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Hubáček M, Wey LT, Kourist R, Malihan-Yap L, Nikkanen L, Allahverdiyeva Y. Strong heterologous electron sink outcompetes alternative electron transport pathways in photosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 39008444 DOI: 10.1111/tpj.16935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 05/27/2024] [Accepted: 07/03/2024] [Indexed: 07/17/2024]
Abstract
Improvement of photosynthesis requires a thorough understanding of electron partitioning under both natural and strong electron sink conditions. We applied a wide array of state-of-the-art biophysical and biochemical techniques to thoroughly investigate the fate of photosynthetic electrons in the engineered cyanobacterium Synechocystis sp. PCC 6803, a blueprint for photosynthetic biotechnology, expressing the heterologous gene for ene-reductase, YqjM. This recombinant enzyme catalyses the reduction of an exogenously added substrate into the desired product by utilising photosynthetically produced NAD(P)H, enabling whole-cell biotransformation. Through coupling the biotransformation reaction with biophysical measurements, we demonstrated that the strong artificial electron sink, outcompetes the natural electron valves, the flavodiiron protein-driven Mehler-like reaction and cyclic electron transport. These results show that ferredoxin-NAD(P)H-oxidoreductase is the preferred route for delivering photosynthetic electrons from reduced ferredoxin and the cellular NADPH/NADP+ ratio as a key factor in orchestrating photosynthetic electron flux. These insights are crucial for understanding molecular mechanisms of photosynthetic electron transport and harnessing photosynthesis for sustainable bioproduction by engineering the cellular source/sink balance. Furthermore, we conclude that identifying the bioenergetic bottleneck of a heterologous electron sink is a crucial prerequisite for targeted engineering of photosynthetic biotransformation platforms.
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Affiliation(s)
- Michal Hubáček
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, 20014, Finland
| | - Laura T Wey
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, 20014, Finland
| | - Robert Kourist
- Institute of Molecular Biotechnology, NAWI Graz, BioTechMed, Graz University of Technology, Graz, 8010, Austria
| | - Lenny Malihan-Yap
- Institute of Molecular Biotechnology, NAWI Graz, BioTechMed, Graz University of Technology, Graz, 8010, Austria
| | - Lauri Nikkanen
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, 20014, Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, 20014, Finland
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2
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Khan S, Ansari A, Brachi M, Das D, El Housseini W, Minteer S, Miller AF. Structure, dynamics, and redox reactivity of an all-purpose flavodoxin. J Biol Chem 2024; 300:107122. [PMID: 38417793 PMCID: PMC10979112 DOI: 10.1016/j.jbc.2024.107122] [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: 12/13/2023] [Revised: 02/15/2024] [Accepted: 02/21/2024] [Indexed: 03/01/2024] Open
Abstract
The flavodoxin of Rhodopseudomonas palustris CGA009 (Rp9Fld) supplies highly reducing equivalents to crucial enzymes such as hydrogenase, especially when the organism is iron-restricted. By acquiring those electrons from photodriven electron flow via the bifurcating electron transfer flavoprotein, Rp9Fld provides solar power to vital metabolic processes. To understand Rp9Fld's ability to work with diverse partners, we solved its crystal structure. We observed the canonical flavodoxin (Fld) fold and features common to other long-chain Flds but not all the surface loops thought to recognize partner proteins. Moreover, some of the loops display alternative structures and dynamics. To advance studies of protein-protein associations and conformational consequences, we assigned the 19F NMR signals of all five tyrosines (Tyrs). Our electrochemical measurements show that incorporation of 3-19F-Tyr in place of Tyr has only a modest effect on Rp9Fld's redox properties even though Tyrs flank the flavin on both sides. Meanwhile, the 19F probes demonstrate the expected paramagnetic effect, with signals from nearby Tyrs becoming broadened beyond detection when the flavin semiquinone is formed. However, the temperature dependencies of chemical shifts and linewidths reveal dynamics affecting loops close to the flavin and regions that bind to partners in a variety of systems. These coincide with patterns of amino acid type conservation but not retention of specific residues, arguing against detailed specificity with respect to partners. We propose that the loops surrounding the flavin adopt altered conformations upon binding to partners and may even participate actively in electron transfer.
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Affiliation(s)
- Sharique Khan
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | - Ahmadullah Ansari
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Monica Brachi
- Department of Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Debarati Das
- Department of Chemistry, University of Kentucky, Lexington, Kentucky, USA
| | | | - Shelley Minteer
- Department of Chemistry, University of Utah, Salt Lake City, Utah, USA; Department of Chemistry, Kummer Institute Center for Resource Sustainability, Missouri University of Science and Technology, Rolla, Missouri, USA
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3
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Kisgeropoulos E, Bharadwaj VS, Ledinina A, Lubner CE, Mulder DW, Smolinski SL, Boehm M, Gutekunst K, King PW, Svedruzic D. Structural and biophysical properties of a [4Fe4S] ferredoxin-like protein from Synechocystis sp. PCC 6803 with a unique two domain structure. J Inorg Biochem 2024; 251:112428. [PMID: 38008043 DOI: 10.1016/j.jinorgbio.2023.112428] [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: 09/06/2023] [Revised: 10/23/2023] [Accepted: 11/11/2023] [Indexed: 11/28/2023]
Abstract
Electron carrier proteins (ECPs), binding iron-sulfur clusters, are vital components within the intricate network of metabolic and photosynthetic reactions. They play a crucial role in the distribution of reducing equivalents. In Synechocystis sp. PCC 6803, the ECP network includes at least nine ferredoxins. Previous research, including global expression analyses and protein binding studies, has offered initial insights into the functional roles of individual ferredoxins within this network. This study primarily focuses on Ferredoxin 9 (slr2059). Through sequence analysis and computational modeling, Ferredoxin 9 emerges as a unique ECP with a distinctive two-domain architecture. It consists of a C-terminal iron‑sulfur binding domain and an N-terminal domain with homology to Nil-domain proteins, connected by a structurally rigid 4-amino acid linker. Notably, in contrast to canonical [2Fe2S] ferredoxins exemplified by PetF (ssl0020), which feature highly acidic surfaces facilitating electron transfer with photosystem I reaction centers, models of Ferredoxin 9 reveal a more neutral to basic protein surface. Using a combination of electron paramagnetic resonance spectroscopy and square-wave voltammetry on heterologously produced Ferredoxin 9, this study demonstrates that the protein coordinates 2×[4Fe4S]2+/1+ redox-active and magnetically interacting clusters, with measured redox potentials of -420 ± 9 mV and - 516 ± 10 mV vs SHE. A more in-depth analysis of Fdx9's unique structure and protein sequence suggests that this type of Nil-2[4Fe4S] multi-domain ferredoxin is well conserved in cyanobacteria, bearing structural similarities to proteins involved in homocysteine synthesis in methanogens.
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Affiliation(s)
- Effie Kisgeropoulos
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Vivek S Bharadwaj
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Anastasia Ledinina
- Department of Molecular and Structural Biochemistry, North Carolina State University, USA
| | - Carolyn E Lubner
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Sharon L Smolinski
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Marko Boehm
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany; Department of Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Kirstin Gutekunst
- Department of Biology, Botanical Institute, Christian-Albrechts-University, Kiel, Germany; Department of Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Drazenka Svedruzic
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
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Akiyama M, Osanai T. Regulation of organic acid and hydrogen production by NADH/NAD + ratio in Synechocystis sp. PCC 6803. Front Microbiol 2024; 14:1332449. [PMID: 38249449 PMCID: PMC10797119 DOI: 10.3389/fmicb.2023.1332449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 12/12/2023] [Indexed: 01/23/2024] Open
Abstract
Cyanobacteria serve as useful hosts in the production of substances to support a low-carbon society. Specifically, the unicellular cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis 6803) can produce organic acids, such as acetate, lactate, and succinate, as well as hydrogen, under dark, anaerobic conditions. The efficient production of these compounds appears to be closely linked to the regulation of intracellular redox balance. Notably, alterations in intracellular redox balance have been believed to influence the production of organic acids and hydrogen. To achieve these alterations, genetic manipulations involved overexpressing malate dehydrogenase (MDH), knocking out d-lactate dehydrogenase (DDH), or knocking out acetate kinase (AK), which subsequently modified the quantities and ratios of organic acids and hydrogen under dark, anaerobic conditions. Furthermore, the mutants generated displayed changes in the oxidation of reducing powers and the nicotinamide adenine dinucleotide hydrogen (NADH)/NAD+ ratio when compared to the parental wild-type strain. These findings strongly suggest that intracellular redox balance, especially the NADH/NAD+ ratio, plays a pivotal role in the production of organic acids and hydrogen in Synechocystis 6803.
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Affiliation(s)
| | - Takashi Osanai
- School of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan
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5
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Truong A, Myerscough D, Campbell I, Atkinson J, Silberg JJ. A cellular selection identifies elongated flavodoxins that support electron transfer to sulfite reductase. Protein Sci 2023; 32:e4746. [PMID: 37551563 PMCID: PMC10503412 DOI: 10.1002/pro.4746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 07/17/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Flavodoxins (Flds) mediate the flux of electrons between oxidoreductases in diverse metabolic pathways. To investigate whether Flds can support electron transfer to a sulfite reductase (SIR) that evolved to couple with a ferredoxin, we evaluated the ability of Flds to transfer electrons from a ferredoxin-NADP reductase (FNR) to a ferredoxin-dependent SIR using growth complementation of an Escherichia coli strain with a sulfur metabolism defect. We show that Flds from cyanobacteria complement this growth defect when coexpressed with an FNR and an SIR that evolved to couple with a plant ferredoxin. When we evaluated the effect of peptide insertion on Fld-mediated electron transfer, we observed a sensitivity to insertions within regions predicted to be proximal to the cofactor and partner binding sites, while a high insertion tolerance was detected within loops distal from the cofactor and within regions of helices and sheets that are proximal to those loops. Bioinformatic analysis showed that natural Fld sequence variability predicts a large fraction of the motifs that tolerate insertion of the octapeptide SGRPGSLS. These results represent the first evidence that Flds can support electron transfer to assimilatory SIRs, and they suggest that the pattern of insertion tolerance is influenced by interactions with oxidoreductase partners.
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Affiliation(s)
- Albert Truong
- Biochemistry and Cell Biology Graduate Program, Rice University, Houston, Texas, USA
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Dru Myerscough
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Ian Campbell
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Joshua Atkinson
- Department of Biosciences, Rice University, Houston, Texas, USA
| | - Jonathan J Silberg
- Department of Biosciences, Rice University, Houston, Texas, USA
- Department of Bioengineering, Rice University, Houston, Texas, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, USA
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Schumann C, Fernández Méndez J, Berggren G, Lindblad P. Novel concepts and engineering strategies for heterologous expression of efficient hydrogenases in photosynthetic microorganisms. Front Microbiol 2023; 14:1179607. [PMID: 37502399 PMCID: PMC10369191 DOI: 10.3389/fmicb.2023.1179607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 06/09/2023] [Indexed: 07/29/2023] Open
Abstract
Hydrogen is considered one of the key enablers of the transition towards a sustainable and net-zero carbon economy. When produced from renewable sources, hydrogen can be used as a clean and carbon-free energy carrier, as well as improve the sustainability of a wide range of industrial processes. Photobiological hydrogen production is considered one of the most promising technologies, avoiding the need for renewable electricity and rare earth metal elements, the demands for which are greatly increasing due to the current simultaneous electrification and decarbonization goals. Photobiological hydrogen production employs photosynthetic microorganisms to harvest solar energy and split water into molecular oxygen and hydrogen gas, unlocking the long-pursued target of solar energy storage. However, photobiological hydrogen production has to-date been constrained by several limitations. This review aims to discuss the current state-of-the art regarding hydrogenase-driven photobiological hydrogen production. Emphasis is placed on engineering strategies for the expression of improved, non-native, hydrogenases or photosynthesis re-engineering, as well as their combination as one of the most promising pathways to develop viable large-scale hydrogen green cell factories. Herein we provide an overview of the current knowledge and technological gaps curbing the development of photobiological hydrogenase-driven hydrogen production, as well as summarizing the recent advances and future prospects regarding the expression of non-native hydrogenases in cyanobacteria and green algae with an emphasis on [FeFe] hydrogenases.
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Affiliation(s)
- Conrad Schumann
- Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, Uppsala, Sweden
| | - Jorge Fernández Méndez
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Uppsala, Sweden
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry - Ångström, Uppsala University, Uppsala, Sweden
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry - Ångström, Uppsala University, Uppsala, Sweden
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Shimakawa G. Electron transport in cyanobacterial thylakoid membranes: Are cyanobacteria simple models for photosynthetic organisms? JOURNAL OF EXPERIMENTAL BOTANY 2023:erad118. [PMID: 37025010 DOI: 10.1093/jxb/erad118] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Indexed: 06/19/2023]
Abstract
Cyanobacteria are structurally the simplest oxygenic phototrophs, which makes it difficult to understand the regulation of photosynthesis because the photosynthetic and respiratory processes share the same thylakoid membranes and cytosolic space. This review aimed to summarise the molecular mechanisms and in vivo activities of electron transport in cyanobacterial thylakoid membranes based on the latest progress in photosynthesis research in cyanobacteria. Photosynthetic linear electron transport for CO2 assimilation has the dominant electron flux in the thylakoid membranes. The capacity of O2 photoreduction in cyanobacteria is comparable to the photosynthetic CO2 assimilation, which is mediated by flavodiiron proteins. Additionally, cyanobacterial thylakoid membranes harbour the significant electron flux of respiratory electron transport through a homologue of respiratory complex I, which is also recognized as the part of cyclic electron transport chain if it is coupled with photosystem I in the light. Further, O2-independent alternative electron transports through hydrogenase and nitrate reductase function with reduced ferredoxin as the electron donor. Whereas all these electron transports are recently being understood one by one, the complexity as the whole regulatory system remains to be uncovered in near future.
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Affiliation(s)
- Ginga Shimakawa
- Department of Bioscience, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda, Hyogo 669-1330, Japan
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Chinchusak N, Incharoensakdi A, Phunpruch S. Dark fermentative hydrogen production and transcriptional analysis of genes involved in the unicellular halotolerant cyanobacterium Aphanothece halophytica under nitrogen and potassium deprivation. Front Bioeng Biotechnol 2023; 10:1028151. [PMID: 36686224 PMCID: PMC9852855 DOI: 10.3389/fbioe.2022.1028151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 12/19/2022] [Indexed: 01/09/2023] Open
Abstract
The unicellular halotolerant cyanobacterium Aphanothece halophytica is known as a potential hydrogen (H2) producer. This study aimed to investigate the enhancement of H2 production under nutrient deprivation. The results showed that nitrogen and potassium deprivation induced dark fermentative H2 production by A. halophytica, while no differences in H2 production were found under sulfur and phosphorus deprivation. In addition, deprivation of nitrogen and potassium resulted in the highest H2 production in A. halophytica due to the stimulation of hydrogenase activity. The effect of adaptation time under nitrogen and potassium deprivation on H2 production was investigated. The results showed that the highest H2 accumulation of 1,261.96 ± 96.99 µmol H2 g dry wt-1 and maximum hydrogenase activity of 179.39 ± 8.18 µmol H2 g dry wt-1 min-1 were obtained from A. halophytica cells adapted in the nitrogen- and potassium-deprived BG11 medium supplemented with Turk Island salt solution (BG110-K) for 48 h. An increase in hydrogenase activity was attributed to the decreased O2 concentration in the system, due to a reduction of photosynthetic O2 evolution rate and a promotion of dark respiration rate. Moreover, nitrogen and potassium deprivation stimulated glycogen accumulation and decreased specific activity of pyruvate kinase. Transcriptional analysis of genes involved in H2 metabolism using RNA-seq confirmed the above results. Several genes involved in glycogen biosynthesis (glgA, glgB, and glgP) were upregulated under both nitrogen and potassium deprivation, but genes regulating enzymes in the glycolytic pathway were downregulated, especially pyk encoding pyruvate kinase. Interestingly, genes involved in the oxidative pentose phosphate pathway (OPP) were upregulated. Thus, OPP became the favored pathway for glycogen catabolism and the generation of reduced nicotinamide adenine dinucleotide phosphate (NADPH), which resulted in an increase in H2 production under dark anaerobic condition in both nitrogen- and potassium-deprived cells.
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Affiliation(s)
- Nattanon Chinchusak
- Department of Biology, School of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand
| | - Aran Incharoensakdi
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand,Academy of Science, Royal Society of Thailand, Bangkok, Thailand
| | - Saranya Phunpruch
- Department of Biology, School of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand,Bioenergy Research Unit, School of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand,*Correspondence: Saranya Phunpruch,
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Khetkorn W, Raksajit W, Maneeruttanarungroj C, Lindblad P. Photobiohydrogen Production and Strategies for H 2 Yield Improvements in Cyanobacteria. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:253-279. [PMID: 37009974 DOI: 10.1007/10_2023_216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
Hydrogen gas (H2) is one of the potential future sustainable and clean energy carriers that may substitute the use of fossil resources including fuels since it has a high energy content (heating value of 141.65 MJ/kg) when compared to traditional hydrocarbon fuels [1]. Water is a primary product of combustion being a most significant advantage of H2 being environmentally friendly with the capacity to reduce global greenhouse gas emissions. H2 is used in various applications. It generates electricity in fuel cells, including applications in transportation, and can be applied as fuel in rocket engines [2]. Moreover, H2 is an important gas and raw material in many industrial applications. However, the high cost of the H2 production processes requiring the use of other energy sources is a significant disadvantage. At present, H2 can be prepared in many conventional ways, such as steam reforming, electrolysis, and biohydrogen production processes. Steam reforming uses high-temperature steam to produce hydrogen gas from fossil resources including natural gas. Electrolysis is an electrolytic process to decompose water molecules into O2 and H2. However, both these two methods are energy-intensive and producing hydrogen from natural gas, which is mostly methane (CH4) and in steam reforming generates CO2 and pollutants as by-products. On the other hand, biological hydrogen production is more environmentally sustainable and less energy intensive than thermochemical and electrochemical processes [3], but most concepts are not yet developed to production scale.
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Affiliation(s)
- Wanthanee Khetkorn
- Division of Biology, Faculty of Science and Technology, Rajamangala University of Technology, Thanyaburi, Pathum Thani, Thailand
| | - Wuttinun Raksajit
- Faculty of Veterinary Technology, Program of Animal Health Technology, Kasetsart University, Bangkok, Thailand
| | - Cherdsak Maneeruttanarungroj
- Department of Biology, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
- Bioenergy Research Unit, School of Science, King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Uppsala, Sweden.
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Spasic J, Oliveira P, Pacheco C, Kourist R, Tamagnini P. Engineering cyanobacterial chassis for improved electron supply toward a heterologous ene-reductase. J Biotechnol 2022; 360:152-159. [PMID: 36370921 DOI: 10.1016/j.jbiotec.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 11/10/2022]
Abstract
Cyanobacteria are noteworthy hosts for industrially relevant redox reactions, owing to a light-driven cofactor recycling system using water as electron donor. Customizing Synechocystis sp. PCC 6803 chassis by redirecting electron flow offers a particularly interesting approach to further improve light-driven biotransformations. Therefore, different chassis expressing the heterologous ene-reductase YqjM (namely ΔhoxYH, Δflv3, ΔndhD2 and ΔhoxYHΔflv3) were generated/evaluated. The results showed the robustness of the chassis, that exhibited growth and oxygen evolution rates similar to Synechocystis wild-type, even when expressing YqjM. By engineering the electron flow, the YqjM light-driven stereoselective reduction of 2-methylmaleimide to 2-methylsuccinimide was significantly enhanced in all chassis. In the best performing chassis (ΔhoxYH, lacking an active bidirectional hydrogenase) a 39 % increase was observed, reaching an in vivo specific activity of 116 U gDCW-1 and an initial reaction rate of 16.7 mM h-1. In addition, the presence of the heterologous YqjM mitigated substrate toxicity, and the conversion of 2-methylmaleimide increased oxygen evolution rates, in particular at higher light intensity. In conclusion, this work demonstrates that rational engineering of electron transfer pathways is a valid strategy to increase in vivo specific activities and initial reaction rates in cyanobacterial chassis harboring oxidoreductases.
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Affiliation(s)
- Jelena Spasic
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal; Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Paulo Oliveira
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Catarina Pacheco
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal
| | - Robert Kourist
- Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria
| | - Paula Tamagnini
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen 208, 4200-135 Porto, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
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11
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Redding KE, Appel J, Boehm M, Schuhmann W, Nowaczyk MM, Yacoby I, Gutekunst K. Advances and challenges in photosynthetic hydrogen production. Trends Biotechnol 2022; 40:1313-1325. [PMID: 35581021 DOI: 10.1016/j.tibtech.2022.04.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 01/21/2023]
Abstract
The vision to replace coal with hydrogen goes back to Jules Verne in 1874. However, sustainable hydrogen production remains challenging. The most elegant approach is to utilize photosynthesis for water splitting and to subsequently save solar energy as hydrogen. Cyanobacteria and green algae are unicellular photosynthetic organisms that contain hydrogenases and thereby possess the enzymatic equipment for photosynthetic hydrogen production. These features of cyanobacteria and algae have inspired artificial and semi-artificial in vitro techniques, that connect photoexcited materials or enzymes with hydrogenases or mimics of these for hydrogen production. These in vitro methods have on their part been models for the fusion of cyanobacterial and algal hydrogenases to photosynthetic photosystem I (PSI) in vivo, which recently succeeded as proofs of principle.
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Affiliation(s)
- Kevin E Redding
- School of Molecular Sciences and Center for Bioenergy & Photosynthesis, Arizona State University, Tempe, AZ, USA
| | - Jens Appel
- Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University Kassel, 34132 Kassel, Germany
| | - Marko Boehm
- Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University Kassel, 34132 Kassel, Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
| | - Marc M Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitätsstrasse 150, D-44780 Bochum, Germany
| | - Iftach Yacoby
- School of Plant Sciences and Food Security, The George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat Aviv, 69978, Israel
| | - Kirstin Gutekunst
- Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University Kassel, 34132 Kassel, Germany.
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12
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Evidence for Electron Transfer from the Bidirectional Hydrogenase to the Photosynthetic Complex I (NDH-1) in the Cyanobacterium Synechocystis sp. PCC 6803. Microorganisms 2022; 10:microorganisms10081617. [PMID: 36014035 PMCID: PMC9414918 DOI: 10.3390/microorganisms10081617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 12/12/2022] Open
Abstract
The cyanobacterial bidirectional [NiFe]-hydrogenase is a pentameric enzyme. Apart from the small and large hydrogenase subunits (HoxYH) it contains a diaphorase module (HoxEFU) that interacts with NAD(P)+ and ferredoxin. HoxEFU shows strong similarity to the outermost subunits (NuoEFG) of canonical respiratory complexes I. Photosynthetic complex I (NDH-1) lacks these three subunits. This led to the idea that HoxEFU might interact with NDH-1 instead. HoxEFUYH utilizes excited electrons from PSI for photohydrogen production and it catalyzes the reverse reaction and feeds electrons into the photosynthetic electron transport. We analyzed hydrogenase activity, photohydrogen evolution and hydrogen uptake, the respiration and photosynthetic electron transport of ΔhoxEFUYH, and a knock-out strain with dysfunctional NDH-1 (ΔndhD1/ΔndhD2) of the cyanobacterium Synechocystis sp. PCC 6803. Photohydrogen production was prolonged in ΔndhD1/ΔndhD2 due to diminished hydrogen uptake. Electrons from hydrogen oxidation must follow a different route into the photosynthetic electron transport in this mutant compared to wild type cells. Furthermore, respiration was reduced in ΔhoxEFUYH and the ΔndhD1/ΔndhD2 localization of the hydrogenase to the membrane was impaired. These data indicate that electron transfer from the hydrogenase to the NDH-1 complex is either direct, by the binding of the hydrogenase to the complex, or indirect, via an additional mediator.
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13
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Burgstaller H, Wang Y, Caliebe J, Hueren V, Appel J, Boehm M, Leitzke S, Theune M, King PW, Gutekunst K. Synechocystis sp. PCC 6803 Requires the Bidirectional Hydrogenase to Metabolize Glucose and Arginine Under Oxic Conditions. Front Microbiol 2022; 13:896190. [PMID: 35711753 PMCID: PMC9195167 DOI: 10.3389/fmicb.2022.896190] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/27/2022] [Indexed: 11/17/2022] Open
Abstract
The cyanobacterium Synechocystis sp.PCC 6803 possesses a bidirectional NiFe-hydrogenase, HoxEFUYH. It functions to produce hydrogen under dark, fermentative conditions and photoproduces hydrogen when dark-adapted cells are illuminated. Unexpectedly, we found that the deletion of the large subunit of the hydrogenase (HoxH) in Synechocystis leads to an inability to grow on arginine and glucose under continuous light in the presence of oxygen. This is surprising, as the hydrogenase is an oxygen-sensitive enzyme. In wild-type (WT) cells, thylakoid membranes largely disappeared, cyanophycin accumulated, and the plastoquinone (PQ) pool was highly reduced, whereas ΔhoxH cells entered a dormant-like state and neither consumed glucose nor arginine at comparable rates to the WT. Hydrogen production was not traceable in the WT under these conditions. We tested and could show that the hydrogenase does not work as an oxidase on arginine and glucose but has an impact on the redox states of photosynthetic complexes in the presence of oxygen. It acts as an electron valve as an immediate response to the supply of arginine and glucose but supports the input of electrons from arginine and glucose oxidation into the photosynthetic electron chain in the long run, possibly via the NDH-1 complex. Despite the data presented in this study, the latter scenario requires further proof. The exact role of the hydrogenase in the presence of arginine and glucose remains unresolved. In addition, a unique feature of the hydrogenase is its ability to shift electrons between NAD(H), NADP(H), ferredoxin, and flavodoxin, which was recently shown in vitro and might be required for fine-tuning. Taken together, our data show that Synechocystis depends on the hydrogenase to metabolize organic carbon and nitrogen in the presence of oxygen, which might be an explanation for its prevalence in aerobic cyanobacteria.
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Affiliation(s)
- Heinrich Burgstaller
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany
| | - Yingying Wang
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany
| | - Johanna Caliebe
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany.,Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Vanessa Hueren
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany
| | - Jens Appel
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany.,Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Marko Boehm
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany.,Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Sinje Leitzke
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany
| | - Marius Theune
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany.,Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
| | - Paul W King
- National Renewable Energy Laboratory, Biosciences Center, Golden, CO, United States
| | - Kirstin Gutekunst
- Plant Cell Physiology and Biotechnology, Botanical Institute, University of Kiel, Kiel, Germany.,Molecular Plant Physiology, Bioenergetics in Photoautotrophs, University of Kassel, Kassel, Germany
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14
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Genomic and Functional Variation of the Chlorophyll d-Producing Cyanobacterium Acaryochloris marina. Microorganisms 2022; 10:microorganisms10030569. [PMID: 35336144 PMCID: PMC8949462 DOI: 10.3390/microorganisms10030569] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/01/2022] [Accepted: 03/04/2022] [Indexed: 02/01/2023] Open
Abstract
The Chlorophyll d-producing cyanobacterium Acaryochloris marina is widely distributed in marine environments enriched in far-red light, but our understanding of its genomic and functional diversity is limited. Here, we take an integrative approach to investigate A. marina diversity for 37 strains, which includes twelve newly isolated strains from previously unsampled locations in Europe and the Pacific Northwest of North America. A genome-wide phylogeny revealed both that closely related A. marina have migrated within geographic regions and that distantly related A. marina lineages can co-occur. The distribution of traits mapped onto the phylogeny provided evidence of a dynamic evolutionary history of gene gain and loss during A. marina diversification. Ancestral genes that were differentially retained or lost by strains include plasmid-encoded sodium-transporting ATPase and bidirectional NiFe-hydrogenase genes that may be involved in salt tolerance and redox balance under fermentative conditions, respectively. The acquisition of genes by horizontal transfer has also played an important role in the evolution of new functions, such as nitrogen fixation. Together, our results resolve examples in which genome content and ecotypic variation for nutrient metabolism and environmental tolerance have diversified during the evolutionary history of this unusual photosynthetic bacterium.
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15
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Wang Y, Chen X, Spengler K, Terberger K, Boehm M, Appel J, Barske T, Timm S, Battchikova N, Hagemann M, Gutekunst K. Pyruvate:ferredoxin oxidoreductase and low abundant ferredoxins support aerobic photomixotrophic growth in cyanobacteria. eLife 2022; 11:71339. [PMID: 35138247 PMCID: PMC8887894 DOI: 10.7554/elife.71339] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 02/06/2022] [Indexed: 11/24/2022] Open
Abstract
The decarboxylation of pyruvate is a central reaction in the carbon metabolism of all organisms. It is catalyzed by the pyruvate:ferredoxin oxidoreductase (PFOR) and the pyruvate dehydrogenase (PDH) complex. Whereas PFOR reduces ferredoxin, the PDH complex utilizes NAD+. Anaerobes rely on PFOR, which was replaced during evolution by the PDH complex found in aerobes. Cyanobacteria possess both enzyme systems. Our data challenge the view that PFOR is exclusively utilized for fermentation. Instead, we show, that the cyanobacterial PFOR is stable in the presence of oxygen in vitro and is required for optimal photomixotrophic growth under aerobic and highly reducing conditions while the PDH complex is inactivated. We found that cells rely on a general shift from utilizing NAD(H)- to ferredoxin-dependent enzymes under these conditions. The utilization of ferredoxins instead of NAD(H) saves a greater share of the Gibbs-free energy, instead of wasting it as heat. This obviously simultaneously decelerates metabolic reactions as they operate closer to their thermodynamic equilibrium. It is common thought that during evolution, ferredoxins were replaced by NAD(P)H due to their higher stability in an oxidizing atmosphere. However, the utilization of NAD(P)H could also have been favored due to a higher competitiveness because of an accelerated metabolism.
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Affiliation(s)
- Yingying Wang
- Department of Biology, Christian-Albrechts University, Kiel, Germany
| | - Xi Chen
- Department of Biology, Christian-Albrechts University, Kiel, Germany
| | | | | | - Marko Boehm
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
| | - Jens Appel
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
| | - Thomas Barske
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Stefan Timm
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | | | - Martin Hagemann
- Plant Physiology Department, University of Rostock, Rostock, Germany
| | - Kirstin Gutekunst
- Department of Molecular Plant Physiology, University of Kassel, Kassel, Germany
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16
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Lupacchini S, Appel J, Stauder R, Bolay P, Klähn S, Lettau E, Adrian L, Lauterbach L, Bühler B, Schmid A, Toepel J. Rewiring cyanobacterial photosynthesis by the implementation of an oxygen-tolerant hydrogenase. Metab Eng 2021; 68:199-209. [PMID: 34673236 DOI: 10.1016/j.ymben.2021.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/11/2021] [Accepted: 10/16/2021] [Indexed: 10/20/2022]
Abstract
Molecular hydrogen (H2) is considered as an ideal energy carrier to replace fossil fuels in future. Biotechnological H2 production driven by oxygenic photosynthesis appears highly promising, as biocatalyst and H2 syntheses rely mainly on light, water, and CO2 and not on rare metals. This biological process requires coupling of the photosynthetic water oxidizing apparatus to a H2-producing hydrogenase. However, this strategy is impeded by the simultaneous release of oxygen (O2) which is a strong inhibitor of most hydrogenases. Here, we addressed this challenge, by the introduction of an O2-tolerant hydrogenase into phototrophic bacteria, namely the cyanobacterial model strain Synechocystis sp. PCC 6803. To this end, the gene cluster encoding the soluble, O2-tolerant, and NAD(H)-dependent hydrogenase from Ralstonia eutropha (ReSH) was functionally transferred to a Synechocystis strain featuring a knockout of the native O2 sensitive hydrogenase. Intriguingly, photosynthetically active cells produced the O2 tolerant ReSH, and activity was confirmed in vitro and in vivo. Further, ReSH enabled the constructed strain Syn_ReSH+ to utilize H2 as sole electron source to fix CO2. Syn_ReSH+ also was able to produce H2 under dark fermentative conditions as well as in presence of light, under conditions fostering intracellular NADH excess. These findings highlight a high level of interconnection between ReSH and cyanobacterial redox metabolism. This study lays a foundation for further engineering, e.g., of electron transfer to ReSH via NADPH or ferredoxin, to finally enable photosynthesis-driven H2 production.
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Affiliation(s)
- Sara Lupacchini
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Jens Appel
- Department of Biology, Botanical Institute, University Kiel, 24118, Kiel, Germany
| | - Ron Stauder
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Paul Bolay
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Stephan Klähn
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Elisabeth Lettau
- Institute for Chemistry, Technische Universität Berlin, 10623, Berlin, Germany
| | - Lorenz Adrian
- Department of Environmental Biotechnology, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany; Chair of Geobiotechnology, Technische Universität Berlin, 10923, Berlin, Germany
| | - Lars Lauterbach
- Institute for Chemistry, Technische Universität Berlin, 10623, Berlin, Germany; Institute of Applied Microbiology, Rheinisch-Westfälische Technische Hochschule Aachen, 52074, Aachen, Germany
| | - Bruno Bühler
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Andreas Schmid
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany
| | - Jörg Toepel
- Department of Solar Materials, Helmholtz Centre for Environmental Research -UFZ, 04318, Leipzig, Germany.
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17
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Kosourov S, Böhm M, Senger M, Berggren G, Stensjö K, Mamedov F, Lindblad P, Allahverdiyeva Y. Photosynthetic hydrogen production: Novel protocols, promising engineering approaches and application of semi-synthetic hydrogenases. PHYSIOLOGIA PLANTARUM 2021; 173:555-567. [PMID: 33860946 DOI: 10.1111/ppl.13428] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/05/2021] [Indexed: 06/12/2023]
Abstract
Photosynthetic production of molecular hydrogen (H2 ) by cyanobacteria and green algae is a potential source of renewable energy. These organisms are capable of water biophotolysis by taking advantage of photosynthetic apparatus that links water oxidation at Photosystem II and reduction of protons to H2 downstream of Photosystem I. Although the process has a theoretical potential to displace fossil fuels, photosynthetic H2 production in its current state is not yet efficient enough for industrial applications due to a number of physiological, biochemical, and engineering barriers. This article presents a short overview of the metabolic pathways and enzymes involved in H2 photoproduction in cyanobacteria and green algae and our present understanding of the mechanisms of this process. We also summarize recent advances in engineering photosynthetic cell factories capable of overcoming the major barriers to efficient and sustainable H2 production.
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Affiliation(s)
- Sergey Kosourov
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
| | - Maximilian Böhm
- Molecular Biomimetics, Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Moritz Senger
- Molecular Biomimetics, Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Gustav Berggren
- Molecular Biomimetics, Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Karin Stensjö
- Microbial Chemistry, Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Fikret Mamedov
- Molecular Biomimetics, Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Ångström Laboratory, Uppsala University, Uppsala, Sweden
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, Finland
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18
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Palevich N, Maclean PH, Kelly WJ, Leahy SC, Rakonjac J, Attwood GT. Complete Genome Sequence of the Polysaccharide-Degrading Rumen Bacterium Pseudobutyrivibrio xylanivorans MA3014 Reveals an Incomplete Glycolytic Pathway. Genome Biol Evol 2021; 12:1566-1572. [PMID: 32770231 PMCID: PMC7523725 DOI: 10.1093/gbe/evaa165] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2020] [Indexed: 11/24/2022] Open
Abstract
Bacterial species belonging to the genus Pseudobutyrivibrio are important members of the rumen microbiome contributing to the degradation of complex plant polysaccharides. Pseudobutyrivibrio xylanivorans MA3014 was selected for genome sequencing to examine its ability to breakdown and utilize plant polysaccharides. The complete genome sequence of MA3014 is 3.58 Mb, consists of three replicons (a chromosome, chromid, and plasmid), has an overall G + C content of 39.6%, and encodes 3,265 putative protein-coding genes (CDS). Comparative pan-genomic analysis of all cultivated and currently available P. xylanivorans genomes has revealed a strong correlation of orthologous genes within this rumen bacterial species. MA3014 is metabolically versatile and capable of growing on a range of simple mono- or oligosaccharides derived from complex plant polysaccharides such as pectins, mannans, starch, and hemicelluloses, with lactate, butyrate, and formate as the principal fermentation end products. The genes encoding these metabolic pathways have been identified and MA3014 is predicted to encode an extensive range of Carbohydrate-Active enZYmes with 78 glycoside hydrolases, 13 carbohydrate esterases, and 54 glycosyl transferases, suggesting an important role in solubilization of plant matter in the rumen.
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Affiliation(s)
- Nikola Palevich
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand.,Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Paul H Maclean
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | | | - Sinead C Leahy
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
| | - Jasna Rakonjac
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Graeme T Attwood
- AgResearch Limited, Grasslands Research Centre, Palmerston North, New Zealand
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19
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Zuchan K, Baymann F, Baffert C, Brugna M, Nitschke W. The dyad of the Y-junction- and a flavin module unites diverse redox enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148401. [PMID: 33684340 DOI: 10.1016/j.bbabio.2021.148401] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 11/26/2022]
Abstract
The concomitant presence of two distinctive polypeptide modules, which we have chosen to denominate as the "Y-junction" and the "flavin" module, is observed in 3D structures of enzymes as functionally diverse as complex I, NAD(P)-dependent [NiFe]-hydrogenases and NAD(P)-dependent formate dehydrogenases. Amino acid sequence conservation furthermore suggests that both modules are also part of NAD(P)-dependent [FeFe]-hydrogenases for which no 3D structure model is available yet. The flavin module harbours the site of interaction with the substrate NAD(P) which exchanges two electrons with a strictly conserved flavin moiety. The Y-junction module typically contains four iron-sulphur centres arranged to form a Y-shaped electron transfer conduit and mediates electron transfer between the flavin module and the catalytic units of the respective enzymes. The Y-junction module represents an electron transfer hub with three potential electron entry/exit sites. The pattern of specific redox centres present both in the Y-junction and the flavin module is correlated to present knowledge of these enzymes' functional properties. We have searched publicly accessible genomes for gene clusters containing both the Y-junction and the flavin module to assemble a comprehensive picture of the diversity of enzymes harbouring this dyad of modules and to reconstruct their phylogenetic relationships. These analyses indicate the presence of the dyad already in the last universal common ancestor and the emergence of complex I's EFG-module out of a subgroup of NAD(P)- dependent formate dehydrogenases.
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Affiliation(s)
- Kilian Zuchan
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Frauke Baymann
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Carole Baffert
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Myriam Brugna
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France.
| | - Wolfgang Nitschke
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
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20
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Loh HQ, Hervé V, Brune A. Metabolic Potential for Reductive Acetogenesis and a Novel Energy-Converting [NiFe] Hydrogenase in Bathyarchaeia From Termite Guts - A Genome-Centric Analysis. Front Microbiol 2021; 11:635786. [PMID: 33613473 PMCID: PMC7886697 DOI: 10.3389/fmicb.2020.635786] [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: 11/30/2020] [Accepted: 12/31/2020] [Indexed: 12/11/2022] Open
Abstract
Symbiotic digestion of lignocellulose in the hindgut of higher termites is mediated by a diverse assemblage of bacteria and archaea. During a large-scale metagenomic study, we reconstructed 15 metagenome-assembled genomes of Bathyarchaeia that represent two distinct lineages in subgroup 6 (formerly MCG-6) unique to termite guts. One lineage (TB2; Candidatus Termitimicrobium) encodes all enzymes required for reductive acetogenesis from CO2 via an archaeal variant of the Wood–Ljungdahl pathway, involving tetrahydromethanopterin as C1 carrier and an (ADP-forming) acetyl-CoA synthase. This includes a novel 11-subunit hydrogenase, which possesses the genomic architecture of the respiratory Fpo-complex of other archaea but whose catalytic subunit is phylogenetically related to and shares the conserved [NiFe] cofactor-binding motif with [NiFe] hydrogenases of subgroup 4 g. We propose that this novel Fpo-like hydrogenase provides part of the reduced ferredoxin required for CO2 reduction and is driven by the electrochemical membrane potential generated from the ATP conserved by substrate-level phosphorylation; the other part may require the oxidation of organic electron donors, which would make members of TB2 mixotrophic acetogens. Members of the other lineage (TB1; Candidatus Termiticorpusculum) are definitely organotrophic because they consistently lack hydrogenases and/or methylene-tetrahydromethanopterin reductase, a key enzyme of the archaeal Wood–Ljungdahl pathway. Both lineages have the genomic capacity to reduce ferredoxin by oxidizing amino acids and might conduct methylotrophic acetogenesis using unidentified methylated compound(s). Our results indicate that Bathyarchaeia of subgroup 6 contribute to acetate formation in the guts of higher termites and substantiate the genomic evidence for reductive acetogenesis from organic substrates, possibly including methylated compounds, in other uncultured representatives of the phylum.
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Affiliation(s)
- Hui Qi Loh
- Research Group Insect Microbiology and Symbiosis, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Vincent Hervé
- Research Group Insect Microbiology and Symbiosis, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Andreas Brune
- Research Group Insect Microbiology and Symbiosis, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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21
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Abstract
Hydrogenases are metalloenzymes that catalyze proton reduction and H2 oxidation with outstanding efficiency. They are model systems for bioinorganic chemistry, including low-valent transition metals, hydride chemistry, and proton-coupled electron transfer. In this Account, we describe how photochemistry and infrared difference spectroscopy can be used to identify the dynamic hydrogen-bonding changes that facilitate proton transfer in [NiFe]- and [FeFe]-hydrogenase.[NiFe]-hydrogenase binds a heterobimetallic nickel/iron site embedded in the protein by four cysteine ligands. [FeFe]-hydrogenase carries a homobimetallic iron/iron site attached to the protein by only a single cysteine. Carbon monoxide and cyanide ligands in the active site facilitate detailed investigations of hydrogenase catalysis by infrared spectroscopy because of their strong signals and redox-dependent frequency shifts. We found that specific redox-state transitions in [NiFe]- and [FeFe]-hydrogenase can be triggered by visible light to record extremely sensitive "light-minus-dark" infrared difference spectra monitoring key amino acid residues. As these transitions are coupled to protonation changes, our data allowed investigation of dynamic hydrogen-bonding changes that go well beyond the resolution of protein crystallography.In [NiFe]-hydrogenase, photolysis of the bridging hydride ligand in the Ni-C state was followed by infrared difference spectroscopy. Our data clearly indicate the formation of a protonated cysteine residue as well as hydrogen-bonding changes involving a glutamic acid residue and a "dangling water" molecule. These findings are in excellent agreement with crystallographic analyses of [NiFe]-hydrogenase. In [FeFe]-hydrogenase, an external redox dye was used to accumulate the Hred state. Infrared difference spectra indicate hydrogen-bonding changes involving two glutamic acid residues and a conserved arginine residue. While crystallographic analyses of [FeFe]-hydrogenase in the oxidized state failed to explain the rapid proton transfer because of a breach in the succession of residues, our findings facilitated a precise molecular model of discontinued proton transfer.Comparing both systems, our data emphasize the role of the outer coordination sphere in bimetallic hydrogenases: we suggest that protonation of a nickel-ligating cysteine in [NiFe]-hydrogenase causes the notable preference toward H2 oxidation. On the contrary, proton transfer in [FeFe]-hydrogenase involves an adjacent cysteine as a relay group, promoting both H2 oxidation and proton reduction. These observations may guide the design of organometallic compounds that mimic the catalytic properties of hydrogenases.
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Affiliation(s)
- Hulin Tai
- Department of Chemistry, National Demonstration Centre for Experimental Chemistry Education, Yanbian University, Yanji, Jilin 133002, China
| | - Shun Hirota
- Division of Materials Science, Graduate School of Science and Technology, Nara Institute of Science and Technology, Ikoma, Nara 630-0192, Japan
| | - Sven T. Stripp
- Bioinorganic Spectroscopy, Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany
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22
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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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Fan Q, Neubauer P, Lenz O, Gimpel M. Heterologous Hydrogenase Overproduction Systems for Biotechnology-An Overview. Int J Mol Sci 2020; 21:E5890. [PMID: 32824336 PMCID: PMC7460606 DOI: 10.3390/ijms21165890] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/06/2020] [Accepted: 08/14/2020] [Indexed: 01/16/2023] Open
Abstract
Hydrogenases are complex metalloenzymes, showing tremendous potential as H2-converting redox catalysts for application in light-driven H2 production, enzymatic fuel cells and H2-driven cofactor regeneration. They catalyze the reversible oxidation of hydrogen into protons and electrons. The apo-enzymes are not active unless they are modified by a complicated post-translational maturation process that is responsible for the assembly and incorporation of the complex metal center. The catalytic center is usually easily inactivated by oxidation, and the separation and purification of the active protein is challenging. The understanding of the catalytic mechanisms progresses slowly, since the purification of the enzymes from their native hosts is often difficult, and in some case impossible. Over the past decades, only a limited number of studies report the homologous or heterologous production of high yields of hydrogenase. In this review, we emphasize recent discoveries that have greatly improved our understanding of microbial hydrogenases. We compare various heterologous hydrogenase production systems as well as in vitro hydrogenase maturation systems and discuss their perspectives for enhanced biohydrogen production. Additionally, activities of hydrogenases isolated from either recombinant organisms or in vivo/in vitro maturation approaches were systematically compared, and future perspectives for this research area are discussed.
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Affiliation(s)
- Qin Fan
- Institute of Biotechnology, Technical University of Berlin, Ackerstraße 76, 13355 Berlin, Germany; (Q.F.); (P.N.)
| | - Peter Neubauer
- Institute of Biotechnology, Technical University of Berlin, Ackerstraße 76, 13355 Berlin, Germany; (Q.F.); (P.N.)
| | - Oliver Lenz
- Department of Chemistry, Technical University of Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany;
| | - Matthias Gimpel
- Institute of Biotechnology, Technical University of Berlin, Ackerstraße 76, 13355 Berlin, Germany; (Q.F.); (P.N.)
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Nitrogen Source Governs Community Carbon Metabolism in a Model Hypersaline Benthic Phototrophic Biofilm. mSystems 2020; 5:5/3/e00260-20. [PMID: 32518194 PMCID: PMC7289588 DOI: 10.1128/msystems.00260-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Increasing anthropogenic inputs of fixed nitrogen are leading to greater eutrophication of aquatic environments, but it is unclear how this impacts the flux and fate of carbon in lacustrine and riverine systems. Here, we present evidence that the form of nitrogen governs the partitioning of carbon among members in a genome-sequenced, model phototrophic biofilm of 20 members. Consumption of NO3 - as the sole nitrogen source unexpectedly resulted in more rapid transfer of carbon to heterotrophs than when NH4 + was also provided, suggesting alterations in the form of carbon exchanged. The form of nitrogen dramatically impacted net community nitrogen, but not carbon, uptake rates. Furthermore, this alteration in nitrogen form caused very large but focused alterations to community structure, strongly impacting the abundance of only two species within the biofilm and modestly impacting a third member species. Our data suggest that nitrogen metabolism may coordinate coupled carbon-nitrogen biogeochemical cycling in benthic biofilms and, potentially, in phototroph-heterotroph consortia more broadly. It further indicates that the form of nitrogen inputs may significantly impact the contribution of these communities to carbon partitioning across the terrestrial-aquatic interface.IMPORTANCE Anthropogenic inputs of nitrogen into aquatic ecosystems, and especially those of agricultural origin, involve a mix of chemical species. Although it is well-known in general that nitrogen eutrophication markedly influences the metabolism of aquatic phototrophic communities, relatively little is known regarding whether the specific chemical form of nitrogen inputs matter. Our data suggest that the nitrogen form alters the rate of nitrogen uptake significantly, whereas corresponding alterations in carbon uptake were minor. However, differences imposed by uptake of divergent nitrogen forms may result in alterations among phototroph-heterotroph interactions that rewire community metabolism. Furthermore, our data hint that availability of other nutrients (i.e., iron) might mediate the linkage between carbon and nitrogen cycling in these communities. Taken together, our data suggest that different nitrogen forms should be examined for divergent impacts on phototrophic communities in fluvial systems and that these anthropogenic nitrogen inputs may significantly differ in their ultimate biogeochemical impacts.
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Artz JH, Tokmina-Lukaszewska M, Mulder DW, Lubner CE, Gutekunst K, Appel J, Bothner B, Boehm M, King PW. The structure and reactivity of the HoxEFU complex from the cyanobacterium Synechocystis sp. PCC 6803. J Biol Chem 2020; 295:9445-9454. [PMID: 32409585 PMCID: PMC7363133 DOI: 10.1074/jbc.ra120.013136] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/11/2020] [Indexed: 11/19/2022] Open
Abstract
Cyanobacterial Hox is a [NiFe] hydrogenase that consists of the hydrogen (H2)-activating subunits HoxYH, which form a complex with the HoxEFU assembly to mediate reactions with soluble electron carriers like NAD(P)H and ferredoxin (Fdx), thereby coupling photosynthetic electron transfer to energy-transforming catalytic reactions. Researchers studying the HoxEFUYH complex have observed that HoxEFU can be isolated independently of HoxYH, leading to the hypothesis that HoxEFU is a distinct functional subcomplex rather than an artifact of Hox complex isolation. Moreover, outstanding questions about the reactivity of Hox with natural substrates and the site(s) of substrate interactions and coupling of H2, NAD(P)H, and Fdx remain to be resolved. To address these questions, here we analyzed recombinantly produced HoxEFU by electron paramagnetic resonance spectroscopy and kinetic assays with natural substrates. The purified HoxEFU subcomplex catalyzed electron transfer reactions among NAD(P)H, flavodoxin, and several ferredoxins, thus functioning in vitro as a shuttle among different cyanobacterial pools of reducing equivalents. Both Fdx1-dependent reductions of NAD+ and NADP+ were cooperative. HoxEFU also catalyzed the flavodoxin-dependent reduction of NAD(P)+, Fdx2-dependent oxidation of NADH and Fdx4- and Fdx11-dependent reduction of NAD+. MS-based mapping identified an Fdx1-binding site at the junction of HoxE and HoxF, adjacent to iron-sulfur (FeS) clusters in both subunits. Overall, the reactivity of HoxEFU observed here suggests that it functions in managing peripheral electron flow from photosynthetic electron transfer, findings that reveal detailed insights into how ubiquitous cellular components may be used to allocate energy flow into specific bioenergetic products.
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Affiliation(s)
- Jacob H Artz
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | | | - David W Mulder
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | - Carolyn E Lubner
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
| | | | - Jens Appel
- Botanical Institute, Christian-Albrechts-University, Kiel, Germany
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Marko Boehm
- Botanical Institute, Christian-Albrechts-University, Kiel, Germany
| | - Paul W King
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado, USA
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Tai H, Hirota S. Mechanism and Application of the Catalytic Reaction of [NiFe] Hydrogenase: Recent Developments. Chembiochem 2020; 21:1573-1581. [DOI: 10.1002/cbic.202000058] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/25/2020] [Indexed: 01/28/2023]
Affiliation(s)
- Hulin Tai
- MOE Key Laboratory of Natural Resources of the Changbai Mountain and Functional MoleculesDepartment of ChemistryYanbian University Park Road 977 Yanji 133002 Jilin China
| | - Shun Hirota
- Division of Materials ScienceGraduate School of Science and TechnologyNara Institute of Science and Technology 8916-5 Takayama Ikoma Nara 630-0192 Japan
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27
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RNA-Seq comparative analysis reveals the response of Enterococcus faecalis TV4 under fluoride exposure. Gene 2020; 726:144197. [DOI: 10.1016/j.gene.2019.144197] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 10/08/2019] [Accepted: 10/20/2019] [Indexed: 12/14/2022]
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Comparative Genomics of Rumen Butyrivibrio spp. Uncovers a Continuum of Polysaccharide-Degrading Capabilities. Appl Environ Microbiol 2019; 86:AEM.01993-19. [PMID: 31653790 PMCID: PMC6912079 DOI: 10.1128/aem.01993-19] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 10/16/2019] [Indexed: 12/20/2022] Open
Abstract
Feeding a global population of 8 billion people and climate change are the primary challenges facing agriculture today. Ruminant livestock are important food-producing animals, and maximizing their productivity requires an understanding of their digestive systems and the roles played by rumen microbes in plant polysaccharide degradation. Members of the genera Butyrivibrio and Pseudobutyrivibrio are a phylogenetically diverse group of bacteria and are commonly found in the rumen, where they are a substantial source of polysaccharide-degrading enzymes for the depolymerization of lignocellulosic material. Our findings have highlighted the immense enzymatic machinery of Butyrivibrio and Pseudobutyrivibrio species for the degradation of plant fiber, suggesting that these bacteria occupy similar niches but apply different degradation strategies in order to coexist in the competitive rumen environment. Plant polysaccharide breakdown by microbes in the rumen is fundamental to digestion in ruminant livestock. Bacterial species belonging to the rumen genera Butyrivibrio and Pseudobutyrivibrio are important degraders and utilizers of lignocellulosic plant material. These bacteria degrade polysaccharides and ferment the released monosaccharides to yield short-chain fatty acids that are used by the ruminant for growth and the production of meat, milk, and fiber products. Although rumen Butyrivibrio and Pseudobutyrivibrio species are regarded as common rumen inhabitants, their polysaccharide-degrading and carbohydrate-utilizing enzymes are not well understood. In this study, we analyzed the genomes of 40 Butyrivibrio and 6 Pseudobutyrivibrio strains isolated from the plant-adherent fraction of New Zealand dairy cows to explore the polysaccharide-degrading potential of these important rumen bacteria. Comparative genome analyses combined with phylogenetic analysis of their 16S rRNA genes and short-chain fatty acid production patterns provide insight into the genomic diversity and physiology of these bacteria and divide Butyrivibrio into 3 species clusters. Rumen Butyrivibrio bacteria were found to encode a large and diverse spectrum of degradative carbohydrate-active enzymes (CAZymes) and binding proteins. In total, 4,421 glycoside hydrolases (GHs), 1,283 carbohydrate esterases (CEs), 110 polysaccharide lyases (PLs), 3,605 glycosyltransferases (GTs), and 1,706 carbohydrate-binding protein modules (CBM) with predicted activities involved in the depolymerization and transport of the insoluble plant polysaccharides were identified. Butyrivibrio genomes had similar patterns of CAZyme families but varied greatly in the number of genes within each category in the Carbohydrate-Active Enzymes database (CAZy), suggesting some level of functional redundancy. These results suggest that rumen Butyrivibrio species occupy similar niches but apply different degradation strategies to be able to coexist in the rumen. IMPORTANCE Feeding a global population of 8 billion people and climate change are the primary challenges facing agriculture today. Ruminant livestock are important food-producing animals, and maximizing their productivity requires an understanding of their digestive systems and the roles played by rumen microbes in plant polysaccharide degradation. Members of the genera Butyrivibrio and Pseudobutyrivibrio are a phylogenetically diverse group of bacteria and are commonly found in the rumen, where they are a substantial source of polysaccharide-degrading enzymes for the depolymerization of lignocellulosic material. Our findings have highlighted the immense enzymatic machinery of Butyrivibrio and Pseudobutyrivibrio species for the degradation of plant fiber, suggesting that these bacteria occupy similar niches but apply different degradation strategies in order to coexist in the competitive rumen environment.
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Mus F, Colman DR, Peters JW, Boyd ES. Geobiological feedbacks, oxygen, and the evolution of nitrogenase. Free Radic Biol Med 2019; 140:250-259. [PMID: 30735835 DOI: 10.1016/j.freeradbiomed.2019.01.050] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/31/2019] [Indexed: 12/21/2022]
Abstract
Biological nitrogen fixation via the activity of nitrogenase is one of the most important biological innovations, allowing for an increase in global productivity that eventually permitted the emergence of higher forms of life. The complex metalloenzyme termed nitrogenase contains complex iron-sulfur cofactors. Three versions of nitrogenase exist that differ mainly by the presence or absence of a heterometal at the active site metal cluster (either Mo or V). Mo-dependent nitrogenase is the most common while V-dependent or heterometal independent (Fe-only) versions are often termed alternative nitrogenases since they have apparent lower activities for N2 reduction and are expressed in the absence of Mo. Phylogenetic data indicates that biological nitrogen fixation emerged in an anaerobic, thermophilic ancestor of hydrogenotrophic methanogens and later diversified via lateral gene transfer into anaerobic bacteria, and eventually aerobic bacteria including Cyanobacteria. Isotopic evidence suggests that nitrogenase activity existed at 3.2 Ga, prior to the advent of oxygenic photosynthesis and rise of oxygen in the atmosphere, implying the presence of favorable environmental conditions for oxygen-sensitive nitrogenase to evolve. Following the proliferation of oxygenic phototrophs, diazotrophic organisms had to develop strategies to protect nitrogenase from oxygen inactivation and generate the right balance of low potential reducing equivalents and cellular energy for growth and nitrogen fixation activity. Here we review the fundamental advances in our understanding of biological nitrogen fixation in the context of the emergence, evolution, and taxonomic distribution of nitrogenase, with an emphasis placed on key events associated with its emergence and diversification from anoxic to oxic environments.
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Affiliation(s)
- Florence Mus
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA
| | - Daniel R Colman
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA
| | - John W Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA, USA.
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, USA.
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Garlapati D, Chandrasekaran M, Devanesan A, Mathimani T, Pugazhendhi A. Role of cyanobacteria in agricultural and industrial sectors: an outlook on economically important byproducts. Appl Microbiol Biotechnol 2019; 103:4709-4721. [PMID: 31030286 DOI: 10.1007/s00253-019-09811-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/29/2019] [Accepted: 03/31/2019] [Indexed: 01/22/2023]
Abstract
Cyanobacteria are potential organisms, which are used as food, feed and fuel. The unique characters of cyanobacteria include short generation times, their ubiquitous presence and efficient nitrogen fixing potential. Cyanobacteria are unique organisms performing photosynthesis, bioremediation of wastewater, high biomass and biofuel productions etc. They are also used in the treatment of industrial and domestic wastewaters for the utilization or removal of ammonia, phosphates and other heavy metals (Cr, Pb, Co, Cu, Zn). Biomasses of cyanobacteria are used as biofertilizers for the improvement of nutrient or mineral status and water-holding capacity of the soil. The secondary metabolites of cyanobacteria are used in pharmaceuticals, nutraceutical and chemical industries. In the industrial sector, value-added products from cyanobacteria such as pigments, enzymes and exopolysaccharides are being produced in large scales for biomedical and health applications. Age-old applications of cyanobacteria in agroecosystems as biofertilizers (Anabaena sp; Nostoc sp.) and in industrial sectors as food products (Spirulina) have motivated the researchers to come up with much more specific applications of cyanobacteria both in agricultural and in industrial sectors. Therefore, considering the effectiveness and efficiency of cyanobacteria, the present review has enlisted the standout qualities of cyanobacteria and their potential applications in agricultural and industrial sectors for the benefit of human beings and environment.
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Affiliation(s)
- Deviram Garlapati
- National Centre for Coastal Research (NCCR), Ministry of Earth Sciences (MoES), Chennai, Tamil Nadu, 600 100, India
| | - Muthukumar Chandrasekaran
- National Centre for Coastal Research (NCCR), Ministry of Earth Sciences (MoES), Chennai, Tamil Nadu, 600 100, India
| | - ArulAnanth Devanesan
- Department of Food Quality and Safety, Gilat Research Center, Agricultural Research Organization, 85280, Negev, MP, Israel
| | - Thangavel Mathimani
- Department of Energy and Environment, National Institute of Technology, Tiruchirappalli, Tamil Nadu, 620015, India
| | - Arivalagan Pugazhendhi
- Innovative Green Product Synthesis and Renewable Environment Development Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
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31
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Pernil R, Schleiff E. Metalloproteins in the Biology of Heterocysts. Life (Basel) 2019; 9:E32. [PMID: 30987221 PMCID: PMC6616624 DOI: 10.3390/life9020032] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/18/2019] [Accepted: 03/28/2019] [Indexed: 12/15/2022] Open
Abstract
Cyanobacteria are photoautotrophic microorganisms present in almost all ecologically niches on Earth. They exist as single-cell or filamentous forms and the latter often contain specialized cells for N₂ fixation known as heterocysts. Heterocysts arise from photosynthetic active vegetative cells by multiple morphological and physiological rearrangements including the absence of O₂ evolution and CO₂ fixation. The key function of this cell type is carried out by the metalloprotein complex known as nitrogenase. Additionally, many other important processes in heterocysts also depend on metalloproteins. This leads to a high metal demand exceeding the one of other bacteria in content and concentration during heterocyst development and in mature heterocysts. This review provides an overview on the current knowledge of the transition metals and metalloproteins required by heterocysts in heterocyst-forming cyanobacteria. It discusses the molecular, physiological, and physicochemical properties of metalloproteins involved in N₂ fixation, H₂ metabolism, electron transport chains, oxidative stress management, storage, energy metabolism, and metabolic networks in the diazotrophic filament. This provides a detailed and comprehensive picture on the heterocyst demands for Fe, Cu, Mo, Ni, Mn, V, and Zn as cofactors for metalloproteins and highlights the importance of such metalloproteins for the biology of cyanobacterial heterocysts.
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Affiliation(s)
- Rafael Pernil
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
| | - Enrico Schleiff
- Institute for Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt am Main, Germany.
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Max-von-Laue-Straβe 15, 60438 Frankfurt am Main, Germany.
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Veaudor T, Ortega-Ramos M, Jittawuttipoka T, Bottin H, Cassier-Chauvat C, Chauvat F. Overproduction of the cyanobacterial hydrogenase and selection of a mutant thriving on urea, as a possible step towards the future production of hydrogen coupled with water treatment. PLoS One 2018; 13:e0198836. [PMID: 29879209 PMCID: PMC5991728 DOI: 10.1371/journal.pone.0198836] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 05/25/2018] [Indexed: 01/01/2023] Open
Abstract
Using a combination of various types of genetic manipulations (promoter replacement and gene cloning in replicating plasmid expression vector), we have overproduced the complex hydrogenase enzyme in the model cyanobacterium Synechocystis PCC6803. This new strain overproduces all twelve following proteins: HoxEFUYH (hydrogen production), HoxW (maturation of the HoxH subunit of hydrogenase) and HypABCDEF (assembly of the [NiFe] redox center of HoxHY hydrogenase). This strain when grown in the presence of a suitable quantities of nickel and iron used here exhibits a strong (25-fold) increase in hydrogenase activity, as compared to the WT strain growing in the standard medium. Hence, this strain can be very useful for future analyses of the cyanobacterial [NiFe] hydrogenase to determine its structure and, in turn, improve its tolerance to oxygen with the future goal of increasing hydrogen production. We also report the counterintuitive notion that lowering the activity of the Synechocystis urease can increase the photoproduction of biomass from urea-polluted waters, without decreasing hydrogenase activity. Such cyanobacterial factories with high hydrogenase activity and a healthy growth on urea constitute an important step towards the future development of an economical industrial processes coupling H2 production from solar energy and CO2, with wastewater treatment (urea depollution).
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Affiliation(s)
- Théo Veaudor
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette, France
| | - Marcia Ortega-Ramos
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette, France
| | - Thichakorn Jittawuttipoka
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette, France
| | - Hervé Bottin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette, France
| | - Corinne Cassier-Chauvat
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette, France
| | - Franck Chauvat
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette, France
- * E-mail:
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Gutekunst K. Hypothesis on the Synchronistic Evolution of Autotrophy and Heterotrophy. Trends Biochem Sci 2018; 43:402-411. [DOI: 10.1016/j.tibs.2018.03.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 03/05/2018] [Accepted: 03/20/2018] [Indexed: 10/17/2022]
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Avilan L, Roumezi B, Risoul V, Bernard CS, Kpebe A, Belhadjhassine M, Rousset M, Brugna M, Latifi A. Phototrophic hydrogen production from a clostridial [FeFe] hydrogenase expressed in the heterocysts of the cyanobacterium Nostoc PCC 7120. Appl Microbiol Biotechnol 2018; 102:5775-5783. [DOI: 10.1007/s00253-018-8989-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 03/11/2018] [Accepted: 04/05/2018] [Indexed: 12/28/2022]
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Electron Transfer to Nitrogenase in Different Genomic and Metabolic Backgrounds. J Bacteriol 2018; 200:JB.00757-17. [PMID: 29483165 DOI: 10.1128/jb.00757-17] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/16/2018] [Indexed: 11/20/2022] Open
Abstract
Nitrogenase catalyzes the reduction of dinitrogen (N2) using low-potential electrons from ferredoxin (Fd) or flavodoxin (Fld) through an ATP-dependent process. Since its emergence in an anaerobic chemoautotroph, this oxygen (O2)-sensitive enzyme complex has evolved to operate in a variety of genomic and metabolic backgrounds, including those of aerobes, anaerobes, chemotrophs, and phototrophs. However, whether pathways of electron delivery to nitrogenase are influenced by these different metabolic backgrounds is not well understood. Here, we report the distribution of homologs of Fds, Flds, and Fd-/Fld-reducing enzymes in 359 genomes of putative N2 fixers (diazotrophs). Six distinct lineages of nitrogenase were identified, and their distributions largely corresponded to differences in the host cells' ability to integrate O2 or light into energy metabolism. The predicted pathways of electron transfer to nitrogenase in aerobes, facultative anaerobes, and phototrophs varied from those in anaerobes at the levels of Fds/Flds used to reduce nitrogenase, the enzymes that generate reduced Fds/Flds, and the putative substrates of these enzymes. Proteins that putatively reduce Fd with hydrogen or pyruvate were enriched in anaerobes, while those that reduce Fd with NADH/NADPH were enriched in aerobes, facultative anaerobes, and anoxygenic phototrophs. The energy metabolism of aerobic, facultatively anaerobic, and anoxygenic phototrophic diazotrophs often yields reduced NADH/NADPH that is not sufficiently reduced to drive N2 reduction. At least two mechanisms have been acquired by these taxa to overcome this limitation and to generate electrons with potentials capable of reducing Fd. These include the bifurcation of electrons or the coupling of Fd reduction to reverse ion translocation.IMPORTANCE Nitrogen fixation supplies fixed nitrogen to cells from a variety of genomic and metabolic backgrounds, including those of aerobes, facultative anaerobes, chemotrophs, and phototrophs. Here, using informatics approaches applied to genomic data, we show that pathways of electron transfer to nitrogenase in metabolically diverse diazotrophic taxa have diversified primarily in response to host cells' acquired ability to integrate O2 or light into their energy metabolism. The acquisition of two key enzyme complexes enabled aerobic and facultatively anaerobic phototrophic taxa to generate electrons of sufficiently low potential to reduce nitrogenase: the bifurcation of electrons via the Fix complex or the coupling of Fd reduction to reverse ion translocation via the Rhodobacter nitrogen fixation (Rnf) complex.
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Gutekunst K, Hoffmann D, Westernströer U, Schulz R, Garbe-Schönberg D, Appel J. In-vivo turnover frequency of the cyanobacterial NiFe-hydrogenase during photohydrogen production outperforms in-vitro systems. Sci Rep 2018; 8:6083. [PMID: 29666458 PMCID: PMC5904137 DOI: 10.1038/s41598-018-24430-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/28/2018] [Indexed: 12/12/2022] Open
Abstract
Cyanobacteria provide all components for sunlight driven biohydrogen production. Their bidirectional NiFe-hydrogenase is resistant against low levels of oxygen with a preference for hydrogen evolution. However, until now it was unclear if its catalytic efficiency can keep pace with the photosynthetic electron transfer rate. We identified NikKLMQO (sll0381-sll0385) as a nickel transporter, which is required for hydrogen production. ICP-MS measurements were used to quantify hydrogenase molecules per cell. We found 400 to 2000 hydrogenase molecules per cell depending on the conditions. In-vivo turnover frequencies of the enzyme ranged from 62 H2/s in the wild type to 120 H2/s in a mutant during photohydrogen production. These frequencies are above maximum in-vivo photosynthetic electron transfer rates of 47 e-/s (equivalent to 24 H2/s). They are also above those of existing in-vitro systems working with unlimited electron supply and show that in-vivo photohydrogen production is limited by electron delivery to the enzyme.
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Affiliation(s)
- Kirstin Gutekunst
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany
| | - Dörte Hoffmann
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany
| | | | - Rüdiger Schulz
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany
| | | | - Jens Appel
- Botanical Institute, Christian-Albrechts-University, 24118, Kiel, Germany.
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Wiegand K, Winkler M, Rumpel S, Kannchen D, Rexroth S, Hase T, Farès C, Happe T, Lubitz W, Rögner M. Rational redesign of the ferredoxin-NADP +-oxido-reductase/ferredoxin-interaction for photosynthesis-dependent H 2-production. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:253-262. [PMID: 29378161 DOI: 10.1016/j.bbabio.2018.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/18/2018] [Accepted: 01/22/2018] [Indexed: 01/11/2023]
Abstract
Utilization of electrons from the photosynthetic water splitting reaction for the generation of biofuels, commodities as well as application in biotransformations requires a partial rerouting of the photosynthetic electron transport chain. Due to its rather negative redox potential and its bifurcational function, ferredoxin at the acceptor side of Photosystem 1 is one of the focal points for such an engineering. With hydrogen production as model system, we show here the impact and potential of redox partner design involving ferredoxin (Fd), ferredoxin-oxido-reductase (FNR) and [FeFe]‑hydrogenase HydA1 on electron transport in a future cyanobacterial design cell of Synechocystis PCC 6803. X-ray-structure-based rational design and the allocation of specific interaction residues by NMR-analysis led to the construction of Fd- and FNR-mutants, which in appropriate combination enabled an about 18-fold enhanced electron flow from Fd to HydA1 (in competition with equimolar amounts of FNR) in in vitro assays. The negative impact of these mutations on the Fd-FNR electron transport which indirectly facilitates H2 production (with a contribution of ≤42% by FNR variants and ≤23% by Fd-variants) and the direct positive impact on the Fd-HydA1 electron transport (≤23% by Fd-mutants) provide an excellent basis for the construction of a hydrogen-producing design cell and the study of photosynthetic efficiency-optimization with cyanobacteria.
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Affiliation(s)
- K Wiegand
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - M Winkler
- Photobiotechnology, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - S Rumpel
- Max-Planck-Institut für Chemische Energiekonversion, 45470 Mülheim, Germany
| | - D Kannchen
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - S Rexroth
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - T Hase
- Institute for Protein Research, Osaka University, Suita 565-0871, Osaka, Japan
| | - C Farès
- Max-Planck-Institut für Kohlenforschung, 45470 Mülheim, Germany
| | - T Happe
- Photobiotechnology, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany
| | - W Lubitz
- Max-Planck-Institut für Chemische Energiekonversion, 45470 Mülheim, Germany
| | - M Rögner
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr University Bochum, 44780 Bochum, Germany.
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Rewiring of Cyanobacterial Metabolism for Hydrogen Production: Synthetic Biology Approaches and Challenges. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1080:171-213. [PMID: 30091096 DOI: 10.1007/978-981-13-0854-3_8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
With the demand for renewable energy growing, hydrogen (H2) is becoming an attractive energy carrier. Developing H2 production technologies with near-net zero carbon emissions is a major challenge for the "H2 economy." Certain cyanobacteria inherently possess enzymes, nitrogenases, and bidirectional hydrogenases that are capable of H2 evolution using sunlight, making them ideal cell factories for photocatalytic conversion of water to H2. With the advances in synthetic biology, cyanobacteria are currently being developed as a "plug and play" chassis to produce H2. This chapter describes the metabolic pathways involved and the theoretical limits to cyanobacterial H2 production and summarizes the metabolic engineering technologies pursued.
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The complete genome sequence of the rumen bacterium Butyrivibrio hungatei MB2003. Stand Genomic Sci 2017; 12:72. [PMID: 29225728 PMCID: PMC5716241 DOI: 10.1186/s40793-017-0285-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 11/23/2017] [Indexed: 12/04/2022] Open
Abstract
Butyrivibrio hungatei MB2003 was isolated from the plant-adherent fraction of rumen contents from a pasture-grazed New Zealand dairy cow, and was selected for genome sequencing in order to examine its ability to degrade plant polysaccharides. The genome of MB2003 is 3.39 Mb and consists of four replicons; a chromosome, a secondary chromosome or chromid, a megaplasmid and a small plasmid. The genome has an average G + C content of 39.7%, and encodes 2983 putative protein-coding genes. MB2003 is able to use a variety of monosaccharide substrates for growth, with acetate, butyrate and formate as the principal fermentation end-products, and the genes encoding these metabolic pathways have been identified. MB2003 is predicted to encode an extensive repertoire of CAZymes with 78 GHs, 7 CEs, 1 PL and 78 GTs. MB2003 is unable to grow on xylan or pectin, and its role in the rumen appears to be as a utilizer of monosaccharides, disaccharides and oligosaccharides made available by the degradative activities of other bacterial species.
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40
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Khetkorn W, Rastogi RP, Incharoensakdi A, Lindblad P, Madamwar D, Pandey A, Larroche C. Microalgal hydrogen production - A review. BIORESOURCE TECHNOLOGY 2017; 243:1194-1206. [PMID: 28774676 DOI: 10.1016/j.biortech.2017.07.085] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/13/2017] [Accepted: 07/17/2017] [Indexed: 06/07/2023]
Abstract
Bio-hydrogen from microalgae including cyanobacteria has attracted commercial awareness due to its potential as an alternative, reliable and renewable energy source. Photosynthetic hydrogen production from microalgae can be interesting and promising options for clean energy. Advances in hydrogen-fuel-cell technology may attest an eco-friendly way of biofuel production, since, the use of H2 to generate electricity releases only water as a by-product. Progress in genetic/metabolic engineering may significantly enhance the photobiological hydrogen production from microalgae. Manipulation of competing metabolic pathways by modulating the certain key enzymes such as hydrogenase and nitrogenase may enhance the evolution of H2 from photoautotrophic cells. Moreover, biological H2 production at low operating costs is requisite for economic viability. Several photobioreactors have been developed for large-scale biomass and hydrogen production. This review highlights the recent technological progress, enzymes involved and genetic as well as metabolic engineering approaches towards sustainable hydrogen production from microalgae.
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Affiliation(s)
- Wanthanee Khetkorn
- Division of Biology, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi, Thanyaburi, Pathumthani 12110, Thailand
| | - Rajesh P Rastogi
- Ministry of Environment, Forest and Climate Change, Indira Paryavaran Bhawan, Jor Bagh Road, New Delhi 110 003, India.
| | - Aran Incharoensakdi
- Laboratory of Cyanobacterial Biotechnology, Department of Biochemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Bangkok 10330, Thailand
| | - Peter Lindblad
- Microbial Chemistry, Department of Chemistry-Ångström, Uppsala University, Box 523, SE-75120 Uppsala, Sweden
| | - Datta Madamwar
- Department of Biosciences, UGC-Centre of Advanced Study, Sardar Patel University, Vadtal Road, Satellite Campus, Bakrol, Anand, Gujarat 388 315, India
| | - Ashok Pandey
- Center of Innovative and Applied Bioprocessing, C-127 2nd Floor Phase 8 Industrial Area, SAS Nagar, Mohali 160 071, Punjab, India
| | - Christian Larroche
- Labex IMobS3 and Institut Pascal, 4 Avenue Blaise Pascal, TSA 60026/CS 60026, 63178 Aubière Cedex, France
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Enzymatic and spectroscopic properties of a thermostable [NiFe]‑hydrogenase performing H 2-driven NAD +-reduction in the presence of O 2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1859:8-18. [PMID: 28970007 DOI: 10.1016/j.bbabio.2017.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/17/2017] [Accepted: 09/28/2017] [Indexed: 12/18/2022]
Abstract
Biocatalysts that mediate the H2-dependent reduction of NAD+ to NADH are attractive from both a fundamental and applied perspective. Here we present the first biochemical and spectroscopic characterization of an NAD+-reducing [NiFe]‑hydrogenase that sustains catalytic activity at high temperatures and in the presence of O2, which usually acts as an inhibitor. We isolated and sequenced the four structural genes, hoxFUYH, encoding the soluble NAD+-reducing [NiFe]‑hydrogenase (SH) from the thermophilic betaproteobacterium, Hydrogenophilus thermoluteolus TH-1T (Ht). The HtSH was recombinantly overproduced in a hydrogenase-free mutant of the well-studied, H2-oxidizing betaproteobacterium Ralstonia eutropha H16 (Re). The enzyme was purified and characterized with various biochemical and spectroscopic techniques. Highest H2-mediated NAD+ reduction activity was observed at 80°C and pH6.5, and catalytic activity was found to be sustained at low O2 concentrations. Infrared spectroscopic analyses revealed a spectral pattern for as-isolated HtSH that is remarkably different from those of the closely related ReSH and other [NiFe]‑hydrogenases. This indicates an unusual configuration of the oxidized catalytic center in HtSH. Complementary electron paramagnetic resonance spectroscopic analyses revealed spectral signatures similar to related NAD+-reducing [NiFe]‑hydrogenases. This study lays the groundwork for structural and functional analyses of the HtSH as well as application of this enzyme for H2-driven cofactor recycling under oxic conditions at elevated temperatures.
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Lamont CM, Kelly CL, Pinske C, Buchanan G, Palmer T, Sargent F. Expanding the substrates for a bacterial hydrogenlyase reaction. MICROBIOLOGY-SGM 2017; 163:649-653. [PMID: 28488566 PMCID: PMC5817251 DOI: 10.1099/mic.0.000471] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Escherichia coli produces enzymes dedicated to hydrogen metabolism under anaerobic conditions. In particular, a formate hydrogenlyase (FHL) enzyme is responsible for the majority of hydrogen gas produced under fermentative conditions. FHL comprises a formate dehydrogenase (encoded by fdhF) linked directly to [NiFe]-hydrogenase-3 (Hyd-3), and formate is the only natural substrate known for proton reduction by this hydrogenase. In this work, the possibility of engineering an alternative electron donor for hydrogen production has been explored. Rational design and genetic engineering led to the construction of a fusion between Thermotoga maritima ferredoxin (Fd) and Hyd-3. The Fd-Hyd-3 fusion was found to evolve hydrogen when co-produced with T. maritima pyruvate :: ferredoxin oxidoreductase (PFOR), which links pyruvate oxidation to the reduction of ferredoxin. Analysis of the key organic acids produced during fermentation suggested that the PFOR/Fd-Hyd-3 fusion system successfully diverted pyruvate onto a new pathway towards hydrogen production.
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Affiliation(s)
- Ciaran M Lamont
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.,Present address: Oxford BioMedica, Windrush Court, Transport Way, Oxford OX4 6LT, UK
| | - Ciarán L Kelly
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.,Present address: Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Constanze Pinske
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK.,Present address: Institute of Biology/Microbiology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle (Saale), Germany
| | - Grant Buchanan
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Tracy Palmer
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Frank Sargent
- School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
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43
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Immethun CM, DeLorenzo DM, Focht CM, Gupta D, Johnson CB, Moon TS. Physical, chemical, and metabolic state sensors expand the synthetic biology toolbox for Synechocystis sp. PCC 6803. Biotechnol Bioeng 2017; 114:1561-1569. [PMID: 28244586 DOI: 10.1002/bit.26275] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 01/19/2017] [Accepted: 02/19/2017] [Indexed: 02/04/2023]
Abstract
Many under-developed organisms possess important traits that can boost the effectiveness and sustainability of microbial biotechnology. Photoautotrophic cyanobacteria can utilize the energy captured from light to fix carbon dioxide for their metabolic needs while living in environments not suited for growing crops. Various value-added compounds have been produced by cyanobacteria in the laboratory; yet, the products' titers and yields are often not industrially relevant and lag behind what have been accomplished in heterotrophic microbes. Genetic tools for biological process control are needed to take advantage of cyanobacteria's beneficial qualities, as tool development also lags behind what has been created in common heterotrophic hosts. To address this problem, we developed a suite of sensors that regulate transcription in the model cyanobacterium Synechocystis sp. PCC 6803 in response to metabolically relevant signals, including light and the cell's nitrogen status, and a family of sensors that respond to the inexpensive chemical, l-arabinose. Increasing the number of available tools enables more complex and precise control of gene expression. Expanding the synthetic biology toolbox for this cyanobacterium also improves our ability to utilize this important under-developed organism in biotechnology. Biotechnol. Bioeng. 2017;114: 1561-1569. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Cheryl M Immethun
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Drew M DeLorenzo
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Caroline M Focht
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Dinesh Gupta
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Charles B Johnson
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
| | - Tae Seok Moon
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri
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44
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Halan B, Tschörtner J, Schmid A. Generating Electric Current by Bioartificial Photosynthesis. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2017; 167:361-393. [PMID: 29224082 DOI: 10.1007/10_2017_44] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Abundant solar energy can be a sustainable source of energy. This chapter highlights recent advancements, challenges, and future scenarios in bioartificial photosynthesis, which is a new subset of bioelectrochemical systems (BESs) and technologies. BES technologies exploit the catalytic interactions between biological moieties and electrodes. At the nexus of BES and photovoltaics, this review focuses on light-harvesting technologies based on bioartificial photosynthesis. Such technologies are promising because electrical energy is generated from sunlight and water without the need for additional organic feedstock. This review focuses on photosynthetic electron generation and transfer and compares the current status of bioartificial photosynthesis with other artificial systems that mimic the chemistry of photosynthetic energy transformation.The fundamental principles and the operation of functional units of bioartificial photosynthesis are addressed. Selected photobioelectrochemical systems employed to obtain light-driven electric currents from photosynthetic organisms are presented. The achievable current output and theoretical maxima are revisited by conceptualizing operational and process window techniques. Factors affecting overall photocurrent efficiency, performance limitations, and scaleup bottlenecks are highlighted in view of enhancing the energy conversion efficiency of photobioelectrochemical systems. To finish, the challenges associated with bioartificial photosynthetic technologies are outlined. Graphical Abstract Operational window for (bio-)artificial photosynthesis. Green circle in the upper right corner: development objective for research and engineering efforts.
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Affiliation(s)
- Babu Halan
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Jenny Tschörtner
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany
| | - Andreas Schmid
- Department of Solar Materials, Helmholtz Centre for Environmental Research GmbH - UFZ, Leipzig, Germany.
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45
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Puggioni V, Tempel S, Latifi A. Distribution of Hydrogenases in Cyanobacteria: A Phylum-Wide Genomic Survey. Front Genet 2016; 7:223. [PMID: 28083017 PMCID: PMC5186783 DOI: 10.3389/fgene.2016.00223] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 12/13/2016] [Indexed: 01/02/2023] Open
Abstract
Microbial Molecular hydrogen (H2) cycling plays an important role in several ecological niches. Hydrogenases (H2ases), enzymes involved in H2 metabolism, are of great interest for investigating microbial communities, and producing BioH2. To obtain an overall picture of the genetic ability of Cyanobacteria to produce H2ases, we conducted a phylum wide analysis of the distribution of the genes encoding these enzymes in 130 cyanobacterial genomes. The concomitant presence of the H2ase and genes involved in the maturation process, and that of well-conserved catalytic sites in the enzymes were the three minimal criteria used to classify a strain as being able to produce a functional H2ase. The [NiFe] H2ases were found to be the only enzymes present in this phylum. Fifty-five strains were found to be potentially able produce the bidirectional Hox enzyme and 33 to produce the uptake (Hup) enzyme. H2 metabolism in Cyanobacteria has a broad ecological distribution, since only the genomes of strains collected from the open ocean do not possess hox genes. In addition, the presence of H2ase was found to increase in the late branching clades of the phylogenetic tree of the species. Surprisingly, five cyanobacterial genomes were found to possess homologs of oxygen tolerant H2ases belonging to groups 1, 3b, and 3d. Overall, these data show that H2ases are widely distributed, and are therefore probably of great functional importance in Cyanobacteria. The present finding that homologs to oxygen-tolerant H2ases are present in this phylum opens new perspectives for applying the process of photosynthesis in the field of H2 production.
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Affiliation(s)
- Vincenzo Puggioni
- Laboratoire de Chimie Bactérienne UMR 7283, Centre National de la Recherche Scientifique (CNRS), Aix-Marseille University Marseille, France
| | - Sébastien Tempel
- Laboratoire de Chimie Bactérienne UMR 7283, Centre National de la Recherche Scientifique (CNRS), Aix-Marseille University Marseille, France
| | - Amel Latifi
- Laboratoire de Chimie Bactérienne UMR 7283, Centre National de la Recherche Scientifique (CNRS), Aix-Marseille University Marseille, France
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46
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Atkinson JT, Campbell I, Bennett GN, Silberg JJ. Cellular Assays for Ferredoxins: A Strategy for Understanding Electron Flow through Protein Carriers That Link Metabolic Pathways. Biochemistry 2016; 55:7047-7064. [DOI: 10.1021/acs.biochem.6b00831] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua T. Atkinson
- Systems,
Synthetic, and Physical Biology Graduate Program, Rice University, MS-180, 6100 Main Street, Houston, Texas 77005, United States
| | - Ian Campbell
- Biochemistry
and Cell Biology Graduate Program, Rice University, MS-140, 6100
Main Street, Houston, Texas 77005, United States
| | - George N. Bennett
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Chemical and Biomolecular Engineering, Rice University, MS-362,
6100 Main Street, Houston, Texas 77005, United States
| | - Jonathan J. Silberg
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Bioengineering, Rice University, MS-142, 6100 Main Street, Houston, Texas 77005, United States
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47
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de Porcellinis AJ, Klähn S, Rosgaard L, Kirsch R, Gutekunst K, Georg J, Hess WR, Sakuragi Y. The Non-Coding RNA Ncr0700/PmgR1 is Required for Photomixotrophic Growth and the Regulation of Glycogen Accumulation in the Cyanobacterium Synechocystis sp. PCC 6803. PLANT & CELL PHYSIOLOGY 2016; 57:2091-2103. [PMID: 27440548 DOI: 10.1093/pcp/pcw128] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 07/12/2016] [Indexed: 06/06/2023]
Abstract
Carbohydrate metabolism is a tightly regulated process in photosynthetic organisms. In the cyanobacterium Synechocystis sp. PCC 6803, the photomixotrophic growth protein A (PmgA) is involved in the regulation of glucose and storage carbohydrate (i.e. glycogen) metabolism, while its biochemical activity and possible factors acting downstream of PmgA are unknown. Here, a genome-wide microarray analysis of a ΔpmgA strain identified the expression of 36 protein-coding genes and 42 non-coding transcripts as significantly altered. From these, the non-coding RNA Ncr0700 was identified as the transcript most strongly reduced in abundance. Ncr0700 is widely conserved among cyanobacteria. In Synechocystis its expression is inversely correlated with light intensity. Similarly to a ΔpmgA mutant, a Δncr0700 deletion strain showed an approximately 2-fold increase in glycogen content under photoautotrophic conditions and wild-type-like growth. Moreover, its growth was arrested by 38 h after a shift to photomixotrophic conditions. Ectopic expression of Ncr0700 in Δncr0700 and ΔpmgA restored the glycogen content and photomixotrophic growth to wild-type levels. These results indicate that Ncr0700 is required for photomixotrophic growth and the regulation of glycogen accumulation, and acts downstream of PmgA. Hence Ncr0700 is renamed here as PmgR1 for photomixotrophic growth RNA 1.
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Affiliation(s)
- Alice J de Porcellinis
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, DK-1871, Denmark
- These authors contributed equally to this work
| | - Stephan Klähn
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, D-79104, Germany
- These authors contributed equally to this work
| | - Lisa Rosgaard
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, DK-1871, Denmark
- Present address: R&D Renescience Thermal Power, DONG Energy, Skærbæk-7000 Fredericia, Denmark
| | - Rebekka Kirsch
- Botanical Institute, Christian-Albrechts-University, Am Botanischen Garten 5, Kiel, D-24118, Germany
| | - Kirstin Gutekunst
- Botanical Institute, Christian-Albrechts-University, Am Botanischen Garten 5, Kiel, D-24118, Germany
| | - Jens Georg
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, D-79104, Germany
| | - Wolfgang R Hess
- Genetics and Experimental Bioinformatics, Faculty of Biology, University of Freiburg, Schänzlestr. 1, Freiburg, D-79104, Germany
| | - Yumiko Sakuragi
- Copenhagen Plant Science Center, Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, DK-1871, Denmark
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48
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Crawford TS, Hanning KR, Chua JPS, Eaton-Rye JJ, Summerfield TC. Comparison of D1´- and D1-containing PS II reaction centre complexes under different environmental conditions in Synechocystis sp. PCC 6803. PLANT, CELL & ENVIRONMENT 2016; 39:1715-26. [PMID: 26991994 DOI: 10.1111/pce.12738] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 02/22/2016] [Accepted: 03/03/2016] [Indexed: 05/24/2023]
Abstract
In oxygenic photosynthesis, the D1 protein of Photosystem II is the primary target of photodamage and environmental stress can accelerate this process. The cyanobacterial response to stress includes transcriptional regulation of genes encoding D1, including low-oxygen-induction of psbA1 encoding the D1´ protein in Synechocystis sp. PCC 6803. The psbA1 gene is also transiently up-regulated in high light, and its deletion has been reported to increase ammonium-induced photoinhibition. Therefore we investigated the role of D1´-containing PS II centres under different environmental conditions. A strain containing only D1´-PS II centres under aerobic conditions exhibited increased sensitivity to ammonium chloride and high light compared to a D1-containing strain. Additionally a D1´-PS II strain was outperformed by a D1-PS II strain under normal conditions; however, a strain containing low-oxygen-induced D1´-PS II centres was more resilient under high light than an equivalent D1 strain. These D1´-containing centres had chlorophyll a fluorescence characteristics indicative of altered forward electron transport and back charge recombination with the donor side of PS II. Our results indicate D1´-PS II centres are important in the reconfiguration of thylakoid electron transport in response to high light and low oxygen.
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Affiliation(s)
- Tim S Crawford
- Department of Botany, University of Otago, Dunedin, 9054, New Zealand
- Department of Biochemistry, University of Otago, Dunedin, 9054, New Zealand
| | - Kyrin R Hanning
- Department of Botany, University of Otago, Dunedin, 9054, New Zealand
| | - Jocelyn P S Chua
- Department of Botany, University of Otago, Dunedin, 9054, New Zealand
| | - Julian J Eaton-Rye
- Department of Biochemistry, University of Otago, Dunedin, 9054, New Zealand
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Mustila H, Paananen P, Battchikova N, Santana-Sánchez A, Muth-Pawlak D, Hagemann M, Aro EM, Allahverdiyeva Y. The Flavodiiron Protein Flv3 Functions as a Homo-Oligomer During Stress Acclimation and is Distinct from the Flv1/Flv3 Hetero-Oligomer Specific to the O2 Photoreduction Pathway. PLANT & CELL PHYSIOLOGY 2016; 57:1468-1483. [PMID: 26936793 PMCID: PMC4937785 DOI: 10.1093/pcp/pcw047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 02/23/2016] [Indexed: 05/06/2023]
Abstract
The flavodiiron proteins (FDPs) Flv1 and Flv3 in cyanobacteria function in photoreduction of O2 to H2O, without concomitant formation of reactive oxygen species, known as the Mehler-like reaction. Both Flv1 and Flv3 are essential for growth under fluctuating light (FL) intensities, providing protection for PSI. Here we compared the global transcript profiles of the wild type (WT), Δflv1 and Δflv1/Δflv3 grown under constant light (GL) and FL. In the WT, FL induced the largest down-regulation in transcripts involved in carbon-concentrating mechanisms (CCMs), while those of the nitrogen assimilation pathways increased as compared with GL. Already under GL the Δflv1/Δflv3 double mutant demonstrated a partial down-regulation of transcripts for CCM and nitrogen metabolism, while in FL conditions the transcripts for nitrogen assimilation were strongly down-regulated. Many alterations were specific only for Δflv1/Δflv3, and not detected in Δflv1, suggesting that certain transcripts are affected primarily because of the lack of flv3 By constructing the strains overproducing solely either Flv1 or Flv3, we demonstrate that the homo-oligomers of these proteins also function in acclimation of cells to FL, by catalyzing reactions with as yet unidentified components, while the presence of both Flv1 and Flv3 is a prerequisite for the Mehler-like reaction and thus the electron transfer to O2 Considering the low expression of flv1, it is unlikely that the Flv1 homo-oligomer is present in the WT.
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Affiliation(s)
- Henna Mustila
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Pasi Paananen
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Natalia Battchikova
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Anita Santana-Sánchez
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Dorota Muth-Pawlak
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Martin Hagemann
- Institut Biowissenschaften, Pflanzenphysiologie, Universität Rostock, Albert-Einstein-Str. 3, D-18059 Rostock, Germany
| | - Eva-Mari Aro
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
| | - Yagut Allahverdiyeva
- Laboratory of Molecular Plant Biology, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland
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Culturing Synechocystis sp. Strain PCC 6803 with N2 and CO2 in a Diel Regime Reveals Multiphase Glycogen Dynamics with Low Maintenance Costs. Appl Environ Microbiol 2016; 82:4180-4189. [PMID: 27208121 DOI: 10.1128/aem.00256-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/28/2016] [Indexed: 01/22/2023] Open
Abstract
UNLABELLED Investigating the physiology of cyanobacteria cultured under a diel light regime is relevant for a better understanding of the resulting growth characteristics and for specific biotechnological applications that are foreseen for these photosynthetic organisms. Here, we present the results of a multiomics study of the model cyanobacterium Synechocystis sp. strain PCC 6803, cultured in a lab-scale photobioreactor in physiological conditions relevant for large-scale culturing. The culture was sparged with N2 and CO2, leading to an anoxic environment during the dark period. Growth followed the availability of light. Metabolite analysis performed with (1)H nuclear magnetic resonance analysis showed that amino acids involved in nitrogen and sulfur assimilation showed elevated levels in the light. Most protein levels, analyzed through mass spectrometry, remained rather stable. However, several high-light-response proteins and stress-response proteins showed distinct changes at the onset of the light period. Microarray-based transcript analysis found common patterns of ∼56% of the transcriptome following the diel regime. These oscillating transcripts could be grouped coarsely into genes that were upregulated and downregulated in the dark period. The accumulated glycogen was degraded in the anaerobic environment in the dark. A small part was degraded gradually, reflecting basic maintenance requirements of the cells in darkness. Surprisingly, the largest part was degraded rapidly in a short time span at the end of the dark period. This degradation could allow rapid formation of metabolic intermediates at the end of the dark period, preparing the cells for the resumption of growth at the start of the light period. IMPORTANCE Industrial-scale biotechnological applications are anticipated for cyanobacteria. We simulated large-scale high-cell-density culturing of Synechocystis sp. PCC 6803 under a diel light regime in a lab-scale photobioreactor. In BG-11 medium, Synechocystis grew only in the light. Metabolite analysis grouped the collected samples according to the light and dark conditions. Proteome analysis suggested that the majority of enzyme-activity regulation was not hierarchical but rather occurred through enzyme activity regulation. An abrupt light-on condition induced high-light-stress proteins. Transcript analysis showed distinct patterns for the light and dark periods. Glycogen gradually accumulated in the light and was rapidly consumed in the last quarter of the dark period. This suggests that the circadian clock primed the cellular machinery for immediate resumption of growth in the light.
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