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Ribeiro IDA, Paes JA, Wendisch VF, Ferreira HB, Passaglia LMP. Proteome profiling of Paenibacillus sonchi genomovar Riograndensis SBR5 T under conventional and alternative nitrogen fixation. J Proteomics 2024; 294:105061. [PMID: 38154550 DOI: 10.1016/j.jprot.2023.105061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/30/2023]
Abstract
Paenibacillus sonchi SBR5T is a Gram-positive, endospore-forming facultative aerobic diazotrophic bacterium that can fix nitrogen via an alternative Fe-only nitrogenase (AnfHDGK). In several bacteria, this alternative system is expressed under molybdenum (Mo)-limiting conditions when the conventional Mo-dependent nitrogenase (NifHDK) production is impaired. The regulatory mechanisms, metabolic processes, and cellular functions of N2 fixation by alternative and/or conventional systems are poorly understood in the Paenibacillus genus. We conducted a comparative proteomic profiling study of P. sonchi SBR5T grown under N2-fixing conditions with and without Mo supply through an LC-MS/MS and label-free quantification analysis to address this gap. Protein abundances revealed overrepresented processes related to anaerobiosis growth adaption, Fe-S cluster biosynthesis, ammonia assimilation, electron transfer, and sporulation under N2-fixing conditions compared to non-fixing control. Under Mo limitation, the Fe-only nitrogenase components were overrepresented together with the Mo-transporter system, while the dinitrogenase component (NifDK) of Mo‑nitrogenase was underrepresented. The dinitrogenase reductase component (NifH) and accessory proteins encoded by the nif operon had no significant differential expression, suggesting post-transcriptional regulation of nif gene products in this strain. Overall, this was the first comprehensive proteomic analysis of a diazotrophic strain from the Paenibacillaceae family, and it provided insights related to alternative N2-fixation by Fe-only nitrogenase. SIGNIFICANCE: In this work, we try to understand how the alternative nitrogen fixation system, presented by some diazotrophic bacteria, works. For this, we used the SBR5 lineage of P. sonchi, which presents the alternative system in which the nitrogenase cofactor is composed only of iron. In addition, we tried to unravel the proteome of this strain in different situations of nitrogen fixation, since, for Gram-positive bacteria, these systems are little known. The results achieved, through LC-MS/MS and label-free quantitative analysis, showed an overrepresentation of proteins related to different processes involved with growth under stressful conditions in situations of nitrogen deficiency, in addition to suggesting that some encoded proteins by the nif operon may be regulated at post-transcriptional levels. Our findings represent important steps toward the elucidation of nitrogen fixation systems in Gram-positive diazotrophic bacteria.
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Affiliation(s)
- Igor Daniel Alves Ribeiro
- Departamento de Genética and Programa de Pós-graduação em Genética e Biologia Molecular, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500 - Prédio 43312, Porto Alegre, RS, Brazil
| | - Jéssica Andrade Paes
- Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves, 9500 Porto Alegre, RS, Brazil
| | - Volker F Wendisch
- Institute for Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University, 33615 Bielefeld, Germany
| | - Henrique Bunselmeyer Ferreira
- Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves, 9500 Porto Alegre, RS, Brazil
| | - Luciane Maria Pereira Passaglia
- Departamento de Genética and Programa de Pós-graduação em Genética e Biologia Molecular, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Gonçalves, 9500 - Prédio 43312, Porto Alegre, RS, Brazil.
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A Red Fluorescent Protein Reporter System Developed for Measuring Gene Expression in Photosynthetic Bacteria under Anaerobic Conditions. Microorganisms 2022; 10:microorganisms10020201. [PMID: 35208656 PMCID: PMC8880563 DOI: 10.3390/microorganisms10020201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/22/2021] [Accepted: 01/12/2022] [Indexed: 02/04/2023] Open
Abstract
The photosynthetic bacterium Rhodopseudomonas palustris converts nitrogen gas (N2) to fertilizer ammonia (NH3) and also produces clean energy hydrogen gas (H2) from protons (H+) when it is grown anaerobically in nitrogen fixing medium with illumination, a condition that promotes the expression of active nitrogenase. Compared with quantitative real-time PCR (qRT-PCR) and the lacZ reporter system, two methods commonly used for in vivo study of nitrogenase regulation in photosynthetic bacteria, the fluorescent protein reporter system has advantages in terms of its simplicity and sensitivity. However, little is known concerning if the fluorescent protein reporter system can be used in bacterial cells that need to grow anaerobically. Here, we developed an RFP-based method to measure the nitrogenase gene expression in photosynthetic bacteria grown anaerobically. This method was able to determine the levels of both the genome-based and the plasmid-based nitrogenase expression under anaerobic conditions, providing a better method for in vivo study of gene expression affected by oxygen. The RFP reporter system developed here will promote a better understanding of the molecular mechanism of nitrogenase regulation and will be used on other genes of interest in a wider range of anaerobic bacteria.
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3
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Nisar A, Gongye X, Huang Y, Khan S, Chen M, Wu B, He M. Genome-Wide Analyses of Proteome and Acetylome in Zymomonas mobilis Under N 2-Fixing Condition. Front Microbiol 2021; 12:740555. [PMID: 34803957 PMCID: PMC8600466 DOI: 10.3389/fmicb.2021.740555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/15/2021] [Indexed: 11/30/2022] Open
Abstract
Zymomonas mobilis, a promising candidate for industrial biofuel production, is capable of nitrogen fixation naturally without hindering ethanol production. However, little is known about the regulation of nitrogen fixation in Z. mobilis. We herein conducted a high throughput analysis of proteome and protein acetylation in Z. mobilis under N2-fixing conditions and established its first acetylome. The upregulated proteins mainly belong to processes of nitrogen fixation, motility, chemotaxis, flagellar assembly, energy production, transportation, and oxidation–reduction. Whereas, downregulated proteins are mainly related to energy-consuming and biosynthetic processes. Our acetylome analyses revealed 197 uniquely acetylated proteins, belonging to major pathways such as nitrogen fixation, central carbon metabolism, ammonia assimilation pathway, protein biosynthesis, and amino acid metabolism. Further, we observed acetylation in glycolytic enzymes of central carbon metabolism, the nitrogenase complex, the master regulator NifA, and the enzyme in GS/GOGAT cycle. These findings suggest that protein acetylation may play an important role in regulating various aspects of N2-metabolism in Z. mobilis. This study provides new knowledge of specific proteins and their associated cellular processes and pathways that may be regulated by protein acetylation in Z. mobilis.
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Affiliation(s)
- Ayesha Nisar
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China.,Graduate School of Chinese Academy of Agricultural Science, Beijing, China
| | - Xiangxu Gongye
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | - Yuhuan Huang
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China.,Graduate School of Chinese Academy of Agricultural Science, Beijing, China
| | - Sawar Khan
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | - Mao Chen
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China.,Graduate School of Chinese Academy of Agricultural Science, Beijing, China
| | - Bo Wu
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
| | - Mingxiong He
- Key Laboratory of Development and Application of Rural Renewable Energy (Ministry of Agriculture and Rural Affairs), Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu, China
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Zhang Y, Yang Q, Ling J, Long L, Huang H, Yin J, Wu M, Tang X, Lin X, Zhang Y, Dong J. Shifting the microbiome of a coral holobiont and improving host physiology by inoculation with a potentially beneficial bacterial consortium. BMC Microbiol 2021; 21:130. [PMID: 33910503 PMCID: PMC8082877 DOI: 10.1186/s12866-021-02167-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/30/2021] [Indexed: 12/20/2022] Open
Abstract
Background The coral microbiome plays a key role in host health by being involved in energy metabolism, nutrient cycling, and immune system formation. Inoculating coral with beneficial bacterial consortia may enhance the ability of this host to cope with complex and changing marine environments. In this study, the coral Pocillopora damicornis was inoculated with a beneficial microorganisms for corals (BMC) consortium to investigate how the coral host and its associated microbial community would respond. Results High-throughput 16S rRNA gene sequencing revealed no significant differences in bacterial community α-diversity. However, the bacterial community structure differed significantly between the BMC and placebo groups at the end of the experiment. Addition of the BMC consortium significantly increased the relative abundance of potentially beneficial bacteria, including the genera Mameliella and Endozoicomonas. Energy reserves and calcification rates of the coral host were also improved by the addition of the BMC consortium. Co-occurrence network analysis indicated that inoculation of coral with the exogenous BMC consortium improved the physiological status of the host by shifting the coral-associated microbial community structure. Conclusions Manipulating the coral-associated microbial community may enhance the physiology of coral in normal aquarium conditions (no stress applied), which may hypothetically contribute to resilience and resistance in this host. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02167-5.
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Affiliation(s)
- Ying Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.,Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences and Hainan Key Laboratory of Tropical Marine Biotechnology, Sanya, 572000, China.,Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Qingsong Yang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.,Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Juan Ling
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.,Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Lijuan Long
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.,Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences and Hainan Key Laboratory of Tropical Marine Biotechnology, Sanya, 572000, China.,Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Hui Huang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China.,Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences and Hainan Key Laboratory of Tropical Marine Biotechnology, Sanya, 572000, China.,Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China
| | - Jianping Yin
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China
| | - Meilin Wu
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China
| | - Xiaoyu Tang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiancheng Lin
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanying Zhang
- Ocean school, Yantai University, Yantai, 264005, China.
| | - Junde Dong
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, 510301, China. .,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, 511458, China. .,Tropical Marine Biological Research Station in Hainan, Chinese Academy of Sciences and Hainan Key Laboratory of Tropical Marine Biotechnology, Sanya, 572000, China. .,Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, 510301, China.
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Construction of a new T7 promoter compatible Escherichia coli Nissle 1917 strain for recombinant production of heme-dependent proteins. Microb Cell Fact 2020; 19:190. [PMID: 33023596 PMCID: PMC7542351 DOI: 10.1186/s12934-020-01447-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/25/2020] [Indexed: 11/10/2022] Open
Abstract
Background Heme proteins and heme-derived molecules are essential in numerous cellular processes. Research into their in vitro functionality requires the production of large amounts of protein. Unfortunately, high yield expression is hampered by the lack of E. coli strains naturally capable of taking up heme from the medium. We recently reported the use of the probiotic E. coli strain Nissle 1917 (EcN) to sufficiently produce heme containing proteins, as it encodes the outer membrane heme receptor, ChuA, which allows for natural uptake of heme. The EcN strain however lacks the gene for T7 RNA polymerase, which is necessary for the expression of genes under the control of the T7-promotor, widely used in expression vectors like the pET or pDuet series. Results A new T7-promoter compatible EcN strain was constructed by integrating the gene for T7-RNA polymerase under the control of a lacUV5 promoter into the malEFG operon of EcN. Test expressions of genes via T7 promoter-based vectors in the new EcN(T7) strain were successful. Expression in EcN(T7) resulted in the efficient production of recombinant heme proteins in which the heme cofactor was incorporated during protein production. In addition, the new EcN(T7) strain can be used to co-express genes for the production of heme-derived molecules like biliverdin or other linear tetrapyrroles. We demonstrate the successful recombinant production of the phytochromes BphP, from Pseudomonas aeruginosa, and Cph1, from Synechocystis sp. PCC6803, loaded with their linear tetrapyrrole cofactors, biliverdin and phycocyanobilin, respectively. Conclusion We present a new E. coli strain for efficient production of heme proteins and heme-derived molecules using T7-promoter based expression vectors. The new EcN(T7) strain enables the use of a broader spectrum of expression vectors, as well as the co-expression of genes using the pDuet expression vectors, for expressing heme containing proteins. By utilizing E. coli strains EcN and EcN(T7), capable of being fed heme, the rate limiting step of heme biosynthesis in E. coli is eliminated, thereby permitting higher heme saturation of heme proteins and also higher yields of heme-derived molecules.
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Knoke LR, Abad Herrera S, Götz K, Justesen BH, Günther Pomorski T, Fritz C, Schäkermann S, Bandow JE, Aktas M. Agrobacterium tumefaciens Small Lipoprotein Atu8019 Is Involved in Selective Outer Membrane Vesicle (OMV) Docking to Bacterial Cells. Front Microbiol 2020; 11:1228. [PMID: 32582124 PMCID: PMC7296081 DOI: 10.3389/fmicb.2020.01228] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/14/2020] [Indexed: 12/02/2022] Open
Abstract
Outer membrane vesicles (OMVs), released from Gram-negative bacteria, have been attributed to intra- and interspecies communication and pathogenicity in diverse bacteria. OMVs carry various components including genetic material, toxins, signaling molecules, or proteins. Although the molecular mechanism(s) of cargo delivery is not fully understood, recent studies showed that transfer of the OMV content to surrounding cells is mediated by selective interactions. Here, we show that the phytopathogen Agrobacterium tumefaciens, the causative agent of crown gall disease, releases OMVs, which attach to the cell surface of various Gram-negative bacteria. The OMVs contain the conserved small lipoprotein Atu8019. An atu8019-deletion mutant produced wildtype-like amounts of OMVs with a subtle but reproducible reduction in cell-attachment. Otherwise, loss of atu8019 did not alter growth, susceptibility against cations or antibiotics, attachment to plant cells, virulence, motility, or biofilm formation. In contrast, overproduction of Atu8019 in A. tumefaciens triggered cell aggregation and biofilm formation. Localization studies revealed that Atu8019 is surface exposed in Agrobacterium cells and in OMVs supporting a role in cell adhesion. Purified Atu8019 protein reconstituted into liposomes interacted with model membranes and with the surface of several Gram-negative bacteria. Collectively, our data suggest that the small lipoprotein Atu8019 is involved in OMV docking to specific bacteria.
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Affiliation(s)
- Lisa Roxanne Knoke
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Sara Abad Herrera
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Katrin Götz
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Bo Højen Justesen
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Thomas Günther Pomorski
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Christiane Fritz
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Sina Schäkermann
- Faculty of Biology and Biotechnology, Department of Applied Microbiology, Ruhr University Bochum, Bochum, Germany
| | - Julia Elisabeth Bandow
- Faculty of Biology and Biotechnology, Department of Applied Microbiology, Ruhr University Bochum, Bochum, Germany
| | - Meriyem Aktas
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
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Selamoglu N, Önder Ö, Öztürk Y, Khalfaoui-Hassani B, Blaby-Haas CE, Garcia BA, Koch HG, Daldal F. Comparative differential cuproproteomes of Rhodobacter capsulatus reveal novel copper homeostasis related proteins. Metallomics 2020; 12:572-591. [PMID: 32149296 PMCID: PMC7192791 DOI: 10.1039/c9mt00314b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 02/28/2020] [Indexed: 12/20/2022]
Abstract
Copper (Cu) is an essential, but toxic, micronutrient for living organisms and cells have developed sophisticated response mechanisms towards both the lack and the excess of Cu in their environments. In this study, we achieved a global view of Cu-responsive changes in the prokaryotic model organism Rhodobacter capsulatus using label-free quantitative differential proteomics. Semi-aerobically grown cells under heterotrophic conditions in minimal medium (∼0.3 μM Cu) were compared with cells supplemented with either 5 μM Cu or with 5 mM of the Cu-chelator bathocuproine sulfonate. Mass spectrometry based bottom-up proteomics of unfractionated cell lysates identified 2430 of the 3632 putative proteins encoded by the genome, producing a robust proteome dataset for R. capsulatus. Use of biological and technical replicates for each growth condition yielded high reproducibility and reliable quantification for 1926 of the identified proteins. Comparison of cells grown under Cu-excess or Cu-depleted conditions to those grown under minimal Cu-sufficient conditions revealed that 75 proteins exhibited statistically significant (p < 0.05) abundance changes, ranging from 2- to 300-fold. A subset of the highly Cu-responsive proteins was orthogonally probed using molecular genetics, validating that several of them were indeed involved in cellular Cu homeostasis.
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Affiliation(s)
- Nur Selamoglu
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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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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9
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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: 11] [Impact Index Per Article: 2.2] [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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10
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Varghese F, Kabasakal BV, Cotton CAR, Schumacher J, Rutherford AW, Fantuzzi A, Murray JW. A low-potential terminal oxidase associated with the iron-only nitrogenase from the nitrogen-fixing bacterium Azotobacter vinelandii. J Biol Chem 2019; 294:9367-9376. [PMID: 31043481 PMCID: PMC6579470 DOI: 10.1074/jbc.ra118.007285] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 04/26/2019] [Indexed: 11/06/2022] Open
Abstract
The biological route for nitrogen gas entering the biosphere is reduction to ammonia by the nitrogenase enzyme, which is inactivated by oxygen. Three types of nitrogenase exist, the least-studied of which is the iron-only nitrogenase. The Anf3 protein in the bacterium Rhodobacter capsulatus is essential for diazotrophic (i.e. nitrogen-fixing) growth with the iron-only nitrogenase, but its enzymatic activity and function are unknown. Here, we biochemically and structurally characterize Anf3 from the model diazotrophic bacterium Azotobacter vinelandii Determining the Anf3 crystal structure to atomic resolution, we observed that it is a dimeric flavocytochrome with an unusually close interaction between the heme and the FAD cofactors. Measuring the reduction potentials by spectroelectrochemical redox titration, we observed values of -420 ± 10 and -330 ± 10 mV for the two FAD potentials and -340 ± 1 mV for the heme. We further show that Anf3 accepts electrons from spinach ferredoxin and that Anf3 consumes oxygen without generating superoxide or hydrogen peroxide. We predict that Anf3 protects the iron-only nitrogenase from oxygen inactivation by functioning as an oxidase in respiratory protection, with flavodoxin or ferredoxin as the physiological electron donors.
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Affiliation(s)
- Febin Varghese
- From the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Burak Veli Kabasakal
- From the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Charles A R Cotton
- From the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Jörg Schumacher
- From the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - A William Rutherford
- From the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Andrea Fantuzzi
- From the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - James W Murray
- From the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
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11
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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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Abstract
Small regulatory RNAs play an important role in the adaptation to changing conditions. Here, we describe a differentially expressed small regulatory RNA (sRNA) that affects various cellular processes in the plant pathogen Agrobacterium tumefaciens Using a combination of bioinformatic predictions and comparative proteomics, we identified nine targets, most of which are positively regulated by the sRNA. According to these targets, we named the sRNA PmaR for peptidoglycan biosynthesis, motility, and ampicillin resistance regulator. Agrobacterium spp. are long known to be naturally resistant to high ampicillin concentrations, and we can now explain this phenotype by the positive PmaR-mediated regulation of the beta-lactamase gene ampC Structure probing revealed a spoon-like structure of the sRNA, with a single-stranded loop that is engaged in target interaction in vivo and in vitro Several riboregulators have been implicated in antibiotic resistance mechanisms, such as uptake and efflux transporters, but PmaR represents the first example of an sRNA that directly controls the expression of an antibiotic resistance gene.IMPORTANCE The alphaproteobacterium Agrobacterium tumefaciens is able to infect various eudicots causing crown gall tumor formation. Based on its unique ability of interkingdom gene transfer, Agrobacterium serves as a crucial biotechnological tool for genetic manipulation of plant cells. The presence of hundreds of putative sRNAs in this organism suggests a considerable impact of riboregulation on A. tumefaciens physiology. Here, we characterized the biological function of the sRNA PmaR that controls various processes crucial for growth, motility, and virulence. Among the genes directly targeted by PmaR is ampC coding for a beta-lactamase that confers ampicillin resistance, suggesting that the sRNA is crucial for fitness in the competitive microbial composition of the rhizosphere.
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13
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Martin WF, Bryant DA, Beatty JT. A physiological perspective on the origin and evolution of photosynthesis. FEMS Microbiol Rev 2018; 42:205-231. [PMID: 29177446 PMCID: PMC5972617 DOI: 10.1093/femsre/fux056] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/20/2017] [Indexed: 12/22/2022] Open
Abstract
The origin and early evolution of photosynthesis are reviewed from an ecophysiological perspective. Earth's first ecosystems were chemotrophic, fueled by geological H2 at hydrothermal vents and, required flavin-based electron bifurcation to reduce ferredoxin for CO2 fixation. Chlorophyll-based phototrophy (chlorophototrophy) allowed autotrophs to generate reduced ferredoxin without electron bifurcation, providing them access to reductants other than H2. Because high-intensity, short-wavelength electromagnetic radiation at Earth's surface would have been damaging for the first chlorophyll (Chl)-containing cells, photosynthesis probably arose at hydrothermal vents under low-intensity, long-wavelength geothermal light. The first photochemically active pigments were possibly Zn-tetrapyrroles. We suggest that (i) after the evolution of red-absorbing Chl-like pigments, the first light-driven electron transport chains reduced ferredoxin via a type-1 reaction center (RC) progenitor with electrons from H2S; (ii) photothioautotrophy, first with one RC and then with two, was the bridge between H2-dependent chemolithoautotrophy and water-splitting photosynthesis; (iii) photothiotrophy sustained primary production in the photic zone of Archean oceans; (iv) photosynthesis arose in an anoxygenic cyanobacterial progenitor; (v) Chl a is the ancestral Chl; and (vi), anoxygenic chlorophototrophic lineages characterized so far acquired, by horizontal gene transfer, RCs and Chl biosynthesis with or without autotrophy, from the architects of chlorophototrophy-the cyanobacterial lineage.
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Affiliation(s)
- William F Martin
- Institute for Molecular Evolution, University of Düsseldorf, D-40225 Düsseldorf, Germany
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
| | - J Thomas Beatty
- Department of Microbiology and Immunology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
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14
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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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