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Hoan TD, Thao DT, Huong Giang NT, Thuong BT, Thu Huyen NT, Nguyen ND, Hoai Thu VT, Khanh Linh NT, Dung NV, Hiroshi K, Van Phan L, Tuan Anh MN. Molecular Identification and Pathogenicity of Novel Duck-Origin Goose Parvovirus Isolated from Beak Atrophy and Dwarfism Syndrome of Waterfowls in the North of Vietnam. Avian Dis 2022; 66:1-12. [PMID: 36106907 DOI: 10.1637/aviandiseases-d-21-00087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 05/19/2022] [Indexed: 12/14/2022]
Abstract
The aim of this study is to identify and characterize virus isolates (which are named for Bacgiang Agriculture and Forestry University [BAFU]) from diseased Cherry Valley duck and mule duck flocks and investigate the damage caused by a novel parvovirus-related virus (DuPV) to tissues and organs, including the brain, cerebellum, kidney, liver, lung, spleen, and spinal cord. The results of phylogenetic analysis show that DuPV-BAFU evolved from a goose lineage and duck parvoviruses rather than from Muscovy duck parvoviruses. In the genetic lineages, DuPVs were identified from the DuPV samples analyzed, and DuPV-BAFU was found to be closely clustered with two known goose origin parvoviruses (GPVa2006 and GPV1995) and a duck GPVs. Finally, structural modeling revealed that DuPV-BAFU and the closely related viruses GPVa2006 and GPV1995 possessed identical clusters of receptor-interacting amino acid residues in the VP3 protein, a major determinant of viral receptor binding and host specificity. Significantly, these three viruses differed from DuPVs, Muscovy duck parvoviruses, and other goose parvoviruses at these positions. These results also demonstrated that DuPV-BAFU represents a new variant of goose-origin parvovirus that currently circulates in ducklings and causes beak atrophy and dwarfism syndrome, as noted in the previous reports in Europe, Taiwan, and China. This new finding highlights the need for future surveillance of DuPV-BAFU in waterfowl in order to gain a better understanding of both the evolution and the biology of this emerging parvovirus in waterfowl.
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Affiliation(s)
- Tran Duc Hoan
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam,
| | - Doan Thi Thao
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Nguyen Thi Huong Giang
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Bui Thi Thuong
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Nguyen Thi Thu Huyen
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Nguyen Dinh Nguyen
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Vu Thi Hoai Thu
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Nguyen Thi Khanh Linh
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Nguyen Viet Dung
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam
| | - Kondo Hiroshi
- Faculty of Animal Science and Veterinary Medicine, Bacgiang Agriculture and Forestry University, Bắc Giang, Vietnam.,Senior volunteer of Japanese International Cooperation Agency (JICA), Tokyo, Japan
| | - Le Van Phan
- Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hà Nội, Vietnam
| | - Mai Nguyen Tuan Anh
- Faculty of Veterinary Medicine, Vietnam National University of Agriculture, Hà Nội, Vietnam
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Roesel AF, Ugandi M, Huyen NTT, Májek M, Broese T, Roemelt M, Francke R. Electrochemically Catalyzed Newman-Kwart Rearrangement: Mechanism, Structure-Reactivity Relationship, and Parallels to Photoredox Catalysis. J Org Chem 2020; 85:8029-8044. [PMID: 32456428 DOI: 10.1021/acs.joc.0c00831] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The facilitation of redox-neutral reactions by electrochemical injection of holes and electrons, also known as "electrochemical catalysis", is a little explored approach that has the potential to expand the scope of electrosynthesis immensely. To systematically improve existing protocols and to pave the way toward new developments, a better understanding of the underlying principles is crucial. In this context, we have studied the Newman-Kwart rearrangement of O-arylthiocarbamates to the corresponding S-aryl derivatives, the key step in the synthesis of thiophenols from the corresponding phenols. This transformation is a particularly useful example because the conventional method requires temperatures up to 300 °C, whereas electrochemical catalysis facilitates the reaction at room temperature. A combined experimental-quantum chemical approach revealed several reaction channels and rendered an explanation for the relationship between the structure and reactivity. Furthermore, it is shown how rapid cyclic voltammetry measurements can serve as a tool to predict the feasibility for specific substrates. The study also revealed distinct parallels to photoredox-catalyzed reactions, in which back-electron transfer and chain propagation are competing pathways.
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Affiliation(s)
- Arend F Roesel
- Institute of Chemistry, Rostock University, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
| | - Mihkel Ugandi
- Chair for Theoretical Chemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Nguyen Thi Thu Huyen
- Institute of Chemistry, Rostock University, Albert-Einstein-Str. 3a, 18059 Rostock, Germany.,School of Chemical Engineering, Hanoi University of Science and Technology, 1 Dai Co Viet Road, Hanoi, Vietnam
| | - Michal Májek
- Institute of Chemistry, Rostock University, Albert-Einstein-Str. 3a, 18059 Rostock, Germany.,Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská Dolina, Ilkovičova 6, 84215 Bratislava, Slovakia
| | - Timo Broese
- Institute of Chemistry, Rostock University, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
| | - Michael Roemelt
- Chair for Theoretical Chemistry, Ruhr-University Bochum, 44780 Bochum, Germany
| | - Robert Francke
- Institute of Chemistry, Rostock University, Albert-Einstein-Str. 3a, 18059 Rostock, Germany
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Loi VV, Huyen NTT, Busche T, Tung QN, Gruhlke MCH, Kalinowski J, Bernhardt J, Slusarenko AJ, Antelmann H. Staphylococcus aureus responds to allicin by global S-thioallylation - Role of the Brx/BSH/YpdA pathway and the disulfide reductase MerA to overcome allicin stress. Free Radic Biol Med 2019; 139:55-69. [PMID: 31121222 DOI: 10.1016/j.freeradbiomed.2019.05.018] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/08/2019] [Accepted: 05/15/2019] [Indexed: 12/12/2022]
Abstract
The prevalence of methicillin-resitant Staphylococcus aureus (MRSA) in hospitals and the community poses an increasing health burden, which requires the discovery of alternative antimicrobials. Allicin (diallyl thiosulfinate) from garlic exhibits broad-spectrum antimicrobial activity against many multidrug resistant bacteria. The thiol-reactive mode of action of allicin involves its S-thioallylations of low molecular weight (LMW) thiols and protein thiols. To investigate the mode of action and stress response caused by allicin in S. aureus, we analyzed the transcriptome signature, the targets for S-thioallylation in the proteome and the changes in the bacillithiol (BSH) redox potential (EBSH) under allicin stress. Allicin caused a strong thiol-specific oxidative and sulfur stress response and protein damage as revealed by the induction of the PerR, HypR, QsrR, MhqR, CstR, CtsR, HrcA and CymR regulons in the RNA-seq transcriptome. Allicin also interfered with metal and cell wall homeostasis and caused induction of the Zur, CsoR and GraRS regulons. Brx-roGFP2 biosensor measurements revealed a strongly increased EBSH under allicin stress. In the proteome, 57 proteins were identified with S-thioallylations under allicin treatment, including translation factors (EF-Tu, EF-Ts), metabolic and redox enzymes (AldA, GuaB, Tpx, KatA, BrxA, MsrB) as well as redox-sensitive MarR/SarA-family regulators (MgrA, SarA, SarH1, SarS). Phenotype and biochemical analyses revealed that BSH and the HypR-controlled disulfide reductase MerA are involved in allicin detoxification in S. aureus. The reversal of protein S-thioallylation was catalyzed by the Brx/BSH/YpdA pathway. Finally, the BSSB reductase YpdA was shown to use S-allylmercaptobacillithiol (BSSA) as substrate to regenerate BSH in S. aureus. In conclusion, allicin results in an oxidative shift of EBSH and protein S-thioallylation, which can be reversed by YpdA and the Brx/BSH/YpdA electron pathways in S. aureus to regenerate thiol homeostasis.
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Affiliation(s)
- Vu Van Loi
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195, Berlin, Germany
| | - Nguyen Thi Thu Huyen
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195, Berlin, Germany
| | - Tobias Busche
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195, Berlin, Germany; Center for Biotechnology, Bielefeld University, D-33594, Bielefeld, Germany
| | - Quach Ngoc Tung
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195, Berlin, Germany
| | | | - Jörn Kalinowski
- Center for Biotechnology, Bielefeld University, D-33594, Bielefeld, Germany
| | - Jörg Bernhardt
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195, Berlin, Germany; Institute for Microbiology, University of Greifswald, D-17489, Greifswald, Germany
| | - Alan John Slusarenko
- Department of Plant Physiology, RWTH Aachen University, D-52056, Aachen, Germany
| | - Haike Antelmann
- Freie Universität Berlin, Institute for Biology-Microbiology, D-14195, Berlin, Germany.
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Loi VV, Busche T, Tedin K, Bernhardt J, Wollenhaupt J, Huyen NTT, Weise C, Kalinowski J, Wahl MC, Fulde M, Antelmann H. Redox-Sensing Under Hypochlorite Stress and Infection Conditions by the Rrf2-Family Repressor HypR in Staphylococcus aureus. Antioxid Redox Signal 2018; 29:615-636. [PMID: 29237286 PMCID: PMC6067689 DOI: 10.1089/ars.2017.7354] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIMS Staphylococcus aureus is a major human pathogen and has to cope with reactive oxygen and chlorine species (ROS, RCS) during infections, which requires efficient protection mechanisms to avoid destruction. Here, we have investigated the changes in the RNA-seq transcriptome by the strong oxidant sodium hypochlorite (NaOCl) in S. aureus USA300 to identify novel redox-sensing mechanisms that provide protection under infection conditions. RESULTS NaOCl stress caused an oxidative stress response in S. aureus as indicated by the induction of the PerR, QsrR, HrcA, and SigmaB regulons in the RNA-seq transcriptome. The hypR-merA (USA300HOU_0588-87) operon was most strongly upregulated under NaOCl stress, which encodes for the Rrf2-family regulator HypR and the pyridine nucleotide disulfide reductase MerA. We have characterized HypR as a novel redox-sensitive repressor that controls MerA expression and directly senses and responds to NaOCl and diamide stress via a thiol-based mechanism in S. aureus. Mutational analysis identified Cys33 and the conserved Cys99 as essential for NaOCl sensing, while Cys99 is also important for repressor activity of HypR in vivo. The redox-sensing mechanism of HypR involves Cys33-Cys99 intersubunit disulfide formation by NaOCl stress both in vitro and in vivo. Moreover, the HypR-controlled flavin disulfide reductase MerA was shown to protect S. aureus against NaOCl stress and increased survival in J774A.1 macrophage infection assays. Conclusion and Innovation: Here, we identified a new member of the widespread Rrf2 family as redox sensor of NaOCl stress in S. aureus that uses a thiol/disulfide switch to regulate defense mechanisms against the oxidative burst under infections in S. aureus. Antioxid. Redox Signal. 29, 615-636.
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Affiliation(s)
- Vu Van Loi
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Tobias Busche
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany .,2 Center for Biotechnology, Bielefeld University , Bielefeld, Germany
| | - Karsten Tedin
- 3 Centre for Infection Medicine, Institute of Microbiology and Epizootics , Freie Universität Berlin, Berlin, Germany
| | - Jörg Bernhardt
- 4 Institute for Microbiology, Ernst-Moritz-Arndt-University of Greifswald , Greifswald, Germany
| | - Jan Wollenhaupt
- 5 Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Nguyen Thi Thu Huyen
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Christoph Weise
- 6 Institute of Chemistry and Biochemistry , Freie Universität Berlin, Berlin, Germany
| | - Jörn Kalinowski
- 2 Center for Biotechnology, Bielefeld University , Bielefeld, Germany
| | - Markus C Wahl
- 5 Laboratory of Structural Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Marcus Fulde
- 3 Centre for Infection Medicine, Institute of Microbiology and Epizootics , Freie Universität Berlin, Berlin, Germany
| | - Haike Antelmann
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
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Imber M, Huyen NTT, Pietrzyk-Brzezinska AJ, Loi VV, Hillion M, Bernhardt J, Thärichen L, Kolšek K, Saleh M, Hamilton CJ, Adrian L, Gräter F, Wahl MC, Antelmann H. Protein S-Bacillithiolation Functions in Thiol Protection and Redox Regulation of the Glyceraldehyde-3-Phosphate Dehydrogenase Gap in Staphylococcus aureus Under Hypochlorite Stress. Antioxid Redox Signal 2018; 28:410-430. [PMID: 27967218 PMCID: PMC5791933 DOI: 10.1089/ars.2016.6897] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
AIMS Bacillithiol (BSH) is the major low-molecular-weight thiol of the human pathogen Staphylococcus aureus. In this study, we used OxICAT and Voronoi redox treemaps to quantify hypochlorite-sensitive protein thiols in S. aureus USA300 and analyzed the role of BSH in protein S-bacillithiolation. RESULTS The OxICAT analyses enabled the quantification of 228 Cys residues in the redox proteome of S. aureus USA300. Hypochlorite stress resulted in >10% increased oxidation of 58 Cys residues (25.4%) in the thiol redox proteome. Among the highly oxidized sodium hypochlorite (NaOCl)-sensitive proteins are five S-bacillithiolated proteins (Gap, AldA, GuaB, RpmJ, and PpaC). The glyceraldehyde-3-phosphate (G3P) dehydrogenase Gap represents the most abundant S-bacillithiolated protein contributing 4% to the total Cys proteome. The active site Cys151 of Gap was very sensitive to overoxidation and irreversible inactivation by hydrogen peroxide (H2O2) or NaOCl in vitro. Treatment with H2O2 or NaOCl in the presence of BSH resulted in reversible Gap inactivation due to S-bacillithiolation, which could be regenerated by the bacilliredoxin Brx (SAUSA300_1321) in vitro. Molecular docking was used to model the S-bacillithiolated Gap active site, suggesting that formation of the BSH mixed disulfide does not require major structural changes. Conclusion and Innovation: Using OxICAT analyses, we identified 58 novel NaOCl-sensitive proteins in the pathogen S. aureus that could play protective roles against the host immune defense and include the glycolytic Gap as major target for S-bacillithiolation. S-bacillithiolation of Gap did not require structural changes, but efficiently functions in redox regulation and protection of the active site against irreversible overoxidation in S. aureus. Antioxid. Redox Signal. 28, 410-430.
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Affiliation(s)
- Marcel Imber
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Nguyen Thi Thu Huyen
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | | | - Vu Van Loi
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Melanie Hillion
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Jörg Bernhardt
- 3 Institute for Microbiology , Ernst-Moritz-Arndt-Universität of Greifswald, Greifswald, Germany
| | - Lena Thärichen
- 4 Molecular Biomechanics, Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University , Heidelberg, Germany .,5 Heidelberg Institute of Theoretical Studies , Heidelberg, Germany
| | - Katra Kolšek
- 5 Heidelberg Institute of Theoretical Studies , Heidelberg, Germany
| | - Malek Saleh
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Chris J Hamilton
- 6 School of Pharmacy, University of East Anglia , Norwich Research Park, Norwich, United Kingdom
| | - Lorenz Adrian
- 7 Department Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ , Leipzig, Germany
| | - Frauke Gräter
- 4 Molecular Biomechanics, Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University , Heidelberg, Germany .,5 Heidelberg Institute of Theoretical Studies , Heidelberg, Germany
| | - Markus C Wahl
- 2 Laboratory of Structural Biochemistry, Freie Universität Berlin , Berlin, Germany
| | - Haike Antelmann
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
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Loi VV, Harms M, Müller M, Huyen NTT, Hamilton CJ, Hochgräfe F, Pané-Farré J, Antelmann H. Real-Time Imaging of the Bacillithiol Redox Potential in the Human Pathogen Staphylococcus aureus Using a Genetically Encoded Bacilliredoxin-Fused Redox Biosensor. Antioxid Redox Signal 2017; 26:835-848. [PMID: 27462976 PMCID: PMC5444506 DOI: 10.1089/ars.2016.6733] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AIMS Bacillithiol (BSH) is utilized as a major thiol-redox buffer in the human pathogen Staphylococcus aureus. Under oxidative stress, BSH forms mixed disulfides with proteins, termed as S-bacillithiolation, which can be reversed by bacilliredoxins (Brx). In eukaryotes, glutaredoxin-fused roGFP2 biosensors have been applied for dynamic live imaging of the glutathione redox potential. Here, we have constructed a genetically encoded bacilliredoxin-fused redox biosensor (Brx-roGFP2) to monitor dynamic changes in the BSH redox potential in S. aureus. RESULTS The Brx-roGFP2 biosensor showed a specific and rapid response to low levels of bacillithiol disulfide (BSSB) in vitro that required the active-site Cys of Brx. Dynamic live imaging in two methicillin-resistant S. aureus (MRSA) USA300 and COL strains revealed fast and dynamic responses of the Brx-roGFP2 biosensor under hypochlorite and hydrogen peroxide (H2O2) stress and constitutive oxidation of the probe in different BSH-deficient mutants. Furthermore, we found that the Brx-roGFP2 expression level and the dynamic range are higher in S. aureus COL compared with the USA300 strain. In phagocytosis assays with THP-1 macrophages, the biosensor was 87% oxidized in S. aureus COL. However, no changes in the BSH redox potential were measured after treatment with different antibiotics classes, indicating that antibiotics do not cause oxidative stress in S. aureus. Conclusion and Innovation: This Brx-roGFP2 biosensor catalyzes specific equilibration between the BSH and roGFP2 redox couples and can be applied for dynamic live imaging of redox changes in S. aureus and other BSH-producing Firmicutes. Antioxid. Redox Signal. 26, 835-848.
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Affiliation(s)
- Vu Van Loi
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Manuela Harms
- 2 Junior Research Group Pathoproteomics, Ernst-Moritz-Arndt-University of Greifswald , Greifswald, Germany
| | - Marret Müller
- 3 Institute for Microbiology, Ernst-Moritz-Arndt-University of Greifswald , Greifswald, Germany
| | - Nguyen Thi Thu Huyen
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
| | - Chris J Hamilton
- 4 School of Pharmacy, University of East Anglia , Norwich Research Park, Norwich, United Kingdom
| | - Falko Hochgräfe
- 2 Junior Research Group Pathoproteomics, Ernst-Moritz-Arndt-University of Greifswald , Greifswald, Germany
| | - Jan Pané-Farré
- 3 Institute for Microbiology, Ernst-Moritz-Arndt-University of Greifswald , Greifswald, Germany
| | - Haike Antelmann
- 1 Institute for Biology-Microbiology, Freie Universität Berlin , Berlin, Germany
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Leelakriangsak M, Huyen NTT, Töwe S, van Duy N, Becher D, Hecker M, Antelmann H, Zuber P. Regulation of quinone detoxification by the thiol stress sensing DUF24/MarR-like repressor, YodB in Bacillus subtilis. Mol Microbiol 2008; 67:1108-24. [PMID: 18208493 DOI: 10.1111/j.1365-2958.2008.06110.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently, we showed that the MarR-type repressor YkvE (MhqR) regulates multiple dioxygenases/glyoxalases, oxidoreductases and the azoreductase encoding yvaB (azoR2) gene in response to thiol-specific stress conditions, such as diamide, catechol and 2-methylhydroquinone (MHQ). Here we report on the regulation of the yocJ (azoR1) gene encoding another azoreductase by the novel DUF24/MarR-type repressor, YodB after exposure to thiol-reactive compounds. DNA binding activity of YodB is directly inhibited by thiol-reactive compounds in vitro. Mass spectrometry identified YodB-Cys-S-adducts that are formed upon exposure of YodB to MHQ and catechol in vitro. This confirms that catechol and MHQ are auto-oxidized to toxic ortho- and para-benzoquinones which act like diamide as thiol-reactive electrophiles. Mutational analyses further showed that the conserved Cys6 residue of YodB is required for optimal repression in vivo and in vitro while substitution of all three Cys residues of YodB affects induction of azoR1 transcription. Finally, phenotype analyses revealed that both azoreductases, AzoR1 and AzoR2 confer resistance to catechol, MHQ, 1,4-benzoquinone and diamide. Thus, both azoreductases that are controlled by different regulatory mechanisms have common functions in quinone and azo-compound reduction to protect cells against the thiol reactivity of electrophiles.
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Affiliation(s)
- Montira Leelakriangsak
- Department of Environmental and Biomolecular Systems, OGI School of Science and Engineering, Oregon Health and Science University, Beaverton, OR, USA
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