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Panich J, Toppari E, Tejedor-Sanz S, Fong B, Dugan E, Chen Y, Petzold CJ, Zhao Z, Yoshikuni Y, Savage DF, Singer SW. Functional plasticity of HCO 3- uptake and CO 2 fixation in Cupriavidus necator H16. BIORESOURCE TECHNOLOGY 2024; 410:131214. [PMID: 39127361 DOI: 10.1016/j.biortech.2024.131214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Revised: 08/01/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024]
Abstract
Despite its prominence, the ability to engineer Cupriavidus necator H16 for inorganic carbon uptake and fixation is underexplored. We tested the roles of endogenous and heterologous genes on C. necator inorganic carbon metabolism. Deletion of β-carbonic anhydrase can had the most deleterious effect on C. necator autotrophic growth. Replacement of this native uptake system with several classes of dissolved inorganic carbon (DIC) transporters from Cyanobacteria and chemolithoautotrophic bacteria recovered autotrophic growth and supported higher cell densities compared to wild-type (WT) C. necator in batch culture. Strains expressing Halothiobacillus neopolitanus DAB2 (hnDAB2) and diverse rubisco homologs grew in CO2 similarly to the wild-type strain. Our experiments suggest that the primary role of carbonic anhydrase during autotrophic growth is to support anaplerotic metabolism, and an array of DIC transporters can complement this function. This work demonstrates flexibility in HCO3- uptake and CO2 fixation in C. necator, providing new pathways for CO2-based biomanufacturing.
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Affiliation(s)
- Justin Panich
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | - Emili Toppari
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Sara Tejedor-Sanz
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Advanced Biofuel and Bioproducts Process Development Unit, Lawrence Berkeley NationalLaboratory, Emeryville, CA 94608, USA
| | - Bonnie Fong
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Eli Dugan
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA, 94720, USA
| | - Yan Chen
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Christopher J Petzold
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Zhiying Zhao
- The US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, CA 94720, USA
| | - Yasuo Yoshikuni
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; The US Department of Energy Joint Genome Institute, Lawrence Berkeley National Laboratory, CA 94720, USA; Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, CA94720, USA
| | - David F Savage
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley, CA, 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
| | - Steven W Singer
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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2
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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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3
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Gionfriddo M, Rhodes T, Whitney SM. Perspectives on improving crop Rubisco by directed evolution. Semin Cell Dev Biol 2024; 155:37-47. [PMID: 37085353 DOI: 10.1016/j.semcdb.2023.04.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 04/14/2023] [Accepted: 04/15/2023] [Indexed: 04/23/2023]
Abstract
Rubisco catalyses the entry of almost all CO2 into the biosphere and is often the rate-limiting step in plant photosynthesis and growth. Its notoriety as the most abundant protein on Earth stems from the slow and error-prone catalytic properties that require plants, cyanobacteria, algae and photosynthetic bacteria to produce it in high amounts. Efforts to improve the CO2-fixing properties of plant Rubisco has been spurred on by the discovery of more effective isoforms in some algae with the potential to significantly improve crop productivity. Incompatibilities between the protein folding machinery of leaf and algae chloroplasts have, so far, prevented efforts to transplant these more effective Rubisco variants into plants. There is therefore increasing interest in improving Rubisco catalysis by directed (laboratory) evolution. Here we review the advances being made in, and the ongoing challenges with, improving the solubility and/or carboxylation activity of differing non-plant Rubisco lineages. We provide perspectives on new opportunities for the directed evolution of crop Rubiscos and the existing plant transformation capabilities available to evaluate the extent to which Rubisco activity improvements can benefit agricultural productivity.
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Affiliation(s)
- Matteo Gionfriddo
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia; Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Timothy Rhodes
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Spencer M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.
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4
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Zhao L, Cai Z, Li Y, Zhang Y. Engineering Rubisco to enhance CO 2 utilization. Synth Syst Biotechnol 2024; 9:55-68. [PMID: 38273863 PMCID: PMC10809010 DOI: 10.1016/j.synbio.2023.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/15/2023] [Accepted: 12/25/2023] [Indexed: 01/27/2024] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a pivotal enzyme that mediates the fixation of CO2. As the most abundant protein on earth, Rubisco has a significant impact on global carbon, water, and nitrogen cycles. However, the significantly low carboxylation activity and competing oxygenase activity of Rubisco greatly impede high carbon fixation efficiency. This review first summarizes the current efforts in directly or indirectly modifying plant Rubisco, which has been challenging due to its high conservation and limitations in chloroplast transformation techniques. However, recent advancements in understanding Rubisco biogenesis with the assistance of chaperones have enabled successful heterologous expression of all Rubisco forms, including plant Rubisco, in microorganisms. This breakthrough facilitates the acquisition and evaluation of modified proteins, streamlining the measurement of their activity. Moreover, the establishment of a screening system in E. coli opens up possibilities for obtaining high-performance mutant enzymes through directed evolution. Finally, this review emphasizes the utilization of Rubisco in microorganisms, not only expanding their carbon-fixing capabilities but also holding significant potential for enhancing biotransformation processes.
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Affiliation(s)
- Lei Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhen Cai
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yanping Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
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5
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Zheng B, Li YT, Wu QP, Zhao W, Ren TH, Zhang XH, Li G, Ning TY, Zhang ZS. Maize (Zea mays L.) planted at higher density utilizes dynamic light more efficiently. PLANT, CELL & ENVIRONMENT 2023; 46:3305-3322. [PMID: 37485705 DOI: 10.1111/pce.14673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/15/2023] [Accepted: 07/11/2023] [Indexed: 07/25/2023]
Abstract
In nature, plants are exposed to a dynamic light environment. Fluctuations in light decreased the photosynthetic light utilization efficiency (PLUE) of leaves, and much more severely in C4 species than in C3 species. However, little is known about the plasticity of PLUE under dynamic light in C4 species. Present study focused on the influence of planting density to the photosynthesis under dynamic light in maize (Zea mays L.), a most important C4 crop. In addition, the molecular mechanism behind photosynthetic adaptation to planting density were also explored by quantitative proteomics analysis. Results revealed that as planting density increases, maize leaves receive less light that fluctuates more. The maize planted at high density (HD) improved the PLUE under dynamic light, especially in the middle and later growth stages. Quantitative proteomics analysis showed that the transfer of nitrogen from Rubisco to RuBP regeneration and C4 pathway related enzymes contributes to the photosynthetic adaptation to lower and more fluctuating light environment in HD maize. This study provides potential ways to further improve the light energy utilization efficiency of maize in HD.
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Affiliation(s)
- Bin Zheng
- College of Agronomy, Shandong Agricultural University, Tai'an, Shandong, P. R. China
| | - Yu-Ting Li
- College of Agronomy, Shandong Agricultural University, Tai'an, Shandong, P. R. China
| | - Qiu-Ping Wu
- Jining Academy of Agricultural Sciences, Shandong, P. R. China
| | - Wei Zhao
- College of Agronomy, Shandong Agricultural University, Tai'an, Shandong, P. R. China
| | - Ting-Hu Ren
- College of Agronomy, Shandong Agricultural University, Tai'an, Shandong, P. R. China
| | - Xing-Hui Zhang
- College of Agronomy, Shandong Agricultural University, Tai'an, Shandong, P. R. China
| | - Geng Li
- College of Agronomy, Shandong Agricultural University, Tai'an, Shandong, P. R. China
| | - Tang-Yuan Ning
- College of Agronomy, Shandong Agricultural University, Tai'an, Shandong, P. R. China
| | - Zi-Shan Zhang
- College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong, P. R. China
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6
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Gao L, Kantar MB, Moxley D, Ortiz-Barrientos D, Rieseberg LH. Crop adaptation to climate change: An evolutionary perspective. MOLECULAR PLANT 2023; 16:1518-1546. [PMID: 37515323 DOI: 10.1016/j.molp.2023.07.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/20/2023] [Accepted: 07/26/2023] [Indexed: 07/30/2023]
Abstract
The disciplines of evolutionary biology and plant and animal breeding have been intertwined throughout their development, with responses to artificial selection yielding insights into the action of natural selection and evolutionary biology providing statistical and conceptual guidance for modern breeding. Here we offer an evolutionary perspective on a grand challenge of the 21st century: feeding humanity in the face of climate change. We first highlight promising strategies currently under way to adapt crops to current and future climate change. These include methods to match crop varieties with current and predicted environments and to optimize breeding goals, management practices, and crop microbiomes to enhance yield and sustainable production. We also describe the promise of crop wild relatives and recent technological innovations such as speed breeding, genomic selection, and genome editing for improving environmental resilience of existing crop varieties or for developing new crops. Next, we discuss how methods and theory from evolutionary biology can enhance these existing strategies and suggest novel approaches. We focus initially on methods for reconstructing the evolutionary history of crops and their pests and symbionts, because such historical information provides an overall framework for crop-improvement efforts. We then describe how evolutionary approaches can be used to detect and mitigate the accumulation of deleterious mutations in crop genomes, identify alleles and mutations that underlie adaptation (and maladaptation) to agricultural environments, mitigate evolutionary trade-offs, and improve critical proteins. Continuing feedback between the evolution and crop biology communities will ensure optimal design of strategies for adapting crops to climate change.
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Affiliation(s)
- Lexuan Gao
- CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Michael B Kantar
- Department of Tropical Plant & Soil Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
| | - Dylan Moxley
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada
| | - Daniel Ortiz-Barrientos
- School of Biological Sciences and Australian Research Council Centre of Excellence for Plant Success in Nature and Agriculture, The University of Queensland, Brisbane, QLD, Australia
| | - Loren H Rieseberg
- Department of Botany and Biodiversity Research Centre, University of British Columbia, Vancouver, BC, Canada.
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7
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Bouvier JW, Kelly S. Response to Tcherkez and Farquhar: Rubisco adaptation is more limited by phylogenetic constraint than by catalytic trade-off. JOURNAL OF PLANT PHYSIOLOGY 2023; 287:154021. [PMID: 37392528 DOI: 10.1016/j.jplph.2023.154021] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/22/2023] [Accepted: 05/30/2023] [Indexed: 07/03/2023]
Abstract
Rubisco is the primary entry point for carbon into the biosphere. It has been widely proposed that rubisco is highly constrained by catalytic trade-offs due to correlations between the enzyme's kinetic traits across species. In previous work, we have shown that the strength of these correlations, and thus the strength of catalytic trade-offs, have been overestimated due to the presence of phylogenetic signal in the kinetic trait data (Bouvier et al., 2021). We demonstrated that only the trade-offs between the Michaelis constant for CO2 and carboxylase turnover, and between the Michaelis constants for CO2 and O2 were robust to phylogenetic effects. We further demonstrated that phylogenetic constraints have limited rubisco adaptation to a greater extent than the combined action of catalytic trade-offs. Recently, however, our claims have been contested by Tcherkez and Farquhar (2021), who have argued that the phylogenetic signal we detect in rubisco kinetic traits is an artefact of species sampling, the use of rbcL-based trees for phylogenetic inference, laboratory-to-laboratory variability in kinetic measurements, and homoplasy of the C4 trait. In the present article, we respond to these criticisms on a point-by-point basis and conclusively show that all are unfounded. As such, we stand by our original conclusions. Namely, although rubisco kinetic evolution has been limited by biochemical trade-offs, these are not absolute and have been previously overestimated due to phylogenetic biases. Instead, rubisco adaptation has in fact been more limited by phylogenetic constraint.
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Affiliation(s)
- Jacques W Bouvier
- Department of Biology, University of Oxford, South Parks Road, Oxford, OX1 3RB, United Kingdom
| | - Steven Kelly
- Department of Biology, University of Oxford, South Parks Road, Oxford, OX1 3RB, United Kingdom.
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8
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Zhou Y, Gunn LH, Birch R, Andersson I, Whitney SM. Grafting Rhodobacter sphaeroides with red algae Rubisco to accelerate catalysis and plant growth. NATURE PLANTS 2023; 9:978-986. [PMID: 37291398 DOI: 10.1038/s41477-023-01436-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 05/10/2023] [Indexed: 06/10/2023]
Abstract
Improving the carboxylation properties of Rubisco has primarily arisen from unforeseen amino acid substitutions remote from the catalytic site. The unpredictability has frustrated rational design efforts to enhance plant Rubisco towards the prized growth-enhancing carboxylation properties of red algae Griffithsia monilis GmRubisco. To address this, we determined the crystal structure of GmRubisco to 1.7 Å. Three structurally divergent domains were identified relative to the red-type bacterial Rhodobacter sphaeroides RsRubisco that, unlike GmRubisco, are expressed in Escherichia coli and plants. Kinetic comparison of 11 RsRubisco chimaeras revealed that incorporating C329A and A332V substitutions from GmRubisco Loop 6 (corresponding to plant residues 328 and 331) into RsRubisco increased the carboxylation rate (kcatc) by 60%, the carboxylation efficiency in air by 22% and the CO2/O2 specificity (Sc/o) by 7%. Plastome transformation of this RsRubisco Loop 6 mutant into tobacco enhanced photosynthesis and growth up to twofold over tobacco producing wild-type RsRubisco. Our findings demonstrate the utility of RsRubisco for the identification and in planta testing of amino acid grafts from algal Rubisco that can enhance the enzyme's carboxylase potential.
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Affiliation(s)
- Yu Zhou
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Laura H Gunn
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Rosemary Birch
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Inger Andersson
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
- Norwegian College of Fisheries Sciences, UiT Arctic University of Norway, Tromsø, Norway
- Institute of Biotechnology, Academy of Sciences of the Czech Republic, Biocev, Vestec, Czech Republic
| | - Spencer M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia.
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9
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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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10
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Recent developments in the engineering of Rubisco activase for enhanced crop yield. Biochem Soc Trans 2023; 51:627-637. [PMID: 36929563 DOI: 10.1042/bst20221281] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 03/01/2023] [Accepted: 03/03/2023] [Indexed: 03/18/2023]
Abstract
Rubisco activase (RCA) catalyzes the release of inhibitory sugar phosphates from ribulose-1,6-biphosphate carboxylase/oxygenase (Rubisco) and can play an important role in biochemical limitations of photosynthesis under dynamic light and elevated temperatures. There is interest in increasing RCA activity to improve crop productivity, but a lack of understanding about the regulation of photosynthesis complicates engineering strategies. In this review, we discuss work relevant to improving RCA with a focus on advances in understanding the structural cause of RCA instability under heat stress and the regulatory interactions between RCA and components of photosynthesis. This reveals substantial variation in RCA thermostability that can be influenced by single amino acid substitutions, and that engineered variants can perform better in vitro and in vivo under heat stress. In addition, there are indications RCA activity is controlled by transcriptional, post-transcriptional, post-translational, and spatial regulation, which may be important for balancing between carbon fixation and light capture. Finally, we provide an overview of findings from recent field experiments and consider the requirements for commercial validation as part of efforts to increase crop yields in the face of global climate change.
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11
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Chen T, Riaz S, Davey P, Zhao Z, Sun Y, Dykes GF, Zhou F, Hartwell J, Lawson T, Nixon PJ, Lin Y, Liu LN. Producing fast and active Rubisco in tobacco to enhance photosynthesis. THE PLANT CELL 2023; 35:795-807. [PMID: 36471570 PMCID: PMC9940876 DOI: 10.1093/plcell/koac348] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 10/24/2022] [Accepted: 12/02/2022] [Indexed: 05/28/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) performs most of the carbon fixation on Earth. However, plant Rubisco is an intrinsically inefficient enzyme given its low carboxylation rate, representing a major limitation to photosynthesis. Replacing endogenous plant Rubisco with a faster Rubisco is anticipated to enhance crop photosynthesis and productivity. However, the requirement of chaperones for Rubisco expression and assembly has obstructed the efficient production of functional foreign Rubisco in chloroplasts. Here, we report the engineering of a Form 1A Rubisco from the proteobacterium Halothiobacillus neapolitanus in Escherichia coli and tobacco (Nicotiana tabacum) chloroplasts without any cognate chaperones. The native tobacco gene encoding Rubisco large subunit was genetically replaced with H. neapolitanus Rubisco (HnRubisco) large and small subunit genes. We show that HnRubisco subunits can form functional L8S8 hexadecamers in tobacco chloroplasts at high efficiency, accounting for ∼40% of the wild-type tobacco Rubisco content. The chloroplast-expressed HnRubisco displayed a ∼2-fold greater carboxylation rate and supported a similar autotrophic growth rate of transgenic plants to that of wild-type in air supplemented with 1% CO2. This study represents a step toward the engineering of a fast and highly active Rubisco in chloroplasts to improve crop photosynthesis and growth.
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Affiliation(s)
- Taiyu Chen
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Saba Riaz
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Philip Davey
- School of Life Sciences, University of Essex, Colchester CO4 4SQ, UK
| | - Ziyu Zhao
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Yaqi Sun
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Gregory F Dykes
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Fei Zhou
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - James Hartwell
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester CO4 4SQ, UK
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Yongjun Lin
- National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Lu-Ning Liu
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
- 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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12
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Oh ZG, Askey B, Gunn LH. Red Rubiscos and opportunities for engineering green plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:520-542. [PMID: 36055563 PMCID: PMC9833100 DOI: 10.1093/jxb/erac349] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
Nature's vital, but notoriously inefficient, CO2-fixing enzyme Rubisco often limits the growth of photosynthetic organisms including crop species. Form I Rubiscos comprise eight catalytic large subunits and eight auxiliary small subunits and can be classified into two distinct lineages-'red' and 'green'. While red-type Rubiscos (Form IC and ID) are found in rhodophytes, their secondary symbionts, and certain proteobacteria, green-type Rubiscos (Form IA and IB) exist in terrestrial plants, chlorophytes, cyanobacteria, and other proteobacteria. Eukaryotic red-type Rubiscos exhibit desirable kinetic properties, namely high specificity and high catalytic efficiency, with certain isoforms outperforming green-type Rubiscos. However, it is not yet possible to functionally express a high-performing red-type Rubisco in chloroplasts to boost photosynthetic carbon assimilation in green plants. Understanding the molecular and evolutionary basis for divergence between red- and green-type Rubiscos could help us to harness the superior CO2-fixing power of red-type Rubiscos. Here we review our current understanding about red-type Rubisco distribution, biogenesis, and sequence-structure, and present opportunities and challenges for utilizing red-type Rubisco kinetics towards crop improvements.
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Affiliation(s)
- Zhen Guo Oh
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Bryce Askey
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
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13
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Mao Y, Catherall E, Díaz-Ramos A, Greiff GRL, Azinas S, Gunn L, McCormick AJ. The small subunit of Rubisco and its potential as an engineering target. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:543-561. [PMID: 35849331 PMCID: PMC9833052 DOI: 10.1093/jxb/erac309] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/07/2022] [Indexed: 05/06/2023]
Abstract
Rubisco catalyses the first rate-limiting step in CO2 fixation and is responsible for the vast majority of organic carbon present in the biosphere. The function and regulation of Rubisco remain an important research topic and a longstanding engineering target to enhance the efficiency of photosynthesis for agriculture and green biotechnology. The most abundant form of Rubisco (Form I) consists of eight large and eight small subunits, and is found in all plants, algae, cyanobacteria, and most phototrophic and chemolithoautotrophic proteobacteria. Although the active sites of Rubisco are located on the large subunits, expression of the small subunit regulates the size of the Rubisco pool in plants and can influence the overall catalytic efficiency of the Rubisco complex. The small subunit is now receiving increasing attention as a potential engineering target to improve the performance of Rubisco. Here we review our current understanding of the role of the small subunit and our growing capacity to explore its potential to modulate Rubisco catalysis using engineering biology approaches.
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Affiliation(s)
| | | | - Aranzazú Díaz-Ramos
- SynthSys & Institute of Molecular Plant Sciences, School of Biological Sciences, King’s Buildings, University of Edinburgh, Edingburgh EH9 3BF, UK
| | - George R L Greiff
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Stavros Azinas
- Department of Cell and Molecular Biology, Uppsala University, S-751 24 Uppsala, Sweden
| | - Laura Gunn
- Department of Cell and Molecular Biology, Uppsala University, S-751 24 Uppsala, Sweden
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
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14
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Iqbal WA, Lisitsa A, Kapralov MV. Predicting plant Rubisco kinetics from RbcL sequence data using machine learning. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:638-650. [PMID: 36094849 PMCID: PMC9833099 DOI: 10.1093/jxb/erac368] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is responsible for the conversion of atmospheric CO2 to organic carbon during photosynthesis, and often acts as a rate limiting step in the later process. Screening the natural diversity of Rubisco kinetics is the main strategy used to find better Rubisco enzymes for crop engineering efforts. Here, we demonstrate the use of Gaussian processes (GPs), a family of Bayesian models, coupled with protein encoding schemes, for predicting Rubisco kinetics from Rubisco large subunit (RbcL) sequence data. GPs trained on published experimentally obtained Rubisco kinetic datasets were applied to over 9000 sequences encoding RbcL to predict Rubisco kinetic parameters. Notably, our predicted kinetic values were in agreement with known trends, e.g. higher carboxylation turnover rates (Kcat) for Rubisco enzymes from C4 or crassulacean acid metabolism (CAM) species, compared with those found in C3 species. This is the first study demonstrating machine learning approaches as a tool for screening and predicting Rubisco kinetics, which could be applied to other enzymes.
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Affiliation(s)
- Wasim A Iqbal
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Alexei Lisitsa
- Department of Computer Science, University of Liverpool, Liverpool, L69 3BX, United Kingdom
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15
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Buck S, Rhodes T, Gionfriddo M, Skinner T, Yuan D, Birch R, Kapralov MV, Whitney SM. Escherichia coli expressing chloroplast chaperones as a proxy to test heterologous Rubisco production in leaves. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:664-676. [PMID: 36322613 DOI: 10.1093/jxb/erac435] [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: 08/12/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
Rubisco is a fundamental enzyme in photosynthesis and therefore for life. Efforts to improve plant Rubisco performance have been hindered by the enzymes' complex chloroplast biogenesis requirements. New Synbio approaches, however, now allow the production of some plant Rubisco isoforms in Escherichia coli. While this enhances opportunities for catalytic improvement, there remain limitations in the utility of the expression system. Here we generate, optimize, and test a robust Golden Gate cloning E. coli expression system incorporating the protein folding machinery of tobacco chloroplasts. By comparing the expression of different plant Rubiscos in both E. coli and plastome-transformed tobacco, we show that the E. coli expression system can accurately predict high level Rubisco production in chloroplasts but poorly forecasts the biogenesis potential of isoforms with impaired production in planta. We reveal that heterologous Rubisco production in E. coli and tobacco plastids poorly correlates with Rubisco large subunit phylogeny. Our findings highlight the need to fully understand the factors governing Rubisco biogenesis if we are to deliver an efficient, low-cost screening tool that can accurately emulate chloroplast expression.
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Affiliation(s)
- Sally Buck
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Tim Rhodes
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Matteo Gionfriddo
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Tanya Skinner
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Ding Yuan
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Rosemary Birch
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
| | - Maxim V Kapralov
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Spencer M Whitney
- ARC Centre of Excellence in Translational Photosynthesis, Australian National University, Canberra 2000, Australia
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16
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Badger MR, Sharwood RE. Rubisco, the imperfect winner: it's all about the base. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:562-580. [PMID: 36412307 DOI: 10.1093/jxb/erac458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 11/20/2022] [Indexed: 06/16/2023]
Abstract
Rubisco catalysis is complex and includes an activation step through the formation of a carbamate at the conserved active site lysine residue and the formation of a highly reactive enediol that is the key to its catalytic reaction. The formation of this enediol is both the basis of its success and its Achilles' heel, creating imperfections to its catalytic efficiency. While Rubisco originally evolved in an atmosphere of high CO2, the earth's multiple oxidation events provided challenges to Rubisco through the fixation of O2 that competes with CO2 at the active site. Numerous catalytic screens across the Rubisco superfamily have identified significant variation in catalytic properties that have been linked to large and small subunit sequences. Despite this, we still have a rudimentary understanding of Rubisco's catalytic mechanism and how the evolution of kinetic properties has occurred. This review identifies the lysine base that functions both as an activator and a proton abstractor to create the enediol as a key to understanding how Rubisco may optimize its kinetic properties. The ways in which Rubisco and its partners have overcome catalytic and activation imperfections and thrived in a world of high O2, low CO2, and variable climatic regimes is remarkable.
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Affiliation(s)
- Murray R Badger
- Research School of Biology, Building 134 Linnaeus Way, Canberra ACT, 2601, Australia
| | - Robert E Sharwood
- Hawkesbury Institute for the Environment, Western Sydney University, Bourke St, Richmond, NSW, 2753, Australia
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17
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Bauwe H. Photorespiration - Rubisco's repair crew. JOURNAL OF PLANT PHYSIOLOGY 2023; 280:153899. [PMID: 36566670 DOI: 10.1016/j.jplph.2022.153899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/11/2022] [Accepted: 12/11/2022] [Indexed: 06/17/2023]
Abstract
The photorespiratory repair pathway (photorespiration in short) was set up from ancient metabolic modules about three billion years ago in cyanobacteria, the later ancestors of chloroplasts. These prokaryotes developed the capacity for oxygenic photosynthesis, i.e. the use of water as a source of electrons and protons (with O2 as a by-product) for the sunlight-driven synthesis of ATP and NADPH for CO2 fixation in the Calvin cycle. However, the CO2-binding enzyme, ribulose 1,5-bisphosphate carboxylase (known under the acronym Rubisco), is not absolutely selective for CO2 and can also use O2 in a side reaction. It then produces 2-phosphoglycolate (2PG), the accumulation of which would inhibit and potentially stop the Calvin cycle and subsequently photosynthetic electron transport. Photorespiration removes the 2-PG and in this way prevents oxygenic photosynthesis from poisoning itself. In plants, the core of photorespiration consists of ten enzymes distributed over three different types of organelles, requiring interorganellar transport and interaction with several auxiliary enzymes. It goes together with the release and to some extent loss of freshly fixed CO2. This disadvantageous feature can be suppressed by CO2-concentrating mechanisms, such as those that evolved in C4 plants thirty million years ago, which enhance CO2 fixation and reduce 2PG synthesis. Photorespiration itself provided a pioneer variant of such mechanisms in the predecessors of C4 plants, C3-C4 intermediate plants. This article is a review and update particularly on the enzyme components of plant photorespiration and their catalytic mechanisms, on the interaction of photorespiration with other metabolism and on its impact on the evolution of photosynthesis. This focus was chosen because a better knowledge of the enzymes involved and how they are embedded in overall plant metabolism can facilitate the targeted use of the now highly advanced methods of metabolic network modelling and flux analysis. Understanding photorespiration more than before as a process that enables, rather than reduces, plant photosynthesis, will help develop rational strategies for crop improvement.
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Affiliation(s)
- Hermann Bauwe
- University of Rostock, Plant Physiology, Albert-Einstein-Straße 3, D-18051, Rostock, Germany.
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18
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Kim S, Jang YJ, Gong G, Lee SM, Um Y, Kim KH, Ko JK. Engineering Cupriavidus necator H16 for enhanced lithoautotrophic poly(3-hydroxybutyrate) production from CO 2. Microb Cell Fact 2022; 21:231. [PMCID: PMC9636797 DOI: 10.1186/s12934-022-01962-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 10/13/2022] [Indexed: 11/06/2022] Open
Abstract
Background A representative hydrogen-oxidizing bacterium Cupriavidus necator H16 has attracted much attention as hosts to recycle carbon dioxide (CO2) into a biodegradable polymer, poly(R)-3-hydroxybutyrate (PHB). Although C. necator H16 has been used as a model PHB producer, the PHB production rate from CO2 is still too low for commercialization. Results Here, we engineer the carbon fixation metabolism to improve CO2 utilization and increase PHB production. We explore the possibilities to enhance the lithoautotrophic cell growth and PHB production by introducing additional copies of transcriptional regulators involved in Calvin Benson Bassham (CBB) cycle. Both cbbR and regA-overexpressing strains showed the positive phenotypes for 11% increased biomass accumulation and 28% increased PHB production. The transcriptional changes of key genes involved in CO2—fixing metabolism and PHB production were investigated. Conclusions The global transcriptional regulator RegA plays an important role in the regulation of carbon fixation and shows the possibility to improve autotrophic cell growth and PHB accumulation by increasing its expression level. This work represents another step forward in better understanding and improving the lithoautotrophic PHB production by C. necator H16. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-022-01962-7.
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Affiliation(s)
- Soyoung Kim
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Yong Jae Jang
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea
| | - Gyeongtaek Gong
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
| | - Sun-Mi Lee
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
| | - Youngsoon Um
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
| | - Kyoung Heon Kim
- grid.222754.40000 0001 0840 2678Department of Biotechnology, Graduate School, Korea University, Seoul, 02841 Republic of Korea
| | - Ja Kyong Ko
- grid.35541.360000000121053345Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul, 02792 Republic of Korea ,grid.412786.e0000 0004 1791 8264Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul, 02792 Republic of Korea
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19
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Sharwood RE. Reconstructing CO 2 fixation from the past. Science 2022; 378:137-138. [PMID: 36227972 DOI: 10.1126/science.ade6522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Analysis of Rubisco evolution could inform how to engineer a better enzyme.
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Affiliation(s)
- Robert E Sharwood
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
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20
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Raines CA. Improving plant productivity by re-tuning the regeneration of RuBP in the Calvin-Benson-Bassham cycle. THE NEW PHYTOLOGIST 2022; 236:350-356. [PMID: 35860861 PMCID: PMC9833393 DOI: 10.1111/nph.18394] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/30/2022] [Indexed: 05/03/2023]
Abstract
The Calvin-Benson-Bassham (CBB) cycle is arguably the most important pathway on earth, capturing CO2 from the atmosphere and converting it into organic molecules, providing the basis for life on our planet. This cycle has been intensively studied over the 50 yr since it was elucidated, and it is highly conserved across nature, from cyanobacteria to the largest of our land plants. Eight out of the 11 enzymes in this cycle catalyse the regeneration of ribulose-1-5 bisphosphate (RuBP), the CO2 acceptor molecule. The potential to manipulate RuBP regeneration to improve photosynthesis has been demonstrated in a number of plant species, and the development of new technologies, such as omics and synthetic biology provides exciting future opportunities to improve photosynthesis and increase crop yields.
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Affiliation(s)
- Christine A. Raines
- School of Life SciencesUniversity of EssexWivenhoe ParkColchesterEssexCO3 4JEUK
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21
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Sharwood RE, Quick WP, Sargent D, Estavillo GM, Silva-Perez V, Furbank RT. Mining for allelic gold: finding genetic variation in photosynthetic traits in crops and wild relatives. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:3085-3108. [PMID: 35274686 DOI: 10.1093/jxb/erac081] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Improvement of photosynthetic traits in crops to increase yield potential and crop resilience has recently become a major breeding target. Synthetic biology and genetic technologies offer unparalleled opportunities to create new genetics for photosynthetic traits driven by existing fundamental knowledge. However, large 'gene bank' collections of germplasm comprising historical collections of crop species and their relatives offer a wealth of opportunities to find novel allelic variation in the key steps of photosynthesis, to identify new mechanisms and to accelerate genetic progress in crop breeding programmes. Here we explore the available genetic resources in food and fibre crops, strategies to selectively target allelic variation in genes underpinning key photosynthetic processes, and deployment of this variation via gene editing in modern elite material.
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Affiliation(s)
- Robert E Sharwood
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - W Paul Quick
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, Australia
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Demi Sargent
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, NSW, Australia
| | | | | | - Robert T Furbank
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, ACT, Australia
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22
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Rin Kim S, Kim SJ, Kim SK, Seo SO, Park S, Shin J, Kim JS, Park BR, Jin YS, Chang PS, Park YC. Yeast metabolic engineering for carbon dioxide fixation and its application. BIORESOURCE TECHNOLOGY 2022; 346:126349. [PMID: 34800639 DOI: 10.1016/j.biortech.2021.126349] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/09/2021] [Accepted: 11/11/2021] [Indexed: 06/13/2023]
Abstract
As numerous industrial bioprocesses rely on yeast fermentation, developing CO2-fixing yeast strains can be an attractive option toward sustainable industrial processes and carbon neutrality. Recent studies have shown that the expression of ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) in yeasts, such as Saccharomyces cerevisiae and Kluyveromyces marxianus, enables mixotrophic CO2 fixation and production of biofuels. Also, the expression of a synthetic Calvin-Benson-Bassham (CBB) cycle including RuBisCO in Pichia pastoris enables autotrophic growth on CO2. This review highlights recent advances in metabolic engineering strategies to enable CO2 fixation in yeasts. Also, we discuss the potentials of other natural and synthetic metabolic pathways independent of RuBisCO for developing CO2-fixing yeast strains capable of producing value-added biochemicals.
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Affiliation(s)
- Soo Rin Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Soo-Jung Kim
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Sun-Ki Kim
- Department of Food Science and Technology, Chung-Ang University, Anseong, Gyeonggi 17546, Republic of Korea
| | - Seung-Oh Seo
- Department of Food Science and Nutrition, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Sujeong Park
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Jamin Shin
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Jeong-Sun Kim
- Department of Chemistry, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Bo-Ram Park
- Department of Agro-food Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Republic of Korea
| | - Yong-Su Jin
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Pahn-Shick Chang
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea
| | - Yong-Cheol Park
- Department of Bio and Fermentation Convergence Technology, Kookmin University, Seoul 02707, Republic of Korea.
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23
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Kawanishi Y, Matsunaga S. Synthetic Carbon Fixation: Conversion of Heterotrophs into Autotrophs by Calvin-Benson-Bassham Cycle Induction. CYTOLOGIA 2021. [DOI: 10.1508/cytologia.86.277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yuki Kawanishi
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science
| | - Sachihiro Matsunaga
- Laboratory of Integrated Biology, Department of Integrated Biosciences, Graduate School of Frontier Sciences
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24
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Kselíková V, Singh A, Bialevich V, Čížková M, Bišová K. Improving microalgae for biotechnology - From genetics to synthetic biology - Moving forward but not there yet. Biotechnol Adv 2021; 58:107885. [PMID: 34906670 DOI: 10.1016/j.biotechadv.2021.107885] [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: 08/10/2021] [Revised: 11/28/2021] [Accepted: 12/07/2021] [Indexed: 12/28/2022]
Abstract
Microalgae are a diverse group of photosynthetic organisms that can be exploited for the production of different compounds, ranging from crude biomass and biofuels to high value-added biochemicals and synthetic proteins. Traditionally, algal biotechnology relies on bioprospecting to identify new highly productive strains and more recently, on forward genetics to further enhance productivity. However, it has become clear that further improvements in algal productivity for biotechnology is impossible without combining traditional tools with the arising molecular genetics toolkit. We review recent advantages in developing high throughput screening methods, preparing genome-wide mutant libraries, and establishing genome editing techniques. We discuss how algae can be improved in terms of photosynthetic efficiency, biofuel and high value-added compound production. Finally, we critically evaluate developments over recent years and explore future potential in the field.
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Affiliation(s)
- Veronika Kselíková
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic; Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
| | - Anjali Singh
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic
| | - Vitali Bialevich
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic
| | - Mária Čížková
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic
| | - Kateřina Bišová
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic.
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25
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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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26
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Zhang J, Liu G, Carvajal AI, Wilson RH, Cai Z, Li Y. Discovery of a readily heterologously expressed Rubisco from the deep sea with potential for CO 2 capture. BIORESOUR BIOPROCESS 2021; 8:86. [PMID: 38650243 PMCID: PMC10992382 DOI: 10.1186/s40643-021-00439-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 08/27/2021] [Indexed: 11/10/2022] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), the key CO2-fixing enzyme in photosynthesis, is notorious for its low carboxylation. We report a highly active and assembly-competent Form II Rubisco from the endosymbiont of a deep-sea tubeworm Riftia pachyptila (RPE Rubisco), which shows a 50.5% higher carboxylation efficiency than that of a high functioning Rubisco from Synechococcus sp. PCC7002 (7002 Rubisco). It is a simpler hexamer with three pairs of large subunit homodimers around a central threefold symmetry axis. Compared with 7002 Rubisco, it showed a 3.6-fold higher carbon capture efficiency in vivo using a designed CO2 capture model. The simple structure, high carboxylation efficiency, easy heterologous soluble expression/assembly make RPE Rubisco a ready-to-deploy enzyme for CO2 capture that does not require complex co-expression of chaperones. The chemosynthetic CO2 fixation machinery of chemolithoautotrophs, CO2-fixing endosymbionts, may be more efficient than previously realized with great potential for next-generation microbial CO2 sequestration platforms.
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Affiliation(s)
- Junli Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Guoxia Liu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Alonso I Carvajal
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Robert H Wilson
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany.
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Zhen Cai
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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Bouvier JW, Emms DM, Rhodes T, Bolton JS, Brasnett A, Eddershaw A, Nielsen JR, Unitt A, Whitney SM, Kelly S. Rubisco Adaptation Is More Limited by Phylogenetic Constraint Than by Catalytic Trade-off. Mol Biol Evol 2021; 38:2880-2896. [PMID: 33739416 PMCID: PMC8233502 DOI: 10.1093/molbev/msab079] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Rubisco assimilates CO2 to form the sugars that fuel life on earth. Correlations between rubisco kinetic traits across species have led to the proposition that rubisco adaptation is highly constrained by catalytic trade-offs. However, these analyses did not consider the phylogenetic context of the enzymes that were analyzed. Thus, it is possible that the correlations observed were an artefact of the presence of phylogenetic signal in rubisco kinetics and the phylogenetic relationship between the species that were sampled. Here, we conducted a phylogenetically resolved analysis of rubisco kinetics and show that there is a significant phylogenetic signal in rubisco kinetic traits. We re-evaluated the extent of catalytic trade-offs accounting for this phylogenetic signal and found that all were attenuated. Following phylogenetic correction, the largest catalytic trade-offs were observed between the Michaelis constant for CO2 and carboxylase turnover (∼21-37%), and between the Michaelis constants for CO2 and O2 (∼9-19%), respectively. All other catalytic trade-offs were substantially attenuated such that they were marginal (<9%) or non-significant. This phylogenetically resolved analysis of rubisco kinetic evolution also identified kinetic changes that occur concomitant with the evolution of C4 photosynthesis. Finally, we show that phylogenetic constraints have played a larger role than catalytic trade-offs in limiting the evolution of rubisco kinetics. Thus, although there is strong evidence for some catalytic trade-offs, rubisco adaptation has been more limited by phylogenetic constraint than by the combined action of all catalytic trade-offs.
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Affiliation(s)
- Jacques W Bouvier
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
- Doctoral Training Centre, University of Oxford, Oxford, United Kingdom
| | - David M Emms
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
| | - Timothy Rhodes
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Jai S Bolton
- Doctoral Training Centre, University of Oxford, Oxford, United Kingdom
| | - Amelia Brasnett
- Doctoral Training Centre, University of Oxford, Oxford, United Kingdom
| | - Alice Eddershaw
- Doctoral Training Centre, University of Oxford, Oxford, United Kingdom
| | - Jochem R Nielsen
- Doctoral Training Centre, University of Oxford, Oxford, United Kingdom
| | - Anastasia Unitt
- Doctoral Training Centre, University of Oxford, Oxford, United Kingdom
| | - Spencer M Whitney
- Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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Moore CE, Meacham-Hensold K, Lemonnier P, Slattery RA, Benjamin C, Bernacchi CJ, Lawson T, Cavanagh AP. The effect of increasing temperature on crop photosynthesis: from enzymes to ecosystems. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:2822-2844. [PMID: 33619527 PMCID: PMC8023210 DOI: 10.1093/jxb/erab090] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 02/19/2021] [Indexed: 05/03/2023]
Abstract
As global land surface temperature continues to rise and heatwave events increase in frequency, duration, and/or intensity, our key food and fuel cropping systems will likely face increased heat-related stress. A large volume of literature exists on exploring measured and modelled impacts of rising temperature on crop photosynthesis, from enzymatic responses within the leaf up to larger ecosystem-scale responses that reflect seasonal and interannual crop responses to heat. This review discusses (i) how crop photosynthesis changes with temperature at the enzymatic scale within the leaf; (ii) how stomata and plant transport systems are affected by temperature; (iii) what features make a plant susceptible or tolerant to elevated temperature and heat stress; and (iv) how these temperature and heat effects compound at the ecosystem scale to affect crop yields. Throughout the review, we identify current advancements and future research trajectories that are needed to make our cropping systems more resilient to rising temperature and heat stress, which are both projected to occur due to current global fossil fuel emissions.
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Affiliation(s)
- Caitlin E Moore
- School of Agriculture and Environment, The University of Western Australia, Crawley, Australia
- Institute for Sustainability, Energy & Environment, University of Illinois at Urbana-Champaign, Urbana, USA
- Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Katherine Meacham-Hensold
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, USA
| | | | - Rebecca A Slattery
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Claire Benjamin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Carl J Bernacchi
- Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, USA
- Global Change and Photosynthesis Research Unit, United States Department of Agriculture–Agricultural Research Service, Urbana, USA
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, USA
| | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, UK
| | - Amanda P Cavanagh
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, USA
- School of Life Sciences, University of Essex, Colchester, UK
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Synthetic Biology Approaches To Enhance Microalgal Productivity. Trends Biotechnol 2021; 39:1019-1036. [PMID: 33541719 DOI: 10.1016/j.tibtech.2020.12.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/15/2022]
Abstract
The major bottleneck in commercializing biofuels and other commodities produced by microalgae is the high cost associated with phototrophic cultivation. Improving microalgal productivities could be a solution to this problem. Synthetic biology methods have recently been used to engineer the downstream production pathways in several microalgal strains. However, engineering upstream photosynthetic and carbon fixation metabolism to enhance growth, productivity, and yield has barely been explored in microalgae. We describe strategies to improve the generation of reducing power from light, as well as to improve the assimilation of CO2 by either the native Calvin cycle or synthetic alternatives. Overall, we are optimistic that recent technological advances will prompt long-awaited breakthroughs in microalgal research.
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Cummins PL. The Coevolution of RuBisCO, Photorespiration, and Carbon Concentrating Mechanisms in Higher Plants. FRONTIERS IN PLANT SCIENCE 2021; 12:662425. [PMID: 34539685 PMCID: PMC8440988 DOI: 10.3389/fpls.2021.662425] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 07/26/2021] [Indexed: 05/20/2023]
Abstract
Ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (RuBisCO) is the carbon-fixing enzyme present in most photosynthetic organisms, converting CO2 into organic matter. Globally, photosynthetic efficiency in terrestrial plants has become increasingly challenged in recent decades due to a rapid increase in atmospheric CO2 and associated changes toward warmer and dryer environments. Well adapted for these new climatic conditions, the C4 photosynthetic pathway utilizes carbon concentrating mechanisms to increase CO2 concentrations surrounding RuBisCO, suppressing photorespiration from the oxygenase catalyzed reaction with O2. The energy efficiency of C3 photosynthesis, from which the C4 pathway evolved, is thought to rely critically on an uninterrupted supply of chloroplast CO2. Part of the homeostatic mechanism that maintains this constancy of supply involves the CO2 produced as a byproduct of photorespiration in a negative feedback loop. Analyzing the database of RuBisCO kinetic parameters, we suggest that in genera (Flaveria and Panicum) for which both C3 and C4 examples are available, the C4 pathway evolved only from C3 ancestors possessing much lower than the average carboxylase specificity relative to that of the oxygenase reaction (S C/O=S C/S O), and hence, the higher CO2 levels required for development of the photorespiratory CO2 pump (C2 photosynthesis) essential in the initial stages of C4 evolution, while in the later stage (final optimization phase in the Flaveria model) increased CO2 turnover may have occurred, which would have been supported by the higher CO2 levels. Otherwise, C4 RuBisCO kinetic traits remain little changed from the ancestral C3 species. At the opposite end of the spectrum, C3 plants (from Limonium) with higher than average S C/O, which may be associated with the ability of increased CO2, relative to O2, affinity to offset reduced photorespiration and chloroplast CO2 levels, can tolerate high stress environments. It is suggested that, instead of inherently constrained by its kinetic mechanism, RuBisCO possesses the extensive kinetic plasticity necessary for adaptation to changes in photorespiration that occur in the homeostatic regulation of CO2 supply under a broad range of abiotic environmental conditions.
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Liang B, Zhao Y, Yang J. Recent Advances in Developing Artificial Autotrophic Microorganism for Reinforcing CO 2 Fixation. Front Microbiol 2020; 11:592631. [PMID: 33240247 PMCID: PMC7680860 DOI: 10.3389/fmicb.2020.592631] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 10/21/2020] [Indexed: 11/13/2022] Open
Abstract
With the goal of achieving carbon sequestration, emission reduction and cleaner production, biological methods have been employed to convert carbon dioxide (CO2) into fuels and chemicals. However, natural autotrophic organisms are not suitable cell factories due to their poor carbon fixation efficiency and poor growth rate. Heterotrophic microorganisms are promising candidates, since they have been proven to be efficient biofuel and chemical production chassis. This review first briefly summarizes six naturally occurring CO2 fixation pathways, and then focuses on recent advances in artificially designing efficient CO2 fixation pathways. Moreover, this review discusses the transformation of heterotrophic microorganisms into hemiautotrophic microorganisms and delves further into fully autotrophic microorganisms (artificial autotrophy) by use of synthetic biological tools and strategies. Rapid developments in artificial autotrophy have laid a solid foundation for the development of efficient carbon fixation cell factories. Finally, this review highlights future directions toward large-scale applications. Artificial autotrophic microbial cell factories need further improvements in terms of CO2 fixation pathways, reducing power supply, compartmentalization and host selection.
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Affiliation(s)
- Bo Liang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Qingdao Agricultural University, Qingdao, China
- Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Yukun Zhao
- Pony Testing International Group, Qingdao, China
| | - Jianming Yang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Qingdao Agricultural University, Qingdao, China
- Shandong Key Lab of Applied Mycology, College of Life Sciences, Qingdao Agricultural University, Qingdao, China
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32
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Flamholz AI, Dugan E, Blikstad C, Gleizer S, Ben-Nissan R, Amram S, Antonovsky N, Ravishankar S, Noor E, Bar-Even A, Milo R, Savage DF. Functional reconstitution of a bacterial CO 2 concentrating mechanism in Escherichia coli. eLife 2020; 9:59882. [PMID: 33084575 PMCID: PMC7714395 DOI: 10.7554/elife.59882] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 10/20/2020] [Indexed: 12/19/2022] Open
Abstract
Many photosynthetic organisms employ a CO2 concentrating mechanism (CCM) to increase the rate of CO2 fixation via the Calvin cycle. CCMs catalyze ≈50% of global photosynthesis, yet it remains unclear which genes and proteins are required to produce this complex adaptation. We describe the construction of a functional CCM in a non-native host, achieved by expressing genes from an autotrophic bacterium in an Escherichia coli strain engineered to depend on rubisco carboxylation for growth. Expression of 20 CCM genes enabled E. coli to grow by fixing CO2 from ambient air into biomass, with growth in ambient air depending on the components of the CCM. Bacterial CCMs are therefore genetically compact and readily transplanted, rationalizing their presence in diverse bacteria. Reconstitution enabled genetic experiments refining our understanding of the CCM, thereby laying the groundwork for deeper study and engineering of the cell biology supporting CO2 assimilation in diverse organisms.
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Affiliation(s)
- Avi I Flamholz
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Eli Dugan
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Cecilia Blikstad
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Shmuel Gleizer
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Roee Ben-Nissan
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Shira Amram
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Niv Antonovsky
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Sumedha Ravishankar
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
| | - Elad Noor
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Arren Bar-Even
- Max Planck Institute of Molecular Plant PhysiologyPotsdamGermany
| | - Ron Milo
- Department of Plant and Environmental Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - David F Savage
- Department of Molecular and Cell Biology, University of California, BerkeleyBerkeleyUnited States
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33
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Gunn LH, Martin Avila E, Birch R, Whitney SM. The dependency of red Rubisco on its cognate activase for enhancing plant photosynthesis and growth. Proc Natl Acad Sci U S A 2020; 117:25890-25896. [PMID: 32989135 PMCID: PMC7568259 DOI: 10.1073/pnas.2011641117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Plant photosynthesis and growth are often limited by the activity of the CO2-fixing enzyme Rubisco. The broad kinetic diversity of Rubisco in nature is accompanied by differences in the composition and compatibility of the ancillary proteins needed for its folding, assembly, and metabolic regulation. Variations in the protein folding needs of catalytically efficient red algae Rubisco prevent their production in plants. Here, we show this impediment does not extend to Rubisco from Rhodobacter sphaeroides (RsRubisco)-a red-type Rubisco able to assemble in plant chloroplasts. In transplastomic tobRsLS lines expressing a codon optimized Rs-rbcLS operon, the messenger RNA (mRNA) abundance was ∼25% of rbcL transcript and RsRubisco ∼40% the Rubisco content in WT tobacco. To mitigate the low activation status of RsRubisco in tobRsLS (∼23% sites active under ambient CO2), the metabolic repair protein RsRca (Rs-activase) was introduced via nuclear transformation. RsRca production in the tobRsLS::X progeny matched endogenous tobacco Rca levels (∼1 µmol protomer·m2) and enhanced RsRubisco activation to 75% under elevated CO2 (1%, vol/vol) growth. Accordingly, the rate of photosynthesis and growth in the tobRsLS::X lines were improved >twofold relative to tobRsLS. Other tobacco lines producing RsRubisco containing alternate diatom and red algae S-subunits were nonviable as CO2-fixation rates (kcatc) were reduced >95% and CO2/O2 specificity impaired 30-50%. We show differences in hybrid and WT RsRubisco biogenesis in tobacco correlated with assembly in Escherichia coli advocating use of this bacterium to preevaluate the kinetic and chloroplast compatibility of engineered RsRubisco, an isoform amenable to directed evolution.
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Affiliation(s)
- Laura H Gunn
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Elena Martin Avila
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Rosemary Birch
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
| | - Spencer M Whitney
- Plant Science Division, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia
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Lin MT, Stone WD, Chaudhari V, Hanson MR. Small subunits can determine enzyme kinetics of tobacco Rubisco expressed in Escherichia coli. NATURE PLANTS 2020; 6:1289-1299. [PMID: 32929197 DOI: 10.1038/s41477-020-00761-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 07/28/2020] [Indexed: 05/19/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) catalyses the first step in carbon fixation and is a strategic target for improving photosynthetic efficiency. In plants, Rubisco is composed of eight large and eight small subunits, and its biogenesis requires multiple chaperones. Here, we optimized a system to produce tobacco Rubisco in Escherichia coli by coexpressing chaperones in autoinduction medium. We successfully assembled tobacco Rubisco in E. coli with each small subunit that is normally encoded by the nuclear genome. Even though each enzyme carries only a single type of small subunit in E. coli, the enzymes exhibit carboxylation kinetics that are very similar to the carboxylation kinetics of the native Rubisco. Tobacco Rubisco assembled with a recently discovered trichome small subunit has a higher catalytic rate and a lower CO2 affinity compared with Rubisco complexes that are assembled with other small subunits. Our E. coli expression system will enable the analysis of features of both subunits of Rubisco that affect its kinetic properties.
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Affiliation(s)
- Myat T Lin
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - William D Stone
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | | | - Maureen R Hanson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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35
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Affiliation(s)
- Robert E Sharwood
- ARC Centre of Excellence for Translation Photosynthesis, Research School Biology, Australian National University, Canberra, Australian Capital Territory, Australia.
- Hawkesbury Institute for the Environment, Western Sydney University, Richmond, New South Wales, Australia.
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36
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Davidi D, Shamshoum M, Guo Z, Bar‐On YM, Prywes N, Oz A, Jablonska J, Flamholz A, Wernick DG, Antonovsky N, de Pins B, Shachar L, Hochhauser D, Peleg Y, Albeck S, Sharon I, Mueller‐Cajar O, Milo R. Highly active rubiscos discovered by systematic interrogation of natural sequence diversity. EMBO J 2020; 39:e104081. [PMID: 32500941 PMCID: PMC7507306 DOI: 10.15252/embj.2019104081] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 04/30/2020] [Accepted: 05/07/2020] [Indexed: 11/09/2022] Open
Abstract
CO2 is converted into biomass almost solely by the enzyme rubisco. The poor carboxylation properties of plant rubiscos have led to efforts that made it the most kinetically characterized enzyme, yet these studies focused on < 5% of its natural diversity. Here, we searched for fast-carboxylating variants by systematically mining genomic and metagenomic data. Approximately 33,000 unique rubisco sequences were identified and clustered into ≈ 1,000 similarity groups. We then synthesized, purified, and biochemically tested the carboxylation rates of 143 representatives, spanning all clusters of form-II and form-II/III rubiscos. Most variants (> 100) were active in vitro, with the fastest having a turnover number of 22 ± 1 s-1 -sixfold faster than the median plant rubisco and nearly twofold faster than the fastest measured rubisco to date. Unlike rubiscos from plants and cyanobacteria, the fastest variants discovered here are homodimers and exhibit a much simpler folding and activation kinetics. Our pipeline can be utilized to explore the kinetic space of other enzymes of interest, allowing us to get a better view of the biosynthetic potential of the biosphere.
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Affiliation(s)
- Dan Davidi
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
- Present address:
Department of GeneticsHarvard Medical SchoolBostonMAUSA
| | - Melina Shamshoum
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
| | - Zhijun Guo
- School of Biological SciencesNanyang Technological UniversitySingaporeSingapore
| | - Yinon M Bar‐On
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
| | - Noam Prywes
- Department of Molecular and Cell BiologyUniversity of CaliforniaBerkeleyCAUSA
| | - Aia Oz
- Migal Galilee Research InstituteKiryat ShmonaIsrael
- Tel Hai CollegeUpper GalileeIsrael
| | - Jagoda Jablonska
- Department of Biomolecular SciencesWeizmann Institute of ScienceRehovotIsrael
| | - Avi Flamholz
- Department of Molecular and Cell BiologyUniversity of CaliforniaBerkeleyCAUSA
| | - David G Wernick
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
- Present address:
BASF Enzymes LLCSan DiegoCAUSA
| | - Niv Antonovsky
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
- Present address:
Laboratory of Genetically Encoded Small MoleculesThe Rockefeller UniversityNew YorkNYUSA
| | - Benoit de Pins
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
| | - Lior Shachar
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
| | - Dina Hochhauser
- Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Yoav Peleg
- Department of Life Sciences Core FacilitiesWeizmann Institute of ScienceRehovotIsrael
| | - Shira Albeck
- Department of Life Sciences Core FacilitiesWeizmann Institute of ScienceRehovotIsrael
| | - Itai Sharon
- Migal Galilee Research InstituteKiryat ShmonaIsrael
- Tel Hai CollegeUpper GalileeIsrael
| | | | - Ron Milo
- Department of Plant and Environmental SciencesWeizmann Institute of ScienceRehovotIsrael
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37
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Banda DM, Pereira JH, Liu AK, Orr DJ, Hammel M, He C, Parry MAJ, Carmo-Silva E, Adams PD, Banfield JF, Shih PM. Novel bacterial clade reveals origin of form I Rubisco. NATURE PLANTS 2020; 6:1158-1166. [PMID: 32868887 DOI: 10.1038/s41477-020-00762-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 07/28/2020] [Indexed: 05/12/2023]
Abstract
Rubisco sustains the biosphere through the fixation of CO2 into biomass. In plants and cyanobacteria, form I Rubisco is structurally comprised of large and small subunits, whereas all other Rubisco forms lack small subunits. The rise of the form I complex through the innovation of small subunits represents a key, yet poorly understood, transition in Rubisco's evolution. Through metagenomic analyses, we discovered a previously uncharacterized clade sister to form I Rubisco that evolved without small subunits. This clade diverged before the evolution of cyanobacteria and the origin of the small subunit; thus, it provides a unique reference point to advance our understanding of form I Rubisco evolution. Structural and kinetic data presented here reveal how a proto-form I Rubisco assembled and functioned without the structural stability imparted from small subunits. Our findings provide insight into a key evolutionary transition of the most abundant enzyme on Earth and the predominant entry point for nearly all global organic carbon.
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Affiliation(s)
- Douglas M Banda
- Department of Plant Biology, University of California, Davis, Davis, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jose H Pereira
- Technology Division, Joint BioEnergy Institute, Emeryville, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Albert K Liu
- Department of Plant Biology, University of California, Davis, Davis, CA, USA
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Douglas J Orr
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Christine He
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA
| | - Martin A J Parry
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | | | - Paul D Adams
- Technology Division, Joint BioEnergy Institute, Emeryville, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jillian F Banfield
- Department of Earth and Planetary Science, University of California, Berkeley, Berkeley, CA, USA.
- Department of Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA, USA.
- Innovative Genomics Institute, University of California, Berkeley, Berkeley, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
| | - Patrick M Shih
- Department of Plant Biology, University of California, Davis, Davis, CA, USA.
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Feedstocks Division, Joint BioEnergy Institute, Emeryville, CA, USA.
- Genome Center, University of California, Davis, Davis, CA, USA.
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Martin-Avila E, Lim YL, Birch R, Dirk LMA, Buck S, Rhodes T, Sharwood RE, Kapralov MV, Whitney SM. Modifying Plant Photosynthesis and Growth via Simultaneous Chloroplast Transformation of Rubisco Large and Small Subunits. THE PLANT CELL 2020; 32:2898-2916. [PMID: 32647068 PMCID: PMC7474299 DOI: 10.1105/tpc.20.00288] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/15/2020] [Accepted: 07/06/2020] [Indexed: 05/20/2023]
Abstract
Engineering improved Rubisco for the enhancement of photosynthesis is challenged by the alternate locations of the chloroplast rbcL gene and nuclear RbcS genes. Here we develop an RNAi-RbcS tobacco (Nicotiana tabacum) master-line, tobRrΔS, for producing homogenous plant Rubisco by rbcL-rbcS operon chloroplast transformation. Four genotypes encoding alternative rbcS genes and adjoining 5'-intergenic sequences revealed that Rubisco production was highest (50% of the wild type) in the lines incorporating a rbcS gene whose codon use and 5' untranslated-region matched rbcL Additional tobacco genotypes produced here incorporated differing potato (Solanum tuberosum) rbcL-rbcS operons that either encoded one of three mesophyll small subunits (pS1, pS2, and pS3) or the potato trichome pST-subunit. The pS3-subunit caused impairment of potato Rubisco production by ∼15% relative to the lines producing pS1, pS2, or pST However, the βA-βB loop Asn-55-His and Lys-57-Ser substitutions in the pS3-subunit improved carboxylation rates by 13% and carboxylation efficiency (CE) by 17%, relative to potato Rubisco incorporating pS1 or pS2-subunits. Tobacco photosynthesis and growth were most impaired in lines producing potato Rubisco incorporating the pST-subunit, which reduced CE and CO2/O2 specificity 40% and 15%, respectively. Returning the rbcS gene to the plant plastome provides an effective bioengineering chassis for introduction and evaluation of novel homogeneous Rubisco complexes in a whole plant context.
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Affiliation(s)
- Elena Martin-Avila
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Yi-Leen Lim
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Rosemary Birch
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Lynnette M A Dirk
- Department of Horticulture, Seed Biology Group, University of Kentucky, Lexington, Kentucky 40546-0312
| | - Sally Buck
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Timothy Rhodes
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Robert E Sharwood
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Maxim V Kapralov
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Spencer M Whitney
- Research School of Biology, The Australian National University, Acton, Australian Capital Territory 2601, Australia
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Chaperone Machineries of Rubisco – The Most Abundant Enzyme. Trends Biochem Sci 2020; 45:748-763. [DOI: 10.1016/j.tibs.2020.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 04/19/2020] [Accepted: 05/04/2020] [Indexed: 12/14/2022]
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Fernie AR, Bauwe H. Wasteful, essential, evolutionary stepping stone? The multiple personalities of the photorespiratory pathway. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:666-677. [PMID: 31904886 DOI: 10.1111/tpj.14669] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/30/2019] [Accepted: 12/11/2019] [Indexed: 05/08/2023]
Abstract
The photorespiratory pathway, in short photorespiration, is a metabolic repair system that enables the CO2 fixation enzyme Rubisco to sustainably operate in the presence of oxygen, that is, during oxygenic photosynthesis of plants and cyanobacteria. Photorespiration is necessary because an auto-inhibitory metabolite, 2-phosphoglycolate (2PG), is produced when Rubisco binds oxygen instead of CO2 as a substrate and must be removed, to avoid collapse of metabolism, and recycled as efficiently as possible. The basic principle of recycling 2PG very likely evolved several billion years ago in connection with the evolution of oxyphotobacteria. It comprises the multi-step combination of two molecules of 2PG to form 3-phosphoglycerate. The biochemistry of this process dictates that one out of four 2PG carbons is lost as CO2 , which is a long-standing plant breeders' concern because it represents by far the largest fraction of respiratory processes that reduce gross-photosynthesis of major crops down to about 50% and less, lowering potential yields. In addition to the ATP needed for recycling of the 2PG carbon, extra energy is needed for the refixation of liberated equal amounts of ammonia. It is thought that the energy costs of photorespiration have an additional negative impact on crop yields in at least some environments. This paper discusses recent advances concerning the origin and evolution of photorespiration, and gives an overview of contemporary and envisioned strategies to engineer the biochemistry of, or even avoid, photorespiration.
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Affiliation(s)
- Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476, Potsdam-Golm, Germany
| | - Hermann Bauwe
- Plant Physiology Department, University of Rostock, Albert-Einstein-Straße 3, D-18051, Rostock, Germany
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Cummins PL, Gready JE. Kohn-Sham Density Functional Calculations Reveal Proton Wires in the Enolization and Carboxylase Reactions Catalyzed by Rubisco. J Phys Chem B 2020; 124:3015-3026. [PMID: 32208706 DOI: 10.1021/acs.jpcb.0c01169] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Ribulose 1,5-bisphosphate (RuBP) carboxylase-oxygenase (Rubisco) plays a fundamental role in the carbon cycle by fixing the atmospheric CO2 used in photosynthesis. Rubisco is all the more remarkable because it must catalyze some difficult multistep reaction chemistry involving proton transfers within the one active site. In the present study, we have used Kohn-Sham density functional theory at the B3LYP/6-31G* level with basis set superposition error and dispersion corrections (B3LYP-gCP-D3) to examine the possibility that the proton transfers can take place through molecular wires (including active-site water molecules) via the classical Grotthuss proton-shuttle mechanism. The results support an essential role for water molecules found in the crystal structures of Rubisco complexes as facilitators of proton transport in all the rate-limiting (catalytic) reaction steps through a network of short proton wires within the Rubisco active site. We suggest that completion of the initial product turnover (cycle) requires two excess protons produced in the initial carbamylation that is required for Rubisco activation. By use of proton wires, a large number of reaction steps may be accommodated within a single active site without necessitating the input of excessive conformational strain energy arising from the movement of residue side chains into positions where direct protonation of substrates can occur. The involvement of the identified types of proton wires in the kinetic mechanism is capable of providing a unique explanation for various experimental observations, including deuterium isotope effects and the results of site-directed mutagenesis experiments, and may thus provide a realistic solution to the problem of Rubisco's challenging chemistry.
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Affiliation(s)
- Peter L Cummins
- Department of Genome Sciences, John Curtin School of Medical Research, The Australian National University, Canberra, ACT 0200, Australia
| | - Jill E Gready
- Department of Genome Sciences, John Curtin School of Medical Research, The Australian National University, Canberra, ACT 0200, Australia
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