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Bydlowski SP, Levy D. Association of ABCG5 and ABCG8 Transporters with Sitosterolemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:31-42. [PMID: 38036873 DOI: 10.1007/978-3-031-43883-7_2] [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: 12/02/2023]
Abstract
Sitosterolemia is a rare genetic lipid disorder, mainly characterized by the accumulation of dietary xenosterols in plasma and tissues. It is caused by inactivating mutations in either ABCG5 or ABCG8 subunits, a subfamily-G ATP-binding cassette (ABCG) transporters. ABCG5/G8 encodes a pair of ABC half transporters that form a heterodimer (G5G8). This heterodimeric ATP-binding cassette (ABC) sterol transporter, ABCG5/G8, is responsible for the hepatobiliary and transintestinal secretion of cholesterol and dietary plant sterols to the surface of hepatocytes and enterocytes, promoting the secretion of cholesterol and xenosterols into the bile and the intestinal lumen. In this way, ABCG5/G8 function in the reverse cholesterol transport pathway and mediate the efflux of cholesterol and xenosterols to high-density lipoprotein and bile salt micelles, respectively. Here, we review the biological characteristics and function of ABCG5/G8, and how the mutations of ABCG5/G8 can cause sitosterolemia, a loss-of-function disorder characterized by plant sterol accumulation and premature atherosclerosis, among other features.
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Affiliation(s)
- Sergio Paulo Bydlowski
- Lipids, Oxidation and Cell Biology Team, Laboratory of Immunology (LIM19), Heart Institute (InCor), Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, Brazil.
- National Institute of Science and Technology in Regenerative Medicine (INCT-Regenera) CNPq, Rio de Janeiro, Brazil.
| | - Debora Levy
- Lipids, Oxidation and Cell Biology Team, Laboratory of Immunology (LIM19), Heart Institute (InCor), Faculdade de Medicina, Universidade de São Paulo, Sao Paulo, Brazil
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Huang Y, Chen J, Jiang Q, Huang N, Ding X, Peng L, Deng X. The molybdate-binding protein ModA is required for Proteus mirabilis-induced UTI. Front Microbiol 2023; 14:1156273. [PMID: 37180242 PMCID: PMC10174112 DOI: 10.3389/fmicb.2023.1156273] [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: 02/01/2023] [Accepted: 03/28/2023] [Indexed: 05/16/2023] Open
Abstract
Background Proteus mirabilis is one of the pathogens commonly causing urinary tract infections (UTIs). The molybdate-binding protein ModA encoded by modA binds molybdate with high affinity and transports it. Increasing evidence shows that ModA promotes the survival of bacteria in anaerobic environments and participates in bacterial virulence by obtaining molybdenum. However, the role of ModA in the pathogenesis of P. mirabilis remains unknown. Results In this study, a series of phenotypic assays and transcriptomic analyses were used to study the role of ModA in the UTIs induced by P. mirabilis. Our data showed that ModA absorbed molybdate with high affinity and incorporated it into molybdopterin, thus affecting the anaerobic growth of P. mirabilis. Loss of ModA enhanced bacterial swarming and swimming and up-regulated the expression of multiple genes in flagellar assembly pathway. The loss of ModA also resulted in decreased biofilm formation under anaerobic growth conditions. The modA mutant significantly inhibited bacterial adhesion and invasion to urinary tract epithelial cells and down-regulated the expression of multiple genes associated with pilus assembly. Those alterations were not due to anaerobic growth defects. In addition, the decreased bacteria in the bladder tissue, the weakened inflammatory damage, the low level of IL-6, and minor weight change was observed in the UTI mouse model infected with modA mutant. Conclusion Here, we reported that in P. mirabilis, ModA mediated the transport of molybdate, thereby affecting the activity of nitrate reductase and thus affecting the growth of bacteria under anaerobic conditions. Overall, this study clarified the indirect role of ModA in the anaerobic growth, motility, biofilm formation, and pathogenicity of P. mirabilis and its possible pathway, and emphasized the importance of the molybdate-binding protein ModA to P. mirabilis in mediating molybdate uptake, allowing the bacterium to adapt to complex environmental conditions and cause UTIs. Our results provided valuable information on the pathogenesis of ModA-induced P. mirabilis UTIs and may facilitate the development of new treatment strategies.
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Affiliation(s)
- Yi Huang
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, Guangzhou Medical University, Guangzhou, Guangdong, China
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Jinbin Chen
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, Guangzhou Medical University, Guangzhou, Guangdong, China
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Qiao Jiang
- Guangdong 999 Brain Hospital, Guangzhou, Guangdong, China
| | - Nan Huang
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, Guangzhou Medical University, Guangzhou, Guangdong, China
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Xin Ding
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, Guangzhou Medical University, Guangzhou, Guangdong, China
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Liang Peng
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
- The Fifth Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
- *Correspondence: Xiaoyan Deng, ; Liang Peng,
| | - Xiaoyan Deng
- Guangzhou Key Laboratory for Clinical Rapid Diagnosis and Early Warning of Infectious Diseases, Guangzhou Medical University, Guangzhou, Guangdong, China
- KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, Guangdong, China
- *Correspondence: Xiaoyan Deng, ; Liang Peng,
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A comparative study indicates vertical inheritance and horizontal gene transfer of arsenic resistance-related genes in eukaryotes. Mol Phylogenet Evol 2022; 173:107479. [DOI: 10.1016/j.ympev.2022.107479] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 02/10/2022] [Accepted: 04/05/2022] [Indexed: 12/27/2022]
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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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Zhong Q, Kobe B, Kappler U. Molybdenum Enzymes and How They Support Virulence in Pathogenic Bacteria. Front Microbiol 2020; 11:615860. [PMID: 33362753 PMCID: PMC7759655 DOI: 10.3389/fmicb.2020.615860] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/23/2020] [Indexed: 12/11/2022] Open
Abstract
Mononuclear molybdoenzymes are highly versatile catalysts that occur in organisms in all domains of life, where they mediate essential cellular functions such as energy generation and detoxification reactions. Molybdoenzymes are particularly abundant in bacteria, where over 50 distinct types of enzymes have been identified to date. In bacterial pathogens, all aspects of molybdoenzyme biology such as molybdate uptake, cofactor biosynthesis, and function of the enzymes themselves, have been shown to affect fitness in the host as well as virulence. Although current studies are mostly focused on a few key pathogens such as Escherichia coli, Salmonella enterica, Campylobacter jejuni, and Mycobacterium tuberculosis, some common themes for the function and adaptation of the molybdoenzymes to pathogen environmental niches are emerging. Firstly, for many of these enzymes, their role is in supporting bacterial energy generation; and the corresponding pathogen fitness and virulence defects appear to arise from a suboptimally poised metabolic network. Secondly, all substrates converted by virulence-relevant bacterial Mo enzymes belong to classes known to be generated in the host either during inflammation or as part of the host signaling network, with some enzyme groups showing adaptation to the increased conversion of such substrates. Lastly, a specific adaptation to bacterial in-host survival is an emerging link between the regulation of molybdoenzyme expression in bacterial pathogens and the presence of immune system-generated reactive oxygen species. The prevalence of molybdoenzymes in key bacterial pathogens including ESKAPE pathogens, paired with the mounting evidence of their central roles in bacterial fitness during infection, suggest that they could be important future drug targets.
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Affiliation(s)
- Qifeng Zhong
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
| | - Bostjan Kobe
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia.,Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, Australia
| | - Ulrike Kappler
- Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD, Australia
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Demtröder L, Pfänder Y, Masepohl B. Rhodobacter capsulatus AnfA is essential for production of Fe-nitrogenase proteins but dispensable for cofactor biosynthesis and electron supply. Microbiologyopen 2020; 9:1234-1246. [PMID: 32207246 PMCID: PMC7294313 DOI: 10.1002/mbo3.1033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/04/2020] [Accepted: 03/06/2020] [Indexed: 01/07/2023] Open
Abstract
The photosynthetic α‐proteobacterium Rhodobacter capsulatus reduces and thereby fixes atmospheric dinitrogen (N2) by a molybdenum (Mo)‐nitrogenase and an iron‐only (Fe)‐nitrogenase. Differential expression of the structural genes of Mo‐nitrogenase (nifHDK) and Fe‐nitrogenase (anfHDGK) is strictly controlled and activated by NifA and AnfA, respectively. In contrast to NifA‐binding sites, AnfA‐binding sites are poorly defined. Here, we identified two highly similar AnfA‐binding sites in the R. capsulatus anfH promoter by studying the effects of promoter mutations on in vivo anfH expression and in vitro promoter binding by AnfA. Comparison of the experimentally determined R. capsulatus AnfA‐binding sites and presumed AnfA‐binding sites from other α‐proteobacteria revealed a consensus sequence of dyad symmetry, TAC–N6–GTA, suggesting that AnfA proteins bind their target promoters as dimers. Chromosomal replacement of the anfH promoter by the nifH promoter restored anfHDGK expression and Fe‐nitrogenase activity in an R. capsulatus strain lacking AnfA suggesting that AnfA is required for AnfHDGK production, but dispensable for biosynthesis of the iron‐only cofactor and electron delivery to Fe‐nitrogenase, pathways activated by NifA. These observations strengthen our model, in which the Fe‐nitrogenase system in R. capsulatus is largely integrated into the Mo‐nitrogenase system.
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Affiliation(s)
- Lisa Demtröder
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Yvonne Pfänder
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Bernd Masepohl
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
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Anion transport as a target of adaption to perchlorate in sulfate-reducing communities. ISME JOURNAL 2019; 14:450-462. [PMID: 31659234 DOI: 10.1038/s41396-019-0540-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 09/04/2019] [Accepted: 09/12/2019] [Indexed: 11/09/2022]
Abstract
Inhibitors can be used to control the functionality of microbial communities by targeting specific metabolisms. The targeted inhibition of dissimilatory sulfate reduction limits the generation of toxic and corrosive hydrogen sulfide across several industrial systems. Sulfate-reducing microorganisms (SRM) are specifically inhibited by sulfate analogs, such as perchlorate. Previously, we showed pure culture SRM adaptation to perchlorate stress through mutation of the sulfate adenylyltransferase, a central enzyme in the sulfate reduction pathway. Here, we explored adaptation to perchlorate across unconstrained SRM on a community scale. We followed natural and bio-augmented sulfidogenic communities through serial transfers in increasing concentrations of perchlorate. Our results demonstrated that perchlorate stress altered community structure by initially selecting for innately more resistant strains. Isolation, whole-genome sequencing, and molecular biology techniques allowed us to define subsequent genetic mechanisms of adaptation that arose across the dominant adapting SRM. Changes in the regulation of divalent anion:sodium symporter family transporters led to increased intracellular sulfate to perchlorate ratios, allowing SRM to escape the effects of competitive inhibition. Thus, in contrast to pure-culture results, SRM in communities cope with perchlorate stress via changes in anion transport and its regulation. This highlights the value of probing evolutionary questions in an ecological framework, bridging the gap between ecology, evolution, genomics, and physiology.
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8
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Demtröder L, Pfänder Y, Schäkermann S, Bandow JE, Masepohl B. NifA is the master regulator of both nitrogenase systems in Rhodobacter capsulatus. Microbiologyopen 2019; 8:e921. [PMID: 31441241 PMCID: PMC6925177 DOI: 10.1002/mbo3.921] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/16/2019] [Accepted: 07/18/2019] [Indexed: 01/09/2023] Open
Abstract
Rhodobacter capsulatus fixes atmospheric nitrogen (N2) by a molybdenum (Mo)‐nitrogenase and a Mo‐free iron (Fe)‐nitrogenase, whose production is induced or repressed by Mo, respectively. At low nanomolar Mo concentrations, both isoenzymes are synthesized and contribute to nitrogen fixation. Here we examined the regulatory interplay of the central transcriptional activators NifA and AnfA by proteome profiling. As expected from earlier studies, synthesis of the structural proteins of Mo‐nitrogenase (NifHDK) and Fe‐nitrogenase (AnfHDGK) required NifA and AnfA, respectively, both of which depend on the alternative sigma factor RpoN to activate expression of their target genes. Unexpectedly, NifA was found to be essential for the synthesis of Fe‐nitrogenase, electron supply to both nitrogenases, biosynthesis of their cofactors, and production of RpoN. Apparently, RpoN is the only NifA‐dependent factor required for target gene activation by AnfA, since plasmid‐borne rpoN restored anfH transcription in a NifA‐deficient strain. However, plasmid‐borne rpoN did not restore Fe‐nitrogenase activity in this strain. Taken together, NifA requirement for synthesis and activity of both nitrogenases suggests that Fe‐nitrogenase functions as a complementary nitrogenase rather than an alternative isoenzyme in R. capsulatus.
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Affiliation(s)
- Lisa Demtröder
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Yvonne Pfänder
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Sina Schäkermann
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Julia Elisabeth Bandow
- Applied Microbiology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
| | - Bernd Masepohl
- Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany
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9
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Coimbra C, Branco R, Morais PV. Efficient bioaccumulation of tungsten by Escherichia coli cells expressing the Sulfitobacter dubius TupBCA system. Syst Appl Microbiol 2019; 42:126001. [PMID: 31326140 DOI: 10.1016/j.syapm.2019.126001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 01/30/2023]
Abstract
Tungsten (W) is a valuable element with considerable industrial and economic importance that belongs to the European Union list of critical metals with a high supply risk. Therefore, the development of effective and new methods for W recovery is essential to ensure a sustainable supply. In the present study, the Sulfitobacter dubius W transport system TupABC was explored in order to demonstrate both its functionality in Escherichia coli cells and to construct a bioaccumulator (EcotupW). The complete gene cluster tupBCA or partial gene cluster tupBC were cloned in an expression vector and transformed into E. coli. Metal accumulation was evaluated when each construct strain was grown with three separate metal oxyanions (tungstate, molybdate or chromate). The specificity of the bioaccumulator was determined by competition assays using cells grown with mixed solutions of metal oxyanions (W/Mo and W/Cr). The results showed the relevance of the TupA protein in the TupABC transporter system to W-uptake and also allowed Mo and Cr accumulations, although with amounts 1.7 and 2.9-fold lower than W, respectively. To identify the importance of the valine residue in the accumulation efficiency of the VTTS motif, site-directed mutagenesis of tupA was performed. A mutant with a threonine residue, instead of the respective valine, confirmed that W was internalized by nearly double the amount compared to the native form. The findings indicated that cells carrying the native S. dubius TupABC system were great W-bioaccumulators and could be promising tools for W recovery.
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Affiliation(s)
- C Coimbra
- CEMMPRE - Center of Mechanical Engineering, Materials and Processes, University of Coimbra, Coimbra, 3030-788, Portugal
| | - R Branco
- CEMMPRE - Center of Mechanical Engineering, Materials and Processes, University of Coimbra, Coimbra, 3030-788, Portugal; Department of Life Sciences, University of Coimbra, Coimbra, 3001-401, Portugal.
| | - P V Morais
- CEMMPRE - Center of Mechanical Engineering, Materials and Processes, University of Coimbra, Coimbra, 3030-788, Portugal; Department of Life Sciences, University of Coimbra, Coimbra, 3001-401, Portugal
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Stoeva MK, Coates JD. Specific inhibitors of respiratory sulfate reduction: towards a mechanistic understanding. MICROBIOLOGY-SGM 2018; 165:254-269. [PMID: 30556806 DOI: 10.1099/mic.0.000750] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Microbial sulfate reduction (SR) by sulfate-reducing micro-organisms (SRM) is a primary environmental mechanism of anaerobic organic matter mineralization, and as such influences carbon and sulfur cycling in many natural and engineered environments. In industrial systems, SR results in the generation of hydrogen sulfide, a toxic, corrosive gas with adverse human health effects and significant economic and environmental consequences. Therefore, there has been considerable interest in developing strategies for mitigating hydrogen sulfide production, and several specific inhibitors of SRM have been identified and characterized. Specific inhibitors are compounds that disrupt the metabolism of one group of organisms, with little or no effect on the rest of the community. Putative specific inhibitors of SRM have been used to control sulfidogenesis in industrial and engineered systems. Despite the value of these inhibitors, mechanistic and quantitative studies into the molecular mechanisms of their inhibition have been sparse and unsystematic. The insight garnered by such studies is essential if we are to have a more complete understanding of SR, including the past and current selective pressures acting upon it. Furthermore, the ability to reliably control sulfidogenesis - and potentially assimilatory sulfate pathways - relies on a thorough molecular understanding of inhibition. The scope of this review is to summarize the current state of the field: how we measure and understand inhibition, the targets of specific SR inhibitors and how SRM acclimatize and/or adapt to these stressors.
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Affiliation(s)
- Magdalena K Stoeva
- 1Energy Biosciences Institute, University of California - Berkeley, Berkeley, CA, USA
- 2Department of Plant and Microbial Biology, University of California - Berkeley, Berkeley, CA, USA
| | - John D Coates
- 2Department of Plant and Microbial Biology, University of California - Berkeley, Berkeley, CA, USA
- 1Energy Biosciences Institute, University of California - Berkeley, Berkeley, CA, USA
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Demtröder L, Narberhaus F, Masepohl B. Coordinated regulation of nitrogen fixation and molybdate transport by molybdenum. Mol Microbiol 2018; 111:17-30. [PMID: 30325563 DOI: 10.1111/mmi.14152] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2018] [Indexed: 12/01/2022]
Abstract
Biological nitrogen fixation, the reduction of chemically inert dinitrogen to bioavailable ammonia, is a central process in the global nitrogen cycle highly relevant for life on earth. N2 reduction to NH3 is catalyzed by nitrogenases exclusively synthesized by diazotrophic prokaryotes. All diazotrophs have a molybdenum nitrogenase containing the unique iron-molybdenum cofactor FeMoco. In addition, some diazotrophs encode one or two alternative Mo-free nitrogenases that are less efficient at reducing N2 than Mo-nitrogenase. To permit biogenesis of Mo-nitrogenase and other molybdoenzymes when Mo is scarce, bacteria synthesize the high-affinity molybdate transporter ModABC. Generally, Mo supports expression of Mo-nitrogenase genes, while it represses production of Mo-free nitrogenases and ModABC. Since all three nitrogenases and ModABC can reach very high levels at suitable Mo concentrations, tight Mo-mediated control saves considerable resources and energy. This review outlines the similarities and differences in Mo-responsive regulation of nitrogen fixation and molybdate transport in diverse diazotrophs.
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Affiliation(s)
- Lisa Demtröder
- Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | | | - Bernd Masepohl
- Microbial Biology, Ruhr University Bochum, Bochum, Germany
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12
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Marietou A, Røy H, Jørgensen BB, Kjeldsen KU. Sulfate Transporters in Dissimilatory Sulfate Reducing Microorganisms: A Comparative Genomics Analysis. Front Microbiol 2018; 9:309. [PMID: 29551997 PMCID: PMC5840216 DOI: 10.3389/fmicb.2018.00309] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 02/09/2018] [Indexed: 12/31/2022] Open
Abstract
The first step in the sulfate reduction pathway is the transport of sulfate across the cell membrane. This uptake has a major effect on sulfate reduction rates. Much of the information available on sulfate transport was obtained by studies on assimilatory sulfate reduction, where sulfate transporters were identified among several types of protein families. Despite our growing knowledge on the physiology of dissimilatory sulfate-reducing microorganisms (SRM) there are no studies identifying the proteins involved in sulfate uptake in members of this ecologically important group of anaerobes. We surveyed the complete genomes of 44 sulfate-reducing bacteria and archaea across six phyla and identified putative sulfate transporter encoding genes from four out of the five surveyed protein families based on homology. We did not find evidence that ABC-type transporters (SulT) are involved in the uptake of sulfate in SRM. We speculate that members of the CysP sulfate transporters could play a key role in the uptake of sulfate in thermophilic SRM. Putative CysZ-type sulfate transporters were present in all genomes examined suggesting that this overlooked group of sulfate transporters might play a role in sulfate transport in dissimilatory sulfate reducers alongside SulP. Our in silico analysis highlights several targets for further molecular studies in order to understand this key step in the metabolism of SRMs.
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Affiliation(s)
- Angeliki Marietou
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Hans Røy
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Bo B Jørgensen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
| | - Kasper U Kjeldsen
- Center for Geomicrobiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
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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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Simon M, Scheuner C, Meier-Kolthoff JP, Brinkhoff T, Wagner-Döbler I, Ulbrich M, Klenk HP, Schomburg D, Petersen J, Göker M. Phylogenomics of Rhodobacteraceae reveals evolutionary adaptation to marine and non-marine habitats. THE ISME JOURNAL 2017; 11:1483-1499. [PMID: 28106881 PMCID: PMC5437341 DOI: 10.1038/ismej.2016.198] [Citation(s) in RCA: 206] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/29/2016] [Accepted: 11/19/2016] [Indexed: 12/31/2022]
Abstract
Marine Rhodobacteraceae (Alphaproteobacteria) are key players of biogeochemical cycling, comprise up to 30% of bacterial communities in pelagic environments and are often mutualists of eukaryotes. As 'Roseobacter clade', these 'roseobacters' are assumed to be monophyletic, but non-marine Rhodobacteraceae have not yet been included in phylogenomic analyses. Therefore, we analysed 106 genome sequences, particularly emphasizing gene sampling and its effect on phylogenetic stability, and investigated relationships between marine versus non-marine habitat, evolutionary origin and genomic adaptations. Our analyses, providing no unequivocal evidence for the monophyly of roseobacters, indicate several shifts between marine and non-marine habitats that occurred independently and were accompanied by characteristic changes in genomic content of orthologs, enzymes and metabolic pathways. Non-marine Rhodobacteraceae gained high-affinity transporters to cope with much lower sulphate concentrations and lost genes related to the reduced sodium chloride and organohalogen concentrations in their habitats. Marine Rhodobacteraceae gained genes required for fucoidan desulphonation and synthesis of the plant hormone indole 3-acetic acid and the compatible solutes ectoin and carnitin. However, neither plasmid composition, even though typical for the family, nor the degree of oligotrophy shows a systematic difference between marine and non-marine Rhodobacteraceae. We suggest the operational term 'Roseobacter group' for the marine Rhodobacteraceae strains.
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Affiliation(s)
- Meinhard Simon
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Carmen Scheuner
- Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Jan P Meier-Kolthoff
- Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Thorsten Brinkhoff
- Institute for Chemistry and Biology of the Marine Environment, University of Oldenburg, Oldenburg, Germany
| | - Irene Wagner-Döbler
- Helmholtz Centre for Infection Research, Research Group Microbial Communication, Braunschweig, Germany
| | - Marcus Ulbrich
- Institute of Biochemical Engineering, Technical University Braunschweig, Braunschweig, Germany
| | - Hans-Peter Klenk
- School of Biology, Newcastle University, Newcastle upon Tyne, UK
| | - Dietmar Schomburg
- Institute of Biochemical Engineering, Technical University Braunschweig, Braunschweig, Germany
| | - Jörn Petersen
- Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Markus Göker
- Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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15
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Schumacher T, Benndorf RA. ABC Transport Proteins in Cardiovascular Disease-A Brief Summary. Molecules 2017; 22:molecules22040589. [PMID: 28383515 PMCID: PMC6154303 DOI: 10.3390/molecules22040589] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/29/2017] [Accepted: 04/03/2017] [Indexed: 12/17/2022] Open
Abstract
Adenosine triphosphate (ATP)-binding cassette (ABC) transporters may play an important role in the pathogenesis of atherosclerotic vascular diseases due to their involvement in cholesterol homeostasis, blood pressure regulation, endothelial function, vascular inflammation, as well as platelet production and aggregation. In this regard, ABC transporters, such as ABCA1, ABCG5 and ABCG8, were initially found to be responsible for genetically-inherited syndromes like Tangier diseases and sitosterolemia. These findings led to the understanding of those transporter’s function in cellular cholesterol efflux and thereby also linked them to atherosclerosis and cardiovascular diseases (CVD). Subsequently, further ABC transporters, i.e., ABCG1, ABCG4, ABCB6, ABCC1, ABCC6 or ABCC9, have been shown to directly or indirectly affect cellular cholesterol efflux, the inflammatory response in macrophages, megakaryocyte proliferation and thrombus formation, as well as vascular function and blood pressure, and may thereby contribute to the pathogenesis of CVD and its complications. Furthermore, ABC transporters, such as ABCB1, ABCC2 or ABCG2, may affect the safety and efficacy of several drug classes currently in use for CVD treatment. This review will give a brief overview of ABC transporters involved in the process of atherogenesis and CVD pathology. It also aims to briefly summarize the role of ABC transporters in the pharmacokinetics and disposition of drugs frequently used to treat CVD and CVD-related complications.
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Affiliation(s)
- Toni Schumacher
- Institute of Pharmacy, Department of Clinical Pharmacy and Pharmacotherapy, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, D-06120 Halle (Saale), Germany.
| | - Ralf A Benndorf
- Institute of Pharmacy, Department of Clinical Pharmacy and Pharmacotherapy, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, D-06120 Halle (Saale), Germany.
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16
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Tarpgaard IH, Jørgensen BB, Kjeldsen KU, Røy H. The marine sulfate reducer Desulfobacterium autotrophicum HRM2 can switch between low and high apparent half-saturation constants for dissimilatory sulfate reduction. FEMS Microbiol Ecol 2017; 93:2966865. [DOI: 10.1093/femsec/fix012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 02/01/2017] [Indexed: 12/22/2022] Open
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17
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Vaccaro BJ, Lancaster WA, Thorgersen MP, Zane GM, Younkin AD, Kazakov AE, Wetmore KM, Deutschbauer A, Arkin AP, Novichkov PS, Wall JD, Adams MWW. Novel Metal Cation Resistance Systems from Mutant Fitness Analysis of Denitrifying Pseudomonas stutzeri. Appl Environ Microbiol 2016; 82:6046-56. [PMID: 27474723 PMCID: PMC5038046 DOI: 10.1128/aem.01845-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 07/27/2016] [Indexed: 02/02/2023] Open
Abstract
UNLABELLED Metal ion transport systems have been studied extensively, but the specificity of a given transporter is often unclear from amino acid sequence data alone. In this study, predicted Cu(2+) and Zn(2+) resistance systems in Pseudomonas stutzeri strain RCH2 are compared with those experimentally implicated in Cu(2+) and Zn(2+) resistance, as determined by using a DNA-barcoded transposon mutant library. Mutant fitness data obtained under denitrifying conditions are combined with regulon predictions to yield a much more comprehensive picture of Cu(2+) and Zn(2+) resistance in strain RCH2. The results not only considerably expand what is known about well-established metal ion exporters (CzcCBA, CzcD, and CusCBA) and their accessory proteins (CzcI and CusF), they also reveal that isolates with mutations in some predicted Cu(2+) resistance systems do not show decreased fitness relative to the wild type when exposed to Cu(2+) In addition, new genes are identified that have no known connection to Zn(2+) (corB, corC, Psest_3226, Psest_3322, and Psest_0618) or Cu(2+) resistance (Mrp antiporter subunit gene, Psest_2850, and Psest_0584) but are crucial for resistance to these metal cations. Growth of individual deletion mutants lacking corB, corC, Psest_3226, or Psest_3322 confirmed the observed Zn-dependent phenotypes. Notably, to our knowledge, this is the first time a bacterial homolog of TMEM165, a human gene responsible for a congenital glycosylation disorder, has been deleted and the resulting strain characterized. Finally, the fitness values indicate Cu(2+)- and Zn(2+)-based inhibition of nitrite reductase and interference with molybdenum cofactor biosynthesis for nitrate reductase. These results extend the current understanding of Cu(2+) and Zn(2+) efflux and resistance and their effects on denitrifying metabolism. IMPORTANCE In this study, genome-wide mutant fitness data in P. stutzeri RCH2 combined with regulon predictions identify several proteins of unknown function that are involved in resisting zinc and copper toxicity. For zinc, these include a member of the UPF0016 protein family that was previously implicated in Ca(2+)/H(+) antiport and a human congenital glycosylation disorder, CorB and CorC, which were previously linked to Mg(2+) transport, and Psest_3322 and Psest_0618, two proteins with no characterized homologs. Experiments using mutants lacking Psest_3226, Psest_3322, corB, corC, or czcI verified their proposed functions, which will enable future studies of these little-characterized zinc resistance determinants. Likewise, Psest_2850, annotated as an ion antiporter subunit, and the conserved hypothetical protein Psest_0584 are implicated in copper resistance. Physiological connections between previous studies and phenotypes presented here are discussed. Functional and mechanistic understanding of transport proteins improves the understanding of systems in which members of the same protein family, including those in humans, can have different functions.
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Affiliation(s)
- Brian J Vaccaro
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - W Andrew Lancaster
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Michael P Thorgersen
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Grant M Zane
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Adam D Younkin
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Alexey E Kazakov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Kelly M Wetmore
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Adam P Arkin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Pavel S Novichkov
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Judy D Wall
- Department of Biochemistry, University of Missouri, Columbia, Missouri, USA
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
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18
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Hoffmann MC, Ali K, Sonnenschein M, Robrahn L, Strauss D, Narberhaus F, Masepohl B. Molybdate uptake byAgrobacterium tumefacienscorrelates with the cellular molybdenum cofactor status. Mol Microbiol 2016; 101:809-22. [DOI: 10.1111/mmi.13421] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | - Koral Ali
- Microbial Biology, Ruhr University Bochum; Bochum Germany
| | | | | | - Daria Strauss
- Microbial Biology, Ruhr University Bochum; Bochum Germany
| | | | - Bernd Masepohl
- Microbial Biology, Ruhr University Bochum; Bochum Germany
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Périnet S, Jeukens J, Kukavica-Ibrulj I, Ouellet MM, Charette SJ, Levesque RC. Molybdate transporter ModABC is important for Pseudomonas aeruginosa chronic lung infection. BMC Res Notes 2016; 9:23. [PMID: 26758577 PMCID: PMC4710039 DOI: 10.1186/s13104-016-1840-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 01/06/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mechanisms underlying the success of Pseudomonas aeruginosa in chronic lung infection among cystic fibrosis (CF) patients are poorly defined. The modA gene was previously linked to in vivo competitiveness of P. aeruginosa by a genetic screening in the rat lung. This gene encodes a subunit of transporter ModABC, which is responsible for extracellular uptake of molybdate. This compound is essential for molybdoenzymes, including nitrate reductases. Since anaerobic growth conditions are known to occur during CF chronic lung infection, inactivation of a molybdate transporter could inhibit proliferation through the inactivation of denitrification enzymes. Hence, we performed phenotypic characterization of a modA mutant strain obtained by signature-tagged mutagenesis (STM_modA) and assessed its virulence in vivo with two host models. RESULTS The STM_modA mutant was in fact defective for anaerobic growth and unable to use nitrates in the growth medium for anaerobic respiration. Bacterial growth and nitrate usage were restored when the medium was supplemented with molybdate. Most significantly, the mutant strain showed reduced virulence compared to wild-type strain PAO1 according to a competitive index in the rat model of chronic lung infection and a predation assay with Dictyostelium discoideum amoebae. As the latter took place in aerobic conditions, the in vivo impact of the mutation in modA appears to extend beyond its effect on anaerobic growth. CONCLUSIONS These results support the modABC-encoded transporter as important for the pathogenesis of P. aeruginosa, and suggest that enzymatic machinery implicated in anaerobic growth during chronic lung infection in CF merits further investigation as a potential target for therapeutic intervention.
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Affiliation(s)
- Simone Périnet
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada. .,Département de microbiologie-infectiologie-immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.
| | - Julie Jeukens
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada. .,Département de microbiologie-infectiologie-immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.
| | - Irena Kukavica-Ibrulj
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada. .,Département de microbiologie-infectiologie-immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.
| | - Myriam M Ouellet
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada. .,Département de biochimie, de microbiologie et de bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, Canada. .,Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Quebec, QC, Canada.
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada. .,Département de biochimie, de microbiologie et de bio-informatique, Faculté des Sciences et de Génie, Université Laval, Québec, QC, Canada. .,Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec (CRIUCPQ), Quebec, QC, Canada.
| | - Roger C Levesque
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec, QC, Canada. .,Département de microbiologie-infectiologie-immunologie, Faculté de Médecine, Université Laval, Québec, QC, Canada.
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20
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Proteome Profiling of the Rhodobacter capsulatus Molybdenum Response Reveals a Role of IscN in Nitrogen Fixation by Fe-Nitrogenase. J Bacteriol 2015; 198:633-43. [PMID: 26644433 DOI: 10.1128/jb.00750-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/12/2015] [Indexed: 01/11/2023] Open
Abstract
UNLABELLED Rhodobacter capsulatus is capable of synthesizing two nitrogenases, a molybdenum-dependent nitrogenase and an alternative Mo-free iron-only nitrogenase, enabling this diazotroph to grow with molecular dinitrogen (N2) as the sole nitrogen source. Here, the Mo responses of the wild type and of a mutant lacking ModABC, the high-affinity molybdate transporter, were examined by proteome profiling, Western analysis, epitope tagging, and lacZ reporter fusions. Many Mo-controlled proteins identified in this study have documented or presumed roles in nitrogen fixation, demonstrating the relevance of Mo control in this highly ATP-demanding process. The levels of Mo-nitrogenase, NifHDK, and the Mo storage protein, Mop, increased with increasing Mo concentrations. In contrast, Fe-nitrogenase, AnfHDGK, and ModABC, the Mo transporter, were expressed only under Mo-limiting conditions. IscN was identified as a novel Mo-repressed protein. Mo control of Mop, AnfHDGK, and ModABC corresponded to transcriptional regulation of their genes by the Mo-responsive regulators MopA and MopB. Mo control of NifHDK and IscN appeared to be more complex, involving different posttranscriptional mechanisms. In line with the simultaneous control of IscN and Fe-nitrogenase by Mo, IscN was found to be important for Fe-nitrogenase-dependent diazotrophic growth. The possible role of IscN as an A-type carrier providing Fe-nitrogenase with Fe-S clusters is discussed. IMPORTANCE Biological nitrogen fixation is a central process in the global nitrogen cycle by which the abundant but chemically inert dinitrogen (N2) is reduced to ammonia (NH3), a bioavailable form of nitrogen. Nitrogen reduction is catalyzed by nitrogenases found in diazotrophic bacteria and archaea but not in eukaryotes. All diazotrophs synthesize molybdenum-dependent nitrogenases. In addition, some diazotrophs, including Rhodobacter capsulatus, possess catalytically less efficient alternative Mo-free nitrogenases, whose expression is repressed by Mo. Despite the importance of Mo in biological nitrogen fixation, this is the first study analyzing the proteome-wide Mo response in a diazotroph. IscN was recognized as a novel member of the molybdoproteome in R. capsulatus. It was dispensable for Mo-nitrogenase activity but supported diazotrophic growth under Mo-limiting conditions.
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Determining Roles of Accessory Genes in Denitrification by Mutant Fitness Analyses. Appl Environ Microbiol 2015; 82:51-61. [PMID: 26452555 DOI: 10.1128/aem.02602-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 10/07/2015] [Indexed: 01/06/2023] Open
Abstract
Enzymes of the denitrification pathway play an important role in the global nitrogen cycle, including release of nitrous oxide, an ozone-depleting greenhouse gas. In addition, nitric oxide reductase, maturation factors, and proteins associated with nitric oxide detoxification are used by pathogens to combat nitric oxide release by host immune systems. While the core reductases that catalyze the conversion of nitrate to dinitrogen are well understood at a mechanistic level, there are many peripheral proteins required for denitrification whose basic function is unclear. A bar-coded transposon DNA library from Pseudomonas stutzeri strain RCH2 was grown under denitrifying conditions, using nitrate or nitrite as an electron acceptor, and also under molybdenum limitation conditions, with nitrate as the electron acceptor. Analysis of sequencing results from these growths yielded gene fitness data for 3,307 of the 4,265 protein-encoding genes present in strain RCH2. The insights presented here contribute to our understanding of how peripheral proteins contribute to a fully functioning denitrification pathway. We propose a new low-affinity molybdate transporter, OatABC, and show that differential regulation is observed for two MoaA homologs involved in molybdenum cofactor biosynthesis. We also propose that NnrS may function as a membrane-bound NO sensor. The dominant HemN paralog involved in heme biosynthesis is identified, and a CheR homolog is proposed to function in nitrate chemotaxis. In addition, new insights are provided into nitrite reductase redundancy, nitric oxide reductase maturation, nitrous oxide reductase maturation, and regulation.
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Tejada-Jiménez M, Schwarz G. Molybdenum and Tungsten. BINDING, TRANSPORT AND STORAGE OF METAL IONS IN BIOLOGICAL CELLS 2014. [DOI: 10.1039/9781849739979-00223] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Molybdenum (Mo) is an essential micronutrient for the majority of organisms ranging from bacteria to animals. To fulfil its biological role, it is incorporated into a pterin-based Mo-cofactor (Moco) and can be found in the active centre of more than 50 enzymes that are involved in key reactions of carbon, nitrogen and sulfur metabolism. Five of the Mo-enzymes are present in eukaryotes: nitrate reductase (NR), sulfite oxidase (SO), aldehyde oxidase (AO), xanthine oxidase (XO) and the amidoxime-reducing component (mARC). Cells acquire Mo in form of the oxyanion molybdate using specific molybdate transporters. In bacteria, molybdate transport is an extensively studied process and is mediated mainly by the ATP-binding cassette system ModABC. In contrast, in eukaryotes, molybdate transport is poorly understood since specific molybdate transporters remained unknown until recently. Two rather distantly related families of proteins, MOT1 and MOT2, are involved in eukaryotic molybdate transport. They each feature high-affinity molybdate transporters that regulate the intracellular concentration of Mo and thus control activity of Mo-enzymes. The present chapter presents an overview of the biological functions of Mo with special focus on recent data related to its uptake, binding and storage.
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Affiliation(s)
- Manuel Tejada-Jiménez
- Institute of Biochemistry, Department of Chemistry, University of Cologne Zuelpicher Str. 47 Cologne 50674 Germany
| | - Guenter Schwarz
- Institute of Biochemistry, Department of Chemistry, University of Cologne Zuelpicher Str. 47 Cologne 50674 Germany
- Center for Molecular Medicine Cologne, University of Cologne Robert-Koch Str. 21 Cologne 50931 Germany
- Cluster of Excellence in Ageing Research, CECAD Research Center Joseph-Stelzmann-Str. 26 Cologne 50931 Germany
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NifA- and CooA-coordinated cowN expression sustains nitrogen fixation by Rhodobacter capsulatus in the presence of carbon monoxide. J Bacteriol 2014; 196:3494-502. [PMID: 25070737 DOI: 10.1128/jb.01754-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rhodobacter capsulatus fixes atmospheric dinitrogen via two nitrogenases, Mo- and Fe-nitrogenase, which operate under different conditions. Here, we describe the functions in nitrogen fixation and regulation of the rcc00574 (cooA) and rcc00575 (cowN) genes, which are located upstream of the structural genes of Mo-nitrogenase, nifHDK. Disruption of cooA or cowN specifically impaired Mo-nitrogenase-dependent growth at carbon monoxide (CO) concentrations still tolerated by the wild type. The cooA gene was shown to belong to the Mo-nitrogenase regulon, which is exclusively expressed when ammonium is limiting. Its expression was activated by NifA1 and NifA2, the transcriptional activators of nifHDK. AnfA, the transcriptional activator of Fe-nitrogenase genes, repressed cooA, thereby counteracting NifA activation. CooA activated cowN expression in response to increasing CO concentrations. Base substitutions in the presumed CooA binding site located upstream of the cowN transcription start site abolished cowN expression, indicating that cowN regulation by CooA is direct. In conclusion, a transcription factor-based network controls cowN expression to protect Mo-nitrogenase (but not Fe-nitrogenase) under appropriate conditions.
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Coordinated expression of fdxD and molybdenum nitrogenase genes promotes nitrogen fixation by Rhodobacter capsulatus in the presence of oxygen. J Bacteriol 2013; 196:633-40. [PMID: 24272776 DOI: 10.1128/jb.01235-13] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Rhodobacter capsulatus is able to grow with N2 as the sole nitrogen source using either a molybdenum-dependent or a molybdenum-free iron-only nitrogenase whose expression is strictly inhibited by ammonium. Disruption of the fdxD gene, which is located directly upstream of the Mo-nitrogenase genes, nifHDK, abolished diazotrophic growth via Mo-nitrogenase at oxygen concentrations still tolerated by the wild type, thus demonstrating the importance of FdxD under semiaerobic conditions. In contrast, FdxD was not beneficial for diazotrophic growth depending on Fe-nitrogenase. These findings suggest that the 2Fe2S ferredoxin FdxD specifically supports the Mo-nitrogenase system, probably by protecting Mo-nitrogenase against oxygen, as previously shown for its Azotobacter vinelandii counterpart, FeSII. Expression of fdxD occurred under nitrogen-fixing conditions, but not in the presence of ammonium. Expression of fdxD strictly required NifA1 and NifA2, the transcriptional activators of the Mo-nitrogenase genes, but not AnfA, the transcriptional activator of the Fe-nitrogenase genes. Expression of the fdxD and nifH genes, as well as the FdxD and NifH protein levels, increased with increasing molybdate concentrations. Molybdate induction of fdxD was independent of the molybdate-sensing regulators MopA and MopB, which repress anfA transcription at micromolar molybdate concentrations. In this report, we demonstrate the physiological relevance of an fesII-like gene, fdxD, and show that the cellular nitrogen and molybdenum statuses are integrated to control its expression.
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Pahnke J, Fröhlich C, Krohn M, Schumacher T, Paarmann K. Impaired mitochondrial energy production and ABC transporter function-A crucial interconnection in dementing proteopathies of the brain. Mech Ageing Dev 2013; 134:506-15. [PMID: 24012632 DOI: 10.1016/j.mad.2013.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 06/21/2013] [Accepted: 08/24/2013] [Indexed: 01/07/2023]
Abstract
Ageing is the main risk factor for the development of dementing neurodegenerative diseases (NDs) and it is accompanied by the accumulation of variations in mitochondrial DNA. The resulting tissue-specific alterations in ATP production and availability cause deteriorations of cerebral clearance mechanisms that are important for the removal of toxic peptides and its aggregates. ABC transporters were shown to be the most important exporter superfamily for toxic peptides, e.g. β-amyloid and α-synuclein. Their activity is highly dependent on the availability of ATP and forms a directed energy-exporter network, linking decreased mitochondrial function with highly impaired ABC transporter activity and disease progression. In this paper, we describe a network based on interactions between ageing, energy metabolism, regeneration, accumulation of toxic peptides and the development of proteopathies of the brain with a focus on Alzheimer's disease (AD). Additionally, we provide new experimental evidence for interactions within this network in regenerative processes in AD.
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Affiliation(s)
- Jens Pahnke
- Neurodegeneration Research Lab (NRL), Department of Neurology, University of Magdeburg, Leipziger Str. 44, H64, 39120 Magdeburg, Germany; German Center for Neurodegenerative Diseases (DZNE) Magdeburg, Leipziger Str. 44, H64, 39120 Magdeburg, Germany.
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Abstract
Biological trace metals are needed in small quantities, but used by all living organisms. They are employed in key cellular functions in a variety of biological processes, resulting in the various degree of dependence of organisms on metals. Most effort in the field has been placed on experimental studies of metal utilization pathways and metal-dependent proteins. On the other hand, systemic level analyses of metalloproteomes (or metallomes) have been limited for most metals. In this chapter, we focus on the recent advances in comparative genomics, which provides many insights into evolution and function of metal utilization. These studies suggested that iron and zinc are widely used in biology (presumably by all organisms), whereas some other metals such as copper, molybdenum, nickel, and cobalt, show scattered occurrence in various groups of organisms. For these metals, most user proteins are well characterized and their dependence on a specific element is evolutionarily conserved. We also discuss evolutionary dynamics of the dependence of user proteins on different metals. Overall, comparative genomics analysis of metallomes provides a foundation for the systemic level understanding of metal utilization as well as for investigating the general features, functions, and evolutionary dynamics of metal use in the three domains of life.
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27
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Rademacher C, Hoffmann MC, Lackmann JW, Moser R, Pfänder Y, Leimkühler S, Narberhaus F, Masepohl B. Tellurite resistance gene trgB confers copper tolerance to Rhodobacter capsulatus. Biometals 2012; 25:995-1008. [PMID: 22767205 DOI: 10.1007/s10534-012-9566-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 06/15/2012] [Indexed: 11/25/2022]
Abstract
To identify copper homeostasis genes in Rhodobacter capsulatus, we performed random transposon Tn5 mutagenesis. Screening of more than 10,000 Tn5 mutants identified tellurite resistance gene trgB as a so far unrecognized major copper tolerance determinant. The trgB gene is flanked by tellurite resistance gene trgA and cysteine synthase gene cysK2. While growth of trgA mutants was only moderately restricted by tellurite, trgB and cysK2 mutants were severely affected by tellurite, which implies that viability under tellurite stress requires increased cysteine levels. Mutational analyses revealed that trgB was the only gene in this chromosomal region conferring cross-tolerance towards copper. Expression of the monocistronic trgB gene required promoter elements overlapping the trgA coding region as shown by nested deletions. Neither copper nor tellurite affected trgB transcription as demonstrated by reverse transcriptase PCR and trgB-lacZ fusions. Addition of tellurite or copper gave rise to increased cellular tellurium and copper concentrations, respectively, as determined by inductively coupled plasma-optical emission spectroscopy. By contrast, cellular iron concentrations remained fairly constant irrespective of tellurite or copper addition. This is the first study demonstrating a direct link between copper and tellurite response in bacteria.
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Affiliation(s)
- Corinna Rademacher
- Biologie der Mikroorganismen, Fakultät für Biologie und Biotechnologie, Ruhr-Universität Bochum, 44780, Bochum, Germany
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Schumacher T, Krohn M, Hofrichter J, Lange C, Stenzel J, Steffen J, Dunkelmann T, Paarmann K, Fröhlich C, Uecker A, Plath AS, Sommer A, Brüning T, Heinze HJ, Pahnke J. ABC transporters B1, C1 and G2 differentially regulate neuroregeneration in mice. PLoS One 2012; 7:e35613. [PMID: 22545122 PMCID: PMC3335815 DOI: 10.1371/journal.pone.0035613] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 03/19/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND ATP-binding cassette (ABC) transporters are essential regulators of organismic homeostasis, and are particularly important in protecting the body from potentially harmful exogenous substances. Recently, an increasing number of in vitro observations have indicated a functional role of ABC transporters in the differentiation and maintenance of stem cells. Therefore, we sought to determine brain-related phenotypic changes in animals lacking the expression of distinct ABC transporters (ABCB1, ABCG2 or ABCC1). METHODOLOGY AND PRINCIPAL FINDINGS Analyzing adult neurogenesis in ABC transporter-deficient animals in vivo and neuronal stem/progenitor cells in vitro resulted in complex findings. In vivo, the differentiation of neuronal progenitors was hindered in ABC transporter-deficient mice (ABCB1(0/0)) as evidenced by lowered numbers of doublecortin(+) (-36%) and calretinin(+) (-37%) cells. In vitro, we confirmed that this finding is not connected to the functional loss of single neural stem/progenitor cells (NSPCs). Furthermore, assessment of activity, exploratory behavior, and anxiety levels revealed behavioral alterations in ABCB1(0/0) and ABCC1(0/0) mice, whereas ABCG2(0/0) mice were mostly unaffected. CONCLUSION AND SIGNIFICANCE Our data show that single ABC transporter-deficiency does not necessarily impair neuronal progenitor homeostasis on the single NSPC level, as suggested by previous studies. However, loss of distinct ABC transporters impacts global brain homeostasis with far ranging consequences, leading to impaired neurogenic functions in vivo and even to distinct behavioral phenotypes. In addition to the known role of ABC transporters in proteopathies such as Parkinson's disease and Alzheimer's disease, our data highlight the importance of understanding the general function of ABC transporters for the brain's homeostasis and the regeneration potential.
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Affiliation(s)
- Toni Schumacher
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Markus Krohn
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Jacqueline Hofrichter
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Cathleen Lange
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Jan Stenzel
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Johannes Steffen
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Tina Dunkelmann
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Kristin Paarmann
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Christina Fröhlich
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Annekathrin Uecker
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
| | - Anne-Sophie Plath
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Alexandra Sommer
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Thomas Brüning
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
| | - Hans-Jochen Heinze
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
| | - Jens Pahnke
- Neurodegeneration Research Laboratory (NRL), Department of Neurology, Universities of Rostock and Magdeburg, Magdeburg, Germany
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany
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Transcriptional and posttranscriptional events control copper-responsive expression of a Rhodobacter capsulatus multicopper oxidase. J Bacteriol 2012; 194:1849-59. [PMID: 22287514 DOI: 10.1128/jb.06274-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The copper-regulated Rhodobacter capsulatus cutO (multicopper oxidase) gene confers copper tolerance and is carried in the tricistronic orf635-cutO-cutR operon. Transcription of cutO strictly depends on the promoter upstream of orf635, as demonstrated by lacZ reporter fusions to nested promoter fragments. Remarkably, orf635 expression was not affected by copper availability, whereas cutO and cutR were expressed only in the presence of copper. Differential regulation was abolished by site-directed mutations within the orf635-cutO intergenic region, suggesting that this region encodes a copper-responsive mRNA element. Bioinformatic predictions and RNA structure probing experiments revealed an intergenic stem-loop structure as the candidate mRNA element. This is the first posttranscriptional copper response mechanism reported in bacteria.
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Choline uptake in Agrobacterium tumefaciens by the high-affinity ChoXWV transporter. J Bacteriol 2011; 193:5119-29. [PMID: 21803998 DOI: 10.1128/jb.05421-11] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Agrobacterium tumefaciens is a facultative phytopathogen that causes crown gall disease. For successful plant transformation A. tumefaciens requires the membrane lipid phosphatidylcholine (PC), which is produced via the methylation and the PC synthase (Pcs) pathways. The latter route is dependent on choline. Although choline uptake has been demonstrated in A. tumefaciens, the responsible transporter(s) remained elusive. In this study, we identified the first choline transport system in A. tumefaciens. The ABC-type choline transporter is encoded by the chromosomally located choXWV operon (ChoX, binding protein; ChoW, permease; and ChoV, ATPase). The Cho system is not critical for growth and PC synthesis. However, [14C]choline uptake is severely reduced in A. tumefaciens choX mutants. Recombinant ChoX is able to bind choline with high affinity (equilibrium dissociation constant [KD] of ≈2 μM). Since other quaternary amines are bound by ChoX with much lower affinities (acetylcholine, KD of ≈80 μM; betaine, KD of ≈470 μM), the ChoXWV system functions as a high-affinity transporter with a preference for choline. Two tryptophan residues (W40 and W87) located in the predicted ligand-binding pocket are essential for choline binding. The structural model of ChoX built on Sinorhizobium meliloti ChoX resembles the typical structure of substrate binding proteins with a so-called "Venus flytrap mechanism" of substrate binding.
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Abstract
The trace element molybdenum (Mo) is the catalytic component of important enzymes involved in global nitrogen, sulfur, and carbon metabolism in both prokaryotes and eukaryotes. With the exception of nitrogenase, Mo is complexed by a pterin compound thus forming the biologically active molybdenum cofactor (Moco) at the catalytic sites of molybdoenzymes. The physiological roles and biochemical functions of many molybdoenzymes have been characterized. However, our understanding of the occurrence and evolution of Mo utilization is limited. This article focuses on recent advances in comparative genomics of Mo utilization in the three domains of life. We begin with a brief introduction of Mo transport systems, the Moco biosynthesis pathway, the role of posttranslational modifications, and enzymes that utilize Mo. Then, we proceed to recent computational and comparative genomics studies of Mo utilization, including a discussion on novel Moco-binding proteins that contain the C-terminal domain of the Moco sulfurase and that are suggested to represent a new family of molybdoenzymes. As most molybdoenzymes need additional cofactors for their catalytic activity, we also discuss interactions between Mo metabolism and other trace elements and finish with an analysis of factors that may influence evolution of Mo utilization.
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Affiliation(s)
- Yan Zhang
- Division of Genetics, Department of Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA 02115, United States
| | - Steffen Rump
- Division of Genetics, Department of Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA 02115, United States
| | - Vadim N. Gladyshev
- Division of Genetics, Department of Medicine, Brigham & Women’s Hospital and Harvard Medical School, Boston, MA 02115, United States
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Aguilar-Barajas E, Díaz-Pérez C, Ramírez-Díaz MI, Riveros-Rosas H, Cervantes C. Bacterial transport of sulfate, molybdate, and related oxyanions. Biometals 2011; 24:687-707. [PMID: 21301930 DOI: 10.1007/s10534-011-9421-x] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 01/26/2011] [Indexed: 12/29/2022]
Affiliation(s)
- Esther Aguilar-Barajas
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana, Edificio B-3, Ciudad Universitaria, 58030 Morelia, Michoacan, Mexico
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