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Zhang J, Zhong H, Xuan N, Mushtaq R, Shao Y, Cao X, Wang P, Chen G. The Na + /Ca 2+ antiporter slr0681 affects carotenoid production in Synechocystis sp. PCC 6803 under high-light stress. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2024; 104:3147-3155. [PMID: 38072645 DOI: 10.1002/jsfa.13205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 12/06/2023] [Accepted: 12/06/2023] [Indexed: 12/22/2023]
Abstract
BACKGROUND Carotenoids play key roles in photosynthesis and are widely used in foods as natural pigments, antioxidants, and health-promoting compounds. Enhancing carotenoid production in microalgae via biotechnology has become an important area of research. RESULTS We knocked out the Na+ /Ca2+ antiporter gene slr0681 in Synechocystis sp. PCC 6803 via homologous recombination and evaluated the effects on carotenoid production under normal (NL) and high-light (HL) conditions. On day 7 of NL treatment in calcium ion (Ca2+ )-free medium, the cell density of Δslr0681 decreased by 29% compared to the wild type (WT). After 8 days of HL treatment, the total carotenoid contents decreased by 35% in Δslr0681, and the contents of individual carotenoids were altered: myxoxanthophyll, echinenone, and β-carotene contents increased by 10%, 50%, and 40%, respectively, while zeaxanthin contents decreased by ~40% in Δslr0681 versus the WT. The expression patterns of carotenoid metabolic pathway genes also differed: ipi expression increased by 1.2- to 8.5-fold, whereas crtO and crtR expression decreased by ~90% and 60%, respectively, in ∆slr0681 versus the WT. In addition, in ∆slr0681, the expression level of psaB (encoding a photosystem I structural protein) doubled, whereas the expression levels of the photosystem II genes psbA2 and psbD decreased by ~53% and 84%, respectively, compared to the WT. CONCLUSION These findings suggest that slr0681 plays important roles in regulating carotenoid biosynthesis and structuring of the photosystems in Synechocystis sp. This study provides a theoretical basis for the genetic engineering of microalgae photosystems to increase their economic benefits and lays the foundation for developing microalgae germplasm resources with high carotenoid contents. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Jiaye Zhang
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
- School of Life Sciences, Shandong Normal University, Jinan, China
| | - Huairong Zhong
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
| | - Ning Xuan
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
| | - Rubina Mushtaq
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
- Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan
| | - Yahui Shao
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
| | - Xue Cao
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
- School of Life Sciences, Shandong Normal University, Jinan, China
| | - Pengchong Wang
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
| | - Gao Chen
- Institute of Crop Germplasm Resources, Shandong Academy of Agricultural Sciences, Jinan, China
- Shandong Provincial Key Laboratory of Crop Genetic Improvement, Ecology and Physiology, Jinan, China
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Duersch BG, Soini SA, Luo Y, Liu X, Chen S, Merk VM. Multimodal Imaging of Nitrogen-fixing Cyanobacteria in the Near-native State. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2023; 29:1953-1954. [PMID: 37612916 DOI: 10.1093/micmic/ozad067.1011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Affiliation(s)
- Bobby G Duersch
- Department of Chemistry and Biochemistry, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, USA
| | - Steven A Soini
- Department of Chemistry and Biochemistry, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, USA
| | - Yanqi Luo
- Advanced Photon Source, Argonne National Laboratory, Argonne National Laboratory, Lemont, IL, USA
| | - Xiaoyang Liu
- Advanced Photon Source, Argonne National Laboratory, Argonne National Laboratory, Lemont, IL, USA
| | - Si Chen
- Advanced Photon Source, Argonne National Laboratory, Argonne National Laboratory, Lemont, IL, USA
| | - Vivian M Merk
- Department of Chemistry and Biochemistry, Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, USA
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Macário IPE, Veloso T, Frankenbach S, Serôdio J, Passos H, Sousa C, Gonçalves FJM, Ventura SPM, Pereira JL. Cyanobacteria as Candidates to Support Mars Colonization: Growth and Biofertilization Potential Using Mars Regolith as a Resource. Front Microbiol 2022; 13:840098. [PMID: 35865930 PMCID: PMC9295076 DOI: 10.3389/fmicb.2022.840098] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria are indicated as organisms that can possibly support Mars colonization, contributing to the production of oxygen and other commodities therein. In this general context, the aim of this work was to evaluate the ability of three species of cyanobacteria (Anabaena cylindrica, Nostoc muscorum, and Arthrospira platensis) and a green microalga (Chlorella vulgaris) to grow using only the resources existing in Mars, i.e., water and Martian regolith stimulant (MGS-1), under an Earth-like atmosphere. A Martian regolith extract was produced and used as a culture medium to grow these species. Their growth was assessed during a period of 25 days, using optical density and fluorometric parameters. After this period, the possible contribution of end-of-life cyanobacteria/microalga as biofertilizing agents was also assessed, using the macrophyte Lemna minor as a vegetable model. Among the three species, N. muscorum showed the best growth performance when compared to the other species, while A. platensis and C. vulgaris were not able to thrive on Mars regolith extract. Therefore, N. muscorum should be the target of future studies not only due to their role in oxygen production but also due to their possible use as a food source, as many members of the Nostoc genus. Cyanobacteria and microalgae (A. platensis and C. vulgaris) showed good abilities as biofertilizing agents, i.e., they stimulated biomass (i.e., dry weight) production at levels comparable to the plants that grew on standard synthetic medium. The highest yield was reached with A. platensis, while the lowest was achieved using the media with N. muscorum. FTIR-ATR (Fourier transform infrared with attenuated total reflectance) spectroscopy showed that the differences between the plants grown on media with or without Martian regolith seem to be related mainly to polysaccharides.
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Affiliation(s)
- Inês P. E. Macário
- Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
- CICECO – Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Telma Veloso
- Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
- CICECO – Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Silja Frankenbach
- Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
| | - João Serôdio
- Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
| | - Helena Passos
- CICECO – Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Clara Sousa
- Laboratório Associado, Centro de Biotecnologia e Química Fina, Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
| | - Fernando J. M. Gonçalves
- Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
| | - Sónia P. M. Ventura
- CICECO – Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Aveiro, Portugal
| | - Joana L. Pereira
- Department of Biology, Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
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Ford BA, Sullivan GJ, Moore L, Varkey D, Zhu H, Ostrowski M, Mabbutt BC, Paulsen IT, Shah BS. Functional characterisation of substrate-binding proteins to address nutrient uptake in marine picocyanobacteria. Biochem Soc Trans 2021; 49:2465-2481. [PMID: 34882230 PMCID: PMC8786288 DOI: 10.1042/bst20200244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/03/2021] [Accepted: 11/16/2021] [Indexed: 12/05/2022]
Abstract
Marine cyanobacteria are key primary producers, contributing significantly to the microbial food web and biogeochemical cycles by releasing and importing many essential nutrients cycled through the environment. A subgroup of these, the picocyanobacteria (Synechococcus and Prochlorococcus), have colonised almost all marine ecosystems, covering a range of distinct light and temperature conditions, and nutrient profiles. The intra-clade diversities displayed by this monophyletic branch of cyanobacteria is indicative of their success across a broad range of environments. Part of this diversity is due to nutrient acquisition mechanisms, such as the use of high-affinity ATP-binding cassette (ABC) transporters to competitively acquire nutrients, particularly in oligotrophic (nutrient scarce) marine environments. The specificity of nutrient uptake in ABC transporters is primarily determined by the peripheral substrate-binding protein (SBP), a receptor protein that mediates ligand recognition and initiates translocation into the cell. The recent availability of large numbers of sequenced picocyanobacterial genomes indicates both Synechococcus and Prochlorococcus apportion >50% of their transport capacity to ABC transport systems. However, the low degree of sequence homology among the SBP family limits the reliability of functional assignments using sequence annotation and prediction tools. This review highlights the use of known SBP structural representatives for the uptake of key nutrient classes by cyanobacteria to compare with predicted SBP functionalities within sequenced marine picocyanobacteria genomes. This review shows the broad range of conserved biochemical functions of picocyanobacteria and the range of novel and hypothetical ABC transport systems that require further functional characterisation.
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Affiliation(s)
- Benjamin A. Ford
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | | | - Lisa Moore
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Deepa Varkey
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Hannah Zhu
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Martin Ostrowski
- Climate Change Cluster (C3), University of Technology Sydney, Sydney, Australia
| | - Bridget C. Mabbutt
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Ian T. Paulsen
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - Bhumika S. Shah
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
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Schätzle H, Arévalo S, Flores E, Schleiff E. A TonB-Like Protein, SjdR, Is Involved in the Structural Definition of the Intercellular Septa in the Heterocyst-Forming Cyanobacterium Anabaena. mBio 2021; 12:e0048321. [PMID: 34101487 PMCID: PMC8262864 DOI: 10.1128/mbio.00483-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/04/2021] [Indexed: 12/11/2022] Open
Abstract
Cyanobacteria are photosynthetic organisms with a Gram-negative envelope structure. Certain filamentous species such as Anabaena sp. strain PCC 7120 can fix dinitrogen upon depletion of combined nitrogen. Because the nitrogen-fixing enzyme, nitrogenase, is oxygen sensitive, photosynthesis and nitrogen fixation are spatially separated in Anabaena. Nitrogen fixation takes place in specialized cells called heterocysts, which differentiate from vegetative cells. During heterocyst differentiation, a microoxic environment is created by dismantling photosystem II and restructuring the cell wall. Moreover, solute exchange between the different cell types is regulated to limit oxygen influx into the heterocyst. The septal zone containing nanopores for solute exchange is constricted between heterocysts and vegetative cells, and cyanophycin plugs are located at the heterocyst poles. We identified a protein previously annotated as TonB1 that is largely conserved among cyanobacteria. A mutant of the encoding gene formed heterocysts but was impaired in diazotrophic growth. Mutant heterocysts appeared elongated and exhibited abnormal morphological features, including a reduced cyanophycin plug, an enhanced septum size, and a restricted nanopore zone in the septum. In spite of this, the intercellular transfer velocity of the fluorescent marker calcein was increased in the mutant compared to the wild type. Thus, the protein is required for proper formation of septal structures, expanding our emerging understanding of Anabaena peptidoglycan plasticity and intercellular solute exchange, and is therefore renamed SjdR (septal junction disk regulator). Notably, calcium supplementation compensated for the impaired diazotrophic growth and alterations in septal peptidoglycan in the sjdR mutant, emphasizing the importance of calcium for cell wall structure. IMPORTANCE Multicellularity in bacteria confers an improved adaptive capacity to environmental conditions and stresses. This includes an enhanced capability of resource utilization through a distribution of biochemical processes between constituent cells. This specialization results in a mutual dependency of different cell types, as is the case for nitrogen-fixing heterocysts and photosynthetically active vegetative cells in Anabaena. In this cyanobacterium, intercellular solute exchange is facilitated through nanopores in the peptidoglycan between adjacent cells. To ensure functionality of the specialized cells, septal size as well as the position, size, and frequency of nanopores in the septum need to be tightly established. The novel septal junction disk regulator SjdR characterized here is conserved in the cyanobacterial phylum. It influences septal size and septal nanopore distribution. Consequently, its absence severely affects the intercellular communication and the strains' growth capacity under nitrogen depletion. Thus, SjdR is involved in septal structure remodeling in cyanobacteria.
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Affiliation(s)
- Hannah Schätzle
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- FIERCE, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Sergio Arévalo
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Enrique Flores
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, Seville, Spain
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- FIERCE, Goethe University Frankfurt, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
- Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany
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Rapid Transcriptional Reprogramming Triggered by Alteration of the Carbon/Nitrogen Balance Has an Impact on Energy Metabolism in Nostoc sp. PCC 7120. Life (Basel) 2020; 10:life10110297. [PMID: 33233741 PMCID: PMC7699953 DOI: 10.3390/life10110297] [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: 10/29/2020] [Revised: 11/12/2020] [Accepted: 11/18/2020] [Indexed: 12/12/2022] Open
Abstract
Nostoc (Anabaena) sp. PCC 7120 is a filamentous cyanobacterial species that fixes N2 to nitrogenous compounds using specialised heterocyst cells. Changes in the intracellular ratio of carbon to nitrogen (C/N balance) is known to trigger major transcriptional reprogramming of the cell, including initiating the differentiation of vegetative cells to heterocysts. Substantial transcriptional analysis has been performed on Nostoc sp. PCC 7120 during N stepdown (low to high C/N), but not during C stepdown (high to low C/N). In the current study, we shifted the metabolic balance of Nostoc sp. PCC 7120 cultures grown at 3% CO2 by introducing them to atmospheric conditions containing 0.04% CO2 for 1 h, after which the changes in gene expression were measured using RNAseq transcriptomics. This analysis revealed strong upregulation of carbon uptake, while nitrogen uptake and metabolism and early stages of heterocyst development were downregulated in response to the shift to low CO2. Furthermore, gene expression changes revealed a decrease in photosynthetic electron transport and increased photoprotection and reactive oxygen metabolism, as well a decrease in iron uptake and metabolism. Differential gene expression was largely attributed to change in the abundances of the metabolites 2-phosphoglycolate and 2-oxoglutarate, which signal a rapid shift from fluent photoassimilation to glycolytic metabolism of carbon after transition to low CO2. This work shows that the C/N balance in Nostoc sp. PCC 7120 rapidly adjusts the metabolic strategy through transcriptional reprogramming, enabling survival in the fluctuating environment.
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Walter J, Leganés F, Aro EM, Gollan PJ. The small Ca 2+-binding protein CSE links Ca 2+ signalling with nitrogen metabolism and filament integrity in Anabaena sp. PCC 7120. BMC Microbiol 2020; 20:57. [PMID: 32160863 PMCID: PMC7065334 DOI: 10.1186/s12866-020-01735-5] [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: 08/02/2019] [Accepted: 02/24/2020] [Indexed: 02/02/2023] Open
Abstract
Background Filamentous cyanobacteria represent model organisms for investigating multicellularity. For many species, nitrogen-fixing heterocysts are formed from photosynthetic vegetative cells under nitrogen limitation. Intracellular Ca2+ has been implicated in the highly regulated process of heterocyst differentiation but its role remains unclear. Ca2+ is known to operate more broadly in metabolic signalling in cyanobacteria, although the signalling mechanisms are virtually unknown. A Ca2+-binding protein called the Ca2+ Sensor EF-hand (CSE) is found almost exclusively in filamentous cyanobacteria. Expression of asr1131 encoding the CSE protein in Anabaena sp. PCC 7120 was strongly induced by low CO2 conditions, and rapidly downregulated during nitrogen step-down. A previous study suggests a role for CSE and Ca2+ in regulation of photosynthetic activity in response to changes in carbon and nitrogen availability. Results In the current study, a mutant Anabaena sp. PCC 7120 strain lacking asr1131 (Δcse) was highly prone to filament fragmentation, leading to a striking phenotype of very short filaments and poor growth under nitrogen-depleted conditions. Transcriptomics analysis under nitrogen-replete conditions revealed that genes involved in heterocyst differentiation and function were downregulated in Δcse, while heterocyst inhibitors were upregulated, compared to the wild-type. Conclusions These results indicate that CSE is required for filament integrity and for proper differentiation and function of heterocysts upon changes in the cellular carbon/nitrogen balance. A role for CSE in transmitting Ca2+ signals during the first response to changes in metabolic homeostasis is discussed.
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Affiliation(s)
- Julia Walter
- Department of Biochemistry, Molecular Plant Biology, University of Turku, Tykistökatu 6A, 6. krs, 20520, Turku, Finland.,Present address: Department of Plant Sciences, Environmental Plant Physiology, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Francisco Leganés
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Calle Darwin 2, 28049, Madrid, Spain
| | - Eva-Mari Aro
- Department of Biochemistry, Molecular Plant Biology, University of Turku, Tykistökatu 6A, 6. krs, 20520, Turku, Finland
| | - Peter J Gollan
- Department of Biochemistry, Molecular Plant Biology, University of Turku, Tykistökatu 6A, 6. krs, 20520, Turku, Finland.
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Kaczmarski JA, Hong NS, Mukherjee B, Wey LT, Rourke L, Förster B, Peat TS, Price GD, Jackson CJ. Structural Basis for the Allosteric Regulation of the SbtA Bicarbonate Transporter by the P II-like Protein, SbtB, from Cyanobium sp. PCC7001. Biochemistry 2019; 58:5030-5039. [PMID: 31746199 DOI: 10.1021/acs.biochem.9b00880] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cyanobacteria have evolved a suite of enzymes and inorganic carbon (Ci) transporters that improve photosynthetic performance by increasing the localized concentration of CO2 around the primary CO2-fixating enzyme, Rubisco. This CO2-concentrating mechanism (CCM) is highly regulated, responds to illumination/darkness cycles, and allows cyanobacteria to thrive under limiting Ci conditions. While the transcriptional control of CCM activity is well understood, less is known about how regulatory proteins might allosterically regulate Ci transporters in response to changing conditions. Cyanobacterial sodium-dependent bicarbonate transporters (SbtAs) are inhibited by PII-like regulatory proteins (SbtBs), with the inhibitory effect being modulated by adenylnucleotides. Here, we used isothermal titration calorimetry to show that SbtB from Cyanobium sp. PCC7001 (SbtB7001) binds AMP, ADP, cAMP, and ATP with micromolar-range affinities. X-ray crystal structures of apo and nucleotide-bound SbtB7001 revealed that while AMP, ADP, and cAMP have little effect on the SbtB7001 structure, binding of ATP stabilizes the otherwise flexible T-loop, and that the flexible C-terminal C-loop adopts several distinct conformations. We also show that ATP binding affinity is increased 10-fold in the presence of Ca2+, and we present an X-ray crystal structure of Ca2+ATP:SbtB7001 that shows how this metal ion facilitates additional stabilizing interactions with the apex of the T-loop. We propose that the Ca2+ATP-induced conformational change observed in SbtB7001 is important for allosteric regulation of SbtA activity by SbtB and is consistent with changing adenylnucleotide levels in illumination/darkness cycles.
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Affiliation(s)
- Joe A Kaczmarski
- Research School of Chemistry , The Australian National University , 137 Sullivans Creek Road , Canberra , ACT 0200 , Australia
| | - Nan-Sook Hong
- Research School of Chemistry , The Australian National University , 137 Sullivans Creek Road , Canberra , ACT 0200 , Australia
| | - Bratati Mukherjee
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology , The Australian National University , 134 Linnaeus Way , Canberra , ACT 0200 , Australia
| | - Laura T Wey
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology , The Australian National University , 134 Linnaeus Way , Canberra , ACT 0200 , Australia
| | - Loraine Rourke
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology , The Australian National University , 134 Linnaeus Way , Canberra , ACT 0200 , Australia
| | - Britta Förster
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology , The Australian National University , 134 Linnaeus Way , Canberra , ACT 0200 , Australia
| | - Thomas S Peat
- CSIRO Biomedical Program , 343 Royal Parade , Parkville , VIC 3052 , Australia
| | - G Dean Price
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology , The Australian National University , 134 Linnaeus Way , Canberra , ACT 0200 , Australia
| | - Colin J Jackson
- Research School of Chemistry , The Australian National University , 137 Sullivans Creek Road , Canberra , ACT 0200 , Australia
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Picciano AL, Crane BR. A nitric oxide synthase-like protein from Synechococcus produces NO/NO 3- from l-arginine and NADPH in a tetrahydrobiopterin- and Ca 2+-dependent manner. J Biol Chem 2019; 294:10708-10719. [PMID: 31113865 PMCID: PMC6615690 DOI: 10.1074/jbc.ra119.008399] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/17/2019] [Indexed: 01/01/2023] Open
Abstract
Nitric oxide synthases (NOSs) are heme-based monooxygenases that convert l-Arg to l-citrulline and nitric oxide (NO), a key signaling molecule and cytotoxic agent in mammals. Bacteria also contain NOS proteins, but the role of NO production within these organisms, where understood, differs considerably from that of mammals. For example, a NOS protein in the marine cyanobacterium Synechococcus sp. PCC 7335 (syNOS) has recently been proposed to function in nitrogen assimilation from l-Arg. syNOS retains the oxygenase (NOSox) and reductase (NOSred) domains present in mammalian NOS enzymes (mNOSs), but also contains an N-terminal globin domain (NOSg) homologous to bacterial flavohemoglobin proteins. Herein, we show that syNOS functions as a dimer and produces NO from l-Arg and NADPH in a tetrahydrobiopterin (H4B)-dependent manner at levels similar to those produced by other NOSs but does not require Ca2+-calmodulin, which regulates NOSred-mediated NOSox reduction in mNOSs. Unlike other bacterial NOSs, syNOS cannot function with tetrahydrofolate and requires high Ca2+ levels (>200 μm) for its activation. NOSg converts NO to NO3- in the presence of O2 and NADPH; however, NOSg did not protect Escherichia coli strains against nitrosative stress, even in a mutant devoid of NO-protective flavohemoglobin. We also found that syNOS does not have NOS activity in E. coli (which lacks H4B) and that the recombinant protein does not confer growth advantages on l-Arg as a nitrogen source. Our findings indicate that syNOS has both NOS and NO oxygenase activities, requires H4B, and may play a role in Ca2+-mediated signaling.
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Affiliation(s)
- Angela L Picciano
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Brian R Crane
- From the Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
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Tiwari A, Singh P, Riyazat Khadim S, Singh AK, Singh U, Singh P, Asthana RK. Role of Ca 2+ as protectant under heat stress by regulation of photosynthesis and membrane saturation in Anabaena PCC 7120. PROTOPLASMA 2019; 256:681-691. [PMID: 30456698 DOI: 10.1007/s00709-018-1328-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 11/12/2018] [Indexed: 05/08/2023]
Abstract
The present study was aimed at understanding the effects of heat stress on selected physiological and biochemical parameters of a model cyanobacterium, Anabaena PCC 7120 in addition to amelioration strategy using exogenous Ca2+. A comparison of the cells exposed to heat stress (0-24 h) in the presence or absence of Ca2+ clearly showed reduction in colony-forming ability and increase in reactive oxygen species (ROS) leading to loss in the viability of cells of Ca2+-deficient cultures. There was higher level of saturation in membrane lipids of the cells supplemented with Ca2+ along with higher accumulation of proline. Similarly, higher quantum yield (7.8-fold) in Ca2+-supplemented cultures indicated role of Ca2+ in regulation of photosynthesis. Relative electron transport rate (rETR) decreased in both the sets with the difference in the rate of decrease (slow) in Ca2+-supplemented cultures. The Ca2+-supplemented sets also maintained high levels of open reaction centers of PS II in comparison to Ca2+-deprived cells. Increase in transcripts of both subunits ((rbcL and rbcS) of RubisCO from Ca2+-supplemented Anabaena cultures pointed out the role of Ca2+ in sustenance of photosynthesis of cells via CO2 fixation, thus, playing an important role in maintaining metabolic status of the heat-stressed cyanobacterium.
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Affiliation(s)
- Anupam Tiwari
- Lovely Professional University, Phagwara, Jalandhar, India
| | - Prabhakar Singh
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Sk Riyazat Khadim
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Ankit Kumar Singh
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Urmilesh Singh
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Priyanka Singh
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India
| | - Ravi Kumar Asthana
- R.N. Singh Memorial Lab, Centre of Advanced study in Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
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A novel Ca 2+-binding protein influences photosynthetic electron transport in Anabaena sp. PCC 7120. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:519-532. [PMID: 31034800 DOI: 10.1016/j.bbabio.2019.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/17/2019] [Accepted: 04/23/2019] [Indexed: 12/25/2022]
Abstract
Ca2+ is a potent signalling molecule that regulates many cellular processes. In cyanobacteria, Ca2+ has been linked to cell growth, stress response and photosynthesis, and to the development of specialist heterocyst cells in certain nitrogen-fixing species. Despite this, the pathways of Ca2+ signal transduction in cyanobacteria are poorly understood, and very few protein components are known. The current study describes a previously unreported Ca2+-binding protein which was called the Ca2+ Sensor EF-hand (CSE), which is conserved in filamentous, nitrogen-fixing cyanobacteria. CSE is shown to bind Ca2+, which induces a conformational change in the protein structure. Poor growth of a strain of Anabaena sp. PCC 7120 overexpressing CSE was attributed to diminished photosynthetic performance. Transcriptomics, biophysics and proteomics analyses revealed modifications in the light-harvesting phycobilisome and photosynthetic reaction centre protein complexes.
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Tailor V, Ballal A. Novel molecular insights into the function and the antioxidative stress response of a Peroxiredoxin Q protein from cyanobacteria. Free Radic Biol Med 2017; 106:278-287. [PMID: 28159708 DOI: 10.1016/j.freeradbiomed.2017.01.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/18/2017] [Accepted: 01/20/2017] [Indexed: 12/11/2022]
Abstract
The Peroxiredoxin Q (PrxQ) proteins are thiol-based peroxidases that are important for maintaining redox homeostasis in several organisms. Activity of PrxQs is mediated by two cysteines, peroxidatic (Cp) and resolving (Cr), in association with a reducing partner. A PrxQ, Alr3183, from the cyanobacterium, Anabaena PCC 7120, was characterized in this study. Alr3183, which required thioredoxin A (TrxA) for peroxidase activity, was an intramolecular disulfide bond-containing monomeric protein. However, Alr3183 lacking Cp (Alr3183C46S) or Cr (Alr3183C51S) formed intermolecular disulfide linkages and was dimeric. Alr3183C46S was completely inactive, while Alr3183C51S required higher concentration of TrxA for peroxidase activity. Surface plasmon resonance analysis showed that unlike Alr3183 or Alr3183C46S, Alr3183C51S bound rather poorly to TrxA. Also, compared to the oxidized protein, the DTT-treated (reduced) Alr3183 displayed decreased interaction with TrxA. In vivo, Alr3183 was found to be induced in response to γ-radiation. On exposure to H2O2, Anabaena strain over-expressing Alr3183 showed reduced formation of ROS, intact photosynthetic pigments and consequently better survival than the wild-type, whereas overproduction of Alr3183C46S did not provide any protection. Significantly, this study (1) reveals the importance of Cr for interaction with thioredoxins and (2) demonstrates that over-expression of PrxQs can protect cyanobacteria from oxidative stresses.
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Affiliation(s)
- Vijay Tailor
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.
| | - Anand Ballal
- Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India; Homi Bhabha National Institute, Anushakti Nagar, Mumbai 400094, India.
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13
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Bell N, Lee JJ, Summers ML. Characterization and in vivo regulon determination of an ECF sigma factor and its cognate anti-sigma factor in Nostoc punctiforme. Mol Microbiol 2017; 104:179-194. [PMID: 28105698 DOI: 10.1111/mmi.13620] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2017] [Indexed: 12/21/2022]
Abstract
Based on primary sequence comparisons and genomic context, Npun_F4153 (SigG)/Npun_F4154 (SapG) of the cyanobacterium Nostoc punctiforme were hypothesized to encode an ECF sigma factor/anti-sigma factor pair. Transcription of sigG increased in heterocysts and akinetes, and after EDTA treatment. Interaction between SigG and the predicted cytoplasmic domain of SapG was observed in vitro. A SigG-GFP translational fusion protein localized to the periphery of vegetative cells in vivo, but lost this association following heat stress. A sigG mutant was unable to survive envelope damage caused by heat or EDTA, but was able to form functional heterocysts. Akinetes in the mutant strain appeared normal, but these cultures were less resistant to lysozyme and cold treatments than those of the wild-type strain. The SigG in vivo regulon was determined before and during akinete differentiation using DNA microarray analysis, and found to include multiple genes with putative association to the cell envelope. Mapped promoters common to both arrays enabled identification of a SigG promoter-binding motif that was supported in vivo by reporter studies, and in vitro by run-off transcription experiments. These findings support SigG/SapG as a sigma/anti-sigma pair involved in repair of envelope damage resulting from exogenous sources or cellular differentiation.
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Affiliation(s)
- Nicole Bell
- Department of Biology, California State University Northridge, 18111 Nordhoff Street, Northridge, CA, 91330-8303, USA
| | - Jamie J Lee
- Department of Biology, California State University Northridge, 18111 Nordhoff Street, Northridge, CA, 91330-8303, USA
| | - Michael L Summers
- Department of Biology, California State University Northridge, 18111 Nordhoff Street, Northridge, CA, 91330-8303, USA
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