Switzerland
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Abstract
The most common prokaryotic signal transduction mechanisms are the one-component systems in which a single polypeptide contains both a sensory domain and a DNA-binding domain. Among the >20 classes of one-component systems, the TetR family of regulators (TFRs) are widely associated with antibiotic resistance and the regulation of genes encoding small-molecule exporters. However, TFRs play a much broader role, controlling genes involved in metabolism, antibiotic production, quorum sensing, and many other aspects of prokaryotic physiology. There are several well-established model systems for understanding these important proteins, and structural studies have begun to unveil the mechanisms by which they bind DNA and recognize small-molecule ligands. The sequences for more than 200,000 TFRs are available in the public databases, and genomics studies are identifying their target genes. Three-dimensional structures have been solved for close to 200 TFRs. Comparison of these structures reveals a common overall architecture of nine conserved α helices. The most important open question concerning TFR biology is the nature and diversity of their ligands and how these relate to the biochemical processes under their control.
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Baumgart M, Luder K, Grover S, Gätgens C, Besra GS, Frunzke J. IpsA, a novel LacI-type regulator, is required for inositol-derived lipid formation in Corynebacteria and Mycobacteria. BMC Biol 2013; 11:122. [PMID: 24377418 PMCID: PMC3899939 DOI: 10.1186/1741-7007-11-122] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/17/2013] [Indexed: 11/10/2022] Open
Abstract
Background The development of new drugs against tuberculosis and diphtheria is focused on disrupting the biogenesis of the cell wall, the unique architecture of which confers resistance against current therapies. The enzymatic pathways involved in the synthesis of the cell wall by these pathogens are well understood, but the underlying regulatory mechanisms are largely unknown. Results Here, we characterize IpsA, a LacI-type transcriptional regulator conserved among Mycobacteria and Corynebacteria that plays a role in the regulation of cell wall biogenesis. IpsA triggers myo-inositol formation by activating ino1, which encodes inositol phosphate synthase. An ipsA deletion mutant of Corynebacterium glutamicum cultured on glucose displayed significantly impaired growth and presented an elongated cell morphology. Further studies revealed the absence of inositol-derived lipids in the cell wall and a complete loss of mycothiol biosynthesis. The phenotype of the C. glutamicum ipsA deletion mutant was complemented to different extend by homologs from Corynebacterium diphtheriae (dip1969) and Mycobacterium tuberculosis (rv3575), indicating the conserved function of IpsA in the pathogenic species. Additional targets of IpsA with putative functions in cell wall biogenesis were identified and IpsA was shown to bind to a conserved palindromic motif within the corresponding promoter regions. Myo-inositol was identified as an effector of IpsA, causing the dissociation of the IpsA-DNA complex in vitro. Conclusions This characterization of IpsA function and of its regulon sheds light on the complex transcriptional control of cell wall biogenesis in the mycolata taxon and generates novel targets for drug development.
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Affiliation(s)
| | | | | | | | | | - Julia Frunzke
- Institut für Bio- und Geowissenschaften, IBG-1: Biotechnologie, Forschungszentrum Jülich, 52425 Jülich, Germany.
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