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Advances in Genetic Engineering in Improving Photosynthesis and Microalgal Productivity. Int J Mol Sci 2023; 24:ijms24031898. [PMID: 36768215 PMCID: PMC9915242 DOI: 10.3390/ijms24031898] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/10/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Even though sunlight energy far outweighs the energy required by human activities, its utilization is a key goal in the field of renewable energies. Microalgae have emerged as a promising new and sustainable feedstock for meeting rising food and feed demand. Because traditional methods of microalgal improvement are likely to have reached their limits, genetic engineering is expected to allow for further increases in the photosynthesis and productivity of microalgae. Understanding the mechanisms that control photosynthesis will enable researchers to identify targets for genetic engineering and, in the end, increase biomass yield, offsetting the costs of cultivation systems and downstream biomass processing. This review describes the molecular events that happen during photosynthesis and microalgal productivity through genetic engineering and discusses future strategies and the limitations of genetic engineering in microalgal productivity. We highlight the major achievements in manipulating the fundamental mechanisms of microalgal photosynthesis and biomass production, as well as promising approaches for making significant contributions to upcoming microalgal-based biotechnology.
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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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3
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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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4
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Qiu LQ, Yao X, Zhang YK, Li HR, He LN. Advancements and Challenges in Reductive Conversion of Carbon Dioxide via Thermo-/Photocatalysis. J Org Chem 2022; 88:4942-4964. [PMID: 36342846 DOI: 10.1021/acs.joc.2c02179] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Carbon dioxide (CO2) is the major greenhouse gas and also an abundant and renewable carbon resource. Therefore, its chemical conversion and utilization are of great attraction for sustainable development. Especially, reductive conversion of CO2 with energy input has become a current hotspot due to its ability to access fuels and various important chemicals. Nowadays, the controllable CO2 hydrogenation to formic acid and alcohols using sustainable H2 resources has been regarded as an appealing solution to hydrogen storage and CO2 accumulation. In addition, photocatalytic CO2 reduction to CO also provides a potential way to utilize this greenhouse gas efficiently. Besides direct CO2 hydrogenation, CO2 reductive functionalization integrates CO2 reduction with subsequent C-X (X = N, S, C, O) bond formation and indirect transformation strategies, enlarging the diverse products derived from CO2 and promoting CO2 reductive conversion into a new stage. In this Perspective, the progress and challenges of CO2 reductive conversion, including hydrogenation, reductive functionalization, photocatalytic reduction, and photocatalytic reductive functionalization are summarized and discussed along with the key issues and future trends/directions in this field. We hope this Perspective can evoke intense interest and inspire much innovation in the promise of CO2 valorization.
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Affiliation(s)
- Li-Qi Qiu
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Xiangyang Yao
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Yong-Kang Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Hong-Ru Li
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
- College of Pharmacy, Nankai University, Tianjin 300353, China
| | - Liang-Nian He
- State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
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5
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Schulz L, Guo Z, Zarzycki J, Steinchen W, Schuller JM, Heimerl T, Prinz S, Mueller-Cajar O, Erb TJ, Hochberg GKA. Evolution of increased complexity and specificity at the dawn of form I Rubiscos. Science 2022; 378:155-160. [PMID: 36227987 DOI: 10.1126/science.abq1416] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The evolution of ribulose-1,5-bisphosphate carboxylase/oxygenases (Rubiscos) that discriminate strongly between their substrate carbon dioxide and the undesired side substrate dioxygen was an important event for photosynthetic organisms adapting to an oxygenated environment. We use ancestral sequence reconstruction to recapitulate this event. We show that Rubisco increased its specificity and carboxylation efficiency through the gain of an accessory subunit before atmospheric oxygen was present. Using structural and biochemical approaches, we retrace how this subunit was gained and became essential. Our work illuminates the emergence of an adaptation to rising ambient oxygen levels, provides a template for investigating the function of interactions that have remained elusive because of their essentiality, and sheds light on the determinants of specificity in Rubisco.
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Affiliation(s)
- Luca Schulz
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Zhijun Guo
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Jan Zarzycki
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
| | - Wieland Steinchen
- Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, 35043 Marburg, Germany.,Department of Chemistry, Philipps University Marburg, 35043 Marburg, Germany
| | - Jan M Schuller
- Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, 35043 Marburg, Germany.,Department of Chemistry, Philipps University Marburg, 35043 Marburg, Germany
| | - Thomas Heimerl
- Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, 35043 Marburg, Germany.,Department of Biology, Philipps University Marburg, 35043 Marburg, Germany
| | - Simone Prinz
- Central Electron Microscopy Facility, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Oliver Mueller-Cajar
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Tobias J Erb
- Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.,Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, 35043 Marburg, Germany
| | - Georg K A Hochberg
- Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, 35043 Marburg, Germany.,Department of Chemistry, Philipps University Marburg, 35043 Marburg, Germany.,Evolutionary Biochemistry Group, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
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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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7
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Abstract
Since the 1950s, microalgae have been grown commercially in man-made cultivation units and used for biomass production as a source of food and feed supplements, pharmaceuticals, cosmetics and lately biofuels, as well as a means for wastewater treatment and mitigation of atmospheric CO2 build-up. In this work, photosynthesis and growth affecting variables—light intensity, pH, CO2/O2 exchange, nutrient supply, culture turbulence, light/dark cell cycling, biomass density and culture depth (light path)—are reviewed as concerns in microalgae mass cultures. Various photosynthesis monitoring techniques were employed to study photosynthetic performance to optimize the growth of microalgae strains in outdoor cultivation units. The most operative and reliable techniques appeared to be fast-response ones based on chlorophyll fluorescence and oxygen production monitoring, which provide analogous results.
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Matsumura H, Shiomi K, Yamamoto A, Taketani Y, Kobayashi N, Yoshizawa T, Tanaka SI, Yoshikawa H, Endo M, Fukayama H. Hybrid Rubisco with Complete Replacement of Rice Rubisco Small Subunits by Sorghum Counterparts Confers C 4 Plant-like High Catalytic Activity. MOLECULAR PLANT 2020; 13:1570-1581. [PMID: 32882392 DOI: 10.1016/j.molp.2020.08.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 07/28/2020] [Accepted: 08/22/2020] [Indexed: 05/25/2023]
Abstract
Photosynthetic rate at the present atmospheric condition is limited by the CO2-fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) because of its extremely low catalytic rate (kcat) and poor affinity for CO2 (Kc) and specificity for CO2 (Sc/o). Rubisco in C4 plants generally shows higher kcat than that in C3 plants. Rubisco consists of eight large subunits and eight small subunits (RbcS). Previously, the chimeric incorporation of sorghum C4-type RbcS significantly increased the kcat of Rubisco in a C3 plant, rice. In this study, we knocked out rice RbcS multigene family using the CRISPR-Cas9 technology and completely replaced rice RbcS with sorghum RbcS in rice Rubisco. Obtained hybrid Rubisco showed almost C4 plant-like catalytic properties, i.e., higher kcat, higher Kc, and lower Sc/o. Transgenic lines expressing the hybrid Rubisco accumulated reduced levels of Rubisco, whereas they showed slightly but significantly higher photosynthetic capacity and similar biomass production under high CO2 condition compared with wild-type rice. High-resolution crystal structural analysis of the wild-type Rubisco and hybrid Rubisco revealed the structural differences around the central pore of Rubisco and the βC-βD hairpin in RbcS. We propose that such differences, particularly in the βC-βD hairpin, may impact the flexibility of Rubisco catalytic site and change its catalytic properties.
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Affiliation(s)
- Hiroyoshi Matsumura
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577, Japan.
| | - Keita Shiomi
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-tyou, Nada-ku, Kobe 657-8501, Japan
| | - Akito Yamamoto
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-tyou, Nada-ku, Kobe 657-8501, Japan
| | - Yuri Taketani
- Faculty of Agriculture, Kobe University, 1-1 Rokkodai-tyou, Nada-ku, Kobe 657-8501, Japan
| | - Noriyuki Kobayashi
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-tyou, Nada-ku, Kobe 657-8501, Japan
| | - Takuya Yoshizawa
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577, Japan
| | - Shun-Ichi Tanaka
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577, Japan
| | - Hiroki Yoshikawa
- Department of Biotechnology, College of Life Sciences, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu 525-8577, Japan
| | - Masaki Endo
- Division of Applied Genetics, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2 Owashi, Tsukuba 305-8634, Japan
| | - Hiroshi Fukayama
- Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-tyou, Nada-ku, Kobe 657-8501, Japan.
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Flecken M, Wang H, Popilka L, Hartl FU, Bracher A, Hayer-Hartl M. Dual Functions of a Rubisco Activase in Metabolic Repair and Recruitment to Carboxysomes. Cell 2020; 183:457-473.e20. [PMID: 32979320 DOI: 10.1016/j.cell.2020.09.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/13/2020] [Accepted: 09/01/2020] [Indexed: 01/19/2023]
Abstract
Rubisco, the key enzyme of CO2 fixation in photosynthesis, is prone to inactivation by inhibitory sugar phosphates. Inhibited Rubisco undergoes conformational repair by the hexameric AAA+ chaperone Rubisco activase (Rca) in a process that is not well understood. Here, we performed a structural and mechanistic analysis of cyanobacterial Rca, a close homolog of plant Rca. In the Rca:Rubisco complex, Rca is positioned over the Rubisco catalytic site under repair and pulls the N-terminal tail of the large Rubisco subunit (RbcL) into the hexamer pore. Simultaneous displacement of the C terminus of the adjacent RbcL opens the catalytic site for inhibitor release. An alternative interaction of Rca with Rubisco is mediated by C-terminal domains that resemble the small Rubisco subunit. These domains, together with the N-terminal AAA+ hexamer, ensure that Rca is packaged with Rubisco into carboxysomes. The cyanobacterial Rca is a dual-purpose protein with functions in Rubisco repair and carboxysome organization.
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Affiliation(s)
- Mirkko Flecken
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Huping Wang
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Leonhard Popilka
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Andreas Bracher
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Manajit Hayer-Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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Vecchi V, Barera S, Bassi R, Dall’Osto L. Potential and Challenges of Improving Photosynthesis in Algae. PLANTS 2020; 9:plants9010067. [PMID: 31947868 PMCID: PMC7020468 DOI: 10.3390/plants9010067] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 11/16/2022]
Abstract
Sunlight energy largely exceeds the energy required by anthropic activities, and therefore its exploitation represents a major target in the field of renewable energies. The interest in the mass cultivation of green microalgae has grown in the last decades, as algal biomass could be employed to cover a significant portion of global energy demand. Advantages of microalgal vs. plant biomass production include higher light-use efficiency, efficient carbon capture and the valorization of marginal lands and wastewaters. Realization of this potential requires a decrease of the current production costs, which can be obtained by increasing the productivity of the most common industrial strains, by the identification of factors limiting biomass yield, and by removing bottlenecks, namely through domestication strategies aimed to fill the gap between the theoretical and real productivity of algal cultures. In particular, the light-to-biomass conversion efficiency represents one of the major constraints for achieving a significant improvement of algal cell lines. This review outlines the molecular events of photosynthesis, which regulate the conversion of light into biomass, and discusses how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. This review highlights the most recent results in the manipulation of the fundamental mechanisms of algal photosynthesis, which revealed that a significant yield enhancement is feasible. Moreover, metabolic engineering of microalgae, focused upon the development of renewable fuel biorefineries, has also drawn attention and resulted in efforts for enhancing productivity of oil or isoprenoids.
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Affiliation(s)
| | | | | | - Luca Dall’Osto
- Correspondence: ; Tel.: +39-045-8027806; Fax: +39-045-8027929
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11
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Hong D, Kawanishi T, Tsukakoshi Y, Kotani H, Ishizuka T, Kojima T. Efficient Photocatalytic CO2 Reduction by a Ni(II) Complex Having Pyridine Pendants through Capturing a Mg2+ Ion as a Lewis-Acid Cocatalyst. J Am Chem Soc 2019; 141:20309-20317. [DOI: 10.1021/jacs.9b10597] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Dachao Hong
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Takuya Kawanishi
- Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Yuto Tsukakoshi
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Hiroaki Kotani
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Tomoya Ishizuka
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Takahiko Kojima
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
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12
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Pottier M, Gilis D, Boutry M. The Hidden Face of Rubisco. TRENDS IN PLANT SCIENCE 2018; 23:382-392. [PMID: 29525130 DOI: 10.1016/j.tplants.2018.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/28/2018] [Accepted: 02/06/2018] [Indexed: 05/21/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) fixes atmospheric CO2 into organic compounds and is composed of eight copies each of a large subunit (RbcL) and a small subunit (RbcS). Recent reports have revealed unusual RbcS, which are expressed in particular tissues and confer higher catalytic rate, lesser affinity for CO2, and a more acidic profile of the activity versus pH. The resulting Rubisco was proposed to be adapted to a high CO2 environment and recycle CO2 generated by the metabolism. These RbcS belong to a cluster named T (for trichome), phylogenetically distant from cluster M, which gathers well-characterized RbcS expressed in mesophyll or bundle-sheath tissues. Cluster T is largely represented in different plant phyla, including pteridophytes and bryophytes, indicating an ancient origin.
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Affiliation(s)
- Mathieu Pottier
- Institut des Sciences de la Vie, University of Louvain, 1348 Louvain-la-Neuve, Belgium
| | - Dimitri Gilis
- Bioinformatique génomique et structurale, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - Marc Boutry
- Institut des Sciences de la Vie, University of Louvain, 1348 Louvain-la-Neuve, Belgium.
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Valegård K, Hasse D, Andersson I, Gunn LH. Structure of Rubisco from Arabidopsis thaliana in complex with 2-carboxyarabinitol-1,5-bisphosphate. Acta Crystallogr D Struct Biol 2018; 74:1-9. [PMID: 29372894 PMCID: PMC5786004 DOI: 10.1107/s2059798317017132] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/28/2017] [Indexed: 11/18/2022] Open
Abstract
The crystal structure of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) from Arabidopsis thaliana is reported at 1.5 Å resolution. In light of the importance of A. thaliana as a model organism for understanding higher plant biology, and the pivotal role of Rubisco in photosynthetic carbon assimilation, there has been a notable absence of an A. thaliana Rubisco crystal structure. A. thaliana Rubisco is an L8S8 hexadecamer comprising eight plastome-encoded catalytic large (L) subunits and eight nuclear-encoded small (S) subunits. A. thaliana produces four distinct small-subunit isoforms (RbcS1A, RbcS1B, RbcS2B and RbcS3B), and this crystal structure provides a snapshot of A. thaliana Rubisco containing the low-abundance RbcS3B small-subunit isoform. Crystals were obtained in the presence of the transition-state analogue 2-carboxy-D-arabinitol-1,5-bisphosphate. A. thaliana Rubisco shares the overall fold characteristic of higher plant Rubiscos, but exhibits an interesting disparity between sequence and structural relatedness to other Rubisco isoforms. These results provide the structural framework to understand A. thaliana Rubisco and the potential catalytic differences that could be conferred by alternative A. thaliana Rubisco small-subunit isoforms.
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Affiliation(s)
- Karin Valegård
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-751 24 Uppsala, Sweden
| | - Dirk Hasse
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-751 24 Uppsala, Sweden
| | - Inger Andersson
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-751 24 Uppsala, Sweden
| | - Laura H. Gunn
- Laboratory of Molecular Biophysics, Department of Cell and Molecular Biology, Uppsala University, Husargatan 3, Box 596, SE-751 24 Uppsala, Sweden
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14
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Atkinson N, Leitão N, Orr DJ, Meyer MT, Carmo‐Silva E, Griffiths H, Smith AM, McCormick AJ. Rubisco small subunits from the unicellular green alga Chlamydomonas complement Rubisco-deficient mutants of Arabidopsis. THE NEW PHYTOLOGIST 2017; 214:655-667. [PMID: 28084636 PMCID: PMC5363358 DOI: 10.1111/nph.14414] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 11/24/2016] [Indexed: 05/03/2023]
Abstract
Introducing components of algal carbon concentrating mechanisms (CCMs) into higher plant chloroplasts could increase photosynthetic productivity. A key component is the Rubisco-containing pyrenoid that is needed to minimise CO2 retro-diffusion for CCM operating efficiency. Rubisco in Arabidopsis was re-engineered to incorporate sequence elements that are thought to be essential for recruitment of Rubisco to the pyrenoid, namely the algal Rubisco small subunit (SSU, encoded by rbcS) or only the surface-exposed algal SSU α-helices. Leaves of Arabidopsis rbcs mutants expressing 'pyrenoid-competent' chimeric Arabidopsis SSUs containing the SSU α-helices from Chlamydomonas reinhardtii can form hybrid Rubisco complexes with catalytic properties similar to those of native Rubisco, suggesting that the α-helices are catalytically neutral. The growth and photosynthetic performance of complemented Arabidopsis rbcs mutants producing near wild-type levels of the hybrid Rubisco were similar to those of wild-type controls. Arabidopsis rbcs mutants expressing a Chlamydomonas SSU differed from wild-type plants with respect to Rubisco catalysis, photosynthesis and growth. This confirms a role for the SSU in influencing Rubisco catalytic properties.
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Affiliation(s)
- Nicky Atkinson
- SynthSys & Institute of Molecular Plant SciencesSchool of Biological SciencesUniversity of EdinburghEdinburghEH9 3BFUK
| | - Nuno Leitão
- Department of Metabolic BiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
| | - Douglas J. Orr
- Lancaster Environment CentreLancaster UniversityLancasterLA1 4YQUK
| | - Moritz T. Meyer
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | | | - Howard Griffiths
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Alison M. Smith
- Department of Metabolic BiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
| | - Alistair J. McCormick
- SynthSys & Institute of Molecular Plant SciencesSchool of Biological SciencesUniversity of EdinburghEdinburghEH9 3BFUK
- Department of Metabolic BiologyJohn Innes CentreNorwich Research ParkNorwichNR4 7UHUK
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15
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Koay TW, Wong HL, Lim BH. Engineering of chimeric eukaryotic/bacterial Rubisco large subunits in Escherichia coli. Genes Genet Syst 2016; 91:139-150. [PMID: 27301279 DOI: 10.1266/ggs.15-00054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a rate-limiting photosynthetic enzyme that catalyzes carbon fixation in the Calvin cycle. Much interest has been devoted to engineering this ubiquitous enzyme with the goal of increasing plant growth. However, experiments that have successfully produced improved Rubisco variants, via directed evolution in Escherichia coli, are limited to bacterial Rubisco because the eukaryotic holoenzyme cannot be produced in E. coli. The present study attempts to determine the specific differences between bacterial and eukaryotic Rubisco large subunit primary structure that are responsible for preventing heterologous eukaryotic holoenzyme formation in E. coli. A series of chimeric Synechococcus Rubiscos were created in which different sections of the large subunit were swapped with those of the homologous Chlamydomonas Rubisco. Chimeric holoenzymes that can form in vivo would indicate that differences within the swapped sections do not disrupt holoenzyme formation. Large subunit residues 1-97, 198-247 and 448-472 were successfully swapped without inhibiting holoenzyme formation. In all ten chimeras, protein expression was observed for the separate subunits at a detectable level. As a first approximation, the regions that can tolerate swapping may be targets for future engineering.
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Affiliation(s)
- Teng Wei Koay
- Department of Chemical Science, Faculty of Science, Universiti Tunku Abdul Rahman
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16
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Joshi J, Mueller-Cajar O, Tsai YCC, Hartl FU, Hayer-Hartl M. Role of small subunit in mediating assembly of red-type form I Rubisco. J Biol Chem 2014; 290:1066-74. [PMID: 25371207 DOI: 10.1074/jbc.m114.613091] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the key enzyme involved in photosynthetic carbon fixation, converting atmospheric CO2 to organic compounds. Form I Rubisco is a cylindrical complex composed of eight large (RbcL) subunits that are capped by four small subunits (RbcS) at the top and four at the bottom. Form I Rubiscos are phylogenetically divided into green- and red-type. Some red-type enzymes have catalytically superior properties. Thus, understanding their folding and assembly is of considerable biotechnological interest. Folding of the green-type RbcL subunits in cyanobacteria is mediated by the GroEL/ES chaperonin system, and assembly to holoenzyme requires specialized chaperones such as RbcX and RAF1. Here, we show that the red-type RbcL subunits in the proteobacterium Rhodobacter sphaeroides also fold with GroEL/ES. However, assembly proceeds in a chaperone-independent manner. We find that the C-terminal β-hairpin extension of red-type RbcS, which is absent in green-type RbcS, is critical for efficient assembly. The β-hairpins of four RbcS subunits form an eight-stranded β-barrel that protrudes into the central solvent channel of the RbcL core complex. The two β-barrels stabilize the complex through multiple interactions with the RbcL subunits. A chimeric green-type RbcS carrying the C-terminal β-hairpin renders the assembly of a cyanobacterial Rubisco independent of RbcX. Our results may facilitate the engineering of crop plants with improved growth properties expressing red-type Rubisco.
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Affiliation(s)
- Jidnyasa Joshi
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Oliver Mueller-Cajar
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Yi-Chin C Tsai
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - F Ulrich Hartl
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Manajit Hayer-Hartl
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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17
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Improving the sunlight-to-biomass conversion efficiency in microalgal biofactories. J Biotechnol 2014; 201:28-42. [PMID: 25160918 DOI: 10.1016/j.jbiotec.2014.08.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/31/2014] [Accepted: 08/18/2014] [Indexed: 12/31/2022]
Abstract
Microalgae represent promising organisms for the sustainable production of commodities, chemicals or fuels. Future use of such systems, however, requires increased productivity of microalgal mass cultures in order to reach an economic viability for microalgae-based production schemes. The efficiency of sunlight-to-biomass conversion that can be observed in bulk cultures is generally far lower (35-80%) than the theoretical maximum, because energy losses occur at multiple steps during the light-driven conversion of carbon dioxide to organic carbon. The light-harvesting system is a major source of energy losses and thus a prime target for strain engineering. Truncation of the light-harvesting antenna in the algal model organism Chlamydomonas reinhardtii was shown to be an effective way of increasing culture productivity at least under saturating light conditions. Furthermore engineering of the Calvin-Benson cycle or the creation of photorespiratory bypasses in A. thaliana proved to be successful in terms of achieving higher biomass productivities. An efficient generation of novel microalgal strains with improved sunlight conversion efficiencies by targeted engineering in the future will require an expanded molecular toolkit. In the meantime random mutagenesis coupled to high-throughput screening for desired phenotypes can be used to provide engineered microalgae.
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18
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Cai Z, Liu G, Zhang J, Li Y. Development of an activity-directed selection system enabled significant improvement of the carboxylation efficiency of Rubisco. Protein Cell 2014; 5:552-62. [PMID: 24870149 PMCID: PMC4085280 DOI: 10.1007/s13238-014-0072-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 04/23/2014] [Indexed: 12/16/2022] Open
Abstract
Photosynthetic CO2 fixation is the ultimate source of organic carbon on earth and thus is essential for crop production and carbon sequestration. Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the first step of photosynthetic CO2 fixation. However, the extreme low carboxylation efficiency of Rubisco makes it the most attractive target for improving photosynthetic efficiency. Extensive studies have focused on re-engineering a more efficient enzyme, but the effort has been impeded by the limited understanding of its structure-function relationships and the lack of an efficient selection system towards its activity. To address the unsuccessful molecular engineering of Rubisco, we developed an Escherichia coli-based activity-directed selection system which links the growth of host cell solely to the Rubisco activity therein. A Synechococcus sp. PCC7002 Rubisco mutant with E49V and D82G substitutions in the small subunit was selected from a total of 15,000 mutants by one round of evolution. This mutant showed an 85% increase in specific carboxylation activity and a 45% improvement in catalytic efficiency towards CO2. The small-subunit E49V mutation was speculated to influence holoenzyme catalysis through interaction with the large-subunit Q225. This interaction is conserved among various Rubisco from higher plants and Chlamydomonas reinhardtii. Knowledge of these might provide clues for engineering Rubisco from higher plants, with the potential of increasing the crop yield.
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Affiliation(s)
- Zhen Cai
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
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19
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Morita K, Hatanaka T, Misoo S, Fukayama H. Unusual small subunit that is not expressed in photosynthetic cells alters the catalytic properties of rubisco in rice. PLANT PHYSIOLOGY 2014; 164:69-79. [PMID: 24254313 PMCID: PMC3875826 DOI: 10.1104/pp.113.228015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Rubisco small subunits (RbcSs) are encoded by a nuclear multigene family in plants. Five RbcS genes, OsRbcS1, OsRbcS2, OsRbcS3, OsRbcS4, and OsRbcS5, have been identified in rice (Oryza sativa). Among them, the amino acid sequence of OsRbcS1 differs notably from those of other rice RbcSs. Phylogenetic analysis showed that OsRbcS1 is genetically distant from other rice RbcS genes and more closely related to RbcS from a fern and two woody plants. Reverse transcription-PCR and promoter β-glucuronidase analyses revealed that OsRbcS1 was not expressed in leaf blade, a major photosynthetic organ in rice, but was expressed in leaf sheath, culm, anther, and root central cylinder. In leaf blade of transgenic rice overexpressing OsRbcS1 and leaf sheath of nontransgenic rice, OsRbcS1 was incorporated into the Rubisco holoenzyme. Incorporation of OsRbcS1 into Rubisco increased the catalytic turnover rate and Km for CO2 of the enzyme and slightly decreased the specificity for CO2, indicating that the catalytic properties were shifted to those of a high-activity type Rubisco. The CO2 assimilation rate at low CO2 partial pressure was decreased in overexpression lines but was not changed under ambient and high CO2 partial pressure compared with nontransgenic rice. Although the Rubisco content was increased, Rubisco activation state was decreased in overexpression lines. These results indicate that the catalytic properties of Rubisco can be altered by ectopic expression of OsRbcS1, with substantial effects on photosynthetic performance in rice. We believe this is the first demonstration of organ-specific expression of individual members of the RbcS gene family resulting in marked effects on Rubisco catalytic activity.
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20
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Esquivel MG, Genkov T, Nogueira AS, Salvucci ME, Spreitzer RJ. Substitutions at the opening of the Rubisco central solvent channel affect holoenzyme stability and CO2/O 2 specificity but not activation by Rubisco activase. PHOTOSYNTHESIS RESEARCH 2013; 118:209-218. [PMID: 24014091 DOI: 10.1007/s11120-013-9916-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 08/19/2013] [Indexed: 06/02/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the initial step of carbon metabolism in photosynthesis. The holoenzyme comprises eight large subunits, arranged as a tetramer of dimers around a central solvent channel that defines a fourfold axis of symmetry, and eight small subunits, arranged as two tetramers at the poles of the axis. The phylogenetically divergent small-subunit loops between β-strands A and B form the entrance to the solvent channel. In the green alga Chlamydomonas reinhardtii, Ile-58 from each of the four small-subunit βA-βB loops defines the minimal diameter of the channel opening. To understand the role of the central solvent channel in Rubisco function, directed mutagenesis and transformation of Chlamydomonas were employed to replace Ile-58 with Ala, Lys, Glu, Trp, or three Trp residues (I58W3) to close the entrance to the channel. The I58E, I58K, and I58W substitutions caused only small decreases in photosynthetic growth at 25 and 35 °C, whereas I58W3 had a substantial effect at both temperatures. The mutant enzymes had decreased carboxylation rates, but the I58W3 enzyme had decreases in both carboxylation and CO2/O2 specificity. The I58E, I58W, and I58W3 enzymes were inactivated at lower temperatures than wild-type Rubisco, and were degraded at slower rates under oxidative stress. However, these mutant enzymes were activated by Rubisco activase at normal rates, indicating that the structural transition required for carboxylation is not affected by altering the solvent channel opening. Structural dynamics alone may not be responsible for these distant effects on the Rubisco active site.
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Affiliation(s)
- M Gloria Esquivel
- Instituto Superior de Agronomia (ISA), Technical University of Lisbon, 1399, Lisbon, Portugal,
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21
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Wachter RM, Salvucci ME, Carmo-Silva AE, Barta C, Genkov T, Spreitzer RJ. Activation of interspecies-hybrid Rubisco enzymes to assess different models for the Rubisco-Rubisco activase interaction. PHOTOSYNTHESIS RESEARCH 2013; 117:557-66. [PMID: 23613007 DOI: 10.1007/s11120-013-9827-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Accepted: 04/08/2013] [Indexed: 06/02/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is prone to inactivation from non-productive binding of sugar-phosphates. Reactivation of Rubisco requires conformational remodeling by a specific chaperone, Rubisco activase. Rubisco activase from tobacco and other plants in the family Solanaceae is an inefficient activator of Rubisco from non-Solanaceae plants and from the green alga Chlamydomonas reinhardtii. To determine if the Rubisco small subunit plays a role in the interaction with Rubisco activase, a hybrid Rubisco (SSNT) composed of tobacco small subunits and Chlamydomonas large subunits was constructed. The SSNT hybrid, like other hybrid Rubiscos containing plant small subunits, supported photoautotrophic growth in Chlamydomonas, but growth in air was much slower than for cells containing wild-type Rubisco. The kinetic properties of the SSNT hybrid Rubisco were similar to the wild-type enzyme, indicating that the poor growth in air was probably caused by disruption of pyrenoid formation and the consequent impairment of the CO2concentrating mechanism. Recombinant Rubisco activase from Arabidopsis activated the SSNT hybrid Rubisco and hybrid Rubiscos containing spinach and Arabidopsis small subunits at rates similar to the rates with wild-type Rubisco. However, none of the hybrid Rubiscos was activated by tobacco Rubisco activase. That replacement of Chlamydomonas small subunits with plant small subunits does not affect the species-specific interaction between Rubisco and Rubisco activase suggests that the association is not dominated by the small subunits that surround the Rubisco central solvent channel. Therefore, the geometry of a side-on binding mode is more consistent with the data than a top-on or ring-stacking binding mode.
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Affiliation(s)
- Rebekka M Wachter
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85287, USA
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22
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Appel AM, Bercaw JE, Bocarsly AB, Dobbek H, DuBois DL, Dupuis M, Ferry JG, Fujita E, Hille R, Kenis PJA, Kerfeld CA, Morris RH, Peden CHF, Portis AR, Ragsdale SW, Rauchfuss TB, Reek JNH, Seefeldt LC, Thauer RK, Waldrop GL. Frontiers, opportunities, and challenges in biochemical and chemical catalysis of CO2 fixation. Chem Rev 2013; 113:6621-58. [PMID: 23767781 PMCID: PMC3895110 DOI: 10.1021/cr300463y] [Citation(s) in RCA: 1274] [Impact Index Per Article: 115.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Aaron M. Appel
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - John E. Bercaw
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Andrew B. Bocarsly
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Holger Dobbek
- Institut für Biologie, Strukturbiologie/Biochemie, Humboldt Universität zu Berlin, Berlin, Germany
| | - Daniel L. DuBois
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Michel Dupuis
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - James G. Ferry
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania 16801, United States
| | - Etsuko Fujita
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Russ Hille
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Paul J. A. Kenis
- Department of Chemical and Biochemical Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Cheryl A. Kerfeld
- DOE Joint Genome Institute, 2800 Mitchell Drive Walnut Creek, California 94598, United States, and Department of Plant and Microbial Biology, University of California, Berkeley, 111 Koshland Hall Berkeley, California 94720, United States
| | - Robert H. Morris
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Charles H. F. Peden
- Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Archie R. Portis
- Departments of Crop Sciences and Plant Biology, University of Illinois, Urbana, Illinois 61801, United States
| | - Stephen W. Ragsdale
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Thomas B. Rauchfuss
- Department of Chemistry, University of Illinois, Urbana, Illinois 61801, United States
| | - Joost N. H. Reek
- van’t Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Lance C. Seefeldt
- Department of Chemistry and Biochemistry, Utah State University, 0300 Old Main Hill, Logan, Utah 84322, United States
| | - Rudolf K. Thauer
- Max Planck Institute for Terrestrial Microbiology, Karl von Frisch Strasse 10, D-35043 Marburg, Germany
| | - Grover L. Waldrop
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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23
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Subunit interface dynamics in hexadecameric rubisco. J Mol Biol 2011; 411:1083-98. [PMID: 21745478 DOI: 10.1016/j.jmb.2011.06.052] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Revised: 06/27/2011] [Accepted: 06/30/2011] [Indexed: 11/23/2022]
Abstract
Ribulose-1,5-bisphosphate (RuBP) carboxylase/oxygenase (Rubisco) plays an important role in the global carbon cycle as a hub for biomass. Rubisco catalyzes not only the carboxylation of RuBP with carbon dioxide but also a competing oxygenation reaction of RuBP with a negative impact on photosynthetic yield. The functional active site is built from two large (L) subunits that form a dimer. The octameric core of four L(2) dimers is held at each end by a cluster of four small (S) subunits, forming a hexadecamer. Each large subunit contacts more than one S subunit. These interactions exploit the dynamic flexibility of Rubisco, which we address in this study. Here, we describe seven different types of interfaces of hexadecameric Rubisco. We have analyzed these interfaces with respect to the size of the interface area and the number of polar interactions, including salt bridges and hydrogen bonds in a variety of Rubisco enzymes from different organisms and different kingdoms of life, including the Rubisco-like proteins. We have also performed molecular dynamics simulations of Rubisco from Chlamydomonas reinhardtii and mutants thereof. From our computational analyses, we propose structural checkpoints of the S subunit to ensure the functionality and/or assembly of the Rubisco holoenzyme. These checkpoints appear to fine-tune the dynamics of the enzyme in a way that could influence enzyme performance.
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24
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Ishikawa C, Hatanaka T, Misoo S, Miyake C, Fukayama H. Functional incorporation of sorghum small subunit increases the catalytic turnover rate of Rubisco in transgenic rice. PLANT PHYSIOLOGY 2011; 156:1603-11. [PMID: 21562335 PMCID: PMC3135941 DOI: 10.1104/pp.111.177030] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 05/06/2011] [Indexed: 05/17/2023]
Abstract
Rubisco limits photosynthetic CO(2) fixation because of its low catalytic turnover rate (k(cat)) and competing oxygenase reaction. Previous attempts to improve the catalytic efficiency of Rubisco by genetic engineering have gained little progress. Here we demonstrate that the introduction of the small subunit (RbcS) of high k(cat) Rubisco from the C(4) plant sorghum (Sorghum bicolor) significantly enhances k(cat) of Rubisco in transgenic rice (Oryza sativa). Three independent transgenic lines expressed sorghum RbcS at a high level, accounting for 30%, 44%, and 79% of the total RbcS. Rubisco was likely present as a chimera of sorghum and rice RbcS, and showed 1.32- to 1.50-fold higher k(cat) than in nontransgenic rice. Rubisco from transgenic lines showed a higher K(m) for CO(2) and slightly lower specificity for CO(2) than nontransgenic controls. These results suggest that Rubisco in rice transformed with sorghum RbcS partially acquires the catalytic properties of sorghum Rubisco. Rubisco content in transgenic lines was significantly increased over wild-type levels but Rubisco activation was slightly decreased. The expression of sorghum RbcS did not affect CO(2) assimilation rates under a range of CO(2) partial pressures. The J(max)/V(cmax) ratio was significantly lower in transgenic line compared to the nontransgenic plants. These observations suggest that the capacity of electron transport is not sufficient to support the increased Rubisco capacity in transgenic rice. Although the photosynthetic rate was not enhanced, the strategy presented here opens the way to engineering Rubisco for improvement of photosynthesis and productivity in the future.
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25
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Whitney SM, Houtz RL, Alonso H. Advancing our understanding and capacity to engineer nature's CO2-sequestering enzyme, Rubisco. PLANT PHYSIOLOGY 2011; 155:27-35. [PMID: 20974895 PMCID: PMC3075749 DOI: 10.1104/pp.110.164814] [Citation(s) in RCA: 289] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Accepted: 10/18/2010] [Indexed: 05/18/2023]
Affiliation(s)
- Spencer M Whitney
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
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26
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Kapralov MV, Kubien DS, Andersson I, Filatov DA. Changes in Rubisco kinetics during the evolution of C4 photosynthesis in Flaveria (Asteraceae) are associated with positive selection on genes encoding the enzyme. Mol Biol Evol 2010; 28:1491-503. [PMID: 21172830 DOI: 10.1093/molbev/msq335] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Rubisco, the primary photosynthetic carboxylase, evolved 3-4 billion years ago in an anaerobic, high CO(2) atmosphere. The combined effect of low CO(2) and high O(2) levels in the modern atmosphere, and the inability of Rubisco to distinguish completely between CO(2) and O(2), leads to the occurrence of an oxygenation reaction that reduces the efficiency of photosynthesis. Among land plants, C(4) photosynthesis largely solves this problem by facilitating a high CO(2)/O(2) ratio at the site of Rubisco that resembles the atmosphere in which the ancestral enzyme evolved. The prediction that such conditions favor Rubiscos with higher kcat(CO2) and lower CO(2)/O(2) specificity (S(C/O)) is well supported, but the structural basis for the differences between C(3) and C(4) Rubiscos is not clear. Flaveria (Asteraceae) includes C(3), C(3)-C(4) intermediate, and C(4) species with kinetically distinct Rubiscos, providing a powerful system in which to study the biochemical transition of Rubisco during the evolution from C(3) to C(4) photosynthesis. We analyzed the molecular evolution of chloroplast rbcL and nuclear rbcS genes encoding the large subunit (LSu) and small subunit (SSu) of Rubisco from 15 Flaveria species. We demonstrate positive selection on both subunits, although selection is much stronger on the LSu. In Flaveria, two positively selected LSu amino acid substitutions, M309I and D149A, distinguish C(4) Rubiscos from the ancestral C(3) species and statistically account for much of the kinetic difference between the two groups. However, although Flaveria lacks a characteristic "C(4)" SSu, our data suggest that specific residue substitutions in the SSu are correlated with the kinetic properties of Rubisco in this genus.
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Affiliation(s)
- Maxim V Kapralov
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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27
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Genkov T, Meyer M, Griffiths H, Spreitzer RJ. Functional hybrid rubisco enzymes with plant small subunits and algal large subunits: engineered rbcS cDNA for expression in chlamydomonas. J Biol Chem 2010; 285:19833-41. [PMID: 20424165 PMCID: PMC2888394 DOI: 10.1074/jbc.m110.124230] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 04/23/2010] [Indexed: 11/06/2022] Open
Abstract
There has been much interest in the chloroplast-encoded large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) as a target for engineering an increase in net CO(2) fixation in photosynthesis. Improvements in the enzyme would lead to an increase in the production of food, fiber, and renewable energy. Although the large subunit contains the active site, a family of rbcS nuclear genes encodes the Rubisco small subunits, which can also influence the carboxylation catalytic efficiency and CO(2)/O(2) specificity of the enzyme. To further define the role of the small subunit in Rubisco function, small subunits from spinach, Arabidopsis, and sunflower were assembled with algal large subunits by transformation of a Chlamydomonas reinhardtii mutant that lacks the rbcS gene family. Foreign rbcS cDNAs were successfully expressed in Chlamydomonas by fusing them to a Chlamydomonas rbcS transit peptide sequence engineered to contain rbcS introns. Although plant Rubisco generally has greater CO(2)/O(2) specificity but a lower carboxylation V(max) than Chlamydomonas Rubisco, the hybrid enzymes have 3-11% increases in CO(2)/O(2) specificity and retain near normal V(max) values. Thus, small subunits may make a significant contribution to the overall catalytic performance of Rubisco. Despite having normal amounts of catalytically proficient Rubisco, the hybrid mutant strains display reduced levels of photosynthetic growth and lack chloroplast pyrenoids. It appears that small subunits contain the structural elements responsible for targeting Rubisco to the algal pyrenoid, which is the site where CO(2) is concentrated for optimal photosynthesis.
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Affiliation(s)
- Todor Genkov
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588 and
| | - Moritz Meyer
- the Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Howard Griffiths
- the Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Robert J. Spreitzer
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588 and
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28
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Yu TY, Singh M, Matsuoka S, Patti GJ, Potter GS, Schaefer J. Variability in C(3)-plant cell-wall biosynthesis in a high-CO(2) atmosphere by solid-state NMR spectroscopy. J Am Chem Soc 2010; 132:6335-41. [PMID: 20394366 DOI: 10.1021/ja909796y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have used a frequency-selective rotational-echo double-resonance (REDOR) solid-state NMR experiment to measure the concentrations of glycine-glycine pairs in proteins (and protein precursors) of intact leaves of plants exposed to both high- and low-CO(2) atomospheres. The results are interpreted in terms of differences in cell-wall biosynthesis between plant species. We illustrate this variability by comparing the assimilation of label in cheatgrass and soybean leaves labeled using (15)N-fertilizer and (13)CO(2) atmospheres. Cheatgrass and soybean are both C(3) plants but differ in their response to a high-CO(2) environment. Based on REDOR results, we determined that cheatgrass (a plant that seems likely to flourish in future low-water, high-CO(2) environments) routes 2% of the assimilated carbon label that remains in the leaf after 1 h in a 600-ppm (13)CO(2) atmosphere to glycine-rich protein (or its precursors), a structural component of cell walls cross-linked to lignins. In contrast, soybean under the same conditions routes none of its assimilated carbon to glycine-rich protein.
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Affiliation(s)
- Tsyr-Yan Yu
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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29
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Zhu XG, Long SP, Ort DR. Improving photosynthetic efficiency for greater yield. ANNUAL REVIEW OF PLANT BIOLOGY 2010; 61:235-61. [PMID: 20192734 DOI: 10.1146/annurev-arplant-042809-112206] [Citation(s) in RCA: 811] [Impact Index Per Article: 57.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Increasing the yield potential of the major food grain crops has contributed very significantly to a rising food supply over the past 50 years, which has until recently more than kept pace with rising global demand. Whereas improved photosynthetic efficiency has played only a minor role in the remarkable increases in productivity achieved in the last half century, further increases in yield potential will rely in large part on improved photosynthesis. Here we examine inefficiencies in photosynthetic energy transduction in crops from light interception to carbohydrate synthesis, and how classical breeding, systems biology, and synthetic biology are providing new opportunities to develop more productive germplasm. Near-term opportunities include improving the display of leaves in crop canopies to avoid light saturation of individual leaves and further investigation of a photorespiratory bypass that has already improved the productivity of model species. Longer-term opportunities include engineering into plants carboxylases that are better adapted to current and forthcoming CO(2) concentrations, and the use of modeling to guide molecular optimization of resource investment among the components of the photosynthetic apparatus, to maximize carbon gain without increasing crop inputs. Collectively, these changes have the potential to more than double the yield potential of our major crops.
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Affiliation(s)
- Xin-Guang Zhu
- CAS-MPG Partner Institute for Computational Biology, SIBS, Shanghai, China.
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30
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Genkov T, Spreitzer RJ. Highly conserved small subunit residues influence rubisco large subunit catalysis. J Biol Chem 2009; 284:30105-12. [PMID: 19734149 PMCID: PMC2781565 DOI: 10.1074/jbc.m109.044081] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 08/20/2009] [Indexed: 11/06/2022] Open
Abstract
The chloroplast enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of photosynthetic CO(2) fixation. With a deeper understanding of its structure-function relationships and competitive inhibition by O(2), it may be possible to engineer an increase in agricultural productivity and renewable energy. The chloroplast-encoded large subunits form the active site, but the nuclear-encoded small subunits can also influence catalytic efficiency and CO(2)/O(2) specificity. To further define the role of the small subunit in Rubisco function, the 10 most conserved residues in all small subunits were substituted with alanine by transformation of a Chlamydomonas reinhardtii mutant that lacks the small subunit gene family. All the mutant strains were able to grow photosynthetically, indicating that none of the residues is essential for function. Three of the substitutions have little or no effect (S16A, P19A, and E92A), one primarily affects holoenzyme stability (L18A), and the remainder affect catalysis with or without some level of associated structural instability (Y32A, E43A, W73A, L78A, P79A, and F81A). Y32A and E43A cause decreases in CO(2)/O(2) specificity. Based on the x-ray crystal structure of Chlamydomonas Rubisco, all but one (Glu-92) of the conserved residues are in contact with large subunits and cluster near the amino- or carboxyl-terminal ends of large subunit alpha-helix 8, which is a structural element of the alpha/beta-barrel active site. Small subunit residues Glu-43 and Trp-73 identify a possible structural connection between active site alpha-helix 8 and the highly variable small subunit loop between beta-strands A and B, which can also influence Rubisco CO(2)/O(2) specificity.
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Affiliation(s)
- Todor Genkov
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Robert J. Spreitzer
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
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31
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Menon BB, Dou Z, Heinhorst S, Shively JM, Cannon GC. Halothiobacillus neapolitanus carboxysomes sequester heterologous and chimeric RubisCO species. PLoS One 2008; 3:e3570. [PMID: 18974784 PMCID: PMC2570492 DOI: 10.1371/journal.pone.0003570] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Accepted: 10/09/2008] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND The carboxysome is a bacterial microcompartment that consists of a polyhedral protein shell filled with ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), the enzyme that catalyzes the first step of CO2 fixation via the Calvin-Benson-Bassham cycle. METHODOLOGY/PRINCIPAL FINDINGS To analyze the role of RubisCO in carboxysome biogenesis in vivo we have created a series of Halothiobacillus neapolitanus RubisCO mutants. We identified the large subunit of the enzyme as an important determinant for its sequestration into alpha-carboxysomes and found that the carboxysomes of H. neapolitanus readily incorporate chimeric and heterologous RubisCO species. Intriguingly, a mutant lacking carboxysomal RubisCO assembles empty carboxysome shells of apparently normal shape and composition. CONCLUSIONS/SIGNIFICANCE These results indicate that carboxysome shell architecture is not determined by the enzyme they normally sequester. Our study provides, for the first time, clear evidence that carboxysome contents can be manipulated and suggests future nanotechnological applications that are based upon engineered protein microcompartments.
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Affiliation(s)
- Balaraj B. Menon
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Zhicheng Dou
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Sabine Heinhorst
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
| | - Jessup M. Shively
- Department of Genetics and Biochemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Gordon C. Cannon
- Department of Chemistry and Biochemistry, The University of Southern Mississippi, Hattiesburg, Mississippi, United States of America
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Structural and functional consequences of the replacement of proximal residues Cys(172) and Cys(192) in the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase from Chlamydomonas reinhardtii. Biochem J 2008; 411:241-7. [PMID: 18072944 DOI: 10.1042/bj20071422] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Proximal Cys(172) and Cys(192) in the large subunit of the photosynthetic enzyme Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase; EC 4.1.1.39) are evolutionarily conserved among cyanobacteria, algae and higher plants. Mutation of Cys(172) has been shown to affect the redox properties of Rubisco in vitro and to delay the degradation of the enzyme in vivo under stress conditions. Here, we report the effect of the replacement of Cys(172) and Cys(192) by serine on the catalytic properties, thermostability and three-dimensional structure of Chlamydomonas reinhardtii Rubisco. The most striking effect of the C172S substitution was an 11% increase in the specificity factor when compared with the wild-type enzyme. The specificity factor of C192S Rubisco was not altered. The V(c) (V(max) for carboxylation) was similar to that of wild-type Rubisco in the case of the C172S enzyme, but approx. 30% lower for the C192S Rubisco. In contrast, the K(m) for CO(2) and O(2) was similar for C192S and wild-type enzymes, but distinctly higher (approximately double) for the C172S enzyme. C172S Rubisco showed a critical denaturation temperature approx. 2 degrees C lower than wild-type Rubisco and a distinctly higher denaturation rate at 55 degrees C, whereas C192S Rubisco was only slightly more sensitive to temperature denaturation than the wild-type enzyme. X-ray crystal structures reveal that the C172S mutation causes a shift of the main-chain backbone atoms of beta-strand 1 of the alpha/beta-barrel affecting a number of amino acid side chains. This may cause the exceptional catalytic features of C172S. In contrast, the C192S mutation does not produce similar structural perturbations.
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33
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Andersson I, Backlund A. Structure and function of Rubisco. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2008; 46:275-91. [PMID: 18294858 DOI: 10.1016/j.plaphy.2008.01.001] [Citation(s) in RCA: 316] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Indexed: 05/18/2023]
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the major enzyme assimilating CO(2) into the biosphere. At the same time Rubisco is an extremely inefficient catalyst and its carboxylase activity is compromised by an opposing oxygenase activity involving atmospheric O(2). The shortcomings of Rubisco have implications for crop yield, nitrogen and water usage, and for the global carbon cycle. Numerous high-resolution crystal structures of different forms of Rubisco are now available, including structures of mutant enzymes. This review uses the information provided in these structures in a structure-based sequence alignment and discusses Rubisco function in the context of structural variations at all levels--amino acid sequence, fold, tertiary and quaternary structure--with an evolutionary perspective and an emphasis on the structural features of the enzyme that may determine its function as a carboxylase.
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Affiliation(s)
- Inger Andersson
- Department of Molecular Biology, Swedish University of Agricultural Sciences, Husargatan 3, BMC Box 590, S-751 24 Uppsala, Sweden.
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Sharwood RE, von Caemmerer S, Maliga P, Whitney SM. The catalytic properties of hybrid Rubisco comprising tobacco small and sunflower large subunits mirror the kinetically equivalent source Rubiscos and can support tobacco growth. PLANT PHYSIOLOGY 2008; 146:83-96. [PMID: 17993544 PMCID: PMC2230571 DOI: 10.1104/pp.107.109058] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 11/01/2007] [Indexed: 05/18/2023]
Abstract
Plastomic replacement of the tobacco (Nicotiana tabacum) Rubisco large subunit gene (rbcL) with that from sunflower (Helianthus annuus; rbcL(S)) produced tobacco(Rst) transformants that produced a hybrid Rubisco consisting of sunflower large and tobacco small subunits (L(s)S(t)). The tobacco(Rst) plants required CO(2) (0.5% v/v) supplementation to grow autotrophically from seed despite the substrate saturated carboxylation rate, K(m), for CO(2) and CO(2)/O(2) selectivity of the L(s)S(t) enzyme mirroring the kinetically equivalent tobacco and sunflower Rubiscos. Consequently, at the onset of exponential growth when the source strength and leaf L(s)S(t) content were sufficient, tobacco(Rst) plants grew to maturity without CO(2) supplementation. When grown under a high pCO(2), the tobacco(Rst) seedlings grew slower than tobacco and exhibited unique growth phenotypes: Juvenile plants formed clusters of 10 to 20 structurally simple oblanceolate leaves, developed multiple apical meristems, and the mature leaves displayed marginal curling and dimpling. Depending on developmental stage, the L(s)S(t) content in tobacco(Rst) leaves was 4- to 7-fold less than tobacco, and gas exchange coupled with chlorophyll fluorescence showed that at 2 mbar pCO(2) and growth illumination CO(2) assimilation in mature tobacco(Rst) leaves remained limited by Rubisco activity and its rate (approximately 11 micromol m(-2) s(-1)) was half that of tobacco controls. (35)S-methionine labeling showed the stability of assembled L(s)S(t) was similar to tobacco Rubisco and measurements of light transient CO(2) assimilation rates showed L(s)S(t) was adequately regulated by tobacco Rubisco activase. We conclude limitations to tobacco(Rst) growth primarily stem from reduced rbcL(S) mRNA levels and the translation and/or assembly of sunflower large with the tobacco small subunits that restricted L(s)S(t) synthesis.
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Affiliation(s)
- Robert Edward Sharwood
- Molecular Plant Physiology Group, Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territory, Australia
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35
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Genkov T, Du YC, Spreitzer RJ. Small-subunit cysteine-65 substitutions can suppress or induce alterations in the large-subunit catalytic efficiency and holoenzyme thermal stability of ribulose-1,5-bisphosphate carboxylase/oxygenase. Arch Biochem Biophys 2006; 451:167-74. [PMID: 16723113 DOI: 10.1016/j.abb.2006.04.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 04/13/2006] [Accepted: 04/14/2006] [Indexed: 11/30/2022]
Abstract
In the green alga Chlamydomonas reinhardtii, an L290F substitution in the chloroplast-encoded large-subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) causes decreases in carboxylation Vmax, CO2/O2 specificity, and thermal stability. Analysis of photosynthesis-competent revertants selected at the 35 degrees C restrictive temperature identified a rare C65S suppressor substitution in the nuclear-encoded small subunit. C65S enhances catalysis and CO2/O2 specificity in the absence of other wild-type small subunits, and restores thermal stability in vivo. C65S, C65A, and C65P mutant strains were created. C65S and C65A enzymes have normal catalysis, but C65P Rubisco, which contains land-plant Pro, has decreases in carboxylation Vmax/Km and CO2/O2 specificity. In contrast to other small-subunit substitutions that affect specificity, Cys-65 contacts the large subunit, and the C65P substitution does not cause a decrease in holoenzyme thermal stability in vivo or in vitro. Further analysis of the C65P protein may identify structural alterations that influence catalysis separate from those that affect stability.
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Affiliation(s)
- Todor Genkov
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588-0664, USA
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36
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Raines CA. Transgenic approaches to manipulate the environmental responses of the C3 carbon fixation cycle. PLANT, CELL & ENVIRONMENT 2006; 29:331-9. [PMID: 17080589 DOI: 10.1111/j.1365-3040.2005.01488.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The limitation to photosynthetic CO2 assimilation in C3 plants in hot, dry environments is dominated by ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco) because CO2 availability is restricted and photorespiration is stimulated. Using a combination of genetic engineering and transgenic technology, three approaches to reduce photorespiration have been taken; two of these focused on increasing the carboxylation efficiency of Rubisco either by reducing the oxygenase reaction directly or by manipulating the Rubisco enzyme by concentrating CO2 in the region of Rubisco through the introduction of enzymes of the C4 pathway. The third approach attempted to reduce photorespiration directly by manipulation of enzymes in this pathway. The progress in each of these areas is discussed, and the most promising approaches are highlighted. Under saturating CO2 conditions, Rubisco did not limit photosynthesis, and limitation shifted to ribulose bisphosphate (RuBP) regeneration capacity of the C3 cycle. Transgenic analysis was used to identify the specific enzymes that may be targets for improving carbon fixation, and the way this may be exploited in the high CO2 future is considered.
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Affiliation(s)
- Christine A Raines
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ, UK.
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Spreitzer RJ, Peddi SR, Satagopan S. Phylogenetic engineering at an interface between large and small subunits imparts land-plant kinetic properties to algal Rubisco. Proc Natl Acad Sci U S A 2005; 102:17225-30. [PMID: 16282373 PMCID: PMC1287997 DOI: 10.1073/pnas.0508042102] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Indexed: 11/18/2022] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step of photosynthetic CO(2) fixation and, thus, limits agricultural productivity. However, Rubisco enzymes from different species have different catalytic constants. If the structural basis for such differences were known, a rationale could be developed for genetically engineering an improved enzyme. Residues at the bottom of the large-subunit alpha/beta-barrel active site of Rubisco from the green alga Chlamydomonas reinhardtii (methyl-Cys-256, Lys-258, and Ile-265) were previously changed through directed mutagenesis and chloroplast transformation to residues characteristic of land-plant Rubisco (Phe-256, Arg-258, and Val-265). The resultant enzyme has decreases in carboxylation efficiency and CO(2)/O(2) specificity, despite the fact that land-plant Rubisco has greater specificity than the Chlamydomonas enzyme. Because the residues are close to a variable loop between beta-strands A and B of the small subunit that can also affect catalysis, additional substitutions were created at this interface. When large-subunit Val-221 and Val-235 were changed to land-plant Cys-221 and Ile-235, they complemented the original substitutions and returned CO(2)/O(2) specificity to the normal level. Further substitution with the shorter betaA-betaB loop of the spinach small subunit caused a 12-17% increase in specificity. The enhanced CO(2)/O(2) specificity of the mutant enzyme is lower than that of the spinach enzyme, but the carboxylation and oxygenation kinetic constants are nearly indistinguishable from those of spinach and substantially different from those of Chlamydomonas Rubisco. Thus, this interface between large and small subunits, far from the active site, contributes significantly to the differences in catalytic properties between algal and land-plant Rubisco enzymes.
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Affiliation(s)
- Robert J Spreitzer
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588-0664, USA.
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