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Verschueren KHG, Dodson EJ, Wilkinson AJ. The Structure of the LysR-type Transcriptional Regulator, CysB, Bound to the Inducer, N-acetylserine. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2024; 53:311-326. [PMID: 38976018 PMCID: PMC11329422 DOI: 10.1007/s00249-024-01716-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Accepted: 06/18/2024] [Indexed: 07/09/2024]
Abstract
In Escherichia coli and Salmonella typhimurium, cysteine biosynthesis requires the products of 20 or more cys genes co-ordinately regulated by CysB. Under conditions of sulphur limitation and in the presence of the inducer, N-acetylserine, CysB binds to cys promoters and activates the transcription of the downstream coding sequences. CysB is a homotetramer, comprising an N-terminal DNA binding domain (DBD) and a C-terminal effector binding domain (EBD). The crystal structure of a dimeric EBD fragment of CysB from Klebsiella aerogenes revealed a protein fold similar to that seen in Lac repressor but with a different symmetry in the dimer so that the mode of DNA binding was not apparent. To elucidate the subunit arrangement in the tetramer, we determined the crystal structure of intact CysB in complex with N-acetylserine. The tetramer has two subunit types that differ in the juxtaposition of their winged helix-turn-helix DNA binding domains with respect to the effector binding domain. In the assembly, the four EBDs form a core with the DNA binding domains arranged in pairs on the surface. N-acetylserine makes extensive polar interactions in an enclosed binding site, and its binding is accompanied by substantial conformational rearrangements of surrounding residues that are propagated to the protein surface where they appear to alter the arrangement of the DNA binding domains. The results are (i) discussed in relation to the extensive mutational data available for CysB and (ii) used to propose a structural mechanism of N-acetylserine induced CysB activation.
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Affiliation(s)
- Koen H G Verschueren
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK
- Unit for Structural Biology, VIB Center for Inflammation Research, Ghent, Belgium; Unit for Structural Biology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Eleanor J Dodson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK
| | - Anthony J Wilkinson
- York Structural Biology Laboratory, Department of Chemistry, University of York, York, YO10 5DD, UK.
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2
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Mori H, Matsui M, Bamba T, Hori Y, Kitamura S, Toya Y, Hidese R, Yasueda H, Hasunuma T, Shimizu H, Taoka N, Kobayashi S. Engineering Escherichia coli for efficient glutathione production. Metab Eng 2024; 84:180-190. [PMID: 38969164 DOI: 10.1016/j.ymben.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 06/06/2024] [Accepted: 07/02/2024] [Indexed: 07/07/2024]
Abstract
Glutathione is a tripeptide of excellent value in the pharmaceutical, food, and cosmetic industries that is currently produced during yeast fermentation. In this case, glutathione accumulates intracellularly, which hinders high production. Here, we engineered Escherichia coli for the efficient production of glutathione. A total of 4.3 g/L glutathione was produced by overexpressing gshA and gshB, which encode cysteine glutamate ligase and glutathione synthetase, respectively, and most of the glutathione was excreted into the culture medium. Further improvements were achieved by inhibiting degradation (Δggt and ΔpepT); deleting gor (Δgor), which encodes glutathione oxide reductase; attenuating glutathione uptake (ΔyliABCD); and enhancing cysteine production (PompF-cysE). The engineered strain KG06 produced 19.6 g/L glutathione after 48 h of fed-batch fermentation with continuous addition of ammonium sulfate as the sulfur source. We also found that continuous feeding of glycine had a crucial role for effective glutathione production. The results of metabolic flux and metabolomic analyses suggested that the conversion of O-acetylserine to cysteine is the rate-limiting step in glutathione production by KG06. The use of sodium thiosulfate largely overcame this limitation, increasing the glutathione titer to 22.0 g/L, which is, to our knowledge, the highest titer reported to date in the literature. This study is the first report of glutathione fermentation without adding cysteine in E. coli. Our findings provide a great potential of E. coli fermentation process for the industrial production of glutathione.
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Affiliation(s)
- Hiroki Mori
- Agri-Bio Research Center, KANEKA CORPORATION, 1-8, Miyamae-cho, Takasago-cho, Takasago, Hyogo, 676-8688, Japan
| | - Misato Matsui
- Agri-Bio Research Center, KANEKA CORPORATION, 1-8, Miyamae-cho, Takasago-cho, Takasago, Hyogo, 676-8688, Japan
| | - Takahiro Bamba
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Yoshimi Hori
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Sayaka Kitamura
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Toya
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ryota Hidese
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan
| | - Hisashi Yasueda
- Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan; Research and Development Center for Precision Medicine, University of Tsukuba, 1-2 Kasuga, Tsukuba-shi, Ibaraki, 305-8550, Japan
| | - Tomohisa Hasunuma
- Engineering Biology Research Center, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan; Graduate School of Science, Technology and Innovation, Kobe University, 1-1 Rokkodai, Nada, Kobe, 657-8501, Japan; RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Hiroshi Shimizu
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Naoaki Taoka
- Agri-Bio Research Center, KANEKA CORPORATION, 1-8, Miyamae-cho, Takasago-cho, Takasago, Hyogo, 676-8688, Japan
| | - Shingo Kobayashi
- Agri-Bio Research Center, KANEKA CORPORATION, 1-8, Miyamae-cho, Takasago-cho, Takasago, Hyogo, 676-8688, Japan.
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Pedretti M, Fernández-Rodríguez C, Conter C, Oyenarte I, Favretto F, di Matteo A, Dominici P, Petrosino M, Martinez-Chantar ML, Majtan T, Astegno A, Martínez-Cruz LA. Catalytic specificity and crystal structure of cystathionine γ-lyase from Pseudomonas aeruginosa. Sci Rep 2024; 14:9364. [PMID: 38654065 PMCID: PMC11039470 DOI: 10.1038/s41598-024-57625-7] [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: 01/16/2024] [Accepted: 03/20/2024] [Indexed: 04/25/2024] Open
Abstract
The escalating drug resistance among microorganisms underscores the urgent need for innovative therapeutic strategies and a comprehensive understanding of bacteria's defense mechanisms against oxidative stress and antibiotics. Among the recently discovered barriers, the endogenous production of hydrogen sulfide (H2S) via the reverse transsulfuration pathway, emerges as a noteworthy factor. In this study, we have explored the catalytic capabilities and crystal structure of cystathionine γ-lyase from Pseudomonas aeruginosa (PaCGL), a multidrug-opportunistic pathogen chiefly responsible for nosocomial infections. In addition to a canonical L-cystathionine hydrolysis, PaCGL efficiently catalyzes the production of H2S using L-cysteine and/or L-homocysteine as alternative substrates. Comparative analysis with the human enzyme and counterparts from other pathogens revealed distinct structural features within the primary enzyme cavities. Specifically, a distinctly folded entrance loop could potentially modulate the access of substrates and/or inhibitors to the catalytic site. Our findings offer significant insights into the structural evolution of CGL enzymes across different pathogens and provide novel opportunities for developing specific inhibitors targeting PaCGL.
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Affiliation(s)
- Marco Pedretti
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Carmen Fernández-Rodríguez
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain
| | - Carolina Conter
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain
| | - Iker Oyenarte
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain
| | - Filippo Favretto
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Adele di Matteo
- CNR Institute of Molecular Biology and Pathology, P.le Aldo Moro 5, 00185, Rome, Italy
| | - Paola Dominici
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy
| | - Maria Petrosino
- Department of Pharmacology, Faculty of Science and Medicine, University of Fribourg, Chemin du Musee 18, Bldg. PER17, 1700, Fribourg, FR, Switzerland
| | - Maria Luz Martinez-Chantar
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Santander, Spain
| | - Tomas Majtan
- Department of Pharmacology, Faculty of Science and Medicine, University of Fribourg, Chemin du Musee 18, Bldg. PER17, 1700, Fribourg, FR, Switzerland
| | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134, Verona, Italy.
| | - Luis Alfonso Martínez-Cruz
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160, Derio, Spain.
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Smirnova G, Tyulenev A, Sutormina L, Kalashnikova T, Muzyka N, Ushakov V, Samoilova Z, Oktyabrsky O. Regulation of Cysteine Homeostasis and Its Effect on Escherichia coli Sensitivity to Ciprofloxacin in LB Medium. Int J Mol Sci 2024; 25:4424. [PMID: 38674008 PMCID: PMC11050555 DOI: 10.3390/ijms25084424] [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: 03/28/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Cysteine and its derivatives, including H2S, can influence bacterial virulence and sensitivity to antibiotics. In minimal sulfate media, H2S is generated under stress to prevent excess cysteine and, together with incorporation into glutathione and export into the medium, is a mechanism of cysteine homeostasis. Here, we studied the features of cysteine homeostasis in LB medium, where the main source of sulfur is cystine, whose import can create excess cysteine inside cells. We used mutants in the mechanisms of cysteine homeostasis and a set of microbiological and biochemical methods, including the real-time monitoring of sulfide and oxygen, the determination of cysteine and glutathione (GSH), and the expression of the Fur, OxyR, and SOS regulons genes. During normal growth, the parental strain generated H2S when switching respiration to another substrate. The mutations affected the onset time, the intensity and duration of H2S production, cysteine and glutathione levels, bacterial growth and respiration rates, and the induction of defense systems. Exposure to chloramphenicol and high doses of ciprofloxacin increased cysteine content and GSH synthesis. A high inverse relationship between log CFU/mL and bacterial growth rate before ciprofloxacin addition was revealed. The study points to the important role of maintaining cysteine homeostasis during normal growth and antibiotic exposure in LB medium.
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Affiliation(s)
- Galina Smirnova
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, Goleva 13, 614081 Perm, Russia; (A.T.); (L.S.); (T.K.); (N.M.); (V.U.); (Z.S.); (O.O.)
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5
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Vazulka S, Schiavinato M, Tauer C, Wagenknecht M, Cserjan-Puschmann M, Striedner G. RNA-seq reveals multifaceted gene expression response to Fab production in Escherichia coli fed-batch processes with particular focus on ribosome stalling. Microb Cell Fact 2024; 23:14. [PMID: 38183013 PMCID: PMC10768439 DOI: 10.1186/s12934-023-02278-w] [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: 10/12/2023] [Accepted: 12/18/2023] [Indexed: 01/07/2024] Open
Abstract
BACKGROUND Escherichia coli is a cost-effective expression system for production of antibody fragments like Fabs. Various yield improvement strategies have been applied, however, Fabs remain challenging to produce. This study aimed to characterize the gene expression response of commonly used E. coli strains BL21(DE3) and HMS174(DE3) to periplasmic Fab expression using RNA sequencing (RNA-seq). Two Fabs, Fabx and FTN2, fused to a post-translational translocation signal sequence, were produced in carbon-limited fed-batch cultivations. RESULTS Production of Fabx impeded cell growth substantially stronger than FTN2 and yields of both Fabs differed considerably. The most noticeable, common changes in Fab-producing cells suggested by our RNA-seq data concern the cell envelope. The Cpx and Psp stress responses, both connected to inner membrane integrity, were activated, presumably by recombinant protein aggregation and impairment of the Sec translocon. The data additionally suggest changes in lipopolysaccharide synthesis, adjustment of membrane permeability, and peptidoglycan maturation and remodeling. Moreover, all Fab-producing strains showed depletion of Mg2+, indicated by activation of the PhoQP two-component signal transduction system during the early stage and sulfur and phosphate starvation during the later stage of the process. Furthermore, our data revealed ribosome stalling, caused by the Fabx amino acid sequence, as a contributor to low Fabx yields. Increased Fabx yields were obtained by a site-specific amino acid exchange replacing the stalling sequence. Contrary to expectations, cell growth was not impacted by presence or removal of the stalling sequence. Considering ribosome rescue is a conserved mechanism, the substantial differences observed in gene expression between BL21(DE3) and HMS174(DE3) in response to ribosome stalling on the recombinant mRNA were surprising. CONCLUSIONS Through characterization of the gene expression response to Fab production under industrially relevant cultivation conditions, we identified potential cell engineering targets. Thereby, we hope to enable rational approaches to improve cell fitness and Fab yields. Furthermore, we highlight ribosome stalling caused by the amino acid sequence of the recombinant protein as a possible challenge during recombinant protein production.
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Affiliation(s)
- Sophie Vazulka
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Matteo Schiavinato
- Department of Biotechnology, Institute of Computational Biology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Christopher Tauer
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
| | - Martin Wagenknecht
- Boehringer Ingelheim RCV, GmbH & Co KG, Dr.-Boehringer-Gasse 5-11, A-1120, Vienna, Austria
| | - Monika Cserjan-Puschmann
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria.
| | - Gerald Striedner
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 18, 1190, Vienna, Austria
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Sepúlveda-Rebolledo P, González-Rosales C, Dopson M, Pérez-Rueda E, Holmes DS, Valdés JH. Comparative genomics sheds light on transcription factor-mediated regulation in the extreme acidophilic Acidithiobacillia representatives. Res Microbiol 2024; 175:104135. [PMID: 37678513 DOI: 10.1016/j.resmic.2023.104135] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 09/09/2023]
Abstract
Extreme acidophiles thrive in acidic environments, confront a multitude of challenges, and demonstrate remarkable adaptability in their metabolism to cope with the ever-changing environmental fluctuations, which encompass variations in temperature, pH levels, and the availability of electron acceptors and donors. The survival and proliferation of members within the Acidithiobacillia class rely on the deployment of transcriptional regulatory systems linked to essential physiological traits. The study of these transcriptional regulatory systems provides valuable insights into critical processes, such as energy metabolism and nutrient assimilation, and how they integrate into major genetic-metabolic circuits. In this study, we examined the transcriptional regulatory repertoires and potential interactions of forty-three Acidithiobacillia complete and draft genomes, encompassing nine species. To investigate the function and diversity of Transcription Factors (TFs) and their DNA Binding Sites (DBSs), we conducted a genome-wide comparative analysis, which allowed us to identify these regulatory elements in representatives of Acidithiobacillia. We classified TFs into gene families and compared their occurrence among all representatives, revealing conservation patterns across the class. The results identified conserved regulators for several pathways, including iron and sulfur oxidation, the main pathways for energy acquisition, providing new evidence for viable regulatory interactions and branch-specific conservation in Acidithiobacillia. The identification of TFs and DBSs not only corroborates existing experimental information for selected species, but also introduces novel candidates for experimental validation. Moreover, these promising candidates have the potential for further extension to new representatives within the class.
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Affiliation(s)
- Pedro Sepúlveda-Rebolledo
- Centro de Genómica y Bioinformática and PhD. Program on Integrative Genomics, Facultad de Ciencias, Universidad Mayor, Santiago (8580745), Chile.
| | - Carolina González-Rosales
- Center for Bioinformatics and Genome Biology, Fundación Ciencia & Vida, Santiago (8580638), Chile; Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, SE-391 82 Kalmar, Sweden.
| | - Mark Dopson
- Centre for Ecology and Evolution in Microbial Model Systems, Linnaeus University, SE-391 82 Kalmar, Sweden.
| | - Ernesto Pérez-Rueda
- Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Unidad Académica del Estado de Yucatán, Mérida, Yucatán, Mexico.
| | - David S Holmes
- Center for Bioinformatics and Genome Biology, Fundación Ciencia & Vida, Santiago (8580638), Chile; Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago (7510156), Chile.
| | - Jorge H Valdés
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago (8370146), Chile.
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Yang H, Zhang B, Wu ZD, Chen LF, Pan JY, Xiu XL, Cai X, Liu ZQ, Zheng YG. Combinatorial Metabolic Engineering of Escherichia coli for Enhanced L-Cysteine Production: Insights into Crucial Regulatory Modes and Optimization of Carbon-Sulfur Metabolism and Cofactor Availability. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:13409-13418. [PMID: 37639615 DOI: 10.1021/acs.jafc.3c03709] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Microbial production of valuable compounds can be enhanced by various metabolic strategies. This study proposed combinatorial metabolic engineering to develop an effective Escherichia coli cell factory dedicated to L-cysteine production. First, the crucial regulatory modes that control L-cysteine levels were investigated to guide metabolic modifications. A two-stage fermentation was achieved by employing multi-copy gene expression, improving the balance between production and growth. Subsequently, carbon flux distribution was further optimized by modifying the C1 unit metabolism and the glycolytic pathway. The modifications of sulfur assimilation demonstrated superior performance of thiosulfate utilization pathways in enhancing L-cysteine titer. Furthermore, the studies focusing on cofactor availability and preference emphasized the vital role of synergistic enhancement of sulfur-carbon metabolism in L-cysteine overproduction. In a 5 L bioreactor, the strain BW15-3/pED accumulated 12.6 g/L of L-cysteine. This work presented an effective metabolic engineering strategy for the development of L-cysteine-producing strains.
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Affiliation(s)
- Hui Yang
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Bo Zhang
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Zi-Dan Wu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Li-Feng Chen
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Jia-Yuan Pan
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Xiao-Ling Xiu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Xue Cai
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Zhi-Qiang Liu
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
| | - Yu-Guo Zheng
- The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310014, P. R. China
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8
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Smirnova G, Tyulenev A, Muzyka N, Ushakov V, Samoilova Z, Oktyabrsky O. Influence of Growth Medium Composition on Physiological Responses of Escherichia coli to the Action of Chloramphenicol and Ciprofloxacin. BIOTECH 2023; 12:43. [PMID: 37366791 DOI: 10.3390/biotech12020043] [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: 04/11/2023] [Revised: 05/03/2023] [Accepted: 05/23/2023] [Indexed: 06/28/2023] Open
Abstract
The ability of hydrogen sulfide (H2S) to protect bacteria from bactericidal antibiotics has previously been described. The main source of H2S is the desulfurization of cysteine, which is either synthesized by cells from sulfate or transported from the medium, depending on its composition. Applying electrochemical sensors and a complex of biochemical and microbiological methods, changes in growth, respiration, membrane potential, SOS response, H2S production and bacterial survival under the action of bactericidal ciprofloxacin and bacteriostatic chloramphenicol in commonly used media were studied. Chloramphenicol caused a sharp inhibition of metabolism in all studied media. The physiological response of bacteria to ciprofloxacin strongly depended on its dose. In rich LB medium, cells retained metabolic activity at higher concentrations of ciprofloxacin than in minimal M9 medium. This decreased number of surviving cells (CFU) by 2-3 orders of magnitude in LB compared to M9 medium, and shifted optimal bactericidal concentration (OBC) from 0.3 µg/mL in M9 to 3 µg/mL in LB. Both drugs induced transient production of H2S in M9 medium. In media containing cystine, H2S was produced independently of antibiotics. Thus, medium composition significantly modifies physiological response of E. coli to bactericidal antibiotic, which should be taken into account when interpreting data and developing drugs.
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Affiliation(s)
- Galina Smirnova
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, Goleva 13, 614081 Perm, Russia
| | - Aleksey Tyulenev
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, Goleva 13, 614081 Perm, Russia
| | - Nadezda Muzyka
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, Goleva 13, 614081 Perm, Russia
| | - Vadim Ushakov
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, Goleva 13, 614081 Perm, Russia
| | - Zoya Samoilova
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, Goleva 13, 614081 Perm, Russia
| | - Oleg Oktyabrsky
- Institute of Ecology and Genetics of Microorganisms, Perm Federal Research Center, Russian Academy of Sciences, Goleva 13, 614081 Perm, Russia
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9
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Cysteine Biosynthesis in Campylobacter jejuni: Substrate Specificity of CysM and the Dualism of Sulfide. Biomolecules 2022; 13:biom13010086. [PMID: 36671471 PMCID: PMC9855970 DOI: 10.3390/biom13010086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 12/28/2022] [Accepted: 12/30/2022] [Indexed: 01/04/2023] Open
Abstract
Campylobacter jejuni is a highly successful enteric pathogen with a small, host-adapted genome (1.64 Mbp, ~1650 coding genes). As a result, C. jejuni has limited capacity in numerous metabolic pathways, including sulfur metabolism. Unable to utilise ionic sulfur, C. jejuni relies on the uptake of exogenous cysteine and its derivatives for its supply of this essential amino acid. Cysteine can also be synthesized de novo by the sole cysteine synthase, CysM. In this study, we explored the substrate specificity of purified C. jejuni CysM and define it as an O-acetyl-L-serine sulfhydrylase with an almost absolute preference for sulfide as sulfur donor. Sulfide is produced in abundance in the intestinal niche C. jejuni colonises, yet sulfide is generally viewed as highly toxic to bacteria. We conducted a series of growth experiments in sulfur-limited media and demonstrate that sulfide is an excellent sulfur source for C. jejuni at physiologically relevant concentrations, combating the view of sulfide as a purely deleterious compound to bacteria. Nonetheless, C. jejuni is indeed inhibited by elevated concentrations of sulfide and we sought to understand the targets involved. Surprisingly, we found that inactivation of the sulfide-sensitive primary terminal oxidase, the cbb3-type cytochrome c oxidase CcoNOPQ, did not explain the majority of growth inhibition by sulfide. Therefore, further work is required to reveal the cellular targets responsible for sulfide toxicity in C. jejuni.
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Alkim C, Farias D, Fredonnet J, Serrano-Bataille H, Herviou P, Picot M, Slama N, Dejean S, Morin N, Enjalbert B, François JM. Toxic effect and inability of L-homoserine to be a nitrogen source for growth of Escherichia coli resolved by a combination of in vivo evolution engineering and omics analyses. Front Microbiol 2022; 13:1051425. [PMID: 36583047 PMCID: PMC9792984 DOI: 10.3389/fmicb.2022.1051425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 11/17/2022] [Indexed: 12/14/2022] Open
Abstract
L-homoserine is a pivotal intermediate in the carbon and nitrogen metabolism of E. coli. However, this non-canonical amino acid cannot be used as a nitrogen source for growth. Furthermore, growth of this bacterium in a synthetic media is potently inhibited by L-homoserine. To understand this dual effect, an adapted laboratory evolution (ALE) was applied, which allowed the isolation of a strain able to grow with L-homoserine as the nitrogen source and was, at the same time, desensitized to growth inhibition by this amino acid. Sequencing of this evolved strain identified only four genomic modifications, including a 49 bp truncation starting from the stop codon of thrL. This mutation resulted in a modified thrL locus carrying a thrL* allele encoding a polypeptide 9 amino acids longer than the thrL encoded leader peptide. Remarkably, the replacement of thrL with thrL* in the original strain MG1655 alleviated L-homoserine inhibition to the same extent as strain 4E, but did not allow growth with this amino acid as a nitrogen source. The loss of L-homoserine toxic effect could be explained by the rapid conversion of L-homoserine into threonine via the thrL*-dependent transcriptional activation of the threonine operon thrABC. On the other hand, the growth of E. coli on a mineral medium with L-homoserine required an activation of the threonine degradation pathway II and glycine cleavage system, resulting in the release of ammonium ions that were likely recaptured by NAD(P)-dependent glutamate dehydrogenase. To infer about the direct molecular targets of L-homoserine toxicity, a transcriptomic analysis of wild-type MG1655 in the presence of 10 mM L-homoserine was performed, which notably identified a potent repression of locomotion-motility-chemotaxis process and of branched-chain amino acids synthesis. Since the magnitude of these effects was lower in a ΔthrL mutant, concomitant with a twofold lower sensitivity of this mutant to L-homoserine, it could be argued that growth inhibition by L-homoserine is due to the repression of these biological processes. In addition, L-homoserine induced a strong upregulation of genes in the sulfate reductive assimilation pathway, including those encoding its transport. How this non-canonical amino acid triggers these transcriptomic changes is discussed.
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Affiliation(s)
- Ceren Alkim
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France,Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Daniele Farias
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Julie Fredonnet
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | | | - Pauline Herviou
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Marc Picot
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Nawel Slama
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | | | - Nicolas Morin
- Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France
| | - Brice Enjalbert
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Jean M. François
- Toulouse Biotechnology Institute (TBI), Université de Toulouse, CNRS, INRA, INSA, Toulouse, France,Toulouse White Biotechnology Center (TWB), UMS-INSA-INRA-CNRS, Toulouse, France,*Correspondence: Jean M. François,
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11
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Bahadur A, Li T, Sajjad W, Nasir F, Zia MA, Wu M, Zhang G, Liu G, Chen T, Zhang W. Transcriptional and biochemical analyses of Planomicrobium strain AX6 from Qinghai-Tibetan Plateau, China, reveal hydrogen peroxide scavenging potential. BMC Microbiol 2022; 22:265. [PMID: 36335290 PMCID: PMC9636757 DOI: 10.1186/s12866-022-02677-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND The bacterial mechanisms responsible for hydrogen peroxide (H2O2) scavenging have been well-reported, yet little is known about how bacteria isolated from cold-environments respond to H2O2 stress. Therefore, we investigated the transcriptional profiling of the Planomicrobium strain AX6 strain isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China, in response to H2O2 stress aiming to uncover the molecular mechanisms associated with H2O2 scavenging potential. METHODS We investigated the H2O2-scavenging potential of the bacterial Planomicrobium strain AX6 isolated from the cold-desert ecosystem in the Qaidam Basin, Qinghai-Tibet Plateau, China. Furthermore, we used high-throughput RNA-sequencing to unravel the molecular aspects associated with the H2O2 scavenging potential of the Planomicrobium strain AX6 isolate. RESULTS In total, 3,427 differentially expressed genes (DEGs) were identified in Planomicrobium strain AX6 isolate in response to 4 h of H2O2 (1.5 mM) exposure. Besides, Kyoto Encyclopedia of Genes and Genomes pathway and Gene Ontology analyses revealed the down- and/or up-regulated pathways following H2O2 treatment. Our study not only identified the H2O2 scavenging capability of the strain nevertheless also a range of mechanisms to cope with the toxic effect of H2O2 through genes involved in oxidative stress response. Compared to control, several genes coding for antioxidant proteins, including glutathione peroxidase (GSH-Px), Coproporphyrinogen III oxidase, and superoxide dismutase (SOD), were relatively up-regulated in Planomicrobium strain AX6, when exposed to H2O2. CONCLUSIONS Overall, the results suggest that the up-regulated genes responsible for antioxidant defense pathways serve as essential regulatory mechanisms for removing H2O2 in Planomicrobium strain AX6. The DEGs identified here could provide a competitive advantage for the existence of Planomicrobium strain AX6 in H2O2-polluted environments.
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Affiliation(s)
- Ali Bahadur
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Gansu Province, Lanzhou, 730000, China
| | - Ting Li
- School of Ecology and Environmental Science, Yunnan University, Kunming, 650091, China
| | - Wasim Sajjad
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Fahad Nasir
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences (CAS), Changchun, 130102, Jilin Province, China
| | - Muhammad Amir Zia
- National Institute for Genomics and Advanced Biotechnology (NIGAB), National Agriculture Research Center (NARC), Islamabad, Pakistan
| | - Minghui Wu
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Gaosen Zhang
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Gansu Province, Lanzhou, 730000, China
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Guangxiu Liu
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Gansu Province, Lanzhou, 730000, China
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Tuo Chen
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Wei Zhang
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Gansu Province, Lanzhou, 730000, China.
- Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
- Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, 730000, Gansu Province, China.
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12
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Yang HD, Jeong H, Kim Y, Lee HS. The cysS gene (ncgl0127) of Corynebacterium glutamicum is required for sulfur assimilation and affects oxidative stress-responsive cysteine import. Res Microbiol 2022; 173:103983. [PMID: 35931248 DOI: 10.1016/j.resmic.2022.103983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 07/20/2022] [Accepted: 07/20/2022] [Indexed: 11/16/2022]
Abstract
The OsnR protein functions as a transcriptional repressor of genes involved in redox-dependent stress responses. Here, we studied Corynebacterium glutamicum ORF ncgl0127 (referred to as cysS in this study), one of the target genes of OsnR, to reveal its role in osnR-mediated stress responses. The ΔcysS strain was found to be a cysteine auxotroph, and the transcription levels of the sulfur assimilatory genes and cysR, the master regulatory gene for sulfur assimilation, were low in this strain. Complementation of the strain with cysR transformed the strain into a cysteine prototroph. Cells challenged with oxidants or cysteine showed transcriptional stimulation of the cysS gene and decreased transcription of the ncgl2463 gene, which encodes a cysteine/cystine importer. The transcription of the ncgl2463 gene was increased in the ΔcysS strain and further stimulated by cysteine. Unlike the wild-type strain, ΔcysS cells grown with an excess amount of cysteine showed an oxidant- and alkylating agent-resistant phenotype, suggesting deregulated cysteine import. Collectively, our data suggest that the cysS gene plays a positive role in sulfur assimilation and a negative role in cysteine import, in particular in cells under oxidative stress.
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Affiliation(s)
- Han-Deul Yang
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Republic of Korea; Interdisciplinary Graduate Program for Artificial Intelligence Smart Convergence Technology, Korea University, Sejong 30019, Republic of Korea.
| | - Haeri Jeong
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Republic of Korea.
| | - Younhee Kim
- Department of Korean Medicine, Semyung University, Jecheon, Chungbuk 27136, Republic of Korea.
| | - Heung-Shick Lee
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Republic of Korea; Interdisciplinary Graduate Program for Artificial Intelligence Smart Convergence Technology, Korea University, Sejong 30019, Republic of Korea.
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Du R, Gao D, Wang Y, Liu L, Cheng J, Liu J, Zhang XH, Yu M. Heterotrophic Sulfur Oxidation of Halomonas titanicae SOB56 and Its Habitat Adaptation to the Hydrothermal Environment. Front Microbiol 2022; 13:888833. [PMID: 35774465 PMCID: PMC9237845 DOI: 10.3389/fmicb.2022.888833] [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: 03/03/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022] Open
Abstract
Halomonas bacteria are ubiquitous in global marine environments, however, their sulfur-oxidizing abilities and survival adaptations in hydrothermal environments are not well understood. In this study, we characterized the sulfur oxidation ability and metabolic mechanisms of Halomonas titanicae SOB56, which was isolated from the sediment of the Tangyin hydrothermal field in the Southern Okinawa Trough. Physiological characterizations showed that it is a heterotrophic sulfur-oxidizing bacterium that can oxidize thiosulfate to tetrathionate, with the Na2S2O3 degradation reaching 94.86%. Two potential thiosulfate dehydrogenase-related genes, tsdA and tsdB, were identified as encoding key catalytic enzymes, and their expression levels in strain SOB56 were significantly upregulated. Nine of fifteen examined Halomonas genomes possess TsdA- and TsdB-homologous proteins, whose amino acid sequences have two typical Cys-X2-Cys-His heme-binding regions. Moreover, the thiosulfate oxidation process in H. titanicae SOB56 might be regulated by quorum sensing, and autoinducer-2 synthesis protein LuxS was identified in its genome. Regarding the mechanisms underlying adaptation to hydrothermal environment, strain SOB56 was capable of forming biofilms and producing EPS. In addition, genes related to complete flagellum assembly system, various signal transduction histidine kinases, heavy metal transporters, anaerobic respiration, and variable osmotic stress regulation were also identified. Our results shed light on the potential functions of heterotrophic Halomonas bacteria in hydrothermal sulfur cycle and revealed possible adaptations for living at deep-sea hydrothermal fields by H. titanicae SOB56.
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Affiliation(s)
- Rui Du
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Di Gao
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Yiting Wang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Lijun Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jingguang Cheng
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jiwen Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Min Yu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- *Correspondence: Min Yu,
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Nishikawa M, Noda S, Henmi K, Ogawa K. Sulphate repression of ssuD-dependent alkanesulphonate-sulphur assimilation in Escherichia coli. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35704379 DOI: 10.1099/mic.0.001190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Escherichia coli cells utilize alkanesulphonates including taurine as the sulphur source. We previously reported that when E. coli cells carrying a double deletion in tauD and cysN were inoculated into a taurine-containing minimal medium, they started to grow only after long-term incubation (Nishikawa et al. 2018, Microbiology 164: 1446-1456). We show here that cells that can induce ssuD-dependent alkanesulphonate-sulphur assimilation (SASSA) are essentially rare, but suppressors that can induce SASSA appear during long-term incubation. Mutant cells carrying ΔtauD and ΔcysN, ΔcysC or ΔcysH generated suppressor cells that can induce SASSA at a frequency of about 10-6 in a population. Whereas ΔtauD ΔcysN cells without prior SASSA did not express ssuD even when necessary, the cells with prior SASSA properly expressed ssuD. Whole-genome DNA sequencing of a clone isolated from ΔtauD ΔcysN cells with prior SASSA revealed that the influx of sulphate or thiosulphate may be related to the regulation of SASSA. To clarify whether sulphate or thiosulphate affects the induction of SASSA, the effect of mutations in sbp and cysP, which are responsible for sulphate and thiosulphate uptake with different preferences for substrates, was examined. Only the ΔtauD ΔcysN Δsbp mutant did not show repression of SASSA when no sulphate was added to the medium. When the concentration of the sulphate added was over 10 μM, the Δsbp mutant showed repression of SASSA. Therefore, it was considered that the influx of extracellular sulphate resulted in repression of SASSA.
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Affiliation(s)
- Masanobu Nishikawa
- Research Institute for Biological Sciences Okayama (RIBS Okayama), Okayama, Japan
| | - Soichiro Noda
- Research Institute for Biological Sciences Okayama (RIBS Okayama), Okayama, Japan
| | - Kenji Henmi
- Research Institute for Biological Sciences Okayama (RIBS Okayama), Okayama, Japan
| | - Ken'ichi Ogawa
- Research Institute for Biological Sciences Okayama (RIBS Okayama), Okayama, Japan
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15
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Mohanty BK, Kushner SR. Inactivation of RNase P in Escherichia coli significantly changes post-transcriptional RNA metabolism. Mol Microbiol 2022; 117:121-142. [PMID: 34486768 PMCID: PMC8766891 DOI: 10.1111/mmi.14808] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 01/03/2023]
Abstract
Ribonuclease P (RNase P), which is required for the 5'-end maturation of tRNAs in every organism, has been shown to play a limited role in other aspects of RNA metabolism in Escherichia coli. Using RNA-sequencing (RNA-seq), we demonstrate that RNase P inactivation affects the abundances of ~46% of the expressed transcripts in E. coli and provide evidence that its essential function is its ability to generate pre-tRNAs from polycistronic tRNA transcripts. The RNA-seq results agreed with the published data and northern blot analyses of 75/83 transcripts (mRNAs, sRNAs, and tRNAs). Changes in transcript abundances in the RNase P mutant also correlated with changes in their half-lives. Inactivating the stringent response did not alter the rnpA49 phenotype. Most notably, increases in the transcript abundances were observed for all genes in the cysteine regulons, multiple toxin-antitoxin modules, and sigma S-controlled genes. Surprisingly, poly(A) polymerase (PAP I) modulated the abundances of ~10% of the transcripts affected by RNase P. A comparison of the transcriptomes of RNase P, RNase E, and RNase III mutants suggests that they affect distinct substrates. Together, our work strongly indicates that RNase P is a major player in all aspects of post-transcriptional RNA metabolism in E. coli.
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Affiliation(s)
| | - Sidney R. Kushner
- Department of Genetics, University of Georgia, Athens, GA 30602,Department of Microbiology, University of Georgia, Athens, GA 30602,To whom correspondence should be addressed.
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16
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Seregina TA, Lobanov KV, Shakulov RS, Mironov AS. Enhancement of the Bactericidal Effect of Antibiotics by Inhibition of Enzymes Involved in Production of Hydrogen Sulfide in Bacteria. Mol Biol 2022; 56:638-648. [PMID: 36217334 PMCID: PMC9534473 DOI: 10.1134/s0026893322050120] [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: 03/02/2022] [Revised: 03/28/2022] [Accepted: 03/28/2022] [Indexed: 11/23/2022]
Abstract
Counteraction of the origin and distribution of multidrug-resistant pathogens responsible for intra-hospital infections is a worldwide issue in medicine. In this brief review, we discuss the results of our recent investigations, which argue that many antibiotics, along with inactivation of their traditional biochemical targets, can induce oxidative stress (ROS production), thus resulting in increased bactericidal efficiency. As we previously showed, hydrogen sulfide, which is produced in the cells of different pathogens protects them not only against oxidative stress but also against bactericidal antibiotics. Next, we clarified the interplay of oxidative stress, cysteine metabolism, and hydrogen sulfide production. Finally, demonstrated that small molecules, which inhibit a bacterial enzyme involved in hydrogen sulfide production, potentiate bactericidal antibiotics including quinolones, beta-lactams, and aminoglycosides against bacterial pathogens in in vitro and in mouse models of infection. These inhibitors also suppress bacterial tolerance to antibiotics by disrupting the biofilm formation and substantially reducing the number of persister bacteria, which survive the antibiotic treatment. We hypothesise that agents which limit hydrogen sulfide biosynthesis are effective tools to counteract the origin and distribution of multidrug-resistant pathogens.
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Affiliation(s)
- T. A. Seregina
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, 119991 Moscow, Russia
| | - K. V. Lobanov
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, 119991 Moscow, Russia
| | - R. S. Shakulov
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, 119991 Moscow, Russia
| | - A. S. Mironov
- Engelhardt Institute of Molecular Biology, Russian Academy of Science, 119991 Moscow, Russia
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17
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Verma D, Gupta V. New insights into the structure and function of an emerging drug target CysE. 3 Biotech 2021; 11:373. [PMID: 34367865 DOI: 10.1007/s13205-021-02891-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 06/09/2021] [Indexed: 11/24/2022] Open
Abstract
The antimicrobial resistant strains of several pathogens are major culprits of hospital-acquired nosocomial infections. An active and urgent action is necessary against these pathogens for the development of unique therapeutics. The cysteine biosynthetic pathway or genes (that are absent in humans) involved in the production of L-cysteine appear to be an attractive target for developing novel antibiotics. CysE, a Serine Acetyltransferase (SAT), catalyzes the first step of cysteine synthesis and is reported to be essential for the survival of persistence in several microbes including Mycobacterium tuberculosis. Structure determination provides fundamental insight into structure and function of protein and aid in drug design/discovery efforts. This review focuses on the overview of current knowledge of structure function, regulatory mechanism, and potential inhibitors (active site as well as allosteric site) of CysE. Despite having conserved structure, slight modification in CysE structure lead to altered the regulatory mechanism and hence affects the cysteine production. Due to its possible role in virulence and vital metabolism of pathogens makes it a potential target in the quest to develop novel therapeutics to treat multi-drug-resistant bacteria.
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Affiliation(s)
- Deepali Verma
- Department of Biotechnology, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, Uttar Pradesh 201309 India
| | - Vibha Gupta
- Department of Biotechnology, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, Uttar Pradesh 201309 India
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18
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Wasilko NP, Ceron JS, Baker ER, Cecere AG, Wollenberg MS, Miyashiro TI. Vibrio fischeri imports and assimilates sulfate during symbiosis with Euprymna scolopes. Mol Microbiol 2021; 116:926-942. [PMID: 34212439 DOI: 10.1111/mmi.14780] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/28/2021] [Accepted: 06/30/2021] [Indexed: 12/24/2022]
Abstract
Sulfur is in cellular components of bacteria and is, therefore, an element necessary for growth. However, mechanisms by which bacteria satisfy their sulfur needs within a host are poorly understood. Vibrio fischeri is a bacterial symbiont that colonizes, grows, and produces bioluminescence within the light organ of the Hawaiian bobtail squid, which provides an experimental platform for investigating sulfur acquisition in vivo. Like other γ-proteobacteria, V. fischeri fuels sulfur-dependent anabolic processes with intracellular cysteine. Within the light organ, the abundance of a ΔcysK mutant, which cannot synthesize cysteine through sulfate assimilation, is attenuated, suggesting sulfate import is necessary for V. fischeri to establish symbiosis. Genes encoding sulfate-import systems of other bacteria that assimilate sulfate were not identified in the V. fischeri genome. A transposon mutagenesis screen implicated YfbS as a sulfate importer. YfbS is necessary for growth on sulfate and in the marine environment. During symbiosis, a ΔyfbS mutant is attenuated and strongly expresses sulfate-assimilation genes, which is a phenotype associated with sulfur-starved cells. Together, these results suggest V. fischeri imports sulfate via YfbS within the squid light organ, which provides insight into the molecular mechanisms by which bacteria harvest sulfur in vivo.
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Affiliation(s)
- Nathan P Wasilko
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Josue S Ceron
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Emily R Baker
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | - Andrew G Cecere
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
| | | | - Tim I Miyashiro
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA, USA
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19
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Marchesani F, Zangelmi E, Bruno S, Bettati S, Peracchi A, Campanini B. A Novel Assay for Phosphoserine Phosphatase Exploiting Serine Acetyltransferase as the Coupling Enzyme. Life (Basel) 2021; 11:life11060485. [PMID: 34073563 PMCID: PMC8229081 DOI: 10.3390/life11060485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/21/2021] [Accepted: 05/23/2021] [Indexed: 01/01/2023] Open
Abstract
Phosphoserine phosphatase (PSP) catalyzes the final step of de novo L-serine biosynthesis—the hydrolysis of phosphoserine to serine and inorganic phosphate—in humans, bacteria, and plants. In published works, the reaction is typically monitored through the discontinuous malachite green phosphate assay or, more rarely, through a continuous assay that couples phosphate release to the phosphorolysis of a chromogenic nucleoside by the enzyme purine nucleoside phosphorylase (PNP). These assays suffer from numerous drawbacks, and both rely on the detection of phosphate. We describe a new continuous assay that monitors the release of serine by exploiting bacterial serine acetyltransferase (SAT) as a reporter enzyme. SAT acetylates serine, consuming acetyl-CoA and releasing CoA-SH. CoA-SH spontaneously reacts with Ellman’s reagent to produce a chromophore that absorbs light at 412 nm. The catalytic parameters estimated through the SAT-coupled assay are fully consistent with those obtained with the published methods, but the new assay exhibits several advantages. Particularly, it depletes L-serine, thus allowing more prolonged linearity in the kinetics. Moreover, as the SAT-coupled assay does not rely on phosphate detection, it can be used to investigate the inhibitory effect of phosphate on PSP.
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Affiliation(s)
- Francesco Marchesani
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (F.M.); (S.B.)
| | - Erika Zangelmi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
| | - Stefano Bruno
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (F.M.); (S.B.)
| | - Stefano Bettati
- Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy;
- Institute of Biophysics, National Research Council, 56124 Pisa, Italy
| | - Alessio Peracchi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy;
- Correspondence: (A.P.); (B.C.); Tel.: +39-0521-905137 (A.P.); +39-0521-906333 (B.C.)
| | - Barbara Campanini
- Department of Food and Drug, University of Parma, 43124 Parma, Italy; (F.M.); (S.B.)
- Correspondence: (A.P.); (B.C.); Tel.: +39-0521-905137 (A.P.); +39-0521-906333 (B.C.)
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20
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Khan MZ, Singha B, Ali MF, Taunk K, Rapole S, Gourinath S, Nandicoori VK. Redox homeostasis in Mycobacterium tuberculosis is modulated by a novel actinomycete-specific transcription factor. EMBO J 2021; 40:e106111. [PMID: 34018220 PMCID: PMC8280819 DOI: 10.15252/embj.2020106111] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 04/17/2021] [Accepted: 04/20/2021] [Indexed: 11/09/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) has evolved diverse cellular processes in response to the multiple stresses it encounters within the infected host. We explored available TnSeq datasets to identify transcription factors (TFs) that are essential for Mtb survival inside the host. The analysis identified a single TF, Rv1332 (AosR), conserved across actinomycetes with a so‐far uncharacterized function. AosR mitigates phagocyte‐derived oxidative and nitrosative stress, thus promoting mycobacterial growth in the murine lungs and spleen. Oxidative stress induces formation of a single intrasubunit disulphide bond in AosR, which in turn facilitates AosR interaction with an extracytoplasmic‐function sigma factor, SigH. This leads to the specific upregulation of the CysM‐dependent non‐canonical cysteine biosynthesis pathway through an auxiliary intragenic stress‐responsive promoter, an axis critical in detoxifying host‐derived oxidative and nitrosative radicals. Failure to upregulate AosR‐dependent cysteine biosynthesis during the redox stress causes differential expression of 6% of Mtb genes. Our study shows that the AosR‐SigH pathway is critical for detoxifying host‐derived oxidative and nitrosative radicals to enhance Mtb survival in the hostile intracellular environment.
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21
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Sharma M, Abayakoon P, Epa R, Jin Y, Lingford JP, Shimada T, Nakano M, Mui JWY, Ishihama A, Goddard-Borger ED, Davies GJ, Williams SJ. Molecular Basis of Sulfosugar Selectivity in Sulfoglycolysis. ACS CENTRAL SCIENCE 2021; 7:476-487. [PMID: 33791429 PMCID: PMC8006165 DOI: 10.1021/acscentsci.0c01285] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Indexed: 06/12/2023]
Abstract
The sulfosugar sulfoquinovose (SQ) is produced by essentially all photosynthetic organisms on Earth and is metabolized by bacteria through the process of sulfoglycolysis. The sulfoglycolytic Embden-Meyerhof-Parnas pathway metabolizes SQ to produce dihydroxyacetone phosphate and sulfolactaldehyde and is analogous to the classical Embden-Meyerhof-Parnas glycolysis pathway for the metabolism of glucose-6-phosphate, though the former only provides one C3 fragment to central metabolism, with excretion of the other C3 fragment as dihydroxypropanesulfonate. Here, we report a comprehensive structural and biochemical analysis of the three core steps of sulfoglycolysis catalyzed by SQ isomerase, sulfofructose (SF) kinase, and sulfofructose-1-phosphate (SFP) aldolase. Our data show that despite the superficial similarity of this pathway to glycolysis, the sulfoglycolytic enzymes are specific for SQ metabolites and are not catalytically active on related metabolites from glycolytic pathways. This observation is rationalized by three-dimensional structures of each enzyme, which reveal the presence of conserved sulfonate binding pockets. We show that SQ isomerase acts preferentially on the β-anomer of SQ and reversibly produces both SF and sulforhamnose (SR), a previously unknown sugar that acts as a derepressor for the transcriptional repressor CsqR that regulates SQ-utilization. We also demonstrate that SF kinase is a key regulatory enzyme for the pathway that experiences complex modulation by the metabolites SQ, SLA, AMP, ADP, ATP, F6P, FBP, PEP, DHAP, and citrate, and we show that SFP aldolase reversibly synthesizes SFP. This body of work provides fresh insights into the mechanism, specificity, and regulation of sulfoglycolysis and has important implications for understanding how this biochemistry interfaces with central metabolism in prokaryotes to process this major repository of biogeochemical sulfur.
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Affiliation(s)
- Mahima Sharma
- York
Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, U.K.
| | - Palika Abayakoon
- School
of Chemistry and Bio21 Molecular Science
and Biotechnology Institute and University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ruwan Epa
- School
of Chemistry and Bio21 Molecular Science
and Biotechnology Institute and University of Melbourne, Parkville, Victoria 3010, Australia
| | - Yi Jin
- York
Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, U.K.
| | - James P. Lingford
- ACRF
Chemical Biology Division, The Walter and
Eliza Hall Institute of Medical Research, Parkville, Victoria 3010, Australia
- Department
of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Tomohiro Shimada
- School
of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan
| | - Masahiro Nakano
- Institute
for Frontier Life and Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Janice W.-Y. Mui
- School
of Chemistry and Bio21 Molecular Science
and Biotechnology Institute and University of Melbourne, Parkville, Victoria 3010, Australia
| | - Akira Ishihama
- Micro-Nano
Technology Research Center, Hosei University, Koganei, Tokyo, Japan
| | - Ethan D. Goddard-Borger
- ACRF
Chemical Biology Division, The Walter and
Eliza Hall Institute of Medical Research, Parkville, Victoria 3010, Australia
- Department
of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Gideon J. Davies
- York
Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, U.K.
| | - Spencer J. Williams
- School
of Chemistry and Bio21 Molecular Science
and Biotechnology Institute and University of Melbourne, Parkville, Victoria 3010, Australia
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22
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Morigasaki S, Umeyama A, Kawano Y, Aizawa Y, Ohtsu I. Defect of RNA pyrophosphohydrolase RppH enhances fermentative production of L-cysteine in Escherichia coli. J GEN APPL MICROBIOL 2021; 66:307-314. [PMID: 32779574 DOI: 10.2323/jgam.2019.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Fermentative production of L-cysteine has been established using Escherichia coli. In that procedure, thiosulfate is a beneficial sulfur source, whereas repressing sulfate utilization. We first found that thiosulfate decreased transcript levels of genes related to sulfur assimilation, particularly whose expression is controlled by the transcription factor CysB. Therefore, a novel approach, i.e. increment of expression of genes involved in sulfur-assimilation, was attempted for further improvement of L-cysteine overproduction. Disruption of the rppH gene significantly augmented transcript levels of the cysD, cysJ, cysM and yeeE genes (≥1.5-times) in medium containing sulfate as a sole sulfur source, probably because the rppH gene encodes mRNA pyrophosphohydrolase that triggers degradation of certain mRNAs. In addition, the ΔrppH strain appeared to preferentially uptake thiosulfate rather than sulfate, though thiosulfate dramatically reduced expression of the known sulfate/thiosulfate transporter complexes in both ΔrppH and wild-type cells. We also found that both YeeE and YeeD are required for the strain without the transporters to grow in the presence of thiosulfate as a sole sulfur source. Therefore, yeeE and yeeD are assigned as genes responsible for thiosulfate uptake (tsuA and tsuB, respectively). In final, we applied the ΔrppH strain to the fermentative production of L-cysteine. Disruption of the rppH gene enhanced L-cysteine biosynthesis, as a result, a strain producing approximately twice as much L-cysteine as the control strain was obtained.
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Affiliation(s)
- Susumu Morigasaki
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | | | - Yusuke Kawano
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | | | - Iwao Ohtsu
- Graduate School of Life and Environmental Sciences, University of Tsukuba
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23
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Zhou Y, Imlay JA. Escherichia coli K-12 Lacks a High-Affinity Assimilatory Cysteine Importer. mBio 2020; 11:e01073-20. [PMID: 32518189 PMCID: PMC7373191 DOI: 10.1128/mbio.01073-20] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 05/05/2020] [Indexed: 01/09/2023] Open
Abstract
The most direct route by which microbes might assimilate sulfur would be by importing cysteine. However, alone among the amino acids, cysteine does not have well-characterized importers. We determined that Escherichia coli can rapidly import cysteine, but in our experiments, it did so primarily through the LIV ATP-driven system that is dedicated to branched-chain amino acids. The affinity of this system for cysteine is far lower than for Leu, Ile, and Val, and so in their presence, cysteine is excluded. Thus, this transport is unlikely to be relevant in natural environments. Growth studies, transcriptomics, and transport assays failed to detect any high-affinity importer that is dedicated to cysteine assimilation. Enteric bacteria do not contain the putative cysteine importer that was identified in Campylobacter jejuni This situation is surprising, because E. coli deploys ion- and/or ATP-driven transporters that import cystine, the oxidized form of cysteine, with high affinity and specificity. We conjecture that in oxic environments, molecular oxygen oxidizes environmental cysteine to cystine, which E. coli imports. In anoxic environments where cysteine is stable, the cell chooses to assimilate hydrogen sulfide instead. Calculations suggest that this alternative is almost as economical, and it avoids the toxic effects that can result when excess cysteine enters the cell.IMPORTANCE This investigation discovered that Escherichia coli lacks a transporter dedicated to the assimilation of cysteine, an outcome that is in striking contrast to the many transporters devoted to the other 19 amino acids. We ascribe the lack of a high-affinity cysteine importer to two considerations. First, the chemical reactivity of this amino acid is unique, and its poorly controlled import can have adverse consequences for the cell. Second, our analysis suggests that the economics of biosynthesis depend sharply upon whether the cell is respiring or fermenting. In the anoxic habitats in which cysteine might be found, the value of import versus biosynthesis is strongly reduced compared to that in oxic habitats. These studies may explain why bacteria choose to synthesize rather than to import other useful biomolecules as well.
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Affiliation(s)
- Yidan Zhou
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
| | - James A Imlay
- Department of Microbiology, University of Illinois, Urbana, Illinois, USA
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24
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Sulfate Ester Detergent Degradation in Pseudomonas aeruginosa Is Subject to both Positive and Negative Regulation. Appl Environ Microbiol 2019; 85:AEM.01352-19. [PMID: 31540990 DOI: 10.1128/aem.01352-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/14/2019] [Indexed: 12/25/2022] Open
Abstract
Bacteria using toxic chemicals, such as detergents, as growth substrates face the challenge of exposing themselves to cell-damaging effects that require protection mechanisms, which demand energy delivered from catabolism of the toxic compound. Thus, adaptations are necessary for ensuring the rapid onset of substrate degradation and the integrity of the cells. Pseudomonas aeruginosa strain PAO1 can use the toxic detergent sodium dodecyl sulfate (SDS) as a growth substrate and employs, among others, cell aggregation as a protection mechanism. The degradation itself is also a protection mechanism and has to be rapidly induced upon contact to SDS. In this study, gene regulation of the enzymes initiating SDS degradation in strain PAO1 was studied. The gene and an atypical DNA-binding site of the LysR-type regulator SdsB1 were identified and shown to activate expression of the alkylsulfatase SdsA1 initiating SDS degradation. Further degradation of the resulting 1-dodecanol is catalyzed by enzymes encoded by laoCBA, which were shown to form an operon. Expression of this operon is regulated by the TetR-type repressor LaoR. Studies with purified LaoR identified its DNA-binding site and 1-dodecanoyl coenzyme A as the ligand causing detachment of LaoR from the DNA. Transcriptional studies revealed that the sulfate ester detergent sodium lauryl ether sulfate (SLES) induced expression of sdsA1 and the lao operon. Growth experiments revealed an essential involvement of the alkylsulfatase SdsA1 for SLES degradation. This study revealed that the genes for the enzymes initiating the degradation of toxic sulfate-ester detergents are induced stepwise by a positive and a negative regulator in P. aeruginosa strain PAO1.IMPORTANCE Bacterial degradation of toxic compounds is important not only for bioremediation but also for the colonization of hostile anthropogenic environments in which biocides are being used. This study with Pseudomonas aeruginosa expands our knowledge of gene regulation of the enzymes initiating degradation of sulfate ester detergents, which occurs in many hygiene and household products and, consequently, also in wastewater. As an opportunistic pathogen, P. aeruginosa causes severe hygienic problems because of its pronounced biocide resistance and its metabolic versatility, often combined with its pronounced biofilm formation. Knowledge about the regulation of detergent degradation, especially regarding the ligands of DNA-binding regulators, may lead to the rational development of specific inhibitors for restricting growth and biofilm formation of P. aeruginosa in hygienic settings. In addition, it may also contribute to optimizing bioremediation strategies not only for detergents but also for alkanes, which when degraded merge with sulfate ester degradation at the level of long-chain alcohols.
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25
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Korshunov S, Imlay KRC, Imlay JA. Cystine import is a valuable but risky process whose hazards Escherichia coli minimizes by inducing a cysteine exporter. Mol Microbiol 2019; 113:22-39. [PMID: 31612555 PMCID: PMC7007315 DOI: 10.1111/mmi.14403] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2019] [Indexed: 12/24/2022]
Abstract
The structure of free cysteine makes it vulnerable to oxidation by molecular oxygen; consequently, organisms that live in oxic habitats have acquired the ability to import cystine as a sulfur source. We show that cystine imported into Escherichia coli can transfer disulfide bonds to cytoplasmic proteins. To minimize this problem, the imported cystine is rapidly reduced. However, this conversion of cystine to cysteine precludes product inhibition of the importer, so cystine import continues into cells that are already sated with cysteine. The burgeoning cysteine pool is itself hazardous, as cysteine promotes the formation of reactive oxygen species, triggers sulfide production and competitively inhibits a key enzyme in the isoleucine biosynthetic pathway. The Lrp transcription factor senses the excess cysteine and induces AlaE, an export protein that pumps cysteine back out of the cell until transcriptional controls succeed in lowering the amount of the importer. While it lasts, the overall phenomenon roughly doubles the NADPH demand of the cell. It comprises another example of the incompatibility of the reduced cytoplasms of microbes with the oxic world in which they dwell. It also reveals one natural source of cytoplasmic disulfide stress and sheds light on a role for broad-spectrum amino acid exporters.
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Affiliation(s)
- Sergey Korshunov
- Department of Microbiology, University of Illinois, Urbana, IL, 61801, USA
| | | | - James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL, 61801, USA
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26
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Smirnova GV, Tyulenev AV, Bezmaternykh KV, Muzyka NG, Ushakov VY, Oktyabrsky ON. Cysteine homeostasis under inhibition of protein synthesis in Escherichia coli cells. Amino Acids 2019; 51:1577-1592. [PMID: 31617110 DOI: 10.1007/s00726-019-02795-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 10/02/2019] [Indexed: 01/23/2023]
Abstract
Increased intracellular cysteine poses a potential danger to cells due to the high ability of cysteine to reduce free iron and promote the Fenton reaction. Here, we studied ways to maintain cysteine homeostasis in E. coli cells while inhibiting protein synthesis with valine or chloramphenicol. When growing wild-type bacteria on minimal medium with sulfate, an excess of cysteine resulting from the inhibition of protein synthesis is mainly incorporated into glutathione (up to 90%), which, therefore, can be considered as cysteine buffer. The share of hydrogen sulfide, which is the product of cysteine degradation by cysteine synthase B (CysM), does not exceed 1-3%, the rest falls on free cysteine, exported from cells. As a result, intracellular free cysteine is maintained at a low level (about 0.1 mM). The lack of glutathione in the gshA mutant increases H2S production and excretion of cysteine and leads to a threefold increase in the level of intracellular cysteine in response to valine and chloramphenicol. The relA mutants, exposed to valine, produce more H2S, dramatically accelerate the export of glutathione and accumulate more cysteine in the cytoplasm than their parent, which indicates that the regulatory nucleotide (p)ppGpp is involved in maintaining cysteine homeostasis. Disruption of cysteine homeostasis in gshA and relA mutants increases their sensitivity to peroxide stress.
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Affiliation(s)
- Galina V Smirnova
- Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Golev Street 13, 614081, Perm, Russia.
| | - Aleksey V Tyulenev
- Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Golev Street 13, 614081, Perm, Russia
| | - Kseniya V Bezmaternykh
- Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Golev Street 13, 614081, Perm, Russia
| | - Nadezda G Muzyka
- Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Golev Street 13, 614081, Perm, Russia
| | - Vadim Y Ushakov
- Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Golev Street 13, 614081, Perm, Russia.,Perm State University, Bukireva Street 15, 614990, Perm, Russia
| | - Oleg N Oktyabrsky
- Institute of Ecology and Genetics of Microorganisms, Russian Academy of Sciences, Golev Street 13, 614081, Perm, Russia.,Perm National Research Polytechnic University, Komsomolsky Pr. 29, 614990, Perm, Russia
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27
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Takahashi H. Sulfate transport systems in plants: functional diversity and molecular mechanisms underlying regulatory coordination. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:4075-4087. [PMID: 30907420 DOI: 10.1093/jxb/erz132] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 03/19/2019] [Indexed: 06/09/2023]
Abstract
Sulfate transporters are integral membrane proteins controlling the flux of sulfate (SO42-) entering the cells and subcellular compartments across the membrane lipid bilayers. Sulfate uptake is a dynamic biological process that occurs in multiple cell layers and organs in plants. In vascular plants, sulfate ions are taken up from the soil environment to the outermost cell layers of roots and horizontally transferred to the vascular tissues for further distribution to distant organs. The amount of sulfate ions being metabolized in the cytosol and chloroplast/plastid or temporarily stored in the vacuole depends on expression levels and functionalities of sulfate transporters bound specifically to the plasma membrane, chloroplast/plastid envelopes, and tonoplast membrane. The entire system for sulfate homeostasis, therefore, requires different types of sulfate transporters to be expressed and coordinately regulated in specific organs, cell types, and subcellular compartments. Transcriptional and post-transcriptional regulatory mechanisms control the expression levels and functions of sulfate transporters to optimize sulfate uptake and internal distribution in response to sulfate availability and demands for synthesis of organic sulfur metabolites. This review article provides an overview of sulfate transport systems and discusses their regulatory aspects investigated in the model plant species Arabidopsis thaliana.
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Affiliation(s)
- Hideki Takahashi
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
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28
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Hanatani Y, Imura M, Taniguchi H, Okano K, Toya Y, Iwakiri R, Honda K. In vitro production of cysteine from glucose. Appl Microbiol Biotechnol 2019; 103:8009-8019. [PMID: 31396682 DOI: 10.1007/s00253-019-10061-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/05/2019] [Accepted: 07/24/2019] [Indexed: 12/19/2022]
Abstract
Cysteine is a commercially valuable amino acid with an increasing demand in the food, cosmetic, and pharmaceutical industries. Although cysteine is conventionally manufactured by extraction from animal proteins, this method has several problems, such as troublesome waste-water treatment and incompatibility with some dietary restrictions. Fermentative production of cysteine from plant-derived substrates is a promising alternative for the industrial production of cysteine. However, it often suffers from low product yield as living organisms are equipped with various regulatory systems to control the intracellular cysteine concentration at a moderate level. In this study, we constructed an in vitro cysteine biosynthetic pathway by assembling 11 thermophilic enzymes. The in vitro pathway was designed to be insensitive to the feedback regulation by cysteine and to balance the intra-pathway consumption and regeneration of cofactors. A kinetic model for the in vitro pathway was built using rate equations of individual enzymes and used to optimize the loading ratio of each enzyme. Consequently, 10.5 mM cysteine could be produced from 20 mM glucose through the optimized pathway. However, the observed yield and production rate of the assay were considerably lower than those predicted by the model. Determination of cofactor concentrations in the reaction mixture indicated that the inconsistency between the model and experimental assay could be attributed to the depletion of ATP and ADP, likely due to host-derived, thermo-stable enzyme(s). Based on these observations, possible approaches to improve the feasibility of cysteine production through an in vitro pathway have been discussed.
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Affiliation(s)
- Yohei Hanatani
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Makoto Imura
- Bio Science Research Center, Mitsubishi Corporation Life Sciences Ltd., Higashihama 1-6, Saiki, Oita, 876-8580, Japan
| | - Hironori Taniguchi
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Kenji Okano
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Toya
- Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, Yamadaoka 1-5, Suita, Osaka, 565-0871, Japan
| | - Ryo Iwakiri
- Bio Science Research Center, Mitsubishi Corporation Life Sciences Ltd., Higashihama 1-6, Saiki, Oita, 876-8580, Japan
| | - Kohsuke Honda
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka, 565-0871, Japan.
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29
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Anderson MT, Mitchell LA, Sintsova A, Rice KA, Mobley HLT. Sulfur Assimilation Alters Flagellar Function and Modulates the Gene Expression Landscape of Serratia marcescens. mSystems 2019; 4:e00285-19. [PMID: 31387930 PMCID: PMC6687942 DOI: 10.1128/msystems.00285-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/24/2019] [Indexed: 11/29/2022] Open
Abstract
Sulfur is an essential nutrient that contributes to cellular redox homeostasis, transcriptional regulation, and translation initiation when incorporated into different biomolecules. Transport and reduction of extracellular sulfate followed by cysteine biosynthesis is a major pathway of bacterial sulfur assimilation. For the opportunistic pathogen Serratia marcescens, function of the cysteine biosynthesis pathway is required for extracellular phospholipase activity and flagellum-mediated surface motility, but little else is known about the influence of sulfur assimilation on the physiology of this organism. In this work, it was determined that an S. marcescens cysteine auxotroph fails to differentiate into hyperflagellated and elongated swarmer cells and that cysteine, but not other organic sulfur molecules, restores swarming motility to these bacteria. The S. marcescens cysteine auxotroph further exhibits reduced transcription of phospholipase, hemolysin, and flagellin genes, each of which is subject to transcriptional control by the flagellar regulatory system. Based on these data and the central role of cysteine in sulfur assimilation, it was reasoned that environmental sulfur availability may contribute to the regulation of these functions in S. marcescens Indeed, bacteria that are starved for sulfate exhibit substantially reduced transcription of the genes for hemolysin, phospholipase, and the FlhD flagellar master regulator. A global transcriptomic analysis further defined a large set of S. marcescens genes that are responsive to extracellular sulfate availability, including genes that encode membrane transport, nutrient utilization, and metabolism functions. Finally, sulfate availability was demonstrated to alter S. marcescens cytolytic activity, suggesting that sulfate assimilation may impact the virulence of this organism.IMPORTANCE Serratia marcescens is a versatile bacterial species that inhabits diverse environmental niches and is capable of pathogenic interactions with host organisms ranging from insects to humans. This report demonstrates for the first time the extensive impacts that environmental sulfate availability and cysteine biosynthesis have on the transcriptome of S. marcescens The finding that greater than 1,000 S. marcescens genes are differentially expressed depending on sulfate availability suggests that sulfur abundance is a crucial factor that controls the physiology of this organism. Furthermore, the high relative expression levels for the putative virulence factors flagella, phospholipase, and hemolysin in the presence of sulfate suggests that a sulfur-rich host environment could contribute to the transcription of these genes during infection.
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Affiliation(s)
- Mark T Anderson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Lindsay A Mitchell
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anna Sintsova
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Katherine A Rice
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Harry L T Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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30
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Geraskina NV, Sycheva EV, Samsonov VV, Eremina NS, Hook CD, Serebrianyi VA, Stoynova NV. Engineering Escherichia coli for autoinducible production of L-valine: An example of an artificial positive feedback loop in amino acid biosynthesis. PLoS One 2019; 14:e0215777. [PMID: 31022249 PMCID: PMC6483228 DOI: 10.1371/journal.pone.0215777] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/08/2019] [Indexed: 12/13/2022] Open
Abstract
Artificial metabolically regulated inducible expression systems are often used for the production of essential compounds. In most cases, the application of such systems enables regulating the expression of an entire group of genes in response to any internal signal such as an aerobic/anaerobic switch, a transition to stationary phase, or the exhausting of essential compounds. In this work, we demonstrate an example of another type of artificial autoinducible module, denoted a positive feedback module. This positive feedback module generates an inducer molecule that in turn enhances its own synthesis, promoting an activation signal. Due to the use of acetolactate, an intermediate of the L-valine biosynthetic pathway, as a specific inducer molecule, we realized a positive feedback loop in the biosynthetic pathway of branched chain amino acids. Such positive feedback was demonstrated to improve the production of a target compound.
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Affiliation(s)
| | - Elena V. Sycheva
- Ajinomoto-Genetika Research Institute, Moscow, Russian Federation
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31
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Huang N, Mao J, Zhao Y, Hu M, Wang X. Multiple Transcriptional Mechanisms Collectively Mediate Copper Resistance in Cupriavidus gilardii CR3. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4609-4618. [PMID: 30920814 DOI: 10.1021/acs.est.8b06787] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Bacteria resist copper (Cu) stress by implementing several metabolic mechanisms. However, these mechanisms are not fully understood. We investigated the mechanism of Cu resistance in Cupriavidus gilardii CR3, a Cu-resistant bacterium with a fully sequenced, annotated genome. The growth of CR3 was inhibited by higher Cu concentrations (≥1.0 mM) but not by lower ones (≤0.5 mM). CR3 accumulated Cu intracellularly (ratios of intercellular to extracellular Cu were 11.6, 4.24, and 3.9 in 0.1, 0.5, and 1.5 mM Cu treatments, respectively). A comparative transcriptome analysis of CR3 respectively revealed 310 and 413 differentially expressed genes under 0.5 and 1.5 mM Cu stress, most of which were up-regulated under Cu treatment. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses uncovered several genotype-specific biological processes related to Cu stress. Besides revealing known Cu resistance-related genes, our global transcriptomics approach indicated that sulfur metabolism, iron-sulfur cluster, and cell secretion systems are involved in mediating Cu resistance in strain CR3. These results suggest that bacteria collectively use multiple systems to cope with Cu stress. Our findings concerning the global transcriptome response to Cu stress in CR3 provide new information for understanding the intricate regulatory network of Cu homeostasis in prokaryotes.
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Affiliation(s)
| | | | - Yan Zhao
- School of Chemistry and Environmental Engineering , Changchun University of Science and Technology , Changchun 130022 , P. R. China
| | - Mingzhong Hu
- School of Chemical Engineering , Changchun University of Technology , Changchun 130012 , P. R. China
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Insights into multifaceted activities of CysK for therapeutic interventions. 3 Biotech 2019; 9:44. [PMID: 30675454 DOI: 10.1007/s13205-019-1572-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 01/10/2019] [Indexed: 01/24/2023] Open
Abstract
CysK (O-acetylserine sulfhydrylase) is a pyridoxal-5' phosphate-dependent enzyme which catalyzes the second step of the de novo cysteine biosynthesis pathway by converting O-acetyl serine (OAS) into l-cysteine in the presence of sulfide. The first step of the cysteine biosynthesis involves formation of OAS from serine and acetyl CoA by CysE (serine acetyltransferase). Apart from role of CysK in cysteine biosynthesis, recent studies have revealed various additional roles of this enzyme in bacterial physiology. Other than the suggested regulatory role in cysteine production, other activities of CysK include involvement of CysK-in contact-dependent toxin activation in Gram-negative pathogens, as a transcriptional regulator of CymR by stabilizing the CymR-DNA interactions, in biofilm formation by providing cysteine and via another mechanism not yet understood, in ofloxacin and tellurite resistance as well as in cysteine desulfurization. Some of these activities involve binding of CysK to another cellular partner, where the complex is regulated by the availability of OAS and/or sulfide (H2S). The aim of this study is to present an overview of current knowledge of multiple functions performed by CysK and identifying structural features involved in alternate functions. Due to possible role in disease, promoting or inhibiting a "moonlighting" function of CysK could be a target for developing novel therapeutic interventions.
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Wasilko NP, Larios-Valencia J, Steingard CH, Nunez BM, Verma SC, Miyashiro T. Sulfur availability for Vibrio fischeri growth during symbiosis establishment depends on biogeography within the squid light organ. Mol Microbiol 2019; 111:621-636. [PMID: 30506600 DOI: 10.1111/mmi.14177] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2018] [Indexed: 12/23/2022]
Abstract
The fitness of host-associated microbes depends on their ability to access nutrients in vivo. Identifying these mechanisms is significant for understanding how microbes have evolved to fill specific ecological niches within a host. Vibrio fischeri is a bioluminescent bacterium that colonizes and proliferates within the light organ of the Hawaiian bobtail squid, which provides an opportunity to study how bacteria grow in vivo. Here, the transcription factor CysB is shown to be necessary for V. fischeri both to grow on several sulfur sources in vitro and to establish symbiosis with juvenile squid. CysB is also found to regulate several genes involved in sulfate assimilation and to contribute to the growth of V. fischeri on cystine, which is the oxidized form of cysteine. A mutant that grows on cystine but not sulfate could establish symbiosis, suggesting that V. fischeri acquires nutrients related to this compound within the host. Finally, CysB-regulated genes are shown to be differentially expressed among the V. fischeri populations occupying the various colonization sites found within the light organ. Together, these results suggest the biogeography of V. fischeri populations within the squid light organ impacts the physiology of this symbiotic bacterium in vivo through CysB-dependent gene regulation.
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Affiliation(s)
- Nathan P Wasilko
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Jessie Larios-Valencia
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Caroline H Steingard
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Briana M Nunez
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Subhash C Verma
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
| | - Tim Miyashiro
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, 410 South Frear Laboratory, University Park, PA, 16802, USA
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Seregina TA, Nagornykh MO, Lobanov KV, Shakulov RS, Mironov AS. The New Role of СysB Transcription Factor in Cysteine Degradation and Production of Hydrogen Sulfide in E. coli. RUSS J GENET+ 2018. [DOI: 10.1134/s1022795418110145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Kumar S, Mahajan S, Jain S. Feedbacks from the metabolic network to the genetic network reveal regulatory modules in E. coli and B. subtilis. PLoS One 2018; 13:e0203311. [PMID: 30286091 PMCID: PMC6171850 DOI: 10.1371/journal.pone.0203311] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 08/18/2018] [Indexed: 11/18/2022] Open
Abstract
The genetic regulatory network (GRN) plays a key role in controlling the response of the cell to changes in the environment. Although the structure of GRNs has been the subject of many studies, their large scale structure in the light of feedbacks from the metabolic network (MN) has received relatively little attention. Here we study the causal structure of the GRNs, namely the chain of influence of one component on the other, taking into account feedback from the MN. First we consider the GRNs of E. coli and B. subtilis without feedback from MN and illustrate their causal structure. Next we augment the GRNs with feedback from their respective MNs by including (a) links from genes coding for enzymes to metabolites produced or consumed in reactions catalyzed by those enzymes and (b) links from metabolites to genes coding for transcription factors whose transcriptional activity the metabolites alter by binding to them. We find that the inclusion of feedback from MN into GRN significantly affects its causal structure, in particular the number of levels and relative positions of nodes in the hierarchy, and the number and size of the strongly connected components (SCCs). We then study the functional significance of the SCCs. For this we identify condition specific feedbacks from the MN into the GRN by retaining only those enzymes that are essential for growth in specific environmental conditions simulated via the technique of flux balance analysis (FBA). We find that the SCCs of the GRN augmented by these feedbacks can be ascribed specific functional roles in the organism. Our algorithmic approach thus reveals relatively autonomous subsystems with specific functionality, or regulatory modules in the organism. This automated approach could be useful in identifying biologically relevant modules in other organisms for which network data is available, but whose biology is less well studied.
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Affiliation(s)
- Santhust Kumar
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India
| | - Saurabh Mahajan
- National Centre for Biological Sciences, Bangalore, Karnataka 560065, India
| | - Sanjay Jain
- Department of Physics and Astrophysics, University of Delhi, Delhi 110007, India
- Santa Fe Institute, 1399 Hyde Park Road, Santa Fe, NM 87501, United States of America
- * E-mail:
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Kawano Y, Suzuki K, Ohtsu I. Current understanding of sulfur assimilation metabolism to biosynthesize L-cysteine and recent progress of its fermentative overproduction in microorganisms. Appl Microbiol Biotechnol 2018; 102:8203-8211. [PMID: 30046857 DOI: 10.1007/s00253-018-9246-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/01/2022]
Abstract
To all organisms, sulfur is an essential and important element. The assimilation of inorganic sulfur molecules such as sulfate and thiosulfate into organic sulfur compounds such as L-cysteine and L-methionine (essential amino acid for human) is largely contributed by microorganisms. Of these, special attention is given to thiosulfate (S2O32-) assimilation, because thiosulfate relative to often utilized sulfate (SO42-) as a sulfur source is proposed to be more advantageous in microbial growth and biotechnological applications like L-cysteine fermentative overproduction toward industrial manufacturing. In Escherichia coli as well as other many bacteria, the thiosulfate assimilation pathway is known to depend on O-acetyl-L-serine sulfhydrylase B. Recently, another yet-unidentified CysM-independent thiosulfate pathway was found in E. coli. This pathway is expected to consist of the initial part of the thiosulfate to sulfite (SO32-) conversion, and the latter part might be shared with the final part of the known sulfate assimilation pathway [sulfite → sulfide (S2-) → L-cysteine]. The catalysis of thiosulfate to sulfite is at least partly mediated by thiosulfate sulfurtransferase (GlpE). In this mini-review, we introduce updated comprehensive information about sulfur assimilation in microorganisms, including this topic. Also, we introduce recent advances of the application study about L-cysteine overproduction, including the GlpE overexpression.
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Affiliation(s)
- Yusuke Kawano
- Innovation Medical Research Institute, University of Tsukuba, Tsukuba, Japan
| | - Kengo Suzuki
- Department of Research and Development, Euglena Co., Ltd., Minato-ku, Tokyo, Japan
| | - Iwao Ohtsu
- Innovation Medical Research Institute, University of Tsukuba, Tsukuba, Japan.
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Arends J, Griego M, Thomanek N, Lindemann C, Kutscher B, Meyer HE, Narberhaus F. An Integrated Proteomic Approach Uncovers Novel Substrates and Functions of the Lon Protease in Escherichia coli. Proteomics 2018; 18:e1800080. [PMID: 29710379 DOI: 10.1002/pmic.201800080] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 04/20/2018] [Indexed: 01/29/2023]
Abstract
Controlling the cellular abundance and proper function of proteins by proteolysis is a universal process in all living organisms. In Escherichia coli, the ATP-dependent Lon protease is crucial for protein quality control and regulatory processes. To understand how diverse substrates are selected and degraded, unbiased global approaches are needed. We employed a quantitative Super-SILAC (stable isotope labeling with amino acids in cell culture) mass spectrometry approach and compared the proteomes of a lon mutant and a strain producing the protease to discover Lon-dependent physiological functions. To identify Lon substrates, we took advantage of a Lon trapping variant, which is able to translocate substrates but unable to degrade them. Lon-associated proteins were identified by label-free LC-MS/MS. The combination of both approaches revealed a total of 14 novel Lon substrates. Besides the identification of known pathways affected by Lon, for example, the superoxide stress response, our cumulative data suggests previously unrecognized fundamental functions of Lon in sulfur assimilation, nucleotide biosynthesis, amino acid and central energy metabolism.
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Affiliation(s)
- Jan Arends
- Department of Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, D-44801, Bochum, Germany
| | - Marcena Griego
- Department of Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, D-44801, Bochum, Germany
| | - Nikolas Thomanek
- Medical Proteome Center, Ruhr University Bochum, Universitätsstraße 150, D-44801, Bochum, Germany
| | - Claudia Lindemann
- Medical Proteome Center, Ruhr University Bochum, Universitätsstraße 150, D-44801, Bochum, Germany
| | - Blanka Kutscher
- Department of Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, D-44801, Bochum, Germany
| | - Helmut E Meyer
- Medical Proteome Center, Ruhr University Bochum, Universitätsstraße 150, D-44801, Bochum, Germany.,Department of Biomedical Research, Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Bunsen-Kirchhoff-Straße 11, D-44139, Dortmund, Germany
| | - Franz Narberhaus
- Department of Microbial Biology, Ruhr University Bochum, Universitätsstraße 150, D-44801, Bochum, Germany
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Jiang L, Lyu J, Shao Z. Sulfur Metabolism of Hydrogenovibrio thermophilus Strain S5 and Its Adaptations to Deep-Sea Hydrothermal Vent Environment. Front Microbiol 2017; 8:2513. [PMID: 29312214 PMCID: PMC5733100 DOI: 10.3389/fmicb.2017.02513] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 12/04/2017] [Indexed: 11/13/2022] Open
Abstract
Hydrogenovibrio bacteria are ubiquitous in global deep-sea hydrothermal vents. However, their adaptations enabling survival in these harsh environments are not well understood. In this study, we characterized the physiology and metabolic mechanisms of Hydrogenovibrio thermophilus strain S5, which was first isolated from an active hydrothermal vent chimney on the Southwest Indian Ridge. Physiological characterizations showed that it is a microaerobic chemolithomixotroph that can utilize sulfide, thiosulfate, elemental sulfur, tetrathionate, thiocyanate or hydrogen as energy sources and molecular oxygen as the sole electron acceptor. During thiosulfate oxidation, the strain produced extracellular sulfur globules 0.7–6.0 μm in diameter that were mainly composed of elemental sulfur and carbon. Some organic substrates including amino acids, tryptone, yeast extract, casamino acids, casein, acetate, formate, citrate, propionate, tartrate, succinate, glucose and fructose can also serve as carbon sources, but growth is weaker than under CO2 conditions, indicating that strain S5 prefers to be chemolithoautotrophic. None of the tested organic carbons could function as energy sources. Growth tests under various conditions confirmed its adaption to a mesophilic mixing zone of hydrothermal vents in which vent fluid was mixed with cold seawater, preferring moderate temperatures (optimal 37°C), alkaline pH (optimal pH 8.0), microaerobic conditions (optimal 4% O2), and reduced sulfur compounds (e.g., sulfide, optimal 100 μM). Comparative genomics showed that strain S5 possesses more complex sulfur metabolism systems than other members of genus Hydrogenovibrio. The genes encoding the intracellular sulfur oxidation protein (DsrEF) and assimilatory sulfate reduction were first reported in the genus Hydrogenovibrio. In summary, the versatility in energy and carbon sources, and unique physiological properties of this bacterium have facilitated its adaptation to deep-sea hydrothermal vent environments.
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Affiliation(s)
- Lijing Jiang
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China.,Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China.,Fujian Collaborative Innovation Center of Marine Biological Resources, Xiamen, China
| | - Jie Lyu
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China.,Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China.,Fujian Collaborative Innovation Center of Marine Biological Resources, Xiamen, China
| | - Zongze Shao
- Key Laboratory of Marine Genetic Resources, Third Institute of Oceanography, State Oceanic Administration, Xiamen, China.,Fujian Key Laboratory of Marine Genetic Resources, Xiamen, China.,Fujian Collaborative Innovation Center of Marine Biological Resources, Xiamen, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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Nonaka G, Takumi K. Cysteine degradation gene yhaM, encoding cysteine desulfidase, serves as a genetic engineering target to improve cysteine production in Escherichia coli. AMB Express 2017; 7:90. [PMID: 28488255 PMCID: PMC5423876 DOI: 10.1186/s13568-017-0389-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 04/21/2017] [Indexed: 11/16/2022] Open
Abstract
Cysteine is an important amino acid for various industries; however, there is no efficient microbial fermentation-based production method available. Owing to its cytotoxicity, bacterial intracellular levels of cysteine are stringently controlled via several modes of regulation, including cysteine degradation by cysteine desulfhydrases and cysteine desulfidases. In Escherichia coli, several metabolic enzymes are known to exhibit cysteine degradative activities, however, their specificity and physiological significance for cysteine detoxification via degradation are unclear. Relaxing the strict regulation of cysteine is crucial for its overproduction; therefore, identifying and modulating the major degradative activity could facilitate the genetic engineering of a cysteine-producing strain. In the present study, we used genetic screening to identify genes that confer cysteine resistance in E. coli and we identified yhaM, which encodes cysteine desulfidase and decomposes cysteine into hydrogen sulfide, pyruvate, and ammonium. Phenotypic characterization of a yhaM mutant via growth under toxic concentrations of cysteine followed by transcriptional analysis of its response to cysteine showed that yhaM is cysteine-inducible, and its physiological role is associated with resisting the deleterious effects of cysteine in E. coli. In addition, we confirmed the effects of this gene on the fermentative production of cysteine using E. coli-based cysteine-producing strains. We propose that yhaM encodes the major cysteine-degrading enzyme and it has the most significant role in cysteine detoxification among the numerous enzymes reported in E. coli, thereby providing a core target for genetic engineering to improve cysteine production in this bacterium.
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Mittal M, Singh AK, Kumaran S. Structural and biochemical characterization of ligand recognition by CysB, the master regulator of sulfate metabolism. Biochimie 2017; 142:112-124. [PMID: 28838607 DOI: 10.1016/j.biochi.2017.08.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
Abstract
CysB, a member of LysR-type transcriptional regulators, up-regulates the expression of genes associated with sulfate metabolism and cysteine biosynthesis. CysB is activated under sulfur limiting conditions by O-acetylserine (OAS) and N-acetylserine (NAS), but the activation mechanism of CysB remain unknown. Here, we report four crystal structures of ligand binding domains of CysB (CysB-LBD) in apo form and in complex with sulfate, OAS, and NAS. Our results show that CysB has two distinct allosteric ligand binding sites; a sulfate and NAS specific site-1 and a second, NAS and OAS specific site-2. All three ligands bind through the induced-fit mechanism. Surprisingly, OAS remodels the site-1 by binding to site-2, suggesting that site-1 and site-2 are coupled allosterically. Using DNA binding and site-directed mutagenesis approach, we show that OAS enhances NAS mediated activation and mutation at site-1 has no effect on site-2 mediated OAS activation. Results indicate that inducer binding triggered signals from OAS-Specific site-2 are relayed to DBD through site-1. Together, results presented here suggest that induced-fit binding and allosteric coupling between two ligand binding sites and DBD underlie the key feature of CysB activation. Further, this study provides first structural glimpse into recognition of inducer ligands by CysB and provides a general framework to understand how LTTR family regulators respond to dual activators.
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Affiliation(s)
- Monica Mittal
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology (IMTECH), G. N. Ramachandran Protein Center, Sector 39-A, Chandigarh, 160036, India
| | - Appu Kumar Singh
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology (IMTECH), G. N. Ramachandran Protein Center, Sector 39-A, Chandigarh, 160036, India
| | - S Kumaran
- Council of Scientific and Industrial Research (CSIR), Institute of Microbial Technology (IMTECH), G. N. Ramachandran Protein Center, Sector 39-A, Chandigarh, 160036, India.
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Bacterial PerO Permeases Transport Sulfate and Related Oxyanions. J Bacteriol 2017; 199:JB.00183-17. [PMID: 28461447 DOI: 10.1128/jb.00183-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 04/22/2017] [Indexed: 01/13/2023] Open
Abstract
Rhodobacter capsulatus synthesizes the high-affinity ABC transporters CysTWA and ModABC to specifically import the chemically related oxyanions sulfate and molybdate, respectively. In addition, R. capsulatus has the low-affinity permease PerO acting as a general oxyanion transporter, whose elimination increases tolerance to molybdate and tungstate. Although PerO-like permeases are widespread in bacteria, their function has not been examined in any other species to date. Here, we present evidence that PerO permeases from the alphaproteobacteria Agrobacterium tumefaciens, Dinoroseobacter shibae, Rhodobacter sphaeroides, and Sinorhizobium meliloti and the gammaproteobacterium Pseudomonas stutzeri functionally substitute for R. capsulatus PerO in sulfate uptake and sulfate-dependent growth, as shown by assimilation of radioactively labeled sulfate and heterologous complementation. Disruption of perO genes in A. tumefaciens, R. sphaeroides, and S. meliloti increased tolerance to tungstate and, in the case of R. sphaeroides, to molybdate, suggesting that heterometal oxyanions are common substrates of PerO permeases. This study supports the view that bacterial PerO permeases typically transport sulfate and related oxyanions and, hence, form a functionally conserved permease family.IMPORTANCE Despite the widespread distribution of PerO-like permeases in bacteria, our knowledge about PerO function until now was limited to one species, Rhodobacter capsulatus In this study, we showed that PerO proteins from diverse bacteria are functionally similar to the R. capsulatus prototype, suggesting that PerO permeases form a conserved family whose members transport sulfate and related oxyanions.
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Mechanism of H 2S-mediated protection against oxidative stress in Escherichia coli. Proc Natl Acad Sci U S A 2017; 114:6022-6027. [PMID: 28533366 DOI: 10.1073/pnas.1703576114] [Citation(s) in RCA: 136] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Endogenous hydrogen sulfide (H2S) renders bacteria highly resistant to oxidative stress, but its mechanism remains poorly understood. Here, we report that 3-mercaptopyruvate sulfurtransferase (3MST) is the major source of endogenous H2S in Escherichia coli Cellular resistance to H2O2 strongly depends on the activity of mstA, a gene that encodes 3MST. Deletion of the ferric uptake regulator (Fur) renders ∆mstA cells hypersensitive to H2O2 Conversely, induction of chromosomal mstA from a strong pLtetO-1 promoter (P tet -mstA) renders ∆fur cells fully resistant to H2O2 Furthermore, the endogenous level of H2S is reduced in ∆fur or ∆sodA ∆sodB cells but restored after the addition of an iron chelator dipyridyl. Using a highly sensitive reporter of the global response to DNA damage (SOS) and the TUNEL assay, we show that 3MST-derived H2S protects chromosomal DNA from oxidative damage. We also show that the induction of the CysB regulon in response to oxidative stress depends on 3MST, whereas the CysB-regulated l-cystine transporter, TcyP, plays the principle role in the 3MST-mediated generation of H2S. These findings led us to propose a model to explain the interplay between l-cysteine metabolism, H2S production, and oxidative stress, in which 3MST protects E. coli against oxidative stress via l-cysteine utilization and H2S-mediated sequestration of free iron necessary for the genotoxic Fenton reaction.
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Puigvert M, Guarischi-Sousa R, Zuluaga P, Coll NS, Macho AP, Setubal JC, Valls M. Transcriptomes of Ralstonia solanacearum during Root Colonization of Solanum commersonii. FRONTIERS IN PLANT SCIENCE 2017; 8:370. [PMID: 28373879 PMCID: PMC5357869 DOI: 10.3389/fpls.2017.00370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 03/02/2017] [Indexed: 05/03/2023]
Abstract
Bacterial wilt of potatoes-also called brown rot-is a devastating disease caused by the vascular pathogen Ralstonia solanacearum that leads to significant yield loss. As in other plant-pathogen interactions, the first contacts established between the bacterium and the plant largely condition the disease outcome. Here, we studied the transcriptome of R. solanacearum UY031 early after infection in two accessions of the wild potato Solanum commersonii showing contrasting resistance to bacterial wilt. Total RNAs obtained from asymptomatic infected roots were deep sequenced and for 4,609 out of the 4,778 annotated genes in strain UY031 were recovered. Only 2 genes were differentially-expressed between the resistant and the susceptible plant accessions, suggesting that the bacterial component plays a minor role in the establishment of disease. On the contrary, 422 genes were differentially expressed (DE) in planta compared to growth on a synthetic rich medium. Only 73 of these genes had been previously identified as DE in a transcriptome of R. solanacearum extracted from infected tomato xylem vessels. Virulence determinants such as the Type Three Secretion System (T3SS) and its effector proteins, motility structures, and reactive oxygen species (ROS) detoxifying enzymes were induced during infection of S. commersonii. On the contrary, metabolic activities were mostly repressed during early root colonization, with the notable exception of nitrogen metabolism, sulfate reduction and phosphate uptake. Several of the R. solanacearum genes identified as significantly up-regulated during infection had not been previously described as virulence factors. This is the first report describing the R. solanacearum transcriptome directly obtained from infected tissue and also the first to analyze bacterial gene expression in the roots, where plant infection takes place. We also demonstrate that the bacterial transcriptome in planta can be studied when pathogen numbers are low by sequencing transcripts from infected tissue avoiding prokaryotic RNA enrichment.
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Affiliation(s)
- Marina Puigvert
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | | | - Paola Zuluaga
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | - Núria S. Coll
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
| | - Alberto P. Macho
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences (CAS)Shanghai, China
| | - João C. Setubal
- Department of Biochemistry, University of São PauloSão Paulo, Brazil
| | - Marc Valls
- Department of Genetics, University of BarcelonaBarcelona, Spain
- Centre for Research in Agricultural Genomics CSIC-IRTA, Autonomous University of BarcelonaBellaterra, Spain
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Fermentative Production of Cysteine by Pantoea ananatis. Appl Environ Microbiol 2017; 83:AEM.02502-16. [PMID: 28003193 DOI: 10.1128/aem.02502-16] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 12/15/2016] [Indexed: 11/20/2022] Open
Abstract
Cysteine is a commercially important amino acid; however, it lacks an efficient fermentative production method. Due to its cytotoxicity, intracellular cysteine levels are stringently controlled via several regulatory modes. Managing its toxic effects as well as understanding and deregulating the complexities of regulation are crucial for establishing the fermentative production of cysteine. The regulatory modes include feedback inhibition of key metabolic enzymes, degradation, efflux pumps, and the transcriptional regulation of biosynthetic genes by a master cysteine regulator, CysB. These processes have been extensively studied using Escherichia coli for overproducing cysteine by fermentation. In this study, we genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to identify key factors required for cysteine production. According to this and our previous studies, we identified a major cysteine desulfhydrase gene, ccdA (formerly PAJ_0331), involved in cysteine degradation, and the cysteine efflux pump genes cefA and cefB (formerly PAJ_3026 and PAJ_p0018, respectively), which may be responsible for downregulating the intracellular cysteine level. Our findings revealed that ccdA deletion and cefA and cefB overexpression are crucial factors for establishing fermentative cysteine production in P. ananatis and for obtaining a higher cysteine yield when combined with genes in the cysteine biosynthetic pathway. To our knowledge, this is the first demonstration of cysteine production in P. ananatis, which has fundamental implications for establishing overproduction in this microbe.IMPORTANCE The efficient production of cysteine is a major challenge in the amino acid fermentation industry. In this study, we identified cysteine efflux pumps and degradation pathways as essential elements and genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to establish the fermentative production of cysteine. This study provides crucial insights into the design and construction of cysteine-producing strains, which may play central roles in realizing commercial basis production.
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Shimada T, Tanaka K, Ishihama A. Transcription factor DecR (YbaO) controls detoxification of L-cysteine in Escherichia coli. Microbiology (Reading) 2016; 162:1698-1707. [DOI: 10.1099/mic.0.000337] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Tomohiro Shimada
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta, 4259-R1-29, Yokohama 226-8503, Japan
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Kan Tanaka
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Nagatsuta, 4259-R1-29, Yokohama 226-8503, Japan
| | - Akira Ishihama
- Research Center for Micro-Nano Technology, Hosei University, Koganei, Tokyo 184-8584, Japan
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Yamazaki S, Takei K, Nonaka G. ydjN encodes an S-sulfocysteine transporter required by Escherichia coli for growth on S-sulfocysteine as a sulfur source. FEMS Microbiol Lett 2016; 363:fnw185. [PMID: 27481704 DOI: 10.1093/femsle/fnw185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2016] [Indexed: 11/13/2022] Open
Abstract
Sulfur is an essential element for growth and many physiological functions. As sulfur sources for Escherichia coli and related bacteria, specific transporters import various sulfur-containing compounds from the environment. In this study, we identified and characterized an alternative function of the cystine transporter YdjN in E. coli as a transporter of S-sulfocysteine, a sulfur-containing intermediate in the assimilatory cysteine biosynthesis that is used as a sulfur source for the growth of E. coli We also demonstrated that the transport of S-sulfocysteine via YdjN depends on the transcriptional regulator CysB, a master regulator that controls most of the genes involved in sulfur assimilation and cysteine metabolism. We found that the use of S-sulfocysteine as a sulfur source depends on glutathione because mutations in glutathione biosynthetic genes abolish growth when S-sulfocysteine is used as a sole sulfur source, thereby supporting the previous findings that the conversion of S-sulfocysteine to cysteine is catalyzed by glutaredoxins. To the best of our knowledge, this is the first report of a functional S-sulfocysteine transporter across organisms, which strongly supports the hypothesis that S-sulfocysteine is not only a metabolic intermediate but also a physiologically significant substance in specific natural environments.
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Affiliation(s)
- Shunsuke Yamazaki
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan
| | - Kensuke Takei
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan
| | - Gen Nonaka
- Research Institute for Bioscience Products and Fine Chemicals, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki, Kanagawa 210-8681, Japan
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Wareham LK, Begg R, Jesse HE, Van Beilen JWA, Ali S, Svistunenko D, McLean S, Hellingwerf KJ, Sanguinetti G, Poole RK. Carbon Monoxide Gas Is Not Inert, but Global, in Its Consequences for Bacterial Gene Expression, Iron Acquisition, and Antibiotic Resistance. Antioxid Redox Signal 2016; 24:1013-28. [PMID: 26907100 PMCID: PMC4921903 DOI: 10.1089/ars.2015.6501] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AIMS Carbon monoxide is a respiratory poison and gaseous signaling molecule. Although CO-releasing molecules (CORMs) deliver CO with temporal and spatial specificity in mammals, and are proven antimicrobial agents, we do not understand the modes of CO toxicity. Our aim was to explore the impact of CO gas per se, without intervention of CORMs, on bacterial physiology and gene expression. RESULTS We used tightly controlled chemostat conditions and integrated transcriptomic datasets with statistical modeling to reveal the global effects of CO. CO is known to inhibit bacterial respiration, and we found expression of genes encoding energy-transducing pathways to be significantly affected via the global regulators, Fnr, Arc, and PdhR. Aerobically, ArcA-the response regulator-is transiently phosphorylated and pyruvate accumulates, mimicking anaerobiosis. Genes implicated in iron acquisition, and the metabolism of sulfur amino acids and arginine, are all perturbed. The global iron-related changes, confirmed by modulation of activity of the transcription factor Fur, may underlie enhanced siderophore excretion, diminished intracellular iron pools, and the sensitivity of CO-challenged bacteria to metal chelators. Although CO gas (unlike H2S and NO) offers little protection from antibiotics, a ruthenium CORM is a potent adjuvant of antibiotic activity. INNOVATION This is the first detailed exploration of global bacterial responses to CO, revealing unexpected targets with implications for employing CORMs therapeutically. CONCLUSION This work reveals the complexity of bacterial responses to CO and provides a basis for understanding the impacts of CO from CORMs, heme oxygenase activity, or environmental sources. Antioxid. Redox Signal. 24, 1013-1028.
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Affiliation(s)
- Lauren K Wareham
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Ronald Begg
- 2 School of Informatics, The University of Edinburgh , Edinburgh, United Kingdom
| | - Helen E Jesse
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Johan W A Van Beilen
- 3 Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam , Amsterdam, The Netherlands
| | - Salar Ali
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Dimitri Svistunenko
- 4 Biomedical EPR Facility, School of Biological Sciences, University of Essex , Colchester, United Kingdom
| | - Samantha McLean
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
| | - Klaas J Hellingwerf
- 3 Molecular Microbial Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam , Amsterdam, The Netherlands
| | - Guido Sanguinetti
- 2 School of Informatics, The University of Edinburgh , Edinburgh, United Kingdom
| | - Robert K Poole
- 1 Department of Molecular Biology and Biotechnology, The University of Sheffield , Sheffield, United Kingdom
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Korshunov S, Imlay KRC, Imlay JA. The cytochrome bd oxidase of Escherichia coli prevents respiratory inhibition by endogenous and exogenous hydrogen sulfide. Mol Microbiol 2016; 101:62-77. [PMID: 26991114 DOI: 10.1111/mmi.13372] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2016] [Indexed: 12/31/2022]
Abstract
When sulfur compounds are scarce or difficult to process, Escherichia coli adapts by inducing the high-level expression of sulfur-compound importers. If cystine then becomes available, the cystine is rapidly overimported and reduced, leading to a burgeoning pool of intracellular cysteine. Most of the excess cysteine is exported, but some is adventitiously degraded, with the consequent release of sulfide. Sulfide is a potent ligand of copper and heme moieties, raising the prospect that it interferes with enzymes. We observed that when cystine was provided and sulfide levels rose, E. coli became strictly dependent upon cytochrome bd oxidase for continued respiration. Inspection revealed that low-micromolar levels of sulfide inhibited the proton-pumping cytochrome bo oxidase that is regarded as the primary respiratory oxidase. In the absence of the back-up cytochrome bd oxidase, growth failed. Exogenous sulfide elicited the same effect. The potency of sulfide was enhanced when oxygen concentrations were low. Natural oxic-anoxic interfaces are often sulfidic, including the intestinal environment where E. coli dwells. We propose that the sulfide resistance of the cytochrome bd oxidase is a key trait that permits respiration in such habitats.
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Affiliation(s)
- Sergey Korshunov
- Department of Microbiology, University of Illinois, Urbana, IL, 61801, USA
| | - Karin R C Imlay
- Department of Microbiology, University of Illinois, Urbana, IL, 61801, USA
| | - James A Imlay
- Department of Microbiology, University of Illinois, Urbana, IL, 61801, USA
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Longo F, Motta S, Mauri P, Landini P, Rossi E. Interplay of the modified nucleotide phosphoadenosine 5'-phosphosulfate (PAPS) with global regulatory proteins in Escherichia coli: modulation of cyclic AMP (cAMP)-dependent gene expression and interaction with the HupA regulatory protein. Chem Biol Interact 2016; 259:39-47. [PMID: 27091548 DOI: 10.1016/j.cbi.2016.04.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/31/2016] [Accepted: 04/11/2016] [Indexed: 11/17/2022]
Abstract
In the bacterium Escherichia coli, some intermediates of the sulfate assimilation and cysteine biosynthesis pathway can act as signal molecules and modulate gene expression. In addition to sensing and utilization of sulphur sources, these signaling mechanisms also impact more global cell processes, such as resistance to antimicrobial agents and biofilm formation. In a recent work, we have shown that inactivation of the cysH gene, encoding phosphoadenosine-phosphosulfate (PAPS) reductase, and the consequent increase in intracellular PAPS concentration, strongly affect production of several cell surface-associated structures, enhancing surface adhesion and cell aggregation. In order to identify the molecular mechanism relaying intracellular PAPS concentration to regulation of cell surface-associated structures, we looked for mutations able to suppress the effects of cysH inactivation. We found that mutations in the adenylate cyclase-encoding cyaA gene abolished the effects of PAPS accumulation; consistent with this result, cyclic AMP (cAMP)-dependent gene expression appears to be increased in the cysH mutant. Experiments aimed at the direct identification of proteins interacting with either CysC or CysH, i.e. the PAPS-related proteins APS kinase and PAPS reductase, allowed us to identify several regulators, namely, CspC, CspE, HNS and HupA. Protein-protein interaction between HupA and CysH was confirmed by a bacterial two hybrid system, and inactivation of the hupA gene enhanced the effects of the cysH mutation in terms of production of cell surface-associated factors. Our results indicate that PAPS can modulate different regulatory systems, providing evidence that this molecule acts as a global signal molecule in E. coli.
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Affiliation(s)
- Francesca Longo
- Department of Biosciences, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy.
| | - Sara Motta
- Institute of Biomedical Technologies, National Research Council, Via Fratelli Cervi 93, 20090, Segrate, Milan, Italy.
| | - Pierluigi Mauri
- Institute of Biomedical Technologies, National Research Council, Via Fratelli Cervi 93, 20090, Segrate, Milan, Italy.
| | - Paolo Landini
- Department of Biosciences, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy.
| | - Elio Rossi
- Department of Biosciences, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy.
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l-Cysteine Metabolism and Fermentation in Microorganisms. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2016; 159:129-151. [DOI: 10.1007/10_2016_29] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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