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de Pins B, Greenspoon L, Bar-On YM, Shamshoum M, Ben-Nissan R, Milshtein E, Davidi D, Sharon I, Mueller-Cajar O, Noor E, Milo R. A systematic exploration of bacterial form I rubisco maximal carboxylation rates. EMBO J 2024:10.1038/s44318-024-00119-z. [PMID: 38806660 DOI: 10.1038/s44318-024-00119-z] [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: 02/01/2024] [Revised: 03/26/2024] [Accepted: 04/22/2024] [Indexed: 05/30/2024] Open
Abstract
Autotrophy is the basis for complex life on Earth. Central to this process is rubisco-the enzyme that catalyzes almost all carbon fixation on the planet. Yet, with only a small fraction of rubisco diversity kinetically characterized so far, the underlying biological factors driving the evolution of fast rubiscos in nature remain unclear. We conducted a high-throughput kinetic characterization of over 100 bacterial form I rubiscos, the most ubiquitous group of rubisco sequences in nature, to uncover the determinants of rubisco's carboxylation velocity. We show that the presence of a carboxysome CO2 concentrating mechanism correlates with faster rubiscos with a median fivefold higher rate. In contrast to prior studies, we find that rubiscos originating from α-cyanobacteria exhibit the highest carboxylation rates among form I enzymes (≈10 s-1 median versus <7 s-1 in other groups). Our study systematically reveals biological and environmental properties associated with kinetic variation across rubiscos from nature.
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Affiliation(s)
- Benoit de Pins
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Lior Greenspoon
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Yinon M Bar-On
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Melina Shamshoum
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Roee Ben-Nissan
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Eliya Milshtein
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Dan Davidi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
- Aleph, Tel Aviv-Yafo, 6688210, Israel
| | - Itai Sharon
- Migal Galilee Research Institute, Kiryat Shmona, 11016, Israel
| | - Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Elad Noor
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Ron Milo
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel.
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2
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Pulsford SB, Outram MA, Förster B, Rhodes T, Williams SJ, Badger MR, Price GD, Jackson CJ, Long BM. Cyanobacterial α-carboxysome carbonic anhydrase is allosterically regulated by the Rubisco substrate RuBP. SCIENCE ADVANCES 2024; 10:eadk7283. [PMID: 38728392 PMCID: PMC11086599 DOI: 10.1126/sciadv.adk7283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 04/08/2024] [Indexed: 05/12/2024]
Abstract
Cyanobacterial CO2 concentrating mechanisms (CCMs) sequester a globally consequential proportion of carbon into the biosphere. Proteinaceous microcompartments, called carboxysomes, play a critical role in CCM function, housing two enzymes to enhance CO2 fixation: carbonic anhydrase (CA) and Rubisco. Despite its importance, our current understanding of the carboxysomal CAs found in α-cyanobacteria, CsoSCA, remains limited, particularly regarding the regulation of its activity. Here, we present a structural and biochemical study of CsoSCA from the cyanobacterium Cyanobium sp. PCC7001. Our results show that the Cyanobium CsoSCA is allosterically activated by the Rubisco substrate ribulose-1,5-bisphosphate and forms a hexameric trimer of dimers. Comprehensive phylogenetic and mutational analyses are consistent with this regulation appearing exclusively in cyanobacterial α-carboxysome CAs. These findings clarify the biologically relevant oligomeric state of α-carboxysomal CAs and advance our understanding of the regulation of photosynthesis in this globally dominant lineage.
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Affiliation(s)
- Sacha B. Pulsford
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Megan A. Outram
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Britta Förster
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Timothy Rhodes
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Simon J. Williams
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Murray R. Badger
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - G. Dean Price
- Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Colin J. Jackson
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Benedict M. Long
- ARC Centre of Excellence in Synthetic Biology, Sydney, NSW, Australia
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
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3
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Nguyen ND, Pulsford SB, Förster B, Rottet S, Rourke L, Long BM, Price GD. A carboxysome-based CO 2 concentrating mechanism for C 3 crop chloroplasts: advances and the road ahead. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:940-952. [PMID: 38321620 DOI: 10.1111/tpj.16667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/17/2024] [Accepted: 01/24/2024] [Indexed: 02/08/2024]
Abstract
The introduction of the carboxysome-based CO2 concentrating mechanism (CCM) into crop plants has been modelled to significantly increase crop yields. This projection serves as motivation for pursuing this strategy to contribute to global food security. The successful implementation of this engineering challenge is reliant upon the transfer of a microcompartment that encapsulates cyanobacterial Rubisco, known as the carboxysome, alongside active bicarbonate transporters. To date, significant progress has been achieved with respect to understanding various aspects of the cyanobacterial CCM, and more recently, different components of the carboxysome have been successfully introduced into plant chloroplasts. In this Perspective piece, we summarise recent findings and offer new research avenues that will accelerate research in this field to ultimately and successfully introduce the carboxysome into crop plants for increased crop yields.
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Affiliation(s)
- Nghiem D Nguyen
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Sacha B Pulsford
- Research School of Chemistry, Australian National University, 137 Sullivan's Ck Rd, Acton, Australian Capital Territory, 2601, Australia
| | - Britta Förster
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Sarah Rottet
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Loraine Rourke
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
| | - Benedict M Long
- Discipline of Biological Sciences, School of Environmental and Life Sciences, ARC Centre of Excellence in Synthetic Biology, The University of Newcastle, University Drive, Callaghan, New South Wales, 2308, Australia
| | - G Dean Price
- Plant Science Division, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory, 2601, Australia
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4
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Zhou RQ, Jiang YL, Li H, Hou P, Kong WW, Deng JX, Chen Y, Zhou CZ, Zeng Q. Structure and assembly of the α-carboxysome in the marine cyanobacterium Prochlorococcus. NATURE PLANTS 2024; 10:661-672. [PMID: 38589484 DOI: 10.1038/s41477-024-01660-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 02/29/2024] [Indexed: 04/10/2024]
Abstract
Carboxysomes are bacterial microcompartments that encapsulate the enzymes RuBisCO and carbonic anhydrase in a proteinaceous shell to enhance the efficiency of photosynthetic carbon fixation. The self-assembly principles of the intact carboxysome remain elusive. Here we purified α-carboxysomes from Prochlorococcus and examined their intact structures using single-particle cryo-electron microscopy to solve the basic principles of their shell construction and internal RuBisCO organization. The 4.2 Å icosahedral-like shell structure reveals 24 CsoS1 hexamers on each facet and one CsoS4A pentamer at each vertex. RuBisCOs are organized into three concentric layers within the shell, consisting of 72, 32 and up to 4 RuBisCOs at the outer, middle and inner layers, respectively. We uniquely show how full-length and shorter forms of the scaffolding protein CsoS2 bind to the inner surface of the shell via repetitive motifs in the middle and C-terminal regions. Combined with previous reports, we propose a concomitant 'outside-in' assembly principle of α-carboxysomes: the inner surface of the self-assembled shell is reinforced by the middle and C-terminal motifs of the scaffolding protein, while the free N-terminal motifs cluster to recruit RuBisCO in concentric, three-layered spherical arrangements. These new insights into the coordinated assembly of α-carboxysomes may guide the rational design and repurposing of carboxysome structures for improving plant photosynthetic efficiency.
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Affiliation(s)
- Rui-Qian Zhou
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yong-Liang Jiang
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
| | - Haofu Li
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Pu Hou
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Wen-Wen Kong
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Jia-Xin Deng
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yuxing Chen
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Cong-Zhao Zhou
- School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
| | - Qinglu Zeng
- Department of Ocean Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
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5
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Trettel DS, Pacheco SL, Laskie AK, Gonzalez-Esquer CR. Modeling bacterial microcompartment architectures for enhanced cyanobacterial carbon fixation. FRONTIERS IN PLANT SCIENCE 2024; 15:1346759. [PMID: 38425792 PMCID: PMC10902431 DOI: 10.3389/fpls.2024.1346759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 01/30/2024] [Indexed: 03/02/2024]
Abstract
The carboxysome is a bacterial microcompartment (BMC) which plays a central role in the cyanobacterial CO2-concentrating mechanism. These proteinaceous structures consist of an outer protein shell that partitions Rubisco and carbonic anhydrase from the rest of the cytosol, thereby providing a favorable microenvironment that enhances carbon fixation. The modular nature of carboxysomal architectures makes them attractive for a variety of biotechnological applications such as carbon capture and utilization. In silico approaches, such as molecular dynamics (MD) simulations, can support future carboxysome redesign efforts by providing new spatio-temporal insights on their structure and function beyond in vivo experimental limitations. However, specific computational studies on carboxysomes are limited. Fortunately, all BMC (including the carboxysome) are highly structurally conserved which allows for practical inferences to be made between classes. Here, we review simulations on BMC architectures which shed light on (1) permeation events through the shell and (2) assembly pathways. These models predict the biophysical properties surrounding the central pore in BMC-H shell subunits, which in turn dictate the efficiency of substrate diffusion. Meanwhile, simulations on BMC assembly demonstrate that assembly pathway is largely dictated kinetically by cargo interactions while final morphology is dependent on shell factors. Overall, these findings are contextualized within the wider experimental BMC literature and framed within the opportunities for carboxysome redesign for biomanufacturing and enhanced carbon fixation.
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Affiliation(s)
- Daniel S. Trettel
- Los Alamos National Laboratory, Bioscience Division, Microbial and Biome Sciences Group, Los Alamos, NM, United States
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6
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Evans SL, Al-Hazeem MMJ, Mann D, Smetacek N, Beavil AJ, Sun Y, Chen T, Dykes GF, Liu LN, Bergeron JRC. Single-particle cryo-EM analysis of the shell architecture and internal organization of an intact α-carboxysome. Structure 2023; 31:677-688.e4. [PMID: 37015227 PMCID: PMC10689251 DOI: 10.1016/j.str.2023.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 01/19/2023] [Accepted: 03/09/2023] [Indexed: 04/05/2023]
Abstract
Carboxysomes are proteinaceous bacterial microcompartments that sequester the key enzymes for carbon fixation in cyanobacteria and some proteobacteria. They consist of a virus-like icosahedral shell, encapsulating several enzymes, including ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO), responsible for the first step of the Calvin-Benson-Bassham cycle. Despite their significance in carbon fixation and great bioengineering potentials, the structural understanding of native carboxysomes is currently limited to low-resolution studies. Here, we report the characterization of a native α-carboxysome from a marine cyanobacterium by single-particle cryoelectron microscopy (cryo-EM). We have determined the structure of its RuBisCO enzyme, and obtained low-resolution maps of its icosahedral shell, and of its concentric interior organization. Using integrative modeling approaches, we have proposed a complete atomic model of an intact carboxysome, providing insight into its organization and assembly. This is critical for a better understanding of the carbon fixation mechanism and toward repurposing carboxysomes in synthetic biology for biotechnological applications.
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Affiliation(s)
- Sasha L Evans
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Monsour M J Al-Hazeem
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Daniel Mann
- Ernst-Ruska Centre 3, Forschungszentrum Jülich, Jülich, Germany
| | - Nicolas Smetacek
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, UK
| | - Andrew J Beavil
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Yaqi Sun
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Taiyu Chen
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Gregory F Dykes
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK; College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, Shandong, China.
| | - Julien R C Bergeron
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK; Department of Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, UK.
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7
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Aguiló-Nicolau P, Galmés J, Fais G, Capó-Bauçà S, Cao G, Iñiguez C. Singular adaptations in the carbon assimilation mechanism of the polyextremophile cyanobacterium Chroococcidiopsis thermalis. PHOTOSYNTHESIS RESEARCH 2023; 156:231-245. [PMID: 36941458 PMCID: PMC10154277 DOI: 10.1007/s11120-023-01008-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/16/2023] [Indexed: 05/03/2023]
Abstract
Cyanobacteria largely contribute to the biogeochemical carbon cycle fixing ~ 25% of the inorganic carbon on Earth. However, the carbon acquisition and assimilation mechanisms in Cyanobacteria are still underexplored regardless of being of great importance for shedding light on the origins of autotropism on Earth and providing new bioengineering tools for crop yield improvement. Here, we fully characterized these mechanisms from the polyextremophile cyanobacterium Chroococcidiopsis thermalis KOMAREK 1964/111 in comparison with the model cyanobacterial strain, Synechococcus sp. PCC6301. In particular, we analyzed the Rubisco kinetics along with the in vivo photosynthetic CO2 assimilation in response to external dissolved inorganic carbon, the effect of CO2 concentrating mechanism (CCM) inhibitors on net photosynthesis and the anatomical particularities of their carboxysomes when grown under either ambient air (0.04% CO2) or 2.5% CO2-enriched air. Our results show that Rubisco from C. thermalis possess the highest specificity factor and carboxylation efficiency ever reported for Cyanobacteria, which were accompanied by a highly effective CCM, concentrating CO2 around Rubisco more than 140-times the external CO2 levels, when grown under ambient CO2 conditions. Our findings provide new insights into the Rubisco kinetics of Cyanobacteria, suggesting that improved Sc/o values can still be compatible with a fast-catalyzing enzyme. The combination of Rubisco kinetics and CCM effectiveness in C. thermalis relative to other cyanobacterial species might indicate that the co-evolution between Rubisco and CCMs in Cyanobacteria is not as constrained as in other phylogenetic groups.
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Affiliation(s)
- Pere Aguiló-Nicolau
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears, INAGEA, Ctra. Valldemossa km. 7.5, 07122, Palma, Balearic Islands, Spain
| | - Jeroni Galmés
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears, INAGEA, Ctra. Valldemossa km. 7.5, 07122, Palma, Balearic Islands, Spain.
| | - Giacomo Fais
- Interdepartmental Centre of Environmental Science and Engineering, University of Cagliari, Via San Giorgio 12, 09124, Cagliari, Italy
| | - Sebastià Capó-Bauçà
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears, INAGEA, Ctra. Valldemossa km. 7.5, 07122, Palma, Balearic Islands, Spain
| | - Giacomo Cao
- Interdepartmental Centre of Environmental Science and Engineering, University of Cagliari, Via San Giorgio 12, 09124, Cagliari, Italy
- Department of Mechanical, Chemical and Materials Engineering, University of Cagliari, Via Marengo 2, 09123, Cagliari, Italy
| | - Concepción Iñiguez
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears, INAGEA, Ctra. Valldemossa km. 7.5, 07122, Palma, Balearic Islands, Spain
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8
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Nguyen ND, Pulsford SB, Hee WY, Rae BD, Rourke LM, Price GD, Long BM. Towards engineering a hybrid carboxysome. PHOTOSYNTHESIS RESEARCH 2023; 156:265-277. [PMID: 36892800 PMCID: PMC10154267 DOI: 10.1007/s11120-023-01009-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 02/17/2023] [Indexed: 05/03/2023]
Abstract
Carboxysomes are bacterial microcompartments, whose structural features enable the encapsulated Rubisco holoenzyme to operate in a high-CO2 environment. Consequently, Rubiscos housed within these compartments possess higher catalytic turnover rates relative to their plant counterparts. This particular enzymatic property has made the carboxysome, along with associated transporters, an attractive prospect to incorporate into plant chloroplasts to increase future crop yields. To date, two carboxysome types have been characterized, the α-type that has fewer shell components and the β-type that houses a faster Rubisco. While research is underway to construct a native carboxysome in planta, work investigating the internal arrangement of carboxysomes has identified conserved Rubisco amino acid residues between the two carboxysome types which could be engineered to produce a new, hybrid carboxysome. In theory, this hybrid carboxysome would benefit from the simpler α-carboxysome shell architecture while simultaneously exploiting the higher Rubisco turnover rates in β-carboxysomes. Here, we demonstrate in an Escherichia coli expression system, that the Thermosynechococcus elongatus Form IB Rubisco can be imperfectly incorporated into simplified Cyanobium α-carboxysome-like structures. While encapsulation of non-native cargo can be achieved, T. elongatus Form IB Rubisco does not interact with the Cyanobium carbonic anhydrase, a core requirement for proper carboxysome functionality. Together, these results suggest a way forward to hybrid carboxysome formation.
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Affiliation(s)
- Nghiem Dinh Nguyen
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Building 134, Linnaeus Way, Acton, ACT, 2601, Australia
| | - Sacha B Pulsford
- Australian Research Council Centre of Excellence in Synthetic Biology, Research School of Chemistry, The Australian National University, Building 46, Sullivan's Creek Road, Acton, ACT, 2601, Australia
| | - Wei Yi Hee
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Benjamin D Rae
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Building 134, Linnaeus Way, Acton, ACT, 2601, Australia
| | - Loraine M Rourke
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Building 134, Linnaeus Way, Acton, ACT, 2601, Australia
| | - G Dean Price
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Building 134, Linnaeus Way, Acton, ACT, 2601, Australia.
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia.
- Division of Plant Sciences, Research School of Biology, The Australian National University, Building 134, Linnaeus Way, Canberra, ACT, 2601, Australia.
| | - Benedict M Long
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, Building 134, Linnaeus Way, Acton, ACT, 2601, Australia
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
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9
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Ang WSL, How JA, How JB, Mueller-Cajar O. The stickers and spacers of Rubiscondensation: assembling the centrepiece of biophysical CO2-concentrating mechanisms. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:612-626. [PMID: 35903998 DOI: 10.1093/jxb/erac321] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
Aquatic autotrophs that fix carbon using ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) frequently expend metabolic energy to pump inorganic carbon towards the enzyme's active site. A central requirement of this strategy is the formation of highly concentrated Rubisco condensates (or Rubiscondensates) known as carboxysomes and pyrenoids, which have convergently evolved multiple times in prokaryotes and eukaryotes, respectively. Recent data indicate that these condensates form by the mechanism of liquid-liquid phase separation. This mechanism requires networks of weak multivalent interactions typically mediated by intrinsically disordered scaffold proteins. Here we comparatively review recent rapid developments that detail the determinants and precise interactions that underlie diverse Rubisco condensates. The burgeoning field of biomolecular condensates has few examples where liquid-liquid phase separation can be linked to clear phenotypic outcomes. When present, Rubisco condensates are essential for photosynthesis and growth, and they are thus emerging as powerful and tractable models to investigate the structure-function relationship of phase separation in biology.
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Affiliation(s)
- Warren Shou Leong Ang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Jian Ann How
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Jian Boon How
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
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10
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Abstract
Cyanobacteria rely on CO2-concentrating mechanisms (CCMs) to grow in today's atmosphere (0.04% CO2). These complex physiological adaptations require ≈15 genes to produce two types of protein complexes: inorganic carbon (Ci) transporters and 100+ nm carboxysome compartments that encapsulate rubisco with a carbonic anhydrase (CA) enzyme. Mutations disrupting any of these genes prohibit growth in ambient air. If any plausible ancestral form-i.e., lacking a single gene-cannot grow, how did the CCM evolve? Here, we test the hypothesis that evolution of the bacterial CCM was "catalyzed" by historically high CO2 levels that decreased over geologic time. Using an E. coli reconstitution of a bacterial CCM, we constructed strains lacking one or more CCM components and evaluated their growth across CO2 concentrations. We expected these experiments to demonstrate the importance of the carboxysome. Instead, we found that partial CCMs expressing CA or Ci uptake genes grew better than controls in intermediate CO2 levels (≈1%) and observed similar phenotypes in two autotrophic bacteria, Halothiobacillus neapolitanus and Cupriavidus necator. To understand how CA and Ci uptake improve growth, we model autotrophy as colimited by CO2 and HCO3-, as both are required to produce biomass. Our experiments and model delineated a viable trajectory for CCM evolution where decreasing atmospheric CO2 induces an HCO3- deficiency that is alleviated by acquisition of CA or Ci uptake, thereby enabling the emergence of a modern CCM. This work underscores the importance of considering physiology and environmental context when studying the evolution of biological complexity.
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11
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Cabello-Yeves PJ, Scanlan DJ, Callieri C, Picazo A, Schallenberg L, Huber P, Roda-Garcia JJ, Bartosiewicz M, Belykh OI, Tikhonova IV, Torcello-Requena A, De Prado PM, Millard AD, Camacho A, Rodriguez-Valera F, Puxty RJ. α-cyanobacteria possessing form IA RuBisCO globally dominate aquatic habitats. THE ISME JOURNAL 2022; 16:2421-2432. [PMID: 35851323 PMCID: PMC9477826 DOI: 10.1038/s41396-022-01282-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 06/21/2022] [Accepted: 06/28/2022] [Indexed: 11/24/2022]
Abstract
RuBisCO (ribulose 1,5-bisphosphate carboxylase/oxygenase) is one the most abundant enzymes on Earth. Virtually all food webs depend on its activity to supply fixed carbon. In aerobic environments, RuBisCO struggles to distinguish efficiently between CO2 and O2. To compensate, organisms have evolved convergent solutions to concentrate CO2 around the active site. The genetic engineering of such inorganic carbon concentrating mechanisms (CCMs) into plants could help facilitate future global food security for humankind. In bacteria, the carboxysome represents one such CCM component, of which two independent forms exist: α and β. Cyanobacteria are important players in the planet's carbon cycle and the vast majority of the phylum possess a β-carboxysome, including most cyanobacteria used as laboratory models. The exceptions are the exclusively marine Prochlorococcus and Synechococcus that numerically dominate open ocean systems. However, the reason why marine systems favor an α-form is currently unknown. Here, we report the genomes of 58 cyanobacteria, closely related to marine Synechococcus that were isolated from freshwater lakes across the globe. We find all these isolates possess α-carboxysomes accompanied by a form 1A RuBisCO. Moreover, we demonstrate α-cyanobacteria dominate freshwater lakes worldwide. Hence, the paradigm of a separation in carboxysome type across the salinity divide does not hold true, and instead the α-form dominates all aquatic systems. We thus question the relevance of β-cyanobacteria as models for aquatic systems at large and pose a hypothesis for the reason for the success of the α-form in nature.
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Affiliation(s)
- Pedro J Cabello-Yeves
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Alicante, Spain.
| | - David J Scanlan
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Cristiana Callieri
- National Research Council (CNR), Institute of Water Research (IRSA), Verbania, Italy
| | - Antonio Picazo
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, E-46980 Paterna, Valencia, Spain
| | | | - Paula Huber
- Instituto Tecnológico de Chascomús (INTECH), UNSAM-CONICET., Av. Intendente Marino Km 8,200, 7130, Chascomús, Buenos Aires, Argentina
- Instituto Nacional de Limnología (INALI), CONICET-UNL., Ciudad Universitaria-Paraje el Pozo s/n, 3000, Santa Fé, Argentina
| | - Juan J Roda-Garcia
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Alicante, Spain
| | - Maciej Bartosiewicz
- Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Olga I Belykh
- Limnological Institute, Russian Academy of Sciences, P.O. Box 278, 664033, Irkutsk, Russia
| | - Irina V Tikhonova
- Limnological Institute, Russian Academy of Sciences, P.O. Box 278, 664033, Irkutsk, Russia
| | | | | | - Andrew D Millard
- Department of Genetics and Genome Biology, University of Leicester, Leicester, LE1 7RH, UK
| | - Antonio Camacho
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, E-46980 Paterna, Valencia, Spain
| | - Francisco Rodriguez-Valera
- Evolutionary Genomics Group, Departamento de Producción Vegetal y Microbiología, Universidad Miguel Hernández, San Juan de Alicante, Alicante, Spain
- Moscow Institute of Physics and Technology, 141701, Dolgoprudny, Russia
| | - Richard J Puxty
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
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12
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Huang J, Jiang Q, Yang M, Dykes GF, Weetman SL, Xin W, He HL, Liu LN. Probing the Internal pH and Permeability of a Carboxysome Shell. Biomacromolecules 2022; 23:4339-4348. [PMID: 36054822 PMCID: PMC9554877 DOI: 10.1021/acs.biomac.2c00781] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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The carboxysome is a protein-based nanoscale organelle
in cyanobacteria
and many proteobacteria, which encapsulates the key CO2-fixing enzymes ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)
and carbonic anhydrase (CA) within a polyhedral protein shell. The
intrinsic self-assembly and architectural features of carboxysomes
and the semipermeability of the protein shell provide the foundation
for the accumulation of CO2 within carboxysomes and enhanced
carboxylation. Here, we develop an approach to determine the interior
pH conditions and inorganic carbon accumulation within an α-carboxysome
shell derived from a chemoautotrophic proteobacterium Halothiobacillus neapolitanus and evaluate the shell
permeability. By incorporating a pH reporter, pHluorin2, within empty
α-carboxysome shells produced in Escherichia
coli, we probe the interior pH of the protein shells
with and without CA. Our in vivo and in vitro results demonstrate a lower interior pH of α-carboxysome shells
than the cytoplasmic pH and buffer pH, as well as the modulation of
the interior pH in response to changes in external environments, indicating
the shell permeability to bicarbonate ions and protons. We further
determine the saturated HCO3– concentration
of 15 mM within α-carboxysome shells and show the CA-mediated
increase in the interior CO2 level. Uncovering the interior
physiochemical microenvironment of carboxysomes is crucial for understanding
the mechanisms underlying carboxysomal shell permeability and enhancement
of Rubisco carboxylation within carboxysomes. Such fundamental knowledge
may inform reprogramming carboxysomes to improve metabolism and recruit
foreign enzymes for enhanced catalytical performance.
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Affiliation(s)
- Jiafeng Huang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom.,School of Life Sciences, Central South University, Changsha 410017, China
| | - Qiuyao Jiang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom.,Department of Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, China
| | - Mengru Yang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| | - Gregory F Dykes
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| | - Samantha L Weetman
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom
| | - Wei Xin
- Department of Central Laboratory, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, China.,Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 271000, China
| | - Hai-Lun He
- School of Life Sciences, Central South University, Changsha 410017, China
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, United Kingdom.,College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266003, China
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13
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Abstract
Carboxysomes are anabolic bacterial microcompartments that play an essential role in carbon fixation in cyanobacteria and some chemoautotrophs. This self-assembling organelle encapsulates the key CO2-fixing enzymes, Rubisco, and carbonic anhydrase using a polyhedral protein shell that is constructed by hundreds of shell protein paralogs. The α-carboxysome from the chemoautotroph Halothiobacillus neapolitanus serves as a model system in fundamental studies and synthetic engineering of carboxysomes. In this study, we adopted a QconCAT-based quantitative mass spectrometry approach to determine the stoichiometric composition of native α-carboxysomes from H. neapolitanus. We further performed an in-depth comparison of the protein stoichiometry of native α-carboxysomes and their recombinant counterparts heterologously generated in Escherichia coli to evaluate the structural variability and remodeling of α-carboxysomes. Our results provide insight into the molecular principles that mediate carboxysome assembly, which may aid in rational design and reprogramming of carboxysomes in new contexts for biotechnological applications. IMPORTANCE A wide range of bacteria use special protein-based organelles, termed bacterial microcompartments, to encase enzymes and reactions to increase the efficiency of biological processes. As a model bacterial microcompartment, the carboxysome contains a protein shell filled with the primary carbon fixation enzyme Rubisco. The self-assembling organelle is generated by hundreds of proteins and plays important roles in converting carbon dioxide to sugar, a process known as carbon fixation. In this study, we uncovered the exact stoichiometry of all building components and the structural plasticity of the functional α-carboxysome, using newly developed quantitative mass spectrometry together with biochemistry, electron microscopy, and enzymatic assay. The study advances our understanding of the architecture and modularity of natural carboxysomes. The knowledge learned from natural carboxysomes will suggest feasible ways to produce functional carboxysomes in other hosts, such as crop plants, with the overwhelming goal of boosting cell metabolism and crop yields.
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14
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Li S, Li X, Ho SH. Microalgae as a solution of third world energy crisis for biofuels production from wastewater toward carbon neutrality: An updated review. CHEMOSPHERE 2022; 291:132863. [PMID: 34774903 DOI: 10.1016/j.chemosphere.2021.132863] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/21/2021] [Accepted: 11/08/2021] [Indexed: 06/13/2023]
Abstract
The boost of the greenhouse gases (GHGs, largely carbon dioxide - CO2) emissions owing to anthropogenic activity is one of the biggest global threats. Bio-CO2 emission reduction has received more and more attention as an environmentally sustainable approach. Microalgae are very popular in this regard because of excellent speed of growth, low costs of production, and resistance to extreme environments. Besides, most microalgae can undergo photosynthesis, where the CO2 and solar energy can be converted into sugar, and subsequently become biomass, providing a renewable and promising biofuel strategy with a few outstanding benefits. This review focuses on presenting CO2 sequestration by microalgae towards wastewater treatment and biodiesel production. First, the CO2 fixation mechanism by microalgae viz., sequestration and assimilation of CO2 in green microalgae as well as cyanobacteria were introduced. Besides, factors affecting CO2 sequestration in microalgae, containing microalgae species and cultivation conditions, such as light condition, photobioreactor, configuration, pH, CO2 concentration, temperature, and medium composition, were then comprehensively discussed. Special attention was given to the production of biodiesel as third-generation biofuel from various wastewater (CO2 biofixation), including processing steps of biodiesel production by microalgae, biodiesel production from wastewater, and improved methods. Furthermore, current life cycle assessment (LCA) and techno-economic analysis (TEA) used in biodiesel production were discussed. Finally, the research challenges and specific prospects were considered. Taken together, this review provides useful and updated information to facilitate the development of microalgal "green chemistry" and "environmental sustainability".
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Affiliation(s)
- Shengnan Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Xue Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Shih-Hsin Ho
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China.
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15
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Chen T, Fang Y, Jiang Q, Dykes GF, Lin Y, Price GD, Long BM, Liu LN. Incorporation of Functional Rubisco Activases into Engineered Carboxysomes to Enhance Carbon Fixation. ACS Synth Biol 2022; 11:154-161. [PMID: 34664944 PMCID: PMC8787814 DOI: 10.1021/acssynbio.1c00311] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
The carboxysome is
a versatile paradigm of prokaryotic organelles
and is a proteinaceous self-assembling microcompartment that plays
essential roles in carbon fixation in all cyanobacteria and some chemoautotrophs.
The carboxysome encapsulates
the central CO2-fixing enzyme, ribulose-1,5-bisphosphate
carboxylase/oxygenase (Rubisco), using a polyhedral protein shell
that is selectively permeable to specific metabolites in favor of
Rubisco carboxylation. There is tremendous interest in repurposing
carboxysomes to boost carbon fixation in heterologous organisms. Here,
we develop the design and engineering of α-carboxysomes by coexpressing
the Rubisco activase components CbbQ and CbbO with α-carboxysomes
in Escherichia coli. Our results show
that CbbQ and CbbO could assemble into the reconstituted α-carboxysome
as intrinsic components. Incorporation of both CbbQ and CbbO within
the carboxysome promotes activation of Rubisco and enhances the CO2-fixation activities of recombinant carboxysomes. We also
show that the structural composition of these carboxysomes could be
modified in different expression systems, representing the plasticity
of the carboxysome architecture. In translational terms, our study
informs strategies for engineering and modulating carboxysomes in
diverse biotechnological applications.
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Affiliation(s)
- Taiyu Chen
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Yi Fang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K
| | - Qiuyao Jiang
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K
| | - Gregory F. Dykes
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K
| | - Yongjun Lin
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - G. Dean Price
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory 2601, Australia
| | - Benedict M. Long
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, 134 Linnaeus Way, Acton, Australian Capital Territory 2601, Australia
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, U.K
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao 266003, China
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16
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Iñiguez C, Aguiló-Nicolau P, Galmés J. Improving photosynthesis through the enhancement of Rubisco carboxylation capacity. Biochem Soc Trans 2021; 49:2007-2019. [PMID: 34623388 DOI: 10.1042/bst20201056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/07/2021] [Accepted: 09/09/2021] [Indexed: 12/14/2022]
Abstract
Rising human population, along with the reduction in arable land and the impacts of global change, sets out the need for continuously improving agricultural resource use efficiency and crop yield (CY). Bioengineering approaches for photosynthesis optimization have largely demonstrated the potential for enhancing CY. This review is focused on the improvement of Rubisco functioning, which catalyzes the rate-limiting step of CO2 fixation required for plant growth, but also catalyzes the ribulose-bisphosphate oxygenation initiating the carbon and energy wasteful photorespiration pathway. Rubisco carboxylation capacity can be enhanced by engineering the Rubisco large and/or small subunit genes to improve its catalytic traits, or by engineering the mechanisms that provide enhanced Rubisco expression, activation and/or elevated [CO2] around the active sites to favor carboxylation over oxygenation. Recent advances have been made in the expression, assembly and activation of foreign (either natural or mutant) faster and/or more CO2-specific Rubisco versions. Some components of CO2 concentrating mechanisms (CCMs) from bacteria, algae and C4 plants has been successfully expressed in tobacco and rice. Still, none of the transformed plant lines expressing foreign Rubisco versions and/or simplified CCM components were able to grow faster than wild type plants under present atmospheric [CO2] and optimum conditions. However, the results obtained up to date suggest that it might be achievable in the near future. In addition, photosynthetic and yield improvements have already been observed when manipulating Rubisco quantity and activation degree in crops. Therefore, engineering Rubisco carboxylation capacity continues being a promising target for the improvement in photosynthesis and yield.
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Affiliation(s)
- Concepción Iñiguez
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
- Department of Ecology, Faculty of Sciences, University of Málaga, Málaga, Spain
| | - Pere Aguiló-Nicolau
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
| | - Jeroni Galmés
- Research Group on Plant Biology Under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
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17
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Huffine CA, Wheeler LC, Wing B, Cameron JC. Computational modeling and evolutionary implications of biochemical reactions in bacterial microcompartments. Curr Opin Microbiol 2021; 65:15-23. [PMID: 34717259 DOI: 10.1016/j.mib.2021.10.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 10/02/2021] [Indexed: 11/19/2022]
Abstract
Bacterial microcompartments (BMCs) are protein-encapsulated compartments found across at least 23 bacterial phyla. BMCs contain a variety of metabolic processes that share the commonality of toxic or volatile intermediates, oxygen-sensitive enzymes and cofactors, or increased substrate concentration for magnified reaction rates. These compartmentalized reactions have been computationally modeled to explore the encapsulated dynamics, ask evolutionary-based questions, and develop a more systematic understanding required for the engineering of novel BMCs. Many crucial aspects of these systems remain unknown or unmeasured, such as substrate permeabilities across the protein shell, feasibility of pH gradients, and transport rates of associated substrates into the cell. This review explores existing BMC models, dominated in the literature by cyanobacterial carboxysomes, and highlights potentially important areas for exploration.
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Affiliation(s)
- Clair A Huffine
- BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Avenue, Boulder, CO 80309, USA; Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA; Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA; Interdisciplinary Quantitative Biology Program (IQ Biology), BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA
| | - Lucas C Wheeler
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Boswell Wing
- Department of Geological Sciences, Boulder, CO 80309, USA
| | - Jeffrey C Cameron
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA; Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA; National Renewable Energy Laboratory, Golden, CO 80401, USA.
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18
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Abstract
Bacterial microcompartments (BMCs) confine a diverse array of metabolic reactions within a selectively permeable protein shell, allowing for specialized biochemistry that would be less efficient or altogether impossible without compartmentalization. BMCs play critical roles in carbon fixation, carbon source utilization, and pathogenesis. Despite their prevalence and importance in bacterial metabolism, little is known about BMC “homeostasis,” a term we use here to encompass BMC assembly, composition, size, copy-number, maintenance, turnover, positioning, and ultimately, function in the cell. The carbon-fixing carboxysome is one of the most well-studied BMCs with regard to mechanisms of self-assembly and subcellular organization. In this minireview, we focus on the only known BMC positioning system to date—the maintenance of carboxysome distribution (Mcd) system, which spatially organizes carboxysomes. We describe the two-component McdAB system and its proposed diffusion-ratchet mechanism for carboxysome positioning. We then discuss the prevalence of McdAB systems among carboxysome-containing bacteria and highlight recent evidence suggesting how liquid-liquid phase separation (LLPS) may play critical roles in carboxysome homeostasis. We end with an outline of future work on the carboxysome distribution system and a perspective on how other BMCs may be spatially regulated. We anticipate that a deeper understanding of BMC organization, including nontraditional homeostasis mechanisms involving LLPS and ATP-driven organization, is on the horizon.
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19
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Rubisco proton production can drive the elevation of CO 2 within condensates and carboxysomes. Proc Natl Acad Sci U S A 2021; 118:2014406118. [PMID: 33931502 PMCID: PMC8106323 DOI: 10.1073/pnas.2014406118] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Membraneless organelles containing the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) are a common feature of organisms utilizing CO2 concentrating mechanisms to enhance photosynthetic carbon acquisition. In cyanobacteria and proteobacteria, the Rubisco condensate is encapsulated in a proteinaceous shell, collectively termed a carboxysome, while some algae and hornworts have evolved Rubisco condensates known as pyrenoids. In both cases, CO2 fixation is enhanced compared with the free enzyme. Previous mathematical models have attributed the improved function of carboxysomes to the generation of elevated CO2 within the organelle via a colocalized carbonic anhydrase (CA) and inwardly diffusing HCO3 -, which have accumulated in the cytoplasm via dedicated transporters. Here, we present a concept in which we consider the net of two protons produced in every Rubisco carboxylase reaction. We evaluate this in a reaction-diffusion compartment model to investigate functional advantages these protons may provide Rubisco condensates and carboxysomes, prior to the evolution of HCO3 - accumulation. Our model highlights that diffusional resistance to reaction species within a condensate allows Rubisco-derived protons to drive the conversion of HCO3 - to CO2 via colocalized CA, enhancing both condensate [CO2] and Rubisco rate. Protonation of Rubisco substrate (RuBP) and product (phosphoglycerate) plays an important role in modulating internal pH and CO2 generation. Application of the model to putative evolutionary ancestors, prior to contemporary cellular HCO3 - accumulation, revealed photosynthetic enhancements along a logical sequence of advancements, via Rubisco condensation, to fully formed carboxysomes. Our model suggests that evolution of Rubisco condensation could be favored under low CO2 and low light environments.
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20
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MacCready JS, Basalla JL, Vecchiarelli AG. Origin and Evolution of Carboxysome Positioning Systems in Cyanobacteria. Mol Biol Evol 2021; 37:1434-1451. [PMID: 31899489 PMCID: PMC7182216 DOI: 10.1093/molbev/msz308] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Carboxysomes are protein-based organelles that are essential for allowing cyanobacteria to fix CO2. Previously, we identified a two-component system, McdAB, responsible for equidistantly positioning carboxysomes in the model cyanobacterium Synechococcus elongatus PCC 7942 (MacCready JS, Hakim P, Young EJ, Hu L, Liu J, Osteryoung KW, Vecchiarelli AG, Ducat DC. 2018. Protein gradients on the nucleoid position the carbon-fixing organelles of cyanobacteria. eLife 7:pii:e39723). McdA, a ParA-type ATPase, nonspecifically binds the nucleoid in the presence of ATP. McdB, a novel factor that directly binds carboxysomes, displaces McdA from the nucleoid. Removal of McdA from the nucleoid in the vicinity of carboxysomes by McdB causes a global break in McdA symmetry, and carboxysome motion occurs via a Brownian-ratchet-based mechanism toward the highest concentration of McdA. Despite the importance for cyanobacteria to properly position their carboxysomes, whether the McdAB system is widespread among cyanobacteria remains an open question. Here, we show that the McdAB system is widespread among β-cyanobacteria, often clustering with carboxysome-related components, and is absent in α-cyanobacteria. Moreover, we show that two distinct McdAB systems exist in β-cyanobacteria, with Type 2 systems being the most ancestral and abundant, and Type 1 systems, like that of S. elongatus, possibly being acquired more recently. Lastly, all McdB proteins share the sequence signatures of a protein capable of undergoing liquid–liquid phase separation. Indeed, we find that representatives of both McdB types undergo liquid–liquid phase separation in vitro, the first example of a ParA-type ATPase partner protein to exhibit this behavior. Our results have broader implications for understanding carboxysome evolution, biogenesis, homeostasis, and positioning in cyanobacteria.
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Affiliation(s)
- Joshua S MacCready
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Joseph L Basalla
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
| | - Anthony G Vecchiarelli
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI
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21
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Hurley SJ, Wing BA, Jasper CE, Hill NC, Cameron JC. Carbon isotope evidence for the global physiology of Proterozoic cyanobacteria. SCIENCE ADVANCES 2021; 7:7/2/eabc8998. [PMID: 33893090 PMCID: PMC7787495 DOI: 10.1126/sciadv.abc8998] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 11/11/2020] [Indexed: 05/03/2023]
Abstract
Ancestral cyanobacteria are assumed to be prominent primary producers after the Great Oxidation Event [≈2.4 to 2.0 billion years (Ga) ago], but carbon isotope fractionation by extant marine cyanobacteria (α-cyanobacteria) is inconsistent with isotopic records of carbon fixation by primary producers in the mid-Proterozoic eon (1.8 to 1.0 Ga ago). To resolve this disagreement, we quantified carbon isotope fractionation by a wild-type planktic β-cyanobacterium (Synechococcus sp. PCC 7002), an engineered Proterozoic analog lacking a CO2-concentrating mechanism, and cyanobacterial mats. At mid-Proterozoic pH and pCO2 values, carbon isotope fractionation by the wild-type β-cyanobacterium is fully consistent with the Proterozoic carbon isotope record, suggesting that cyanobacteria with CO2-concentrating mechanisms were apparently the major primary producers in the pelagic Proterozoic ocean, despite atmospheric CO2 levels up to 100 times modern. The selectively permeable microcompartments central to cyanobacterial CO2-concentrating mechanisms ("carboxysomes") likely emerged to shield rubisco from O2 during the Great Oxidation Event.
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Affiliation(s)
- Sarah J Hurley
- Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80302, USA.
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA
| | - Boswell A Wing
- Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80302, USA
| | - Claire E Jasper
- Department of Geological Sciences, University of Colorado Boulder, Boulder, CO 80302, USA
| | - Nicholas C Hill
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Jeffrey C Cameron
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, CO 80309, USA.
- Department of Biochemistry, University of Colorado, Boulder, CO 80309, USA
- National Renewable Energy Laboratory, Golden, CO 80401, USA
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22
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Raven JA, Suggett DJ, Giordano M. Inorganic carbon concentrating mechanisms in free-living and symbiotic dinoflagellates and chromerids. JOURNAL OF PHYCOLOGY 2020; 56:1377-1397. [PMID: 32654150 DOI: 10.1111/jpy.13050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
Photosynthetic dinoflagellates are ecologically and biogeochemically important in marine and freshwater environments. However, surprisingly little is known of how this group acquires inorganic carbon or how these diverse processes evolved. Consequently, how CO2 availability ultimately influences the success of dinoflagellates over space and time remains poorly resolved compared to other microalgal groups. Here we review the evidence. Photosynthetic core dinoflagellates have a Form II RuBisCO (replaced by Form IB or Form ID in derived dinoflagellates). The in vitro kinetics of the Form II RuBisCO from dinoflagellates are largely unknown, but dinoflagellates with Form II (and other) RuBisCOs have inorganic carbon concentrating mechanisms (CCMs), as indicated by in vivo internal inorganic C accumulation and affinity for external inorganic C. However, the location of the membrane(s) at which the essential active transport component(s) of the CCM occur(s) is (are) unresolved; isolation and characterization of functionally competent chloroplasts would help in this respect. Endosymbiotic Symbiodiniaceae (in Foraminifera, Acantharia, Radiolaria, Ciliata, Porifera, Acoela, Cnidaria, and Mollusca) obtain inorganic C by transport from seawater through host tissue. In corals this transport apparently provides an inorganic C concentration around the photobiont that obviates the need for photobiont CCM. This is not the case for tridacnid bivalves, medusae, or, possibly, Foraminifera. Overcoming these long-standing knowledge gaps relies on technical advances (e.g., the in vitro kinetics of Form II RuBisCO) that can functionally track the fate of inorganic C forms.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, UK
- Faculty of Science, University of Technology, Sydney, Climate Change Cluster, Ultimo, Sydney, New South Wales, 2007, Australia
- School of Biological Science, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - David J Suggett
- Faculty of Science, University of Technology, Sydney, Climate Change Cluster, Ultimo, Sydney, New South Wales, 2007, Australia
| | - Mario Giordano
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131, Ancona, Italy
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Algatech, Trebon, Czech Republic
- National Research Council, Institute of Marine Science ISMAR, Venezia, Italy
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23
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Burlacot A, Burlacot F, Li-Beisson Y, Peltier G. Membrane Inlet Mass Spectrometry: A Powerful Tool for Algal Research. FRONTIERS IN PLANT SCIENCE 2020; 11:1302. [PMID: 33013952 PMCID: PMC7500362 DOI: 10.3389/fpls.2020.01302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/11/2020] [Indexed: 05/15/2023]
Abstract
Since the first great oxygenation event, photosynthetic microorganisms have continuously shaped the Earth's atmosphere. Studying biological mechanisms involved in the interaction between microalgae and cyanobacteria with the Earth's atmosphere requires the monitoring of gas exchange. Membrane inlet mass spectrometry (MIMS) has been developed in the early 1960s to study gas exchange mechanisms of photosynthetic cells. It has since played an important role in investigating various cellular processes that involve gaseous compounds (O2, CO2, NO, or H2) and in characterizing enzymatic activities in vitro or in vivo. With the development of affordable mass spectrometers, MIMS is gaining wide popularity and is now used by an increasing number of laboratories. However, it still requires an important theory and practical considerations to be used. Here, we provide a practical guide describing the current technical basis of a MIMS setup and the general principles of data processing. We further review how MIMS can be used to study various aspects of algal research and discuss how MIMS will be useful in addressing future scientific challenges.
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24
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Laughlin TG, Savage DF, Davies KM. Recent advances on the structure and function of NDH-1: The complex I of oxygenic photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148254. [PMID: 32645407 DOI: 10.1016/j.bbabio.2020.148254] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/07/2020] [Accepted: 06/22/2020] [Indexed: 12/29/2022]
Abstract
Photosynthetic NADH dehydrogenase-like complex type-1 (a.k.a, NDH, NDH-1, or NDH-1L) is a multi-subunit, membrane-bound oxidoreductase related to the respiratory complex I. Although originally discovered 30 years ago, a number of recent advances have revealed significant insight into the structure, function, and physiology of NDH-1. Here, we highlight progress in understanding the function of NDH-1 in the photosynthetic light reactions of both cyanobacteria and chloroplasts from biochemical and structural perspectives. We further examine the cyanobacterial-specific forms of NDH-1 that possess vectorial carbonic anhydrase (vCA) activity and function in the CO2-concentrating mechanism (CCM). We compare the proposed mechanism for the cyanobacterial NDH-1 vCA-activity to that of the DAB (DABs accumulates bicarbonate) complex, another putative vCA. Finally, we discuss both new and remaining questions pertaining to the mechanisms of NDH-1 complexes in light of these recent advances.
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Affiliation(s)
- Thomas G Laughlin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA; Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - David F Savage
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Karen M Davies
- Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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25
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Oltrogge LM, Chaijarasphong T, Chen AW, Bolin ER, Marqusee S, Savage DF. Multivalent interactions between CsoS2 and Rubisco mediate α-carboxysome formation. Nat Struct Mol Biol 2020; 27:281-287. [PMID: 32123388 PMCID: PMC7337323 DOI: 10.1038/s41594-020-0387-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 01/24/2020] [Indexed: 11/23/2022]
Abstract
Carboxysomes are bacterial microcompartments that function as the centerpiece of the bacterial CO2-concentrating mechanism by facilitating high CO2 concentrations near the carboxylase Rubisco. The carboxysome self-assembles from thousands of individual proteins into icosahedral-like particles with a dense enzyme cargo encapsulated within a proteinaceous shell. In the case of the α-carboxysome, there is little molecular insight into protein-protein interactions that drive the assembly process. Here, studies on the α-carboxysome from Halothiobacillus neapolitanus demonstrate that Rubisco interacts with the N-terminus of CsoS2, a multivalent, intrinsically disordered protein. X-ray structural analysis of the CsoS2 interaction motif bound to Rubisco reveals a series of conserved electrostatic interactions that are only made with properly assembled hexadecameric Rubisco. Although biophysical measurements indicate this single interaction is weak, its implicit multivalency induces high-affinity binding through avidity. Taken together, our results indicate CsoS2 acts as an interaction hub to condense Rubisco and enable efficient α-carboxysome formation.
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Affiliation(s)
- Luke M Oltrogge
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA
| | - Thawatchai Chaijarasphong
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.,Department of Biotechnology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Allen W Chen
- Department of Chemistry, University of California Berkeley, Berkeley, CA, USA
| | - Eric R Bolin
- Biophysics Graduate Program, University of California Berkeley, Berkeley, CA, USA.,California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA, USA
| | - Susan Marqusee
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.,Department of Chemistry, University of California Berkeley, Berkeley, CA, USA.,California Institute for Quantitative Biosciences, University of California Berkeley, Berkeley, CA, USA
| | - David F Savage
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA, USA.
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26
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Iñiguez C, Capó-Bauçà S, Niinemets Ü, Stoll H, Aguiló-Nicolau P, Galmés J. Evolutionary trends in RuBisCO kinetics and their co-evolution with CO 2 concentrating mechanisms. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:897-918. [PMID: 31820505 DOI: 10.1111/tpj.14643] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 11/15/2019] [Accepted: 11/27/2019] [Indexed: 05/19/2023]
Abstract
RuBisCO-catalyzed CO2 fixation is the main source of organic carbon in the biosphere. This enzyme is present in all domains of life in different forms (III, II, and I) and its origin goes back to 3500 Mya, when the atmosphere was anoxygenic. However, the RuBisCO active site also catalyzes oxygenation of ribulose 1,5-bisphosphate, therefore, the development of oxygenic photosynthesis and the subsequent oxygen-rich atmosphere promoted the appearance of CO2 concentrating mechanisms (CCMs) and/or the evolution of a more CO2 -specific RuBisCO enzyme. The wide variability in RuBisCO kinetic traits of extant organisms reveals a history of adaptation to the prevailing CO2 /O2 concentrations and the thermal environment throughout evolution. Notable differences in the kinetic parameters are found among the different forms of RuBisCO, but the differences are also associated with the presence and type of CCMs within each form, indicative of co-evolution of RuBisCO and CCMs. Trade-offs between RuBisCO kinetic traits vary among the RuBisCO forms and also among phylogenetic groups within the same form. These results suggest that different biochemical and structural constraints have operated on each type of RuBisCO during evolution, probably reflecting different environmental selective pressures. In a similar way, variations in carbon isotopic fractionation of the enzyme point to significant differences in its relationship to the CO2 specificity among different RuBisCO forms. A deeper knowledge of the natural variability of RuBisCO catalytic traits and the chemical mechanism of RuBisCO carboxylation and oxygenation reactions raises the possibility of finding unrevealed landscapes in RuBisCO evolution.
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Affiliation(s)
- Concepción Iñiguez
- Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
| | - Sebastià Capó-Bauçà
- Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
| | - Ülo Niinemets
- Chair of Crop Science and Plant Biology, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, 51006, Tartu, Estonia
- Estonian Academy of Sciences, Kohtu 6, 10130, Tallinn, Estonia
| | - Heather Stoll
- Department of Earth Sciences, ETH Zürich, Sonnegstrasse 5, 8092, Zürich, Switzerland
| | - Pere Aguiló-Nicolau
- Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
| | - Jeroni Galmés
- Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears-INAGEA, Palma, Balearic Islands, Spain
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27
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Desmarais JJ, Flamholz AI, Blikstad C, Dugan EJ, Laughlin TG, Oltrogge LM, Chen AW, Wetmore K, Diamond S, Wang JY, Savage DF. DABs are inorganic carbon pumps found throughout prokaryotic phyla. Nat Microbiol 2019; 4:2204-2215. [PMID: 31406332 PMCID: PMC10184468 DOI: 10.1038/s41564-019-0520-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 06/13/2019] [Accepted: 06/20/2019] [Indexed: 12/30/2022]
Abstract
Bacterial autotrophs often rely on CO2 concentrating mechanisms (CCMs) to assimilate carbon. Although many CCM proteins have been identified, a systematic screen of the components of CCMs is lacking. Here, we performed a genome-wide barcoded transposon screen to identify essential and CCM-related genes in the γ-proteobacterium Halothiobacillus neapolitanus. Screening revealed that the CCM comprises at least 17 and probably no more than 25 genes, most of which are encoded in 3 operons. Two of these operons (DAB1 and DAB2) contain a two-gene locus that encodes a domain of unknown function (Pfam: PF10070) and a putative cation transporter (Pfam: PF00361). Physiological and biochemical assays demonstrated that these proteins-which we name DabA and DabB, for DABs accumulate bicarbonate-assemble into a heterodimeric complex, which contains a putative β-carbonic anhydrase-like active site and functions as an energy-coupled inorganic carbon (Ci) pump. Interestingly, DAB operons are found in a diverse range of bacteria and archaea. We demonstrate that functional DABs are present in the human pathogens Bacillus anthracis and Vibrio cholerae. On the basis of these results, we propose that DABs constitute a class of energized Ci pumps and play a critical role in the metabolism of Ci throughout prokaryotic phyla.
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Affiliation(s)
- John J Desmarais
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Avi I Flamholz
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Cecilia Blikstad
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Eli J Dugan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Thomas G Laughlin
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Luke M Oltrogge
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Allen W Chen
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - Kelly Wetmore
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Spencer Diamond
- Department of Earth and Planetary Science, University of California, Berkeley, CA, USA
| | - Joy Y Wang
- Department of Chemistry, University of California, Berkeley, CA, USA
| | - David F Savage
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA.
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28
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Reaction of ribulose biphosphate carboxylase/oxygenase assembled on a DNA scaffold. Bioorg Med Chem 2019; 27:115120. [DOI: 10.1016/j.bmc.2019.115120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/10/2019] [Accepted: 09/12/2019] [Indexed: 12/30/2022]
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29
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Sun Y, Wollman AJM, Huang F, Leake MC, Liu LN. Single-Organelle Quantification Reveals Stoichiometric and Structural Variability of Carboxysomes Dependent on the Environment. THE PLANT CELL 2019; 31:1648-1664. [PMID: 31048338 PMCID: PMC6635877 DOI: 10.1105/tpc.18.00787] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 05/02/2019] [Indexed: 05/25/2023]
Abstract
The carboxysome is a complex, proteinaceous organelle that plays essential roles in carbon assimilation in cyanobacteria and chemoautotrophs. It comprises hundreds of protein homologs that self-assemble in space to form an icosahedral structure. Despite its significance in enhancing CO2 fixation and potentials in bioengineering applications, the formation of carboxysomes and their structural composition, stoichiometry, and adaptation to cope with environmental changes remain unclear. Here we use live-cell single-molecule fluorescence microscopy, coupled with confocal and electron microscopy, to decipher the absolute protein stoichiometry and organizational variability of single β-carboxysomes in the model cyanobacterium Synechococcus elongatus PCC7942. We determine the physiological abundance of individual building blocks within the icosahedral carboxysome. We further find that the protein stoichiometry, diameter, localization, and mobility patterns of carboxysomes in cells depend sensitively on the microenvironmental levels of CO2 and light intensity during cell growth, revealing cellular strategies of dynamic regulation. These findings, also applicable to other bacterial microcompartments and macromolecular self-assembling systems, advance our knowledge of the principles that mediate carboxysome formation and structural modulation. It will empower rational design and construction of entire functional metabolic factories in heterologous organisms, for example crop plants, to boost photosynthesis and agricultural productivity.
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Affiliation(s)
- Yaqi Sun
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Adam J M Wollman
- Biological Physical Sciences Institute, Departments of Physics and Biology, University of York, YO10 5DD, United Kingdom
| | - Fang Huang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Mark C Leake
- Biological Physical Sciences Institute, Departments of Physics and Biology, University of York, YO10 5DD, United Kingdom
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
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30
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Abstract
Rubisco is often claimed to be the most abundant protein on Earth, yet the quantitative evidence to support the estimate of its global mass are scarce. Here we provide a robust and detailed estimate of the global mass of Rubisco, which is an order of magnitude larger than previous estimates. We use this estimate to derive the time-average rate of terrestrial and marine Rubisco and show that they are, respectively, 100-fold and sevenfold lower than the in vitro measured kcat of Rubisco at 25 °C. Photosynthetic carbon assimilation enables energy storage in the living world and produces most of the biomass in the biosphere. Rubisco (d-ribulose 1,5-bisphosphate carboxylase/oxygenase) is responsible for the vast majority of global carbon fixation and has been claimed to be the most abundant protein on Earth. Here we provide an updated and rigorous estimate for the total mass of Rubisco on Earth, concluding it is ≈0.7 Gt, more than an order of magnitude higher than previously thought. We find that >90% of Rubisco enzymes are found in the ≈2 × 1014 m2 of leaves of terrestrial plants, and that Rubisco accounts for ≈3% of the total mass of leaves, which we estimate at ≈30 Gt dry weight. We use our estimate for the total mass of Rubisco to derive the effective time-averaged catalytic rate of Rubisco of ≈0.03 s−1 on land and ≈0.6 s−1 in the ocean. Compared with the maximal catalytic rate observed in vitro at 25 °C, the effective rate in the wild is ≈100-fold slower on land and sevenfold slower in the ocean. The lower ambient temperature, and Rubisco not working at night, can explain most of the difference from laboratory conditions in the ocean but not on land, where quantification of many more factors on a global scale is needed. Our analysis helps sharpen the dramatic difference between laboratory and wild environments and between the terrestrial and marine environments.
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31
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Scott KM, Leonard JM, Boden R, Chaput D, Dennison C, Haller E, Harmer TL, Anderson A, Arnold T, Budenstein S, Brown R, Brand J, Byers J, Calarco J, Campbell T, Carter E, Chase M, Cole M, Dwyer D, Grasham J, Hanni C, Hazle A, Johnson C, Johnson R, Kirby B, Lewis K, Neumann B, Nguyen T, Nino Charari J, Morakinyo O, Olsson B, Roundtree S, Skjerve E, Ubaldini A, Whittaker R. Diversity in CO 2-Concentrating Mechanisms among Chemolithoautotrophs from the Genera Hydrogenovibrio, Thiomicrorhabdus, and Thiomicrospira, Ubiquitous in Sulfidic Habitats Worldwide. Appl Environ Microbiol 2019; 85:e02096-18. [PMID: 30446552 PMCID: PMC6344615 DOI: 10.1128/aem.02096-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/05/2018] [Indexed: 12/30/2022] Open
Abstract
Members of the genera Hydrogenovibrio, Thiomicrospira, and Thiomicrorhabdus fix carbon at hydrothermal vents, coastal sediments, hypersaline lakes, and other sulfidic habitats. The genome sequences of these ubiquitous and prolific chemolithoautotrophs suggest a surprising diversity of mechanisms for the uptake and fixation of dissolved inorganic carbon (DIC); these mechanisms are verified here. Carboxysomes are apparent in the transmission electron micrographs of most of these organisms but are lacking in Thiomicrorhabdus sp. strain Milos-T2 and Thiomicrorhabdus arctica, and the inability of Thiomicrorhabdus sp. strain Milos-T2 to grow under low-DIC conditions is consistent with the absence of carboxysome loci in its genome. For the remaining organisms, genes encoding potential DIC transporters from four evolutionarily distinct families (Tcr_0853 and Tcr_0854, Chr, SbtA, and SulP) are located downstream of carboxysome loci. Transporter genes collocated with carboxysome loci, as well as some homologs located elsewhere on the chromosomes, had elevated transcript levels under low-DIC conditions, as assayed by reverse transcription-quantitative PCR (qRT-PCR). DIC uptake was measureable via silicone oil centrifugation when a representative of each of the four types of transporter was expressed in Escherichia coli The expression of these genes in the carbonic anhydrase-deficient E. coli strain EDCM636 enabled it to grow under low-DIC conditions, a result consistent with DIC transport by these proteins. The results from this study expand the range of DIC transporters within the SbtA and SulP transporter families, verify DIC uptake by transporters encoded by Tcr_0853 and Tcr_0854 and their homologs, and introduce DIC as a potential substrate for transporters from the Chr family.IMPORTANCE Autotrophic organisms take up and fix DIC, introducing carbon into the biological portion of the global carbon cycle. The mechanisms for DIC uptake and fixation by autotrophic Bacteria and Archaea are likely to be diverse but have been well characterized only for "Cyanobacteria" Based on genome sequences, members of the genera Hydrogenovibrio, Thiomicrospira, and Thiomicrorhabdus have a variety of mechanisms for DIC uptake and fixation. We verified that most of these organisms are capable of growing under low-DIC conditions, when they upregulate carboxysome loci and transporter genes collocated with these loci on their chromosomes. When these genes, which fall into four evolutionarily independent families of transporters, are expressed in E. coli, DIC transport is detected. This expansion in known DIC transporters across four families, from organisms from a variety of environments, provides insight into the ecophysiology of autotrophs, as well as a toolkit for engineering microorganisms for carbon-neutral biochemistries of industrial importance.
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Affiliation(s)
- Kathleen M Scott
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Juliana M Leonard
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Rich Boden
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, United Kingdom
- Sustainable Earth Institute, University of Plymouth, Plymouth, United Kingdom
| | - Dale Chaput
- Proteomics and Mass Spectrometry Facility, University of South Florida, Tampa, Florida, USA
| | - Clare Dennison
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Edward Haller
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Tara L Harmer
- Biology Program, Stockton University, Galloway, New Jersey, USA
| | - Abigail Anderson
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Tiffany Arnold
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Samantha Budenstein
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Rikki Brown
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Juan Brand
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Jacob Byers
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Jeanette Calarco
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Timothy Campbell
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Erica Carter
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Max Chase
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Montana Cole
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Deandra Dwyer
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Jonathon Grasham
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Christopher Hanni
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Ashlee Hazle
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Cody Johnson
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Ryan Johnson
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Brandi Kirby
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Katherine Lewis
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Brianna Neumann
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Tracy Nguyen
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | | | - Ooreoluwa Morakinyo
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Bengt Olsson
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Shanetta Roundtree
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Emily Skjerve
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Ashley Ubaldini
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
| | - Robert Whittaker
- Department of Integrative Biology, University of South Florida, Tampa, Florida, USA
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32
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Mahinthichaichan P, Morris DM, Wang Y, Jensen GJ, Tajkhorshid E. Selective Permeability of Carboxysome Shell Pores to Anionic Molecules. J Phys Chem B 2018; 122:9110-9118. [PMID: 30193460 PMCID: PMC6311388 DOI: 10.1021/acs.jpcb.8b06822] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Carboxysomes are closed polyhedral cellular microcompartments that increase the efficiency of carbon fixation in autotrophic bacteria. Carboxysome shells consist of small proteins that form hexameric units with semipermeable central pores containing binding sites for anions. This feature is thought to selectively allow access to RuBisCO enzymes inside the carboxysome by HCO3- (the dominant form of CO2 in the aqueous solution at pH 7.4) but not O2, which leads to a nonproductive reaction. To test this hypothesis, here we use molecular dynamics simulations to characterize the energetics and permeability of CO2, O2, and HCO3- through the central pores of two different shell proteins, namely, CsoS1A of α-carboxysome and CcmK4 of β-carboxysome shells. We find that the central pores are in fact selectively permeable to anions such as HCO3-, as predicted by the model.
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Affiliation(s)
- Paween Mahinthichaichan
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801-3028 , United States
| | - Dylan M Morris
- Division of Biology and Biological Engineering , California Institute of Technology , Pasadena , California 91125 , United States
| | - Yi Wang
- Department of Physics , The Chinese University of Hong Kong , Shatin , New Territories, Hong Kong SAR , The People's Republic of China
| | - Grant J Jensen
- Division of Biology and Biological Engineering , California Institute of Technology , Pasadena , California 91125 , United States
- Howard Hughes Medical Institute , California Insitute of Technology , Pasadena , California 91125 , United States
| | - Emad Tajkhorshid
- Department of Biochemistry, NIH Center for Macromolecular Modeling and Bioinformatics, Center for Biophysics and Quantitative Biology, Beckman Institute for Advanced Science and Technology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801-3028 , United States
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33
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Long BM, Hee WY, Sharwood RE, Rae BD, Kaines S, Lim YL, Nguyen ND, Massey B, Bala S, von Caemmerer S, Badger MR, Price GD. Carboxysome encapsulation of the CO 2-fixing enzyme Rubisco in tobacco chloroplasts. Nat Commun 2018; 9:3570. [PMID: 30177711 PMCID: PMC6120970 DOI: 10.1038/s41467-018-06044-0] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 08/12/2018] [Indexed: 12/30/2022] Open
Abstract
A long-term strategy to enhance global crop photosynthesis and yield involves the introduction of cyanobacterial CO2-concentrating mechanisms (CCMs) into plant chloroplasts. Cyanobacterial CCMs enable relatively rapid CO2 fixation by elevating intracellular inorganic carbon as bicarbonate, then concentrating it as CO2 around the enzyme Rubisco in specialized protein micro-compartments called carboxysomes. To date, chloroplastic expression of carboxysomes has been elusive, requiring coordinated expression of almost a dozen proteins. Here we successfully produce simplified carboxysomes, isometric with those of the source organism Cyanobium, within tobacco chloroplasts. We replace the endogenous Rubisco large subunit gene with cyanobacterial Form-1A Rubisco large and small subunit genes, along with genes for two key α-carboxysome structural proteins. This minimal gene set produces carboxysomes, which encapsulate the introduced Rubisco and enable autotrophic growth at elevated CO2. This result demonstrates the formation of α-carboxysomes from a reduced gene set, informing the step-wise construction of fully functional α-carboxysomes in chloroplasts.
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Affiliation(s)
- Benedict M Long
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia.
| | - Wei Yih Hee
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Robert E Sharwood
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Benjamin D Rae
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Sarah Kaines
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Yi-Leen Lim
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Nghiem D Nguyen
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Baxter Massey
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Soumi Bala
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Susanne von Caemmerer
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - Murray R Badger
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
| | - G Dean Price
- Realizing Increased Photosynthetic Efficiency (RIPE), The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton, ACT, 2601, Australia
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Affe HMDJ, Rigonato J, Nunes JMDC, Menezes M. Metagenomic Analysis of Cyanobacteria in an Oligotrophic Tropical Estuary, South Atlantic. Front Microbiol 2018; 9:1393. [PMID: 29997603 PMCID: PMC6029486 DOI: 10.3389/fmicb.2018.01393] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 06/07/2018] [Indexed: 11/20/2022] Open
Abstract
This study assessed the species composition, distribution, and functional profiles of cyanobacteria in Camamu Bay, a tropical oligotrophic estuarine system on the northeast coast of Brazil, using shotgun metagenomic sequencing. Surface-water samples were evaluated in two different rainfall periods (rainy and dry seasons), at nine stations in the three hydrodynamic regions of the bay. At a fixed sampling station, on each season, samples were taken over a tidal cycle at 3-h intervals over 12 h. A total of 219 cyanobacterial taxa were identified, demonstrating a diverse community of freshwater, euryhaline, and marine cyanobacteria. The genera of greater relative abundance, Synechococcus and Prochlorococcus, corresponded to the picoplankton fraction. Although Camamu Bay has conspicuous marine characteristics, the contribution of freshwater during the rainy season caused variation in cyanobacteria community, with an increase in species richness. Due the high prevalence of Synechococcus (90% of the sequences), the functional analysis revealed only minor differences in gene content between the dry and rainy seasons. In both rainy and dry seasons, an increase in Prochlorococcus relative abundance occurred during high tide, demonstrating the tidal influence in the bay. The environmental characteristics of the bay provide niche conditions for a wide variety of cyanobacteria, including freshwater, euryhaline, and marine strains.
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Affiliation(s)
- Helen M de Jesus Affe
- Laboratório de Algas Marinhas, Instituto de Biologia, Universidade Federal da Bahia, Salvador, Brazil
| | - Janaina Rigonato
- Centro de Energia Nuclear e Agricultura, Universidade de São Paulo, Piracicaba, Brazil.,CEA, Centre de Sequençage Genoscope, Institut de Biologie François Jacob, Evry, France
| | - José M de Castro Nunes
- Laboratório de Algas Marinhas, Instituto de Biologia, Universidade Federal da Bahia, Salvador, Brazil
| | - Mariângela Menezes
- Laboratório de Ficologia, Departamento de Botânica, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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Chaijarasphong T, Savage DF. Sequestered: Design and Construction of Synthetic Organelles. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Thawatchai Chaijarasphong
- Mahidol University; Faculty of Science, Department of Biotechnology; Rama VI Rd. Bangkok 10400 Thailand
| | - David F. Savage
- University of California; Department of Molecular and Cell Biology; 2151 Berkeley Way, Berkeley CA 94720 USA
- University of California; Department of Chemistry; 2151 Berkeley Way, Berkeley CA 94720 USA
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Rohnke BA, Singh SP, Pattanaik B, Montgomery BL. RcaE-Dependent Regulation of Carboxysome Structural Proteins Has a Central Role in Environmental Determination of Carboxysome Morphology and Abundance in Fremyella diplosiphon. mSphere 2018; 3:e00617-17. [PMID: 29404416 PMCID: PMC5784247 DOI: 10.1128/msphere.00617-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/08/2018] [Indexed: 11/20/2022] Open
Abstract
Carboxysomes are central to the carbon dioxide-concentrating mechanism (CCM) and carbon fixation in cyanobacteria. Although the structure is well understood, roles of environmental cues in the synthesis, positioning, and functional tuning of carboxysomes have not been systematically studied. Fremyella diplosiphon is a model cyanobacterium for assessing impacts of environmental light cues on photosynthetic pigmentation and tuning of photosynthetic efficiency during complementary chromatic acclimation (CCA), which is controlled by the photoreceptor RcaE. Given the central role of carboxysomes in photosynthesis, we investigated roles of light-dependent RcaE signaling in carboxysome structure and function. A ΔrcaE mutant exhibits altered carboxysome size and number, ccm gene expression, and carboxysome protein accumulation relative to the wild-type (WT) strain. Several Ccm proteins, including carboxysome shell proteins and core-nucleating factors, overaccumulate in ΔrcaE cells relative to WT cells. Additionally, levels of carboxysome cargo RuBisCO in the ΔrcaE mutant are lower than or unchanged from those in the WT strain. This shift in the ratios of carboxysome shell and nucleating components to the carboxysome cargo appears to drive carboxysome morphology and abundance dynamics. Carboxysomes are also occasionally mislocalized spatially to the periphery of spherical mutants within thylakoid membranes, suggesting that carboxysome positioning is impacted by cell shape. The RcaE photoreceptor links perception of external light cues to regulating carboxysome structure and function and, thus, to the cellular capacity for carbon fixation. IMPORTANCE Carboxysomes are proteinaceous subcellular compartments, or bacterial organelles, found in cyanobacteria that consist of a protein shell surrounding a core primarily composed of the enzyme ribulose-1,5-biphosphate carboxylase/oxygenase (RuBisCO) that is central to the carbon dioxide-concentrating mechanism (CCM) and carbon fixation. Whereas significant insights have been gained regarding the structure and synthesis of carboxysomes, limited attention has been given to how their size, abundance, and protein composition are regulated to ensure optimal carbon fixation in dynamic environments. Given the centrality of carboxysomes in photosynthesis, we provide an analysis of the role of a photoreceptor, RcaE, which functions in matching photosynthetic pigmentation to the external environment during complementary chromatic acclimation and thereby optimizing photosynthetic efficiency, in regulating carboxysome dynamics. Our data highlight a role for RcaE in perceiving external light cues and regulating carboxysome structure and function and, thus, in the cellular capacity for carbon fixation and organismal fitness.
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Affiliation(s)
- Brandon A. Rohnke
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
| | - Shailendra P. Singh
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
| | - Bagmi Pattanaik
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
| | - Beronda L. Montgomery
- Department of Energy—Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan, USA
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan, USA
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, Michigan, USA
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Asplund-Samuelsson J, Janasch M, Hudson EP. Thermodynamic analysis of computed pathways integrated into the metabolic networks of E. coli and Synechocystis reveals contrasting expansion potential. Metab Eng 2017; 45:223-236. [PMID: 29278749 DOI: 10.1016/j.ymben.2017.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 12/04/2017] [Accepted: 12/20/2017] [Indexed: 01/09/2023]
Abstract
Introducing biosynthetic pathways into an organism is both reliant on and challenged by endogenous biochemistry. Here we compared the expansion potential of the metabolic network in the photoautotroph Synechocystis with that of the heterotroph E. coli using the novel workflow POPPY (Prospecting Optimal Pathways with PYthon). First, E. coli and Synechocystis metabolomic and fluxomic data were combined with metabolic models to identify thermodynamic constraints on metabolite concentrations (NET analysis). Then, thousands of automatically constructed pathways were placed within each network and subjected to a network-embedded variant of the max-min driving force analysis (NEM). We found that the networks had different capabilities for imparting thermodynamic driving forces toward certain compounds. Key metabolites were constrained differently in Synechocystis due to opposing flux directions in glycolysis and carbon fixation, the forked tri-carboxylic acid cycle, and photorespiration. Furthermore, the lysine biosynthesis pathway in Synechocystis was identified as thermodynamically constrained, impacting both endogenous and heterologous reactions through low 2-oxoglutarate levels. Our study also identified important yet poorly covered areas in existing metabolomics data and provides a reference for future thermodynamics-based engineering in Synechocystis and beyond. The POPPY methodology represents a step in making optimal pathway-host matches, which is likely to become important as the practical range of host organisms is diversified.
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Affiliation(s)
- Johannes Asplund-Samuelsson
- Science for Life Laboratory, School of Biotechnology, KTH Royal Institute of Technology, P-Box 1031, 171 21 Solna, Sweden.
| | - Markus Janasch
- Science for Life Laboratory, School of Biotechnology, KTH Royal Institute of Technology, P-Box 1031, 171 21 Solna, Sweden.
| | - Elton P Hudson
- Science for Life Laboratory, School of Biotechnology, KTH Royal Institute of Technology, P-Box 1031, 171 21 Solna, Sweden.
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38
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Turmo A, Gonzalez-Esquer CR, Kerfeld CA. Carboxysomes: metabolic modules for CO2 fixation. FEMS Microbiol Lett 2017; 364:4082729. [DOI: 10.1093/femsle/fnx176] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 08/12/2017] [Indexed: 11/13/2022] Open
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Faulkner M, Rodriguez-Ramos J, Dykes GF, Owen SV, Casella S, Simpson DM, Beynon RJ, Liu LN. Direct characterization of the native structure and mechanics of cyanobacterial carboxysomes. NANOSCALE 2017; 9:10662-10673. [PMID: 28616951 PMCID: PMC5708340 DOI: 10.1039/c7nr02524f] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Carboxysomes are proteinaceous organelles that play essential roles in enhancing carbon fixation in cyanobacteria and some proteobacteria. These self-assembling organelles encapsulate Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) and carbonic anhydrase using a protein shell structurally resembling an icosahedral viral capsid. The protein shell serves as a physical barrier to protect enzymes from the cytosol and a selectively permeable membrane to mediate transport of enzyme substrates and products. The structural and mechanical nature of native carboxysomes remain unclear. Here, we isolate functional β-carboxysomes from the cyanobacterium Synechococcus elongatus PCC7942 and perform the first characterization of the macromolecular architecture and inherent physical mechanics of single β-carboxysomes using electron microscopy, atomic force microscopy (AFM) and proteomics. Our results illustrate that the intact β-carboxysome comprises three structural domains, a single-layered icosahedral shell, an inner layer and paracrystalline arrays of interior Rubisco. We also observe the protein organization of the shell and partial β-carboxysomes that likely serve as the β-carboxysome assembly intermediates. Furthermore, the topography and intrinsic mechanics of functional β-carboxysomes are determined in native conditions using AFM and AFM-based nanoindentation, revealing the flexible organization and soft mechanical properties of β-carboxysomes compared to rigid viruses. Our study provides new insights into the natural characteristics of β-carboxysome organization and nanomechanics, which can be extended to diverse bacterial microcompartments and are important considerations for the design and engineering of functional carboxysomes in other organisms to supercharge photosynthesis. It offers an approach for inspecting the structural and mechanical features of synthetic metabolic organelles and protein scaffolds in bioengineering.
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Affiliation(s)
- Matthew Faulkner
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | | | - Gregory F Dykes
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Siân V Owen
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Selene Casella
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Deborah M Simpson
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Robert J Beynon
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK.
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Kaplan A. On the cradle of CCM research: discovery, development, and challenges ahead. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3785-3796. [PMID: 28520892 DOI: 10.1093/jxb/erx122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Herein, 40 years after its discovery, I briefly and critically survey the development of ideas that propelled research on CO2-concentrating mechanisms (CCMs; a term proposed by Dean Price) of phytoplankton, mainly focusing on cyanobacteria. This is not a comprehensive review on CCM research, but a personal view on the past developments and challenges that lie ahead.
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Affiliation(s)
- Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190401, Israel
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41
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Rae BD, Long BM, Förster B, Nguyen ND, Velanis CN, Atkinson N, Hee WY, Mukherjee B, Price GD, McCormick AJ. Progress and challenges of engineering a biophysical CO2-concentrating mechanism into higher plants. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3717-3737. [PMID: 28444330 DOI: 10.1093/jxb/erx133] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Growth and productivity in important crop plants is limited by the inefficiencies of the C3 photosynthetic pathway. Introducing CO2-concentrating mechanisms (CCMs) into C3 plants could overcome these limitations and lead to increased yields. Many unicellular microautotrophs, such as cyanobacteria and green algae, possess highly efficient biophysical CCMs that increase CO2 concentrations around the primary carboxylase enzyme, Rubisco, to enhance CO2 assimilation rates. Algal and cyanobacterial CCMs utilize distinct molecular components, but share several functional commonalities. Here we outline the recent progress and current challenges of engineering biophysical CCMs into C3 plants. We review the predicted requirements for a functional biophysical CCM based on current knowledge of cyanobacterial and algal CCMs, the molecular engineering tools and research pipelines required to translate our theoretical knowledge into practice, and the current challenges to achieving these goals.
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Affiliation(s)
- Benjamin D Rae
- Australian Research Council Centre of Excellence for Translational Photosynthesis
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
| | - Benedict M Long
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
| | - Britta Förster
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
| | - Nghiem D Nguyen
- Australian Research Council Centre of Excellence for Translational Photosynthesis
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
| | - Christos N Velanis
- SynthSys and Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Nicky Atkinson
- SynthSys and Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Wei Yih Hee
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
| | - Bratati Mukherjee
- Australian Research Council Centre of Excellence for Translational Photosynthesis
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
| | - G Dean Price
- Australian Research Council Centre of Excellence for Translational Photosynthesis
- Research School of Biology, The Australian National University, 134 Linnaeus Way, Acton ACT 2601, Australia
| | - Alistair J McCormick
- SynthSys and Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3BF, UK
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Celepli N, Sundh J, Ekman M, Dupont CL, Yooseph S, Bergman B, Ininbergs K. Meta-omic analyses of Baltic Sea cyanobacteria: diversity, community structure and salt acclimation. Environ Microbiol 2017; 19:673-686. [PMID: 27871145 DOI: 10.1111/1462-2920.13592] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/16/2016] [Indexed: 01/08/2023]
Abstract
Cyanobacteria are important phytoplankton in the Baltic Sea, an estuarine-like environment with pronounced north to south gradients in salinity and nutrient concentrations. Here, we present a metagenomic and -transcriptomic survey, with subsequent analyses targeting the genetic identity, phylogenetic diversity, and spatial distribution of Baltic Sea cyanobacteria. The cyanobacterial community constituted close to 12% of the microbial population sampled during a pre-bloom period (June-July 2009). The community was dominated by unicellular picocyanobacteria, specifically a few highly abundant taxa (Synechococcus and Cyanobium) with a long tail of low abundance representatives, and local peaks of bloom-forming heterocystous taxa. Cyanobacteria in the Baltic Sea differed genetically from those in adjacent limnic and marine waters as well as from cultivated and sequenced picocyanobacterial strains. Diversity peaked at brackish salinities 3.5-16 psu, with low N:P ratios. A shift in community composition from brackish to marine strains was accompanied by a change in the repertoire and expression of genes involved in salt acclimation. Overall, the pre-bloom cyanobacterial population was more genetically diverse, widespread and abundant than previously documented, with unicellular picocyanobacteria being the most abundant clade along the entire Baltic Sea salinity gradient.
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Affiliation(s)
- Narin Celepli
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
| | - John Sundh
- Centre for Ecology and Evolution in Microbial model Systems, Linnaeus University, Kalmar, 391 82, Sweden
| | - Martin Ekman
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
| | - Chris L Dupont
- Microbial and Environmental Genomics, J. Craig Venter Institute, San Diego, CA, 92037, USA
| | - Shibu Yooseph
- Department of Computer Science, University of Central Florida, Orlando, FL, USA
| | - Birgitta Bergman
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
| | - Karolina Ininbergs
- Department of Ecology, Environment and Plant Sciences, Stockholm University/Science for Life Laboratory, Solna, 17121, Sweden
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Sharwood RE. Engineering chloroplasts to improve Rubisco catalysis: prospects for translating improvements into food and fiber crops. THE NEW PHYTOLOGIST 2017; 213:494-510. [PMID: 27935049 DOI: 10.1111/nph.14351] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 09/10/2016] [Indexed: 05/19/2023]
Abstract
494 I. 495 II. 496 III. 496 IV. 499 V. 499 VI. 501 VII. 501 VIII. 502 IX. 505 X. 506 507 References 507 SUMMARY: The uncertainty of future climate change is placing pressure on cropping systems to continue to provide stable increases in productive yields. To mitigate future climates and the increasing threats against global food security, new solutions to manipulate photosynthesis are required. This review explores the current efforts available to improve carbon assimilation within plant chloroplasts by engineering Rubisco, which catalyzes the rate-limiting step of CO2 fixation. Fixation of CO2 and subsequent cycling of 3-phosphoglycerate through the Calvin cycle provides the necessary carbohydrate building blocks for maintaining plant growth and yield, but has to compete with Rubisco oxygenation, which results in photorespiration that is energetically wasteful for plants. Engineering improvements in Rubisco is a complex challenge and requires an understanding of chloroplast gene regulatory pathways, and the intricate nature of Rubisco catalysis and biogenesis, to transplant more efficient forms of Rubisco into crops. In recent times, major advances in Rubisco engineering have been achieved through improvement of our knowledge of Rubisco synthesis and assembly, and identifying amino acid catalytic switches in the L-subunit responsible for improvements in catalysis. Improving the capacity of CO2 fixation in crops such as rice will require further advances in chloroplast bioengineering and Rubisco biogenesis.
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Affiliation(s)
- Robert E Sharwood
- ARC Center of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, 2601, Australia
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Wheatley NM, Eden KD, Ngo J, Rosinski JS, Sawaya MR, Cascio D, Collazo M, Hoveida H, Hubbell WL, Yeates TO. A PII-Like Protein Regulated by Bicarbonate: Structural and Biochemical Studies of the Carboxysome-Associated CPII Protein. J Mol Biol 2016; 428:4013-4030. [PMID: 27464895 PMCID: PMC5048545 DOI: 10.1016/j.jmb.2016.07.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/11/2016] [Accepted: 07/18/2016] [Indexed: 11/18/2022]
Abstract
Autotrophic bacteria rely on various mechanisms to increase intracellular concentrations of inorganic forms of carbon (i.e., bicarbonate and CO2) in order to improve the efficiency with which they can be converted to organic forms. Transmembrane bicarbonate transporters and carboxysomes play key roles in accumulating bicarbonate and CO2, but other regulatory elements of carbon concentration mechanisms in bacteria are less understood. In this study, after analyzing the genomic regions around α-type carboxysome operons, we characterize a protein that is conserved across these operons but has not been previously studied. On the basis of a series of apo- and ligand-bound crystal structures and supporting biochemical data, we show that this protein, which we refer to as the carboxysome-associated PII protein (CPII), represents a new and distinct subfamily within the broad superfamily of previously studied PII regulatory proteins, which are generally involved in regulating nitrogen metabolism in bacteria. CPII undergoes dramatic conformational changes in response to ADP binding, and the affinity for nucleotide binding is strongly enhanced by the presence of bicarbonate. CPII therefore appears to be a unique type of PII protein that senses bicarbonate availability, consistent with its apparent genomic association with the carboxysome and its constituents.
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Affiliation(s)
- Nicole M Wheatley
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Kevin D Eden
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Joanna Ngo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Justin S Rosinski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Michael R Sawaya
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Duilio Cascio
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Michael Collazo
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA
| | - Hamidreza Hoveida
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
| | - Wayne L Hubbell
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA; Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA
| | - Todd O Yeates
- UCLA-DOE Institute for Genomics and Proteomics, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA.
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45
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pH determines the energetic efficiency of the cyanobacterial CO2 concentrating mechanism. Proc Natl Acad Sci U S A 2016; 113:E5354-62. [PMID: 27551079 DOI: 10.1073/pnas.1525145113] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Many carbon-fixing bacteria rely on a CO2 concentrating mechanism (CCM) to elevate the CO2 concentration around the carboxylating enzyme ribulose bisphosphate carboxylase/oxygenase (RuBisCO). The CCM is postulated to simultaneously enhance the rate of carboxylation and minimize oxygenation, a competitive reaction with O2 also catalyzed by RuBisCO. To achieve this effect, the CCM combines two features: active transport of inorganic carbon into the cell and colocalization of carbonic anhydrase and RuBisCO inside proteinaceous microcompartments called carboxysomes. Understanding the significance of the various CCM components requires reconciling biochemical intuition with a quantitative description of the system. To this end, we have developed a mathematical model of the CCM to analyze its energetic costs and the inherent intertwining of physiology and pH. We find that intracellular pH greatly affects the cost of inorganic carbon accumulation. At low pH the inorganic carbon pool contains more of the highly cell-permeable H2CO3, necessitating a substantial expenditure of energy on transport to maintain internal inorganic carbon levels. An intracellular pH ≈8 reduces leakage, making the CCM significantly more energetically efficient. This pH prediction coincides well with our measurement of intracellular pH in a model cyanobacterium. We also demonstrate that CO2 retention in the carboxysome is necessary, whereas selective uptake of HCO3 (-) into the carboxysome would not appreciably enhance energetic efficiency. Altogether, integration of pH produces a model that is quantitatively consistent with cyanobacterial physiology, emphasizing that pH cannot be neglected when describing biological systems interacting with inorganic carbon pools.
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Frey R, Mantri S, Rocca M, Hilvert D. Bottom-up Construction of a Primordial Carboxysome Mimic. J Am Chem Soc 2016; 138:10072-5. [DOI: 10.1021/jacs.6b04744] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Raphael Frey
- Laboratory of Organic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Shiksha Mantri
- Laboratory of Organic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Marco Rocca
- Laboratory of Organic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Donald Hilvert
- Laboratory of Organic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
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Hanson MR, Lin MT, Carmo-Silva AE, Parry MA. Towards engineering carboxysomes into C3 plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:38-50. [PMID: 26867858 PMCID: PMC4970904 DOI: 10.1111/tpj.13139] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/29/2016] [Accepted: 02/02/2016] [Indexed: 05/18/2023]
Abstract
Photosynthesis in C3 plants is limited by features of the carbon-fixing enzyme Rubisco, which exhibits a low turnover rate and can react with O2 instead of CO2 , leading to photorespiration. In cyanobacteria, bacterial microcompartments, known as carboxysomes, improve the efficiency of photosynthesis by concentrating CO2 near the enzyme Rubisco. Cyanobacterial Rubisco enzymes are faster than those of C3 plants, though they have lower specificity toward CO2 than the land plant enzyme. Replacement of land plant Rubisco by faster bacterial variants with lower CO2 specificity will improve photosynthesis only if a microcompartment capable of concentrating CO2 can also be installed into the chloroplast. We review current information about cyanobacterial microcompartments and carbon-concentrating mechanisms, plant transformation strategies, replacement of Rubisco in a model C3 plant with cyanobacterial Rubisco and progress toward synthesizing a carboxysome in chloroplasts.
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Affiliation(s)
- Maureen R. Hanson
- Department of Molecular Biology and Genetics, Cornell University, Biotechnology Building, Ithaca, NY 14853 USA
| | - Myat T. Lin
- Department of Molecular Biology and Genetics, Cornell University, Biotechnology Building, Ithaca, NY 14853 USA
| | | | - Martin A.J. Parry
- Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom
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Long BM, Rae BD, Rolland V, Förster B, Price GD. Cyanobacterial CO2-concentrating mechanism components: function and prospects for plant metabolic engineering. CURRENT OPINION IN PLANT BIOLOGY 2016; 31:1-8. [PMID: 26999306 DOI: 10.1016/j.pbi.2016.03.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/25/2016] [Accepted: 03/02/2016] [Indexed: 05/21/2023]
Abstract
Global population growth is projected to outpace plant-breeding improvements in major crop yields within decades. To ensure future food security, multiple creative efforts seek to overcome limitations to crop yield. Perhaps the greatest limitation to increased crop yield is photosynthetic inefficiency, particularly in C3 crop plants. Recently, great strides have been made toward crop improvement by researchers seeking to introduce the cyanobacterial CO2-concentrating mechanism (CCM) into plant chloroplasts. This strategy recognises the C3 chloroplast as lacking a CCM, and being a primordial cyanobacterium at its essence. Hence the collection of solute transporters, enzymes, and physical structures that make cyanobacterial CO2-fixation so efficient are viewed as a natural source of genetic material for C3 chloroplast improvement. Also we highlight recent outstanding research aimed toward the goal of introducing a cyanobacterial CCM into C3 chloroplasts and consider future research directions.
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Affiliation(s)
- Benedict M Long
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia.
| | - Benjamin D Rae
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Vivien Rolland
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Britta Förster
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - G Dean Price
- ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
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Sun Y, Casella S, Fang Y, Huang F, Faulkner M, Barrett S, Liu LN. Light Modulates the Biosynthesis and Organization of Cyanobacterial Carbon Fixation Machinery through Photosynthetic Electron Flow. PLANT PHYSIOLOGY 2016; 171:530-41. [PMID: 26956667 PMCID: PMC4854705 DOI: 10.1104/pp.16.00107] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/06/2016] [Indexed: 05/08/2023]
Abstract
Cyanobacteria have evolved effective adaptive mechanisms to improve photosynthesis and CO2 fixation. The central CO2-fixing machinery is the carboxysome, which is composed of an icosahedral proteinaceous shell encapsulating the key carbon fixation enzyme, Rubisco, in the interior. Controlled biosynthesis and ordered organization of carboxysomes are vital to the CO2-fixing activity of cyanobacterial cells. However, little is known about how carboxysome biosynthesis and spatial positioning are physiologically regulated to adjust to dynamic changes in the environment. Here, we used fluorescence tagging and live-cell confocal fluorescence imaging to explore the biosynthesis and subcellular localization of β-carboxysomes within a model cyanobacterium, Synechococcus elongatus PCC7942, in response to light variation. We demonstrated that β-carboxysome biosynthesis is accelerated in response to increasing light intensity, thereby enhancing the carbon fixation activity of the cell. Inhibition of photosynthetic electron flow impairs the accumulation of carboxysomes, indicating a close coordination between β-carboxysome biogenesis and photosynthetic electron transport. Likewise, the spatial organization of carboxysomes in the cell correlates with the redox state of photosynthetic electron transport chain. This study provides essential knowledge for us to modulate the β-carboxysome biosynthesis and function in cyanobacteria. In translational terms, the knowledge is instrumental for design and synthetic engineering of functional carboxysomes into higher plants to improve photosynthesis performance and CO2 fixation.
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Affiliation(s)
- Yaqi Sun
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Selene Casella
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Yi Fang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Fang Huang
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Matthew Faulkner
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Steve Barrett
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom (Y.S., S.C., Y.F., F.H., M.F., L.-N.L.); and Department of Physics, University of Liverpool, Liverpool L69 7ZE, United Kingdom (S.B.)
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50
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Young JN, Heureux AMC, Sharwood RE, Rickaby REM, Morel FMM, Whitney SM. Large variation in the Rubisco kinetics of diatoms reveals diversity among their carbon-concentrating mechanisms. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3445-56. [PMID: 27129950 PMCID: PMC4892730 DOI: 10.1093/jxb/erw163] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
While marine phytoplankton rival plants in their contribution to global primary productivity, our understanding of their photosynthesis remains rudimentary. In particular, the kinetic diversity of the CO2-fixing enzyme, Rubisco, in phytoplankton remains unknown. Here we quantify the maximum rates of carboxylation (k cat (c)), oxygenation (k cat (o)), Michaelis constants (K m) for CO2 (K C) and O2 (K O), and specificity for CO2 over O2 (SC/O) for Form I Rubisco from 11 diatom species. Diatom Rubisco shows greater variation in K C (23-68 µM), SC/O (57-116mol mol(-1)), and K O (413-2032 µM) relative to plant and algal Rubisco. The broad range of K C values mostly exceed those of C4 plant Rubisco, suggesting that the strength of the carbon-concentrating mechanism (CCM) in diatoms is more diverse, and more effective than previously predicted. The measured k cat (c) for each diatom Rubisco showed less variation (2.1-3.7s(-1)), thus averting the canonical trade-off typically observed between K C and k cat (c) for plant Form I Rubisco. Uniquely, a negative relationship between K C and cellular Rubisco content was found, suggesting variation among diatom species in how they allocate their limited cellular resources between Rubisco synthesis and their CCM. The activation status of Rubisco in each diatom was low, indicating a requirement for Rubisco activase. This work highlights the need to better understand the correlative natural diversity between the Rubisco kinetics and CCM of diatoms and the underpinning mechanistic differences in catalytic chemistry among the Form I Rubisco superfamily.
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Affiliation(s)
- Jodi N Young
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Ana M C Heureux
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Robert E Sharwood
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
| | - Rosalind E M Rickaby
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - François M M Morel
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - Spencer M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia
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