1
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Karikomi M, Katayama N, Osanai T. Pyruvate kinase 2 from Synechocystis sp. PCC 6803 increased substrate affinity via glucose-6-phosphate and ribose-5-phosphate for phosphoenolpyruvate consumption. PLANT MOLECULAR BIOLOGY 2024; 114:60. [PMID: 38758412 PMCID: PMC11101554 DOI: 10.1007/s11103-023-01401-0] [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: 06/08/2023] [Accepted: 11/30/2023] [Indexed: 05/18/2024]
Abstract
Pyruvate kinase (Pyk, EC 2.7.1.40) is a glycolytic enzyme that generates pyruvate and adenosine triphosphate (ATP) from phosphoenolpyruvate (PEP) and adenosine diphosphate (ADP), respectively. Pyk couples pyruvate and tricarboxylic acid metabolisms. Synechocystis sp. PCC 6803 possesses two pyk genes (encoded pyk1, sll0587 and pyk2, sll1275). A previous study suggested that pyk2 and not pyk1 is essential for cell viability; however, its biochemical analysis is yet to be performed. Herein, we biochemically analyzed Synechocystis Pyk2 (hereafter, SyPyk2). The optimum pH and temperature of SyPyk2 were 7.0 and 55 °C, respectively, and the Km values for PEP and ADP under optimal conditions were 1.5 and 0.053 mM, respectively. SyPyk2 is activated in the presence of glucose-6-phosphate (G6P) and ribose-5-phosphate (R5P); however, it remains unaltered in the presence of adenosine monophosphate (AMP) or fructose-1,6-bisphosphate. These results indicate that SyPyk2 is classified as PykA type rather than PykF, stimulated by sugar monophosphates, such as G6P and R5P, but not by AMP. SyPyk2, considering substrate affinity and effectors, can play pivotal roles in sugar catabolism under nonphotosynthetic conditions.
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Affiliation(s)
- Masahiro Karikomi
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-Ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Noriaki Katayama
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-Ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Takashi Osanai
- School of Agriculture, Meiji University, 1-1-1, Higashimita, Tama-Ku, Kawasaki, Kanagawa, 214-8571, Japan.
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2
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Bolay P, Dodge N, Janssen K, Jensen PE, Lindberg P. Tailoring regulatory components for metabolic engineering in cyanobacteria. PHYSIOLOGIA PLANTARUM 2024; 176:e14316. [PMID: 38686633 DOI: 10.1111/ppl.14316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/26/2024] [Accepted: 04/03/2024] [Indexed: 05/02/2024]
Abstract
The looming climate crisis has prompted an ever-growing interest in cyanobacteria due to their potential as sustainable production platforms for the synthesis of energy carriers and value-added chemicals from CO2 and sunlight. Nonetheless, cyanobacteria are yet to compete with heterotrophic systems in terms of space-time yields and consequently production costs. One major drawback leading to the low production performance observed in cyanobacteria is the limited ability to utilize the full capacity of the photosynthetic apparatus and its associated systems, i.e. CO2 fixation and the directly connected metabolism. In this review, novel insights into various levels of metabolic regulation of cyanobacteria are discussed, including the potential of targeting these regulatory mechanisms to create a chassis with a phenotype favorable for photoautotrophic production. Compared to conventional metabolic engineering approaches, minor perturbations of regulatory mechanisms can have wide-ranging effects.
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Affiliation(s)
- Paul Bolay
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Uppsala, SE, Sweden
| | - Nadia Dodge
- Plant Based Foods and Biochemistry, Food Analytics and Biotechnology, Department of Food Science, University of Copenhagen, Denmark
| | - Kim Janssen
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Uppsala, SE, Sweden
| | - Poul Erik Jensen
- Plant Based Foods and Biochemistry, Food Analytics and Biotechnology, Department of Food Science, University of Copenhagen, Denmark
| | - Pia Lindberg
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Uppsala, SE, Sweden
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3
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Wright Z, Seymour M, Paszczak K, Truttmann T, Senn K, Stilp S, Jansen N, Gosz M, Goeden L, Anantharaman V, Aravind L, Waters LS. The small protein MntS evolved from a signal peptide and acquired a novel function regulating manganese homeostasis in Escherichia coli. Mol Microbiol 2024; 121:152-166. [PMID: 38104967 PMCID: PMC10842292 DOI: 10.1111/mmi.15206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/17/2023] [Accepted: 11/24/2023] [Indexed: 12/19/2023]
Abstract
Small proteins (<50 amino acids) are emerging as ubiquitous and important regulators in organisms ranging from bacteria to humans, where they commonly bind to and regulate larger proteins during stress responses. However, fundamental aspects of small proteins, such as their molecular mechanism of action, downregulation after they are no longer needed, and their evolutionary provenance, are poorly understood. Here, we show that the MntS small protein involved in manganese (Mn) homeostasis binds and inhibits the MntP Mn transporter. Mn is crucial for bacterial survival in stressful environments but is toxic in excess. Thus, Mn transport is tightly controlled at multiple levels to maintain optimal Mn levels. The small protein MntS adds a new level of regulation for Mn transporters, beyond the known transcriptional and post-transcriptional control. We also found that MntS binds to itself in the presence of Mn, providing a possible mechanism of downregulating MntS activity to terminate its inhibition of MntP Mn export. MntS is homologous to the signal peptide of SitA, the periplasmic metal-binding subunit of a Mn importer. Remarkably, the homologous signal peptide regions can substitute for MntS, demonstrating a functional relationship between MntS and these signal peptides. Conserved gene neighborhoods support that MntS evolved from the signal peptide of an ancestral SitA protein, acquiring a life of its own with a distinct function in Mn homeostasis.
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Affiliation(s)
- Zachary Wright
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Mackenzie Seymour
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Kalista Paszczak
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Taylor Truttmann
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Katherine Senn
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Samuel Stilp
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Nickolas Jansen
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Magdalyn Gosz
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Lindsay Goeden
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
| | - Vivek Anantharaman
- National Center for Biotechnology Information, National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, USA
| | - L. Aravind
- National Center for Biotechnology Information, National Library of Medicine, 8600 Rockville Pike, Bethesda, MD 20894, USA
| | - Lauren S. Waters
- Department of Chemistry, 800 Algoma Blvd, University of Wisconsin, Oshkosh, WI 54901, USA
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4
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Jordan B, Weidenbach K, Schmitz RA. The power of the small: the underestimated role of small proteins in bacterial and archaeal physiology. Curr Opin Microbiol 2023; 76:102384. [PMID: 37776678 DOI: 10.1016/j.mib.2023.102384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/04/2023] [Accepted: 09/04/2023] [Indexed: 10/02/2023]
Abstract
Small proteins encoded by small open-reading frames (sORFs) (≤70 aa) were overlooked for decades due to methodological reasons and are thus often missing in genome annotations. Novel detection methods such as ribosome profiling (Ribo-Seq) and mass spectrometry optimized for small proteins (peptidomics) have opened up a new field of interest and several catalogs of small proteins in bacteria and archaea have been recently reported. Many translated sORFs have been discovered in genomic locations previously thought to be noncoding, such as 5' or 3' untranslated regions or well-studied regulatory small RNAs (sRNAs). Even within longer ORFs, additional functional sORFs have been detected. Today, only a small proportion is characterized, but those small proteins indicate important and diverse functions in cellular physiology. Here, we summarize recently characterized small proteins involved in microbial metabolism.
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Affiliation(s)
- Britta Jordan
- Institute for General Microbiology, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Katrin Weidenbach
- Institute for General Microbiology, Christian-Albrechts-University, 24118 Kiel, Germany
| | - Ruth A Schmitz
- Institute for General Microbiology, Christian-Albrechts-University, 24118 Kiel, Germany.
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5
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Wright Z, Seymour M, Paszczak K, Truttmann T, Senn K, Stilp S, Jansen N, Gosz M, Goeden L, Anantharaman V, Aravind L, Waters LS. The small protein MntS evolved from a signal peptide and acquired a novel function regulating manganese homeostasis in Escherichia coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.02.543501. [PMID: 37398132 PMCID: PMC10312517 DOI: 10.1101/2023.06.02.543501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Small proteins (< 50 amino acids) are emerging as ubiquitous and important regulators in organisms ranging from bacteria to humans, where they commonly bind to and regulate larger proteins during stress responses. However, fundamental aspects of small proteins, such as their molecular mechanism of action, downregulation after they are no longer needed, and their evolutionary provenance are poorly understood. Here we show that the MntS small protein involved in manganese (Mn) homeostasis binds and inhibits the MntP Mn transporter. Mn is crucial for bacterial survival in stressful environments, but is toxic in excess. Thus, Mn transport is tightly controlled at multiple levels to maintain optimal Mn levels. The small protein MntS adds a new level of regulation for Mn transporters, beyond the known transcriptional and post-transcriptional control. We also found that MntS binds to itself in the presence of Mn, providing a possible mechanism of downregulating MntS activity to terminate its inhibition of MntP Mn export. MntS is homologous to the signal peptide of SitA, the periplasmic metal-binding subunit of a Mn importer. Remarkably, the homologous signal peptide regions can substitute for MntS, demonstrating a functional relationship between MntS and these signal peptides. Conserved gene-neighborhoods support that MntS evolved from an ancestral SitA, acquiring a life of its own with a distinct function in Mn homeostasis. Significance This study demonstrates that the MntS small protein binds and inhibits the MntP Mn exporter, adding another layer to the complex regulation of Mn homeostasis. MntS also interacts with itself in cells with Mn, which could prevent it from regulating MntP. We propose that MntS and other small proteins might sense environmental signals and shut off their own regulation via binding to ligands (e.g., metals) or other proteins. We also provide evidence that MntS evolved from the signal peptide region of the Mn importer, SitA. Homologous SitA signal peptides can recapitulate MntS activities, showing that they have a second function beyond protein secretion. Overall, we establish that small proteins can emerge and develop novel functionalities from gene remnants.
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6
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Toepel J, Karande R, Klähn S, Bühler B. Cyanobacteria as whole-cell factories: current status and future prospectives. Curr Opin Biotechnol 2023; 80:102892. [PMID: 36669448 DOI: 10.1016/j.copbio.2023.102892] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 12/08/2022] [Accepted: 12/20/2022] [Indexed: 01/20/2023]
Abstract
Cyanobacteria as phototrophic microorganisms bear great potential to produce chemicals from sustainable resources such as light and CO2. Most studies focus on either strain engineering or tackling metabolic constraints. Recently gained knowledge on internal electron and carbon fluxes and their regulation provides new opportunities to efficiently channel cellular resources toward product formation. Concomitantly, novel photobioreactor concepts are developed to ensure sufficient light supply. This review summarizes the newest developments in the field of cyanobacterial engineering to finally establish photosynthesis-based production processes. A holistic approach tackling genetic, metabolic, and biochemical engineering in parallel is considered essential to turn their application into an ecoefficient and economically feasible option for a future green bioeconomy.
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Affiliation(s)
- Jörg Toepel
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Rohan Karande
- Research and Transfer Center for bioactive Matter b-ACTmatter, University of Leipzig, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany
| | - Bruno Bühler
- Department of Environmental Microbiology, Helmholtz Centre for Environmental Research - UFZ, Leipzig, Germany.
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7
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Yamane M, Osanai T. Nondiazotrophic cyanobacteria metabolic engineering for succinate and lactate production. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.103088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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8
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Abstract
In recent years, there has been increased appreciation that a whole category of proteins, small proteins of around 50 amino acids or fewer in length, has been missed by annotation as well as by genetic and biochemical assays. With the increased recognition that small proteins are stable within cells and have regulatory functions, there has been intensified study of these proteins. As a result, important questions about small proteins in bacteria and archaea are coming to the fore. Here, we give an overview of these questions, the initial answers, and the approaches needed to address these questions more fully. More detailed discussions of how small proteins can be identified by ribosome profiling and mass spectrometry approaches are provided by two accompanying reviews (N. Vazquez-Laslop, C. M. Sharma, A. S. Mankin, and A. R. Buskirk, J Bacteriol 204:e00294-21, 2022, https://doi.org/10.1128/JB.00294-21; C. H. Ahrens, J. T. Wade, M. M. Champion, and J. D. Langer, J Bacteriol 204:e00353-21, 2022, https://doi.org/10.1128/JB.00353-21). We are excited by the prospects of new insights and possible therapeutic approaches coming from this emerging field.
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Affiliation(s)
- Todd Gray
- Wadsworth Center, New York State Department of Health, Albany, New York, USA
- Department of Biomedical Sciences, University at Albany, Albany, New York, USA
| | - Gisela Storz
- Division of Molecular and Cellular Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland, USA
| | - Kai Papenfort
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
- Microverse Cluster, Friedrich Schiller University, Jena, Germany
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9
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Song K, Baumgartner D, Hagemann M, Muro-Pastor AM, Maaß S, Becher D, Hess WR. AtpΘ is an inhibitor of F 0F 1 ATP synthase to arrest ATP hydrolysis during low-energy conditions in cyanobacteria. Curr Biol 2021; 32:136-148.e5. [PMID: 34762820 DOI: 10.1016/j.cub.2021.10.051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/14/2021] [Accepted: 10/22/2021] [Indexed: 10/19/2022]
Abstract
Biological processes in all living cells are powered by ATP, a nearly universal molecule of energy transfer. ATP synthases produce ATP utilizing proton gradients that are usually generated by either respiration or photosynthesis. However, cyanobacteria are unique in combining photosynthetic and respiratory electron transport chains in the same membrane system, the thylakoids. How cyanobacteria prevent the futile reverse operation of ATP synthase under unfavorable conditions pumping protons while hydrolyzing ATP is mostly unclear. Here, we provide evidence that the small protein AtpΘ, which is widely conserved in cyanobacteria, is mainly fulfilling this task. The expression of AtpΘ becomes induced under conditions such as darkness or heat shock, which can lead to a weakening of the proton gradient. Translational fusions of AtpΘ to the green fluorescent protein revealed targeting to the thylakoid membrane. Immunoprecipitation assays followed by mass spectrometry and far western blots identified subunits of ATP synthase as interacting partners of AtpΘ. ATP hydrolysis assays with isolated membrane fractions, as well as purified ATP synthase complexes, demonstrated that AtpΘ inhibits ATPase activity in a dose-dependent manner similar to the F0F1-ATP synthase inhibitor N,N-dicyclohexylcarbodimide. The results show that, even in a well-investigated process, crucial new players can be discovered if small proteins are taken into consideration and indicate that ATP synthase activity can be controlled in surprisingly different ways.
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Affiliation(s)
- Kuo Song
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Desirée Baumgartner
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, 79104 Freiburg, Germany
| | - Martin Hagemann
- University of Rostock, Institute of Biosciences, Plant Physiology Department, Albert-Einstein-Str. 3, 18059 Rostock, Germany
| | - Alicia M Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Sevilla, Spain
| | - Sandra Maaß
- University of Greifswald, Department of Microbial Proteomics, Institute of Microbiology, 17489 Greifswald, Germany
| | - Dörte Becher
- University of Greifswald, Department of Microbial Proteomics, Institute of Microbiology, 17489 Greifswald, Germany
| | - Wolfgang R Hess
- University of Freiburg, Faculty of Biology, Genetics and Experimental Bioinformatics, Schänzlestr. 1, 79104 Freiburg, Germany.
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10
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Biochemical elucidation of citrate accumulation in Synechocystis sp. PCC 6803 via kinetic analysis of aconitase. Sci Rep 2021; 11:17131. [PMID: 34429477 PMCID: PMC8385029 DOI: 10.1038/s41598-021-96432-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 08/04/2021] [Indexed: 12/03/2022] Open
Abstract
A unicellular cyanobacterium Synechocystis sp. PCC 6803 possesses a unique tricarboxylic acid (TCA) cycle, wherein the intracellular citrate levels are approximately 1.5–10 times higher than the levels of other TCA cycle metabolite. Aconitase catalyses the reversible isomerisation of citrate and isocitrate. Herein, we biochemically analysed Synechocystis sp. PCC 6803 aconitase (SyAcnB), using citrate and isocitrate as the substrates. We observed that the activity of SyAcnB for citrate was highest at pH 7.7 and 45 °C and for isocitrate at pH 8.0 and 53 °C. The Km value of SyAcnB for citrate was higher than that for isocitrate under the same conditions. The Km value of SyAcnB for isocitrate was 3.6-fold higher than the reported Km values of isocitrate dehydrogenase for isocitrate. Therefore, we suggest that citrate accumulation depends on the enzyme kinetics of SyAcnB, and 2-oxoglutarate production depends on the chemical equilibrium in this cyanobacterium.
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11
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Genetic, Genomics, and Responses to Stresses in Cyanobacteria: Biotechnological Implications. Genes (Basel) 2021; 12:genes12040500. [PMID: 33805386 PMCID: PMC8066212 DOI: 10.3390/genes12040500] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 02/07/2023] Open
Abstract
Cyanobacteria are widely-diverse, environmentally crucial photosynthetic prokaryotes of great interests for basic and applied science. Work to date has focused mostly on the three non-nitrogen fixing unicellular species Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002, which have been selected for their genetic and physiological interests summarized in this review. Extensive "omics" data sets have been generated, and genome-scale models (GSM) have been developed for the rational engineering of these cyanobacteria for biotechnological purposes. We presently discuss what should be done to improve our understanding of the genotype-phenotype relationships of these models and generate robust and predictive models of their metabolism. Furthermore, we also emphasize that because Synechocystis PCC 6803, Synechococcus PCC 7942, and Synechococcus PCC 7002 represent only a limited part of the wide biodiversity of cyanobacteria, other species distantly related to these three models, should be studied. Finally, we highlight the need to strengthen the communication between academic researchers, who know well cyanobacteria and can engineer them for biotechnological purposes, but have a limited access to large photobioreactors, and industrial partners who attempt to use natural or engineered cyanobacteria to produce interesting chemicals at reasonable costs, but may lack knowledge on cyanobacterial physiology and metabolism.
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12
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Steinberg R, Koch HG. The largely unexplored biology of small proteins in pro- and eukaryotes. FEBS J 2021; 288:7002-7024. [PMID: 33780127 DOI: 10.1111/febs.15845] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/11/2021] [Accepted: 03/26/2021] [Indexed: 12/29/2022]
Abstract
The large abundance of small open reading frames (smORFs) in prokaryotic and eukaryotic genomes and the plethora of smORF-encoded small proteins became only apparent with the constant advancements in bioinformatic, genomic, proteomic, and biochemical tools. Small proteins are typically defined as proteins of < 50 amino acids in prokaryotes and of less than 100 amino acids in eukaryotes, and their importance for cell physiology and cellular adaptation is only beginning to emerge. In contrast to antimicrobial peptides, which are secreted by prokaryotic and eukaryotic cells for combatting pathogens and competitors, small proteins act within the producing cell mainly by stabilizing protein assemblies and by modifying the activity of larger proteins. Production of small proteins is frequently linked to stress conditions or environmental changes, and therefore, cells seem to use small proteins as intracellular modifiers for adjusting cell metabolism to different intra- and extracellular cues. However, the size of small proteins imposes a major challenge for the cellular machinery required for protein folding and intracellular trafficking and recent data indicate that small proteins can engage distinct trafficking pathways. In the current review, we describe the diversity of small proteins in prokaryotes and eukaryotes, highlight distinct and common features, and illustrate how they are handled by the protein trafficking machineries in prokaryotic and eukaryotic cells. Finally, we also discuss future topics of research on this fascinating but largely unexplored group of proteins.
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Affiliation(s)
- Ruth Steinberg
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert-Ludwigs-Universität Freiburg, Germany
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13
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Phycobilisome breakdown effector NblD is required to maintain the cellular amino acid composition during nitrogen starvation. J Bacteriol 2021; 204:JB0015821. [PMID: 34228497 PMCID: PMC8765419 DOI: 10.1128/jb.00158-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Small proteins are critically involved in the acclimation response of photosynthetic cyanobacteria to nitrogen starvation. NblD is the 66-amino-acid effector of nitrogen-limitation-induced phycobilisome breakdown, which is believed to replenish the cellular amino acid pools. To address the physiological functions of NblD, the concentrations of amino acids, intermediates of the arginine catabolism pathway and several organic acids were measured during the response to nitrogen starvation in the cyanobacterium Synechocystis sp. PCC 6803 wild type and in an nblD deletion strain. A characteristic signature of metabolite pool composition was identified, which shows that NblD-mediated phycobilisome degradation is required to maintain the cellular amino acid and organic acid pools during nitrogen starvation. Specific deviations from the wild type suggest wider-reaching effects that also affect such processes as redox homeostasis via glutathione and tetrapyrrole biosynthesis, both of which are linked to the strongly decreased glutamate pool, and transcriptional reprogramming via an enhanced concentration of 2-oxoglutarate, the metabolite co-regulator of the NtcA transcription factor. The essential role played by NblD in metabolic homeostasis is consistent with the widespread occurrence of NblD throughout the cyanobacterial radiation and the previously observed strong positive selection for the nblD gene under fluctuating nitrogen supply. Importance Cyanobacteria play important roles in the global carbon and nitrogen cycles. In their natural environment, these organisms are exposed to fluctuating nutrient conditions. Nitrogen starvation induces a coordinated nitrogen-saving program that includes the breakdown of nitrogen-rich photosynthetic pigments, particularly phycobiliproteins. The small protein NblD was recently identified as an effector of phycobilisome breakdown in cyanobacteria. In this study, we demonstrate that the NblD-mediated degradation of phycobiliproteins is needed to sustain cellular pools of soluble amino acids and other crucial metabolites. The essential role played by NblD in metabolic homeostasis explains why genes encoding this small protein are conserved in almost all members of cyanobacterial radiation.
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14
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Brandenburg F, Klähn S. Small but Smart: On the Diverse Role of Small Proteins in the Regulation of Cyanobacterial Metabolism. Life (Basel) 2020; 10:E322. [PMID: 33271798 PMCID: PMC7760959 DOI: 10.3390/life10120322] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/17/2022] Open
Abstract
Over the past few decades, bioengineered cyanobacteria have become a major focus of research for the production of energy carriers and high value chemical compounds. Besides improvements in cultivation routines and reactor technology, the integral understanding of the regulation of metabolic fluxes is the key to designing production strains that are able to compete with established industrial processes. In cyanobacteria, many enzymes and metabolic pathways are regulated differently compared to other bacteria. For instance, while glutamine synthetase in proteobacteria is mainly regulated by covalent enzyme modifications, the same enzyme in cyanobacteria is controlled by the interaction with unique small proteins. Other prominent examples, such as the small protein CP12 which controls the Calvin-Benson cycle, indicate that the regulation of enzymes and/or pathways via the attachment of small proteins might be a widespread mechanism in cyanobacteria. Accordingly, this review highlights the diverse role of small proteins in the control of cyanobacterial metabolism, focusing on well-studied examples as well as those most recently described. Moreover, it will discuss their potential to implement metabolic engineering strategies in order to make cyanobacteria more definable for biotechnological applications.
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Affiliation(s)
| | - Stephan Klähn
- Helmholtz Centre for Environmental Research—UFZ, 04318 Leipzig, Germany;
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15
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Jeong Y, Cho SH, Lee H, Choi HK, Kim DM, Lee CG, Cho S, Cho BK. Current Status and Future Strategies to Increase Secondary Metabolite Production from Cyanobacteria. Microorganisms 2020; 8:E1849. [PMID: 33255283 PMCID: PMC7761380 DOI: 10.3390/microorganisms8121849] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/15/2020] [Accepted: 11/23/2020] [Indexed: 12/16/2022] Open
Abstract
Cyanobacteria, given their ability to produce various secondary metabolites utilizing solar energy and carbon dioxide, are a potential platform for sustainable production of biochemicals. Until now, conventional metabolic engineering approaches have been applied to various cyanobacterial species for enhanced production of industrially valued compounds, including secondary metabolites and non-natural biochemicals. However, the shortage of understanding of cyanobacterial metabolic and regulatory networks for atmospheric carbon fixation to biochemical production and the lack of available engineering tools limit the potential of cyanobacteria for industrial applications. Recently, to overcome the limitations, synthetic biology tools and systems biology approaches such as genome-scale modeling based on diverse omics data have been applied to cyanobacteria. This review covers the synthetic and systems biology approaches for advanced metabolic engineering of cyanobacteria.
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Affiliation(s)
- Yujin Jeong
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Sang-Hyeok Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Hookeun Lee
- Institute of Pharmaceutical Research, College of Pharmacy, Gachon University, Incheon 21999, Korea;
| | | | - Dong-Myung Kim
- Department of Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Korea;
| | - Choul-Gyun Lee
- Department of Biological Engineering, Inha University, Incheon 22212, Korea;
| | - Suhyung Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
| | - Byung-Kwan Cho
- Department of Biological Sciences and KAIST Institutes for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon 34141, Korea; (Y.J.); (S.-H.C.)
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