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Gnanagobal H, Cao T, Hossain A, Vasquez I, Chakraborty S, Chukwu-Osazuwa J, Boyce D, Espinoza MJ, García-Angulo VA, Santander J. Role of riboflavin biosynthesis gene duplication and transporter in Aeromonas salmonicida virulence in marine teleost fish. Virulence 2023; 14:2187025. [PMID: 36895132 PMCID: PMC10012899 DOI: 10.1080/21505594.2023.2187025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
Abstract
Active flavins derived from riboflavin (vitamin B2) are essential for life. Bacteria biosynthesize riboflavin or scavenge it through uptake systems, and both mechanisms may be present. Because of riboflavin's critical importance, the redundancy of riboflavin biosynthetic pathway (RBP) genes might be present. Aeromonas salmonicida, the aetiological agent of furunculosis, is a pathogen of freshwater and marine fish, and its riboflavin pathways have not been studied. This study characterized the A. salmonicida riboflavin provision pathways. Homology search and transcriptional orchestration analysis showed that A. salmonicida has a main riboflavin biosynthetic operon that includes ribD, ribE1, ribBA, and ribH genes. Outside the main operon, putative duplicated genes ribA, ribB and ribE, and a ribN riboflavin importer encoding gene, were found. Monocistronic mRNA ribA, ribB and ribE2 encode for their corresponding functional riboflavin biosynthetic enzyme. While the product of ribBA conserved the RibB function, it lacked the RibA function. Likewise, ribN encodes a functional riboflavin importer. Transcriptomics analysis indicated that external riboflavin affected the expression of a relatively small number of genes, including a few involved in iron metabolism. ribB was downregulated in response to external riboflavin, suggesting negative feedback. Deletion of ribA, ribB and ribE1 showed that these genes are required for A. salmonicida riboflavin biosynthesis and virulence in Atlantic lumpfish (Cyclopterus lumpus). A. salmonicida riboflavin auxotrophic attenuated mutants conferred low protection to lumpfish against virulent A. salmonicida. Overall, A. salmonicida has multiple riboflavin endowment forms, and duplicated riboflavin provision genes are critical for A. salmonicida infection.
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Affiliation(s)
- Hajarooba Gnanagobal
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Trung Cao
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Ahmed Hossain
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Ignacio Vasquez
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Setu Chakraborty
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Joy Chukwu-Osazuwa
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
| | - Danny Boyce
- The Dr. Joe Brown Aquatic Research Building (JBARB), Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Canada
| | - María Jesus Espinoza
- Microbiology and Mycology Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Mycology Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Javier Santander
- Marine Microbial Pathogenesis and Vaccinology Laboratory, Department of Ocean Sciences, Memorial University of Newfoundland, St John's, Canada
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2
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Yang J, Zhao D, Liu T, Zhang S, Wang W, Yan L, Gu JD. Growth and genome-based insights of Fe(III) reduction of the high-temperature and NaCl-tolerant Shewanella xiamenensis from Changqing oilfield of China. Front Microbiol 2022; 13:1028030. [PMID: 36545192 PMCID: PMC9760863 DOI: 10.3389/fmicb.2022.1028030] [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: 08/25/2022] [Accepted: 11/17/2022] [Indexed: 12/09/2022] Open
Abstract
Introduction A facultative anaerobe bacterium Shewanella xiamenensis CQ-Y1 was isolated from the wastewater of Changqing oilfield in Shaanxi Province of China. Shewanella is the important dissimilatory metal-reducing bacteria. It exhibited a well potential application in biodegradation and bioremediation. Methods Genome sequencing, assembling and functional annotation were conducted to explore the genome information of CQ-Y1. The effect of temperatures and NaCl concentrations on the CQ-Y1 growth and Fe(III) reduction were investigated by UV visible spectrophotometry, SEM and XRD. Results Genomic analysis revealed its complete genome was a circular chromosome of 4,710,887 bp with a GC content of 46.50% and 4,110 CDSs genes, 86 tRNAs and 26 rRNAs. It contains genes encoding for Na+/H+ antiporter, K+/Cl- transporter, heat shock protein associated with NaCl and high-temperature resistance. The presence of genes related to flavin, Cytochrome c, siderophore, and other related proteins supported Fe(III) reduction. In addition, CQ-Y1 could survive at 10% NaCl (w/v) and 45°C, and temperature showed more pronounced effects than NaCl concentration on the bacterial growth. The maximum Fe(III) reduction ratio of CQ-Y1 reached 70.1% at 30°C without NaCl, and the reduction reaction remained active at 40°C with 3% NaCl (w/v). NaCl concentration was more effective than temperature on microbial Fe(III) reduction. And the reduction products under high temperature and high NaCl conditions were characterized as Fe3(PO4)2, FeCl2 and Fe(OH)2. Discussion Accordingly, a Fe(III) reduction mechanism of CQ-Y1 mediated by Cytochrome c and flavin was hypothesised. These findings could provide information for a better understanding of the origin and evolution of genomic and metabolic diversity of S. xiamenensis.
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Affiliation(s)
- Jiani Yang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Dan Zhao
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Tao Liu
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China,Key Laboratory of Low-Carbon Green Agriculture in Northeastern China, Ministry of Agriculture and Rural Affairs, Daqing, China
| | - Shuang Zhang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Weidong Wang
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China,Key Laboratory of Low-Carbon Green Agriculture in Northeastern China, Ministry of Agriculture and Rural Affairs, Daqing, China
| | - Lei Yan
- Heilongjiang Provincial Key Laboratory of Environmental Microbiology and Recycling of Argo-Waste in Cold Region, College of Life Science and Biotechnology, Heilongjiang Bayi Agricultural University, Daqing, China,*Correspondence: Lei Yan,
| | - Ji-Dong Gu
- Environmental Science and Engineering Research Group, Guangdong Technion – Israel Institute of Technology, Shantou, Guangdong, China,Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion, Guangdong Technion – Israel Institute of Technology, Shantou, Guangdong, China
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Mahwish N, Bairy LK, Srinivasamurthy S. Antivitamins: A Silver Lining in the Era of Antimicrobial Resistance. J Pharmacol Pharmacother 2022. [DOI: 10.1177/0976500x221080378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Antivitamins are compounds that negate the biological effects of vitamins. They have been successfully exploited for the development of various classes of drugs. In the early 19th century, the antifolate prontosil was developed for the treatment of puerperal fever. Since then, numerous other antifolates have been used to treat a wide range of infections. Antifolates, such as methotrexate, are potent anticancer agents and antivitamin K, such as warfarin, are used as anticoagulants. Despite several years of research, most antivitamin-based drugs are limited to vitamin K and B9, and the development of antagonists for other vitamins is still in the nascent stage. In the era of antimicrobial resistance, antivitamins can be considered as a promising alternative to develop newer antimicrobials and are worth exploring further. This review discusses key antivitamins at different stages of development which have potential utility as antibiotic drug candidates. The summary of studies of antivitamins in clinical development is also narrated.
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Affiliation(s)
- Nayesha Mahwish
- Department of Pharmacology, Ras Al Khaimah College of Medical Sciences (RAKCOMS), RAK Medical and Health Sciences University Ras Al Khaimah (RAKMHSU), Ras Al Khaimah, United Arab Emirates
| | - Laxminarayana Kurady Bairy
- Department of Pharmacology, Ras Al Khaimah College of Medical Sciences (RAKCOMS), RAK Medical and Health Sciences University Ras Al Khaimah (RAKMHSU), Ras Al Khaimah, United Arab Emirates
| | - Sureshkumar Srinivasamurthy
- Department of Pharmacology, Ras Al Khaimah College of Medical Sciences (RAKCOMS), RAK Medical and Health Sciences University Ras Al Khaimah (RAKMHSU), Ras Al Khaimah, United Arab Emirates
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4
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Schneider C, Mack M. A second riboflavin import system is present in flavinogenic Streptomyces davaonensis and supports roseoflavin biosynthesis. Mol Microbiol 2021; 116:470-482. [PMID: 33829573 DOI: 10.1111/mmi.14726] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/01/2021] [Accepted: 04/02/2021] [Indexed: 12/01/2022]
Abstract
The antibiotic roseoflavin is produced by Streptomyces davaonensis in the stationary phase of growth. To support biosynthesis of the secondary metabolite roseoflavin, S. davaonensis underwent several genetic adaptations with regard to metabolism of the roseoflavin precursor and primary metabolite riboflavin. In addition to 17 riboflavin biosynthesis genes at different chromosomal locations, S. davaonensis contains the riboflavin transporter gene ribM being part of the riboflavin biosynthetic operon ribE1MAB5H. Deletion of this operon generated riboflavin auxotrophic S. davaonensis strains. The finding that S. davaonensis ΔribE1MAB5H was able to grow in a culture medium containing low levels of riboflavin indicated that in addition to RibM, a second riboflavin transporter is present in this bacterium. The S. davaonensis genes ribXY (former rosXY) represented candidate genes for such a second riboflavin transport system and the results of our experiments now show that RibXY from S. davaonensis is a highly efficient riboflavin importer but not a roseoflavin importer.
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Affiliation(s)
- Carmen Schneider
- Institute for Technical Microbiology, Department of Biotechnology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - Matthias Mack
- Institute for Technical Microbiology, Department of Biotechnology, Mannheim University of Applied Sciences, Mannheim, Germany
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5
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Schneider C, Konjik V, Kißling L, Mack M. The novel phosphatase RosC catalyzes the last unknown step of roseoflavin biosynthesis in Streptomyces davaonensis. Mol Microbiol 2020; 114:609-625. [PMID: 32621340 DOI: 10.1111/mmi.14567] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 12/31/2022]
Abstract
The bacterium Streptomyces davaonensis produces the antibiotic roseoflavin, which is a riboflavin (vitamin B2 ) analog. The key enzyme of roseoflavin biosynthesis is the 8-demethyl-8-amino-riboflavin-5'-phosphate (AFP) synthase RosB which synthesizes AFP from riboflavin-5'-phosphate. AFP is not a substrate for the last enzyme of roseoflavin biosynthesis the N, N-dimethyltransferase RosA, which generates roseoflavin from 8-demethyl-8-amino-riboflavin (AF). Consequently, the roseoflavin biosynthetic pathway depends on a phosphatase, which dephosphorylates AFP to AF. Here, we report on the identification and characterization of such an AFP phosphatase which we named RosC. The gene rosC is located immediately downstream of rosA and both genes are part of a cluster comprising 10 genes. Deletion of rosC from the chromosome of S. davaonensis led to reduced roseoflavin levels in the corresponding recombinant strain. In contrast to wild-type S. davaonensis, cell-free extracts of the rosC deletion strain did not catalyze dephosphorylation of AFP. RosC was purified from an overproducing Escherichia coli strain. RosC is the fastest enzyme of roseoflavin biosynthesis (kcat 31.3 ± 1.4 min-1 ). The apparent KM for the substrate AFP was 34.5 µM. Roseoflavin biosynthesis is now completely understood--it takes three enzymes (RosB, RosC, and RosA) to convert the flavin cofactor riboflavin-5'-phosphate into a potent antibiotic.
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Affiliation(s)
- Carmen Schneider
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - Valentino Konjik
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - Lena Kißling
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - Matthias Mack
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, Mannheim, Germany
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6
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Kißling L, Schneider C, Seibel K, Dorjjugder N, Busche T, Kalinowski J, Mack M. The roseoflavin producer
Streptomyces davaonensis
has a high catalytic capacity and specific genetic adaptations with regard to the biosynthesis of riboflavin. Environ Microbiol 2020; 22:3248-3265. [DOI: 10.1111/1462-2920.15066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/06/2020] [Accepted: 05/10/2020] [Indexed: 11/29/2022]
Affiliation(s)
- Lena Kißling
- Institute for Technical Microbiology, Department of Biotechnology Mannheim University of Applied Sciences Mannheim 68163 Germany
| | - Carmen Schneider
- Institute for Technical Microbiology, Department of Biotechnology Mannheim University of Applied Sciences Mannheim 68163 Germany
| | - Katharina Seibel
- Institute for Technical Microbiology, Department of Biotechnology Mannheim University of Applied Sciences Mannheim 68163 Germany
| | - Nasanjargal Dorjjugder
- Institute for Technical Microbiology, Department of Biotechnology Mannheim University of Applied Sciences Mannheim 68163 Germany
| | - Tobias Busche
- Center for Biotechnology Bielefeld University Bielefeld 33594 Germany
| | - Jörn Kalinowski
- Center for Biotechnology Bielefeld University Bielefeld 33594 Germany
| | - Matthias Mack
- Institute for Technical Microbiology, Department of Biotechnology Mannheim University of Applied Sciences Mannheim 68163 Germany
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7
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Zhang Y, Blaby-Haas CE, Steimle S, Verissimo AF, Garcia-Angulo VA, Koch HG, Daldal F, Khalfaoui-Hassani B. Cu Transport by the Extended Family of CcoA-like Transporters (CalT) in Proteobacteria. Sci Rep 2019; 9:1208. [PMID: 30718766 PMCID: PMC6362234 DOI: 10.1038/s41598-018-37988-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 12/11/2018] [Indexed: 01/01/2023] Open
Abstract
Comparative genomic studies of the bacterial MFS-type copper importer CcoA, required for cbb3-type cytochrome c oxidase (cbb3-Cox) biogenesis, revealed a widespread CcoA-like transporters (CalT) family, containing the conserved CcoA Cu-binding MxxxM and HxxxM motifs. Surprisingly, this family also included the RfnT-like proteins, earlier suggested to transport riboflavin. However, presence of the Cu-binding motifs in these proteins raised the possibility that they might be Cu transporters. To test this hypothesis, the genomic context of the corresponding genes was examined, and three of such genes from Ochrobactrum anthropi, Rhodopseudomonas palustris and Agrobacterium tumefaciens were expressed in Escherichia coli (ΔribB) and Rhodobacter capsulatus (ΔccoA) mutants. Copper and riboflavin uptake abilities of these strains were compared with those expressing R. capsulatus CcoA and Rhizobium leguminosarum RibN as bona fide copper and riboflavin importers, respectively. Overall data demonstrated that the "RfnT-like" CalT proteins are unable to efficiently transport riboflavin, but they import copper like CcoA. Nevertheless, even though expressed and membrane-localized in a R. capsulatus mutant lacking CcoA, these transporters were unable to accumulate Cu or complement for cbb3-Cox defect. This lack of functional exchangeability between the different subfamilies of CalT homologs suggests that MFS-type bacterial copper importers might be species-specific.
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Affiliation(s)
- Yang Zhang
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- School of Life Science, Xiamen University, Xiamen, 361102, China
| | | | - Stefan Steimle
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Andreia F Verissimo
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- bioMT-Institute for Biomolecular Targeting, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
| | - Victor A Garcia-Angulo
- Microbiology and Mycology Department, Insituto de Ciencias Biomédicas, University of Chile, Santiago, Chile
| | - Hans-Georg Koch
- Institut für Biochemie und Molekularbiologie, ZBMZ, Faculty of Medicine, Stefan-Meier-Strasse 17, Albert-Ludwigs-Universität Freiburg, 79104, Freiburg, Germany
| | - Fevzi Daldal
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Bahia Khalfaoui-Hassani
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA
- IPREM, UMR CNRS 5254, and Université de Pau et des Pays de l'Adour, BP1155, Pau, France
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8
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Sebastián M, Serrano A, Velázquez-Campoy A, Medina M. Kinetics and thermodynamics of the protein-ligand interactions in the riboflavin kinase activity of the FAD synthetase from Corynebacterium ammoniagenes. Sci Rep 2017; 7:7281. [PMID: 28779158 PMCID: PMC5544777 DOI: 10.1038/s41598-017-07875-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/04/2017] [Indexed: 01/20/2023] Open
Abstract
Enzymes known as bifunctional and bimodular prokaryotic type-I FAD synthetase (FADS) exhibit ATP:riboflavin kinase (RFK) and FMN:ATP adenylyltransferase (FMNAT) activities in their C-terminal and N-terminal modules, respectively, and produce flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). These act as cofactors of a plethora of flavoproteins in all organisms. Therefore, regulation of their production maintains the cellular flavoproteome homeostasis. Here, we focus on regulation of the FMN synthesis in Corynebacterium ammoniagenes (Ca) by the inhibition of its RFK activity by substrates and products of the reaction. We use a truncated CaFADS variant consisting in the isolated C-terminal RFK module, whose RFK activity is similar to that of the full-length enzyme. Inhibition of the RFK activity by the RF substrate is independent of the FMNAT module, and FMN production, in addition to being inhibited by an excess of RF, is also inhibited by both of the reaction products. Pre-steady-state kinetic and thermodynamic studies reveal key aspects to the substrates induced fit to produce the catalytically competent complex. Among them, the role of Mg2+ in the concerted allocation of substrates for catalysis and the ensemble of non-competent complexes that contribute to the regulated inhibition of the RFK activity are particularly relevant.
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Affiliation(s)
- María Sebastián
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, and Institute of Biocomputation and Physics of Complex Systems (Joint Units: BIFI-IQFR and GBsC-CSIC), University of Zaragoza, Zaragoza, Spain
| | - Ana Serrano
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, and Institute of Biocomputation and Physics of Complex Systems (Joint Units: BIFI-IQFR and GBsC-CSIC), University of Zaragoza, Zaragoza, Spain.,Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, Madrid, Spain
| | - Adrián Velázquez-Campoy
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, and Institute of Biocomputation and Physics of Complex Systems (Joint Units: BIFI-IQFR and GBsC-CSIC), University of Zaragoza, Zaragoza, Spain.,ARAID Foundation, Diputación General de Aragón, Zaragoza, Spain.,Aragon Institute for Health Research (IIS Aragon), Zaragoza, Spain
| | - Milagros Medina
- Department of Biochemistry and Molecular and Cellular Biology, Faculty of Sciences, and Institute of Biocomputation and Physics of Complex Systems (Joint Units: BIFI-IQFR and GBsC-CSIC), University of Zaragoza, Zaragoza, Spain.
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9
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Cisternas IS, Torres A, Flores AF, Angulo VAG. Differential regulation of riboflavin supply genes in Vibrio cholerae. Gut Pathog 2017; 9:10. [PMID: 28239422 PMCID: PMC5312566 DOI: 10.1186/s13099-017-0159-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 02/09/2017] [Indexed: 12/01/2022] Open
Abstract
Background Riboflavin is the precursor of important redox cofactors such as flavin mononucleotide (FMN) and flavin adenine dinucleotide, required for several biological processes. Vibrio cholerae, a pathogenic bacterium responsible for the cholera disease, possesses the ability to biosynthesize de novo as well as to uptake riboflavin through the riboflavin biosynthetic pathway (RBP) and the RibN importer, respectively. The intra-organism relationship between riboflavin biosynthesis and uptake functions has not been studied. Results This work determined the transcriptional organization of RBP genes and ribN in V. cholerae through reverse transcription polymerase chain reaction and analyzed their expression when growing with or without extracellular riboflavin using real time PCR. The RBP is organized in three transcriptional units, the major one containing ribD, ribE, ribA and ribH together with genes involved in functions not directly related to riboflavin biosynthesis such as nrdR and nusB. In addition, two independent monocistronic units contain ribA2 and ribB, the later conserving a putative FMN riboswitch. The ribN gene is encoded in operon with a gene coding for a predicted outer membrane protein and a gene encoding a protein with a glutaredoxin domain. Regulation analysis showed that among these transcriptional units, only ribB is negatively regulated by riboflavin and that its repression depends on the RibN riboflavin importer. Moreover, external riboflavin highly induced ribB transcription in a ΔribN strain. Also, a genomic database search found a negative correlation between the presence of nrdR and nusB and the FMN riboswitch in bacterial RBP operons. Conclusions Growing in the presence of riboflavin downregulates only a single element among the transcriptional units of riboflavin supply pathways. Thus, endogenous riboflavin biosynthesis seems to be negatively regulated by extracellular riboflavin through its specific effect on transcription of ribB in V. cholerae. Electronic supplementary material The online version of this article (doi:10.1186/s13099-017-0159-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ignacio Sepúlveda Cisternas
- Escuela de Biotecnología, Universidad Mayor, Campus Huechuraba, Santiago, Chile.,Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina Norte, Universidad de Chile, Pabellón L. Independencia, 1027, 8380453 Santiago, Chile
| | - Alexia Torres
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina Norte, Universidad de Chile, Pabellón L. Independencia, 1027, 8380453 Santiago, Chile
| | - Andrés Fuentes Flores
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina Norte, Universidad de Chile, Pabellón L. Independencia, 1027, 8380453 Santiago, Chile
| | - Víctor Antonio García Angulo
- Programa de Microbiología y Micología, Instituto de Ciencias Biomédicas, Facultad de Medicina Norte, Universidad de Chile, Pabellón L. Independencia, 1027, 8380453 Santiago, Chile
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10
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Konjik V, Brünle S, Demmer U, Vanselow A, Sandhoff R, Ermler U, Mack M. Die Kristallstruktur von RosB: Einblicke in den Reaktionsmechanismus des ersten Mitglieds einer flavodoxinähnlichen Enzymfamilie. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201610292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Valentino Konjik
- Hochschule Mannheim; Paul-Wittsack-Straße 10 68163 Mannheim Deutschland
| | - Steffen Brünle
- Max-Planck-Institut für Biophysik; Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Ulrike Demmer
- Max-Planck-Institut für Biophysik; Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Amanda Vanselow
- Hochschule Mannheim; Paul-Wittsack-Straße 10 68163 Mannheim Deutschland
| | - Roger Sandhoff
- Deutsches Krebsforschungszentrum (DKFZ); Im Neuenheimer Feld 280 69120 Heidelberg Deutschland
| | - Ulrich Ermler
- Max-Planck-Institut für Biophysik; Max-von-Laue-Straße 3 60438 Frankfurt am Main Deutschland
| | - Matthias Mack
- Hochschule Mannheim; Paul-Wittsack-Straße 10 68163 Mannheim Deutschland
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11
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Konjik V, Brünle S, Demmer U, Vanselow A, Sandhoff R, Ermler U, Mack M. The Crystal Structure of RosB: Insights into the Reaction Mechanism of the First Member of a Family of Flavodoxin-like Enzymes. Angew Chem Int Ed Engl 2016; 56:1146-1151. [DOI: 10.1002/anie.201610292] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Valentino Konjik
- Mannheim University of Applied Sciences; Paul-Wittsack-Strasse 10 68163 Mannheim Germany
| | - Steffen Brünle
- Max-Planck-Institute for Biophysics; Max-von-Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Ulrike Demmer
- Max-Planck-Institute for Biophysics; Max-von-Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Amanda Vanselow
- Mannheim University of Applied Sciences; Paul-Wittsack-Strasse 10 68163 Mannheim Germany
| | - Roger Sandhoff
- German Cancer Research Center (DKFZ); Im Neuenheimer Feld 280 69120 Heidelberg Germany
| | - Ulrich Ermler
- Max-Planck-Institute for Biophysics; Max-von-Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Matthias Mack
- Mannheim University of Applied Sciences; Paul-Wittsack-Strasse 10 68163 Mannheim Germany
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Abstract
Riboflavin derivatives are essential cofactors for a myriad of flavoproteins. In bacteria, flavins importance extends beyond their role as intracellular protein cofactors, as secreted flavins are a key metabolite in a variety of physiological processes. Bacteria obtain riboflavin through the endogenous riboflavin biosynthetic pathway (RBP) or by the use of importer proteins. Bacteria frequently encode multiple paralogs of the RBP enzymes and as for other micronutrient supply pathways, biosynthesis and uptake functions largely coexist. It is proposed that bacteria shut down biosynthesis and would rather uptake riboflavin when the vitamin is environmentally available. Recently, the overlap of riboflavin provisioning elements has gained attention and the functions of duplicated paralogs of RBP enzymes started to be addressed. Results point towards the existence of a modular structure in the bacterial riboflavin supply pathways. Such structure uses subsets of RBP genes to supply riboflavin for specific functions. Given the importance of riboflavin in intra and extracellular bacterial physiology, this complex array of riboflavin provision pathways may have developed to contend with the various riboflavin requirements. In riboflavin-prototrophic bacteria, riboflavin transporters could represent a module for riboflavin provision for particular, yet unidentified processes, rather than substituting for the RBP as usually assumed.
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Affiliation(s)
- Víctor Antonio García-Angulo
- a Microbiology and Mycology Program, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile , Santiago , Chile
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Joo M, Yoo HG, Kim HJ, Kwon HJ. ToxB encodes a canonical GTP cyclohydrolase II in toxoflavin biosynthesis and ribA expression restored toxoflavin production in a ΔtoxB mutant. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s13765-015-0116-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Gutiérrez-Preciado A, Torres AG, Merino E, Bonomi HR, Goldbaum FA, García-Angulo VA. Extensive Identification of Bacterial Riboflavin Transporters and Their Distribution across Bacterial Species. PLoS One 2015; 10:e0126124. [PMID: 25938806 PMCID: PMC4418817 DOI: 10.1371/journal.pone.0126124] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/29/2015] [Indexed: 11/18/2022] Open
Abstract
Riboflavin, the precursor for the cofactors flavin mononucleotide (FMN) and flavin adenine dinucleotide, is an essential metabolite in all organisms. While the functions for de novo riboflavin biosynthesis and riboflavin import may coexist in bacteria, the extent of this co-occurrence is undetermined. The RibM, RibN, RfuABCD and the energy-coupling factor-RibU bacterial riboflavin transporters have been experimentally characterized. In addition, ImpX, RfnT and RibXY are proposed as riboflavin transporters based on positional clustering with riboflavin biosynthetic pathway (RBP) genes or conservation of the FMN riboswitch regulatory element. Here, we searched for the FMN riboswitch in bacterial genomes to identify genes encoding riboflavin transporters and assessed their distribution among bacteria. Two new putative riboflavin transporters were identified: RibZ in Clostridium and RibV in Mesoplasma florum. Trans-complementation of an Escherichia coli riboflavin auxotroph strain confirmed the riboflavin transport activity of RibZ from Clostridium difficile, RibXY from Chloroflexus aurantiacus, ImpX from Fusobacterium nucleatum and RfnT from Ochrobactrum anthropi. The analysis of the genomic distribution of all known bacterial riboflavin transporters revealed that most occur in species possessing the RBP and that some bacteria may even encode functional riboflavin transporters from two different families. Our results indicate that some species possess ancestral riboflavin transporters, while others possess transporters that appear to have evolved recently. Moreover, our data suggest that unidentified riboflavin transporters also exist. The present study doubles the number of experimentally characterized riboflavin transporters and suggests a specific, non-accessory role for these proteins in riboflavin-prototrophic bacteria.
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Affiliation(s)
- Ana Gutiérrez-Preciado
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Alfredo Gabriel Torres
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
- Department of Pathology, Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Enrique Merino
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | | | | | - Víctor Antonio García-Angulo
- Department of Microbiology and Immunology, Sealy Center for Vaccine Development, University of Texas Medical Branch, Galveston, Texas, United States of America
- Centro de Genómica y Bioinformática, Universidad Mayor, Campus Huechuraba, Santiago, Chile
- * E-mail:
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15
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Bacterial flavin mononucleotide riboswitches as targets for flavin analogs. Methods Mol Biol 2014; 1103:165-76. [PMID: 24318894 DOI: 10.1007/978-1-62703-730-3_13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Roseoflavin is a toxic riboflavin (vitamin B2) analog and naturally is produced by Streptomyces davawensis. Roseoflavin is converted to roseoflavin mononucleotide (RoFMN) by promiscuous flavokinases (EC 2.7.1.26). Flavin mononucleotide (FMN) riboswitches control the expression of genes involved in riboflavin biosynthesis and/or transport. RoFMN triggers FMN riboswitches and negatively (or positively) affects expression of the downstream genes. RoFMN binding to the aptamer portion of FMN riboswitch RNAs occurs in the course of transcription by cellular RNA polymerases. We developed an in vitro test system to functionally characterize the interaction between riboflavin/FMN analogs such as roseoflavin/RoFMN and FMN riboswitches in the context of an actively transcribing RNA polymerase.
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Pedrolli DB, Jankowitsch F, Schwarz J, Langer S, Nakanishi S, Mack M. Natural riboflavin analogs. Methods Mol Biol 2014; 1146:41-63. [PMID: 24764087 DOI: 10.1007/978-1-4939-0452-5_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Riboflavin analogs have a good potential to serve as basic structures for the development of novel anti-infectives. Riboflavin analogs have multiple cellular targets, since riboflavin (as a precursor to flavin cofactors) is active at more than one site in the cell. As a result, the frequency of developing resistance to antimicrobials based on riboflavin analogs is expected to be significantly lower. The only known natural riboflavin analog with antibiotic function is roseoflavin from the bacterium Streptomyces davawensis. This antibiotic negatively affects flavoenzymes and FMN riboswitches. Another roseoflavin producer, Streptomyces cinnabarinus, was recently identified. Possibly, flavin analogs with antibiotic activity are more widespread than anticipated. The same could be true for flavin analogs yet to be discovered, which could constitute tools for cellular chemistry, thus allowing a further extension of the catalytic spectrum of flavoenzymes.
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Affiliation(s)
- Danielle Biscaro Pedrolli
- Institute for Technical Microbiology, Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163, Mannheim, Germany
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Identification and characterization of RibN, a novel family of riboflavin transporters from Rhizobium leguminosarum and other proteobacteria. J Bacteriol 2013; 195:4611-9. [PMID: 23935051 DOI: 10.1128/jb.00644-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Rhizobia are symbiotic bacteria able to invade and colonize the roots of legume plants, inducing the formation of nodules, where bacteria reduce atmospheric nitrogen (N2) to ammonia (NH3). Riboflavin availability influences the capacity of rhizobia to survive in the rhizosphere and to colonize roots. In this study, we identified the RL1692 gene of Rhizobium leguminosarum downstream of a flavin mononucleotide (FMN) riboswitch. RL1692 encodes a putative transmembrane permease with two EamA domains. The presence of an FMN riboswitch regulating a transmembrane protein is usually observed in riboflavin transporters, suggesting that RL1692 may be involved in riboflavin uptake. The product of RL1692, which we named RibN, is conserved in members of the alpha-, beta-, and gammaproteobacteria and shares no significant identity with any riboflavin transporter previously identified. In this work, we show that RibN is localized in the membrane cellular fraction and its expression is downregulated by riboflavin. By heterologous expression in a Brucella abortus mutant auxotrophic for riboflavin, we demonstrate that RibN possesses flavin transport activity. Similarly, we also demonstrate that RibN orthologues from Ochrobactrum anthropi and Vibrio cholerae (which lacks the FMN riboswitch) are able to transport riboflavin. An R. leguminosarum ribN null mutant exhibited lower nodule occupancy levels in pea plants during symbiosis assays. Thus, we propose that RibN and its homologues belong to a novel family of riboflavin transporters. This work provides the first experimental description of riboflavin transporters in Gram-negative bacteria.
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18
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Flavoproteins are potential targets for the antibiotic roseoflavin in Escherichia coli. J Bacteriol 2013; 195:4037-45. [PMID: 23836860 DOI: 10.1128/jb.00646-13] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The riboflavin analog roseoflavin is an antibiotic produced by Streptomyces davawensis. Riboflavin transporters are responsible for roseoflavin uptake by target cells. Roseoflavin is converted to the flavin mononucleotide (FMN) analog roseoflavin mononucleotide (RoFMN) by flavokinase and to the flavin adenine dinucleotide (FAD) analog roseoflavin adenine dinucleotide (RoFAD) by FAD synthetase. In order to study the effect of RoFMN and RoFAD in the cytoplasm of target cells, Escherichia coli was used as a model. E. coli is predicted to contain 38 different FMN- or FAD-dependent proteins (flavoproteins). These proteins were overproduced in recombinant E. coli strains grown in the presence of sublethal amounts of roseoflavin. The flavoproteins were purified and analyzed with regard to their cofactor contents. It was found that 37 out of 38 flavoproteins contained either RoFMN or RoFAD. These cofactors have different physicochemical properties than FMN and FAD and were reported to reduce or completely abolish flavoprotein function.
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Langer S, Nakanishi S, Mathes T, Knaus T, Binter A, Macheroux P, Mase T, Miyakawa T, Tanokura M, Mack M. The flavoenzyme azobenzene reductase AzoR from Escherichia coli binds roseoflavin mononucleotide (RoFMN) with high affinity and is less active in its RoFMN form. Biochemistry 2013; 52:4288-95. [PMID: 23713585 DOI: 10.1021/bi400348d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Gram-positive bacterium Streptomyces davawensis is the only organism known to produce the antibiotic roseoflavin. Roseoflavin is a structural riboflavin analogue and is converted to the flavin mononucleotide (FMN) analogue roseoflavin mononucleotide (RoFMN) by flavokinase. FMN-dependent homodimeric azobenzene reductase (AzoR) (EC 1.7.1.6) from Escherichia coli was analyzed as a model enzyme. In vivo and in vitro experiments revealed that RoFMN binds to the AzoR apoenzyme with an even higher affinity compared to that of the "natural" cofactor FMN. Structural analysis (at a resolution of 1.07 Å) revealed that RoFMN binding did not affect the overall topology of the enzyme and also did not interfere with dimerization of AzoR. The AzoR-RoFMN holoenzyme complex was found to be less active (30% of AzoR-FMN activity) in a standard assay. We provide evidence that the different physicochemical properties of RoFMN are responsible for its reduced cofactor activity.
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Affiliation(s)
- Simone Langer
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, Germany
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20
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Genome sequence of the bacterium Streptomyces davawensis JCM 4913 and heterologous production of the unique antibiotic roseoflavin. J Bacteriol 2012; 194:6818-27. [PMID: 23043000 DOI: 10.1128/jb.01592-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Streptomyces davawensis JCM 4913 synthesizes the antibiotic roseoflavin, a structural riboflavin (vitamin B(2)) analog. Here, we report the 9,466,619-bp linear chromosome of S. davawensis JCM 4913 and a 89,331-bp linear plasmid. The sequence has an average G+C content of 70.58% and contains six rRNA operons (16S-23S-5S) and 69 tRNA genes. The 8,616 predicted protein-coding sequences include 32 clusters coding for secondary metabolites, several of which are unique to S. davawensis. The chromosome contains long terminal inverted repeats of 33,255 bp each and atypical telomeres. Sequence analysis with regard to riboflavin biosynthesis revealed three different patterns of gene organization in Streptomyces species. Heterologous expression of a set of genes present on a subgenomic fragment of S. davawensis resulted in the production of roseoflavin by the host Streptomyces coelicolor M1152. Phylogenetic analysis revealed that S. davawensis is a close relative of Streptomyces cinnabarinus, and much to our surprise, we found that the latter bacterium is a roseoflavin producer as well.
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Pedrolli DB, Matern A, Wang J, Ester M, Siedler K, Breaker R, Mack M. A highly specialized flavin mononucleotide riboswitch responds differently to similar ligands and confers roseoflavin resistance to Streptomyces davawensis. Nucleic Acids Res 2012; 40:8662-73. [PMID: 22740651 PMCID: PMC3458559 DOI: 10.1093/nar/gks616] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Streptomyces davawensis is the only organism known to synthesize the antibiotic roseoflavin, a riboflavin (vitamin B2) analog. Roseoflavin is converted to roseoflavin mononucleotide (RoFMN) and roseoflavin adenine dinucleotide in the cytoplasm of target cells. (Ribo-)Flavin mononucleotide (FMN) riboswitches are genetic elements, which in many bacteria control genes responsible for the biosynthesis and transport of riboflavin. Streptomyces davawensis is roseoflavin resistant, and the closely related bacterium Streptomyces coelicolor is roseoflavin sensitive. The two bacteria served as models to investigate roseoflavin resistance of S. davawensis and to analyze the mode of action of roseoflavin in S. coelicolor. Our experiments demonstrate that the ribB FMN riboswitch of S. davawensis (in contrast to the corresponding riboswitch of S. coelicolor) is able to discriminate between the two very similar flavins FMN and RoFMN and shows opposite responses to the latter ligands.
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Affiliation(s)
- Danielle Biscaro Pedrolli
- Fakultät für Biotechnologie, Institut für Technische Mikrobiologie, Hochschule Mannheim, Paul-Wittsack-Str. 10, 68163 Mannheim, Germany
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22
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Hemberger S, Pedrolli DB, Stolz J, Vogl C, Lehmann M, Mack M. RibM from Streptomyces davawensis is a riboflavin/roseoflavin transporter and may be useful for the optimization of riboflavin production strains. BMC Biotechnol 2011; 11:119. [PMID: 22136195 PMCID: PMC3239331 DOI: 10.1186/1472-6750-11-119] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 12/02/2011] [Indexed: 01/15/2023] Open
Abstract
Background The bacterium Bacillus subtilis, which is not a natural riboflavin overproducer, has been converted into an excellent production strain by classical mutagenesis and metabolic engineering. To our knowledge, the enhancement of riboflavin excretion from the cytoplasm of overproducing cells has not yet been considered as a target for (further) strain improvement. Here we evaluate the flavin transporter RibM from Streptomyces davawensis with respect to improvement of a riboflavin production strain. Results The gene ribM from S. davawensis, coding for a putative facilitator of riboflavin uptake, was codon optimized (ribMopt) for expression in B. subtilis. The gene ribMopt was functionally introduced into B. subtilis using the isopropyl-β-thiogalactopyranoside (IPTG)-inducible expression plasmid pHT01: Northern-blot analysis of total RNA from IPTG treated recombinant B. subtilis cells revealed a ribMopt specific transcript. Western blot analysis showed that the his6-tagged heterologous gene product RibM was present in the cytoplasmic membrane. Expression of ribM in Escherichia coli increased [14C]riboflavin uptake, which was not affected by the protonophore carbonyl cyanide m-chlorophenylhydrazone (CCCP). Expression of ribMopt supported growth of a B. subtilis ΔribB::Ermr ΔribU::Kanr double mutant deficient in riboflavin synthesis (ΔribB) and also deficient with respect to riboflavin uptake (ΔribU). Expression of ribMopt increased roseoflavin (a toxic riboflavin analog produced by S. davawensis) sensitivity of a B. subtilis ΔribU::Kanr strain. Riboflavin synthesis by a model riboflavin B. subtilis production strain overproducing RibM was increased significantly depending on the amount of the inducer IPTG. Conclusions The energy independent flavin facilitator RibM could in principle catalyze riboflavin export and thus may be useful to increase the riboflavin yield in a riboflavin production process using a recombinant RibM overproducing B. subtilis strain (or any other microorganism).
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Affiliation(s)
- Sabrina Hemberger
- Institut für Technische Mikrobiologie, Hochschule Mannheim, Mannheim, Germany
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Jankowitsch F, Kühm C, Kellner R, Kalinowski J, Pelzer S, Macheroux P, Mack M. A novel N,N-8-amino-8-demethyl-D-riboflavin Dimethyltransferase (RosA) catalyzing the two terminal steps of roseoflavin biosynthesis in Streptomyces davawensis. J Biol Chem 2011; 286:38275-38285. [PMID: 21911488 PMCID: PMC3207391 DOI: 10.1074/jbc.m111.292300] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 09/12/2011] [Indexed: 11/06/2022] Open
Abstract
Streptomyces davawensis synthesizes the antibiotic roseoflavin (RoF) (8-dimethylamino-8-demethyl-D-riboflavin). It was postulated that RoF is synthesized from riboflavin via 8-amino- (AF) and 8-methylamino-8-demethyl-D-riboflavin (MAF). In a cell-free extract of S. davawensis, an S-adenosyl methionine-dependent conversion of AF into MAF and RoF was observed. The corresponding N,N-8-amino-8-demethyl-d-riboflavin dimethyltransferase activity was enriched by column chromatography. The final most active fraction still contained at least five different proteins that were analyzed by enzymatic digestion and concomitant de novo sequencing by MS/MS. One of the sequences matched a hypothetical peptide fragment derived from an as yet uncharacterized open reading frame (sda77220) located in the middle of a (putative) gene cluster within the S. davawensis genome. Expression of ORF sda77220 in Escherichia coli revealed that the corresponding gene product had N,N-8-amino-8-demethyl-d-riboflavin dimethyltransferase activity. Inactivation of ORF sda77220 led to a S. davawensis strain that synthesized AF but not MAF or RoF. Accordingly, as the first identified gene of RoF biosynthesis, ORF sda77220 was named rosA. RosA (347 amino acids; 38 kDa) was purified from a recombinant E. coli strain (as a His(6)-tagged protein) and was biochemically characterized (apparent K(m) for AF = 57.7 ± 9.2 μm; apparent K(D) for AF = 10.0 μm; k(cat) = 0.37 ± 0.02 s(-1)). RosA is a unique enzyme and may be useful for a variety of applications.
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Affiliation(s)
- Frank Jankowitsch
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, 68163 Mannheim, Germany
| | - Christian Kühm
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, 68163 Mannheim, Germany
| | - Roland Kellner
- Department of Protein and Cell Science, Merck Serono, Frankfurter Strasse 250, 64271 Darmstadt, Germany
| | - Jörn Kalinowski
- Center for Biotechnology-CeBiTec, Bielefeld University, Universitätsstrasse 27, 33615 Bielefeld, Germany
| | - Stefan Pelzer
- B.R.A.I.N. AG, Darmstädter Strasse 34-36, 64723 Zwingenberg, Germany
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, 8010 Graz, Austria
| | - Matthias Mack
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, 68163 Mannheim, Germany.
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Pedrolli DB, Nakanishi S, Barile M, Mansurova M, Carmona EC, Lux A, Gärtner W, Mack M. The antibiotics roseoflavin and 8-demethyl-8-amino-riboflavin from Streptomyces davawensis are metabolized by human flavokinase and human FAD synthetase. Biochem Pharmacol 2011; 82:1853-9. [PMID: 21924249 DOI: 10.1016/j.bcp.2011.08.029] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 08/31/2011] [Accepted: 08/31/2011] [Indexed: 11/26/2022]
Abstract
The non-pathogenic Gram-positive soil bacterium Streptomyces davawensis synthesizes the riboflavin (vitamin B(2)) analogs roseoflavin (RoF) and 8-demethyl-8-amino-riboflavin (AF). Both compounds are antibiotics. Notably, a number of other riboflavin analogs are currently under investigation with regard to the development of novel antiinfectives. As a first step towards understanding the metabolism of riboflavin analogs in humans, the key enzymes flavokinase (EC 2.7.1.26) and FAD synthetase (EC 2.7.7.2) were studied. Human flavokinase efficiently converted RoF and AF to roseoflavin mononucleotide (RoFMN) and 8-demethyl-8-amino-riboflavin mononucleotide (AFMN), respectively. Human FAD synthetase accepted RoFMN but not AFMN as a substrate. Consequently, roseoflavin adenine dinucleotide (RoFAD) was synthesized by the latter enzyme but not 8-demethyl-8-amino-riboflavin adenine dinucleotide (AFAD). The cofactor analogs RoFMN, AFMN and RoFAD have different physicochemical properties as compared to FMN and FAD. Thus, the cofactor analogs have the potential to render flavoenzymes inactive, which may negatively affect human metabolism. RoF, but not AF, was found to inhibit human flavokinase. In summary, we suggest that AF has a lower toxic potential and may be better suited as a lead structure to develop antimicrobial compounds.
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Affiliation(s)
- Danielle B Pedrolli
- Institut für Technische Mikrobiologie, Hochschule Mannheim, Paul-Wittsack-Str. 10, 68163 Mannheim, Germany
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Abbas CA, Sibirny AA. Genetic control of biosynthesis and transport of riboflavin and flavin nucleotides and construction of robust biotechnological producers. Microbiol Mol Biol Rev 2011; 75:321-60. [PMID: 21646432 PMCID: PMC3122625 DOI: 10.1128/mmbr.00030-10] [Citation(s) in RCA: 243] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Riboflavin [7,8-dimethyl-10-(1'-d-ribityl)isoalloxazine, vitamin B₂] is an obligatory component of human and animal diets, as it serves as the precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which are involved in oxidative metabolism and other processes. Commercially produced riboflavin is used in agriculture, medicine, and the food industry. Riboflavin synthesis starts from GTP and ribulose-5-phosphate and proceeds through pyrimidine and pteridine intermediates. Flavin nucleotides are synthesized in two consecutive reactions from riboflavin. Some microorganisms and all animal cells are capable of riboflavin uptake, whereas many microorganisms have distinct systems for riboflavin excretion to the medium. Regulation of riboflavin synthesis in bacteria occurs by repression at the transcriptional level by flavin mononucleotide, which binds to nascent noncoding mRNA and blocks further transcription (named the riboswitch). In flavinogenic molds, riboflavin overproduction starts at the stationary phase and is accompanied by derepression of enzymes involved in riboflavin synthesis, sporulation, and mycelial lysis. In flavinogenic yeasts, transcriptional repression of riboflavin synthesis is exerted by iron ions and not by flavins. The putative transcription factor encoded by SEF1 is somehow involved in this regulation. Most commercial riboflavin is currently produced or was produced earlier by microbial synthesis using special selected strains of Bacillus subtilis, Ashbya gossypii, and Candida famata. Whereas earlier RF overproducers were isolated by classical selection, current producers of riboflavin and flavin nucleotides have been developed using modern approaches of metabolic engineering that involve overexpression of structural and regulatory genes of the RF biosynthetic pathway as well as genes involved in the overproduction of the purine precursor of riboflavin, GTP.
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Affiliation(s)
| | - Andriy A. Sibirny
- Institute of Cell Biology, NAS of Ukraine, Lviv 79005, Ukraine
- University of Rzeszow, Rzeszow 35-601, Poland
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26
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Covington ED, Gelbmann CB, Kotloski NJ, Gralnick JA. An essential role for UshA in processing of extracellular flavin electron shuttles by Shewanella oneidensis. Mol Microbiol 2010; 78:519-32. [PMID: 20807196 DOI: 10.1111/j.1365-2958.2010.07353.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The facultative anaerobe Shewanella oneidensis can reduce a number of insoluble extracellular metals. Direct adsorption of cells to the metal surface is not necessary, and it has been shown that S. oneidensis releases low concentrations flavins, including riboflavin and flavin mononucleotide (FMN), into the surrounding medium to act as extracellular electron shuttles. However, the mechanism of flavin release by Shewanella remains unknown. We have conducted a transposon mutagenesis screen to identify mutants deficient in extracellular flavin accumulation. Mutations in ushA, encoding a predicted 5'-nucleotidase, resulted in accumulation of flavin adenine dinucleotide (FAD) in culture supernatants, with a corresponding decrease in FMN and riboflavin. Cellular extracts of S. oneidensis convert FAD to FMN, whereas extracts of ushA mutants do not, and fractionation experiments show that UshA activity is periplasmic. We hypothesize that S. oneidensis secretes FAD into the periplasmic space, where it is hydrolysed by UshA to FMN and adenosine monophosphate (AMP). FMN diffuses through outer membrane porins where it accelerates extracellular electron transfer, and AMP is dephosphorylated by UshA and reassimilated by the cell. We predict that transport of FAD into the periplasm also satisfies the cofactor requirement of the unusual periplasmic fumarate reductase found in Shewanella.
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Affiliation(s)
- Elizabeth D Covington
- BioTechnology Institute and Department of Microbiology, University of Minnesota-Twin Cities, St. Paul, MN 55108, USA
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27
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Lee ER, Blount KF, Breaker RR. Roseoflavin is a natural antibacterial compound that binds to FMN riboswitches and regulates gene expression. RNA Biol 2009; 6:187-94. [PMID: 19246992 PMCID: PMC5340298 DOI: 10.4161/rna.6.2.7727] [Citation(s) in RCA: 171] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Riboswitches in messenger RNAs carry receptor domains called aptamers that can bind to metabolites and control expression of associated genes. The Gram-positive bacterium Bacillus subtilis has two representatives of a class of riboswitches that bind flavin mononucleotide (FMN). These riboswitches control genes responsible for the biosynthesis and transport of riboflavin, a precursor of FMN. We found that roseoflavin, a chemical analog of FMN and riboflavin that has antimicrobial activity, can directly bind to FMN riboswitch aptamers and downregulate the expression of an FMN riboswitch-lacZ reporter gene in B. subtilis. A role for the riboswitch in the antimicrobial mechanism of roseoflavin is supported by our observation that some previously identified roseoflavin-resistant bacteria have mutations within an FMN aptamer. Riboswitch mutations in these resistant bacteria disrupt ligand binding and derepress reporter gene expression in the presence of either riboflavin or roseoflavin. If FMN riboswitches are a major target for roseoflavin antimicrobial action, then future efforts to develop compounds that trigger FMN riboswitch function could lead to the identification of new antimicrobial drugs.
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Affiliation(s)
- Elaine R Lee
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA
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The proline-dependent transcription factor Put3 regulates the expression of the riboflavin transporter MCH5 in Saccharomyces cerevisiae. Genetics 2008; 180:2007-17. [PMID: 18940788 DOI: 10.1534/genetics.108.094458] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Like most microorganisms, the yeast Saccharomyces cerevisiae is prototrophic for riboflavin (vitamin B2). Riboflavin auxotrophic mutants with deletions in any of the RIB genes frequently segregate colonies with improved growth. We demonstrate by reporter assays and Western blots that these suppressor mutants overexpress the plasma-membrane riboflavin transporter MCH5. Frequently, this overexpression is mediated by the transcription factor Put3, which also regulates the proline catabolic genes PUT1 and PUT2. The increased expression of MCH5 may increase the concentrations of FAD, which is the coenzyme required for the activity of proline oxidase, encoded by PUT1. Thus, Put3 regulates proline oxidase activity by synchronizing the biosynthesis of the apoenzyme and the coenzyme FAD. Put3 is known to bind to the promoters of PUT1 and PUT2 constitutively, and we demonstrate by gel-shift assays that it also binds to the promoter of MCH5. Put3-mediated transcriptional activation requires proline as an inducer. We find that the increased activity of Put3 in one of the suppressor mutants is caused by increased intracellular levels of proline. Alternative PUT3-dependent and -independent mechanisms might operate in other suppressed strains.
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de Berardinis V, Vallenet D, Castelli V, Besnard M, Pinet A, Cruaud C, Samair S, Lechaplais C, Gyapay G, Richez C, Durot M, Kreimeyer A, Le Fèvre F, Schächter V, Pezo V, Döring V, Scarpelli C, Médigue C, Cohen GN, Marlière P, Salanoubat M, Weissenbach J. A complete collection of single-gene deletion mutants of Acinetobacter baylyi ADP1. Mol Syst Biol 2008; 4:174. [PMID: 18319726 PMCID: PMC2290942 DOI: 10.1038/msb.2008.10] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Accepted: 01/22/2008] [Indexed: 11/17/2022] Open
Abstract
We have constructed a collection of single-gene deletion mutants for all dispensable genes of the soil bacterium Acinetobacter baylyi ADP1. A total of 2594 deletion mutants were obtained, whereas 499 (16%) were not, and are therefore candidate essential genes for life on minimal medium. This essentiality data set is 88% consistent with the Escherichia coli data set inferred from the Keio mutant collection profiled for growth on minimal medium, while 80% of the orthologous genes described as essential in Pseudomonas aeruginosa are also essential in ADP1. Several strategies were undertaken to investigate ADP1 metabolism by (1) searching for discrepancies between our essentiality data and current metabolic knowledge, (2) comparing this essentiality data set to those from other organisms, (3) systematic phenotyping of the mutant collection on a variety of carbon sources (quinate, 2-3 butanediol, glucose, etc.). This collection provides a new resource for the study of gene function by forward and reverse genetic approaches and constitutes a robust experimental data source for systems biology approaches.
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The bifunctional flavokinase/flavin adenine dinucleotide synthetase from Streptomyces davawensis produces inactive flavin cofactors and is not involved in resistance to the antibiotic roseoflavin. J Bacteriol 2007; 190:1546-53. [PMID: 18156273 DOI: 10.1128/jb.01586-07] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Streptomyces davawensis synthesizes the antibiotic roseoflavin, one of the few known natural riboflavin analogs, and is roseoflavin resistant. It is thought that the endogenous flavokinase (EC 2.7.1.26)/flavin adenine dinucleotide (FAD) synthetase (EC 2.7.7.2) activities of roseoflavin-sensitive organisms are responsible for the antibiotic effect of roseoflavin, producing the inactive cofactors roseoflavin-5'-monophosphate (RoFMN) and roseoflavin adenine dinucleotide (RoFAD) from roseoflavin. To confirm this, the FAD-dependent Sus scrofa D-amino acid oxidase (EC 1.4.3.3) was tested with RoFAD as a cofactor and found to be inactive. It was hypothesized that a flavokinase/FAD synthetase (RibC) highly specific for riboflavin may be present in S. davawensis, which would not allow the formation of toxic RoFMN/RoFAD. The gene ribC from S. davawensis was cloned. RibC from S. davawensis was overproduced in Escherichia coli and purified. Analysis of the flavokinase activity of RibC revealed that the S. davawensis enzyme is not riboflavin specific (roseoflavin, kcat/Km = 1.7 10(-2) microM(-1) s(-1); riboflavin, kcat/Km = 7.5 10(-3) microM(-1) s(-1)). Similar results were obtained for RibC from the roseoflavin-sensitive bacterium Bacillus subtilis (roseoflavin, kcat/Km = 1.3 10(-2) microM(-1) s(-1); riboflavin, kcat/Km = 1.3 10(-2) microM(-1) s(-1)). Both RibC enzymes synthesized RoFAD and RoFMN. The functional expression of S. davawensis ribC did not confer roseoflavin resistance to a ribC-defective B. subtilis strain.
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Vogl C, Grill S, Schilling O, Stülke J, Mack M, Stolz J. Characterization of riboflavin (vitamin B2) transport proteins from Bacillus subtilis and Corynebacterium glutamicum. J Bacteriol 2007; 189:7367-75. [PMID: 17693491 PMCID: PMC2168442 DOI: 10.1128/jb.00590-07] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Accepted: 08/03/2007] [Indexed: 01/12/2023] Open
Abstract
Riboflavin (vitamin B(2)) is the direct precursor of the flavin cofactors flavin mononucleotide and flavin adenine dinucleotide, essential components of cellular biochemistry. In this work we investigated the unrelated proteins YpaA from Bacillus subtilis and PnuX from Corynebacterium glutamicum for a role in riboflavin uptake. Based on the regulation of the corresponding genes by a riboswitch mechanism, both proteins have been predicted to be involved in flavin metabolism. Moreover, their primary structures suggested that these proteins integrate into the cytoplasmic membrane. We provide experimental evidence that YpaA is a plasma membrane protein with five transmembrane domains and a cytoplasmic C terminus. In B. subtilis, riboflavin uptake was increased when ypaA was overexpressed and abolished when ypaA was deleted. Riboflavin uptake activity and the abundance of the YpaA protein were also increased when riboflavin auxotrophic mutants were grown in limiting amounts of riboflavin. YpaA-mediated riboflavin uptake was sensitive to protonophors and reduced in the absence of glucose, demonstrating that the protein requires metabolic energy for substrate translocation. In addition, we demonstrate that PnuX from C. glutamicum also is a riboflavin transporter. Transport by PnuX was not energy dependent and had high apparent affinity for riboflavin (K(m) 11 microM). Roseoflavin, a toxic riboflavin analog, appears to be a substrate of PnuX and YpaA. We propose to designate the gene names ribU for ypaA and ribM for pnuX to reflect that the encoded proteins function in riboflavin uptake and that the genes have different phylogenetic origins.
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Affiliation(s)
- Christian Vogl
- Lehrstuhl für Ernährungsphysiologie, Technische Universität München, Am Forum 5, 85350, Freising-Weihenstephan, Germany
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