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Amaral J, Lobo AKM, Carmo-Silva E, Orr DJ. Purification of Rubisco from Leaves. Methods Mol Biol 2024; 2790:417-426. [PMID: 38649584 DOI: 10.1007/978-1-0716-3790-6_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Rubisco fixes CO2 through the carboxylation of ribulose 1,5-bisphosphate (RuBP) during photosynthesis, enabling the synthesis of organic compounds. The natural diversity of Rubisco properties represents an opportunity to improve its performance and there is considerable research effort focusing on better understanding the properties and regulation of the enzyme. This chapter describes a method for large-scale purification of Rubisco from leaves. After the extraction of Rubisco from plant leaves, the enzyme is separated from other proteins by fractional precipitation with polyethylene glycol followed by ion-exchange chromatography. This method enables the isolation of Rubisco in large quantities for a wide range of biochemical applications.
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Affiliation(s)
- Joana Amaral
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Ana K M Lobo
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | | | - Douglas J Orr
- Lancaster Environment Centre, Lancaster University, Lancaster, UK.
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2
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Dukić J, Košpić K, Kelava V, Mavrić R, Nutrizio M, Balen B, Butorac A, Halil Öztop M, Režek Jambrak A. Alternative methods for RuBisCO extraction from sugar beet waste: A comparative approach of ultrasound and high voltage electrical discharge. ULTRASONICS SONOCHEMISTRY 2023; 99:106535. [PMID: 37541125 PMCID: PMC10410599 DOI: 10.1016/j.ultsonch.2023.106535] [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: 03/31/2023] [Revised: 07/12/2023] [Accepted: 07/21/2023] [Indexed: 08/06/2023]
Abstract
Ultrasound (US) and high voltage electric discharge (HVED) with water as a green solvent represent promising novel non-thermal techniques for protein extraction from sugar beet (Beta vulgaris subsp. vulgaris var. altissima) leaves. Compared to HVED, US proved to be a better alternative method for total soluble protein extraction with the aim of obtaining high yield of ribulose-1,5-bisphosphate carboxylase-oxygenase enzyme (RuBisCO). Regardless of the solvent temperature, the highest protein yields were observed at 100% amplitude and 9 min treatment time (84.60 ± 3.98 mg/gd.m. with cold and 96.75 ± 4.30 mg/gd.m. with room temperature deionized water). US treatments at 75% amplitude and 9 min treatment time showed the highest abundance of RuBisCO obtained by immunoblotting assay. The highest protein yields recorded among HVED-treated samples were observed at a voltage of 20 kV and a treatment time of 3 min, disregarding the used gas (33.33 ± 1.06 mg/gd.m. with argon and 34.89 ± 1.59 mg/gd.m. with nitrogen as injected gas), while the highest abundance of the RuBisCO among HVED-treated samples was noticed at 25 kV voltage and 3 min treatment time. By optimizing the US and HVED parameters, it is possible to affect the solubility and improve the isolation of RuBisCO, which could then be purified and implemented into new or already existing functional products.
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Affiliation(s)
- Josipa Dukić
- Faculty of Food Technology and Biotechnology, University of Zagreb, 10000 Zagreb, Croatia.
| | - Karla Košpić
- Department of Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia.
| | - Vanja Kelava
- BICRO BIOCentre Ltd, Cent Lab, 10000 Zagreb, Croatia
| | - Renata Mavrić
- Faculty of Food Technology and Biotechnology, University of Zagreb, 10000 Zagreb, Croatia
| | - Marinela Nutrizio
- Faculty of Food Technology and Biotechnology, University of Zagreb, 10000 Zagreb, Croatia
| | - Biljana Balen
- Department of Biology, Faculty of Science, University of Zagreb, 10000 Zagreb, Croatia
| | - Ana Butorac
- BICRO BIOCentre Ltd, Cent Lab, 10000 Zagreb, Croatia
| | - Mecit Halil Öztop
- Department of Food Engineering, Middle East Technical University, 06800 Ankara, Turkey
| | - Anet Režek Jambrak
- Faculty of Food Technology and Biotechnology, University of Zagreb, 10000 Zagreb, Croatia
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3
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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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4
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Pearce FG, Brunke JE. Is now the time for a Rubiscuit or Ruburger? Increased interest in Rubisco as a food protein. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:627-637. [PMID: 36260435 PMCID: PMC9833043 DOI: 10.1093/jxb/erac414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Much of the research on Rubisco aims at increasing crop yields, with the ultimate aim of increasing plant production to feed an increasing global population. However, since the identification of Rubisco as the most abundant protein in leaf material, it has also been touted as a direct source of dietary protein. The nutritional and functional properties of Rubisco are on a par with those of many animal proteins, and are superior to those of many other plant proteins. Purified Rubisco isolates are easily digestible, nutritionally complete, and have excellent foaming, gelling, and emulsifying properties. Despite this potential, challenges in efficiently extracting and separating Rubisco have limited its use as a global foodstuff. Leaves are lower in protein than seeds, requiring large amounts of biomass to be processed. This material normally needs to be processed quickly to avoid degradation of the final product. Extraction of Rubisco from the plant material requires breaking down the cell walls and rupturing the chloroplast. In order to obtain high-quality protein, Rubisco needs to be separated from chlorophyll, and then concentrated for final use. However, with increased consumer demand for plant protein, there is increased interest in the potential of leaf protein, and many commercial plants are now being established aimed at producing Rubisco as a food protein, with over US$60 million of funding invested in the past 5 years. Is now the time for increased use of Rubisco in food production as a nitrogen source, rather than just providing a carbon source?
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Affiliation(s)
| | - Joel E Brunke
- Biomolecular Interactions Centre and School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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Rubisco lysine acetylation occurs at very low stoichiometry in mature Arabidopsis leaves: implications for regulation of enzyme function. Biochem J 2020; 477:3885-3896. [PMID: 32959870 PMCID: PMC7557146 DOI: 10.1042/bcj20200413] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 11/23/2022]
Abstract
Multiple studies have shown ribulose-1,5-bisphosphate carboxylase/oxygenase (E.C. 4.1.1.39; Rubisco) to be subject to Lys-acetylation at various residues; however, opposing reports exist about the biological significance of these post-translational modifications. One aspect of the Lys-acetylation that has not been addressed in plants generally, or with Rubisco specifically, is the stoichiometry at which these Lys-acetylation events occur. As a method to ascertain which Lys-acetylation sites on Arabidopsis Rubisco might be of regulatory importance to its catalytic function in the Calvin–Benson cycle, we purified Rubisco from leaves in both the day and night-time and performed independent mass spectrometry based methods to determine the stoichiometry of Rubisco Lys-acetylation events. The results indicate that Rubisco is acetylated at most Lys residues, but each acetylation event occurs at very low stoichiometry. Furthermore, in vitro treatments that increased the extent of Lys-acetylation on purified Rubisco had no effect on Rubisco maximal activity. Therefore, we are unable to confirm that Lys-acetylation at low stoichiometries can be a regulatory mechanism controlling Rubisco maximal activity. The results highlight the need for further use of stoichiometry measurements when determining the biological significance of reversible PTMs like acetylation.
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Sales CRG, da Silva AB, Carmo-Silva E. Measuring Rubisco activity: challenges and opportunities of NADH-linked microtiter plate-based and 14C-based assays. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5302-5312. [PMID: 32728715 PMCID: PMC7501812 DOI: 10.1093/jxb/eraa289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 06/22/2020] [Indexed: 05/28/2023]
Abstract
Rubisco is central to carbon assimilation, and efforts to improve the efficiency and sustainability of crop production have spurred interest in phenotyping Rubisco activity. We tested the hypothesis that microtiter plate-based methods provide comparable results to those obtained with the radiometric assay that measures the incorporation of 14CO2 into 3-phosphoglycerate (3-PGA). Three NADH-linked assays were tested that use alternative coupling enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and glycerolphosphate dehydrogenase (GlyPDH); phosphoenolpyruvate carboxylase (PEPC) and malate dehydrogenase (MDH); and pyruvate kinase (PK) and lactate dehydrogenase (LDH). To date there has been no thorough evaluation of their reliability by comparison with the 14C-based method. The three NADH-linked assays were used in parallel to estimate (i) the 3-PGA concentration-response curve of NADH oxidation, (ii) the Michaelis-Menten constant for ribulose-1,5-bisphosphate, (iii) fully active and inhibited Rubisco activities, and (iv) Rubisco initial and total activities in fully illuminated and shaded leaves. All three methods correlated strongly with the 14C-based method, and the PK-LDH method showed a strong correlation and was the cheapest method. PEPC-MDH would be a suitable option for situations in which ADP/ATP might interfere with the assay. GAPDH-GlyPDH proved more laborious than the other methods. Thus, we recommend the PK-LDH method as a reliable, cheaper, and higher throughput method to phenotype Rubisco activity for crop improvement efforts.
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Affiliation(s)
- Cristina R G Sales
- Lancaster Environment Centre, Lancaster University, Library Avenue, Lancaster, UK
| | - Anabela Bernardes da Silva
- BioISI - Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
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7
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Perdomo JA, Sales CRG, Carmo-Silva E. Quantification of Photosynthetic Enzymes in Leaf Extracts by Immunoblotting. Methods Mol Biol 2018; 1770:215-227. [PMID: 29978404 DOI: 10.1007/978-1-4939-7786-4_12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this chapter, we describe a method to extract and quantify photosynthetic enzymes using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The method is particularly suitable for characterizing altered protein amounts in leaves of plants produced from genetic engineering or gene-editing approaches. We focus on RuBisCO and RuBisCO activase, a molecular chaperone required to sustain the activity of RuBisCO and CO2 fixation, yet the method can be easily adapted to investigate other leaf proteins of interest.
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Scafaro AP, Gallé A, Van Rie J, Carmo-Silva E, Salvucci ME, Atwell BJ. Heat tolerance in a wild Oryza species is attributed to maintenance of Rubisco activation by a thermally stable Rubisco activase ortholog. THE NEW PHYTOLOGIST 2016; 211:899-911. [PMID: 27145723 DOI: 10.1111/nph.13963] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 03/03/2016] [Indexed: 05/10/2023]
Abstract
The mechanistic basis of tolerance to heat stress was investigated in Oryza sativa and two wild rice species, Oryza meridionalis and Oryza australiensis. The wild relatives are endemic to the hot, arid Australian savannah. Leaf elongation rates and gas exchange were measured during short periods of supra-optimal heat, revealing species differences. The Rubisco activase (RCA) gene from each species was sequenced. Using expressed recombinant RCA and leaf-extracted RCA, the kinetic properties of the two isoforms were studied under high temperatures. Leaf elongation was undiminished at 45°C in O. australiensis. The net photosynthetic rate was almost 50% slower in O. sativa at 45°C than at 28°C, while in O. australiensis it was unaffected. Oryza meridionalis exhibited intermediate heat tolerance. Based on previous reports that RCA is heat-labile, the Rubisco activation state was measured. It correlated positively with leaf elongation rates across all three species and four periods of exposure to 45°C. Sequence analysis revealed numerous polymorphisms in the RCA amino acid sequence from O. australiensis. The O. australiensis RCA enzyme was thermally stable up to 42°C, contrasting with RCA from O. sativa, which was inhibited at 36°C. We attribute heat tolerance in the wild species to thermal stability of RCA, enabling Rubisco to remain active.
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Affiliation(s)
- Andrew P Scafaro
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia
- ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, The Australian National University, Canberra, ACT, 0200, Australia
| | - Alexander Gallé
- Bayer CropScience NV, Innovation Center - Trait Research, Technologiepark 38, Zwijnaarde (Gent), 9052, Belgium
| | - Jeroen Van Rie
- Bayer CropScience NV, Innovation Center - Trait Research, Technologiepark 38, Zwijnaarde (Gent), 9052, Belgium
| | | | - Michael E Salvucci
- US Department of Agriculture, Agricultural Research Service, Arid-Land Agricultural Research Center, Maricopa, AZ, 85138, USA
| | - Brian J Atwell
- Department of Biological Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, 2109, Australia
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9
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Martin AH, Nieuwland M, de Jong GAH. Characterization of heat-set gels from RuBisCO in comparison to those from other proteins. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:10783-10791. [PMID: 25314325 DOI: 10.1021/jf502905g] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
To anticipate a future shortage in functional proteins, it is important to study the functionality of new alternative protein sources. Native RuBisCO was extracted from spinach, and its gelation behavior was compared to other native proteins from animal and plant origins. Protein gels were analyzed for their mechanical gel properties during small and large deformation and for their microstructure. Heat-induced aggregation and network formation of RuBisCO resulted in gels with unique characteristics compared to, for example, whey protein and egg white protein. Having a very low critical gelling concentration and low denaturation temperature, RuBisCO readily forms a network with a very high gel strength (G', fracture stress), but upon deformation it has a brittle character (low critical strain, low fracture strain). This breakdown behavior can be explained by the dominant role of hydrophobic and hydrogen bonds between RuBisCO molecules during network formation and by the coarse microstructure. RuBisCO was shown to exhibit high potential as a functional ingredient giving opportunities for the design of new textures at low protein concentration.
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Affiliation(s)
- Anneke H Martin
- Functional Ingredients, TNO, P.O. Box 360, 3700 AJ Zeist, The Netherlands
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O’Donnelly K, Zhao G, Patel P, Butt MS, Mak LH, Kretschmer S, Woscholski R, Barter LMC. Isolation and kinetic characterisation of hydrophobically distinct populations of form I Rubisco. PLANT METHODS 2014; 10:17. [PMID: 24987448 PMCID: PMC4076768 DOI: 10.1186/1746-4811-10-17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 05/28/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND Rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase) is a Calvin Cycle enzyme involved in CO2 assimilation. It is thought to be a major cause of photosynthetic inefficiency, suffering from both a slow catalytic rate and lack of specificity due to a competing reaction with oxygen. Revealing and understanding the engineering rules that dictate Rubisco's activity could have a significant impact on photosynthetic efficiency and crop yield. RESULTS This paper describes the purification and characterisation of a number of hydrophobically distinct populations of Rubisco from both Spinacia oleracea and Brassica oleracea extracts. The populations were obtained using a novel and rapid purification protocol that employs hydrophobic interaction chromatography (HIC) as a form I Rubisco enrichment procedure, resulting in distinct Rubisco populations of expected enzymatic activities, high purities and integrity. CONCLUSIONS We demonstrate here that HIC can be employed to isolate form I Rubisco with purities and activities comparable to those obtained via ion exchange chromatography (IEC). Interestingly, and in contrast to other published purification methods, HIC resulted in the isolation of a number of hydrophobically distinct Rubisco populations. Our findings reveal a so far unaccounted diversity in the hydrophobic properties within form 1 Rubisco. By employing HIC to isolate and characterise Spinacia oleracea and Brassica oleracea, we show that the presence of these distinct Rubisco populations is not species specific, and we report for the first time the kinetic properties of Rubisco from Brassica oleracea extracts. These observations may aid future studies concerning Rubisco's structural and functional properties.
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Affiliation(s)
- Kerry O’Donnelly
- Institute of Chemical Biology, Department of Chemistry, Imperial College, Flowers Building, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Guangyuan Zhao
- Department of Chemistry, Imperial College, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Priya Patel
- Department of Chemistry, Imperial College, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - M Salman Butt
- Institute of Chemical Biology, Department of Chemistry, Imperial College, Flowers Building, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Lok Hang Mak
- Department of Chemistry, Imperial College, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Simon Kretschmer
- Department of Chemistry, Imperial College, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Rudiger Woscholski
- Institute of Chemical Biology, Department of Chemistry, Imperial College, Flowers Building, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
| | - Laura M C Barter
- Institute of Chemical Biology, Department of Chemistry, Imperial College, Flowers Building, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
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Scales JC, Parry MAJ, Salvucci ME. A non-radioactive method for measuring Rubisco activase activity in the presence of variable ATP: ADP ratios, including modifications for measuring the activity and activation state of Rubisco. PHOTOSYNTHESIS RESEARCH 2014; 119:355-65. [PMID: 24390640 PMCID: PMC3923112 DOI: 10.1007/s11120-013-9964-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 12/19/2013] [Indexed: 05/19/2023]
Abstract
Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) catalyzes carboxylation of ribulose-1,5-bisphosphate, the first in a series of reactions leading to the incorporation of atmospheric CO₂ into biomass. Rubisco requires Rubisco activase (RCA), an AAA+ ATPase that reactivates Rubisco by remodelling the conformation of inhibitor-bound sites. RCA is regulated by the ratio of ADP:ATP, with the precise response potentiated by redox regulation of the alpha-isoform. Measuring the effects of ADP on the activation of Rubisco by RCA using the well-established photometric assay is problematic because of the adenine nucleotide requirement of 3-phosphoglycerate (3-PGA) kinase. Described here is a novel assay for measuring RCA activity in the presence of variable ratios of ADP:ATP. The assay couples the formation of 3-PGA from ribulose 1,5-bisphosphate and CO₂ to NADH oxidation through cofactor-dependent phosphoglycerate mutase, enolase, PEP carboxylase and malate dehydrogenase. The assay was used to determine the effects of Rubisco and RCA concentration and ADP:ATP ratio on RCA activity, and to measure the activation of a modified Rubisco by RCA. Variations of the basic assay were used to measure the activation state of Rubisco in leaf extracts and the activity of purified Rubisco. The assay can be automated for high-throughput processing by conducting the reactions in two stages.
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Affiliation(s)
- Joanna C. Scales
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
| | - Martin A. J. Parry
- Plant Biology and Crop Science, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
| | - Michael E. Salvucci
- Arid-Land Agricultural Research Center, U.S. Department of Agriculture-Agricultural Research Service, 21881 N. Cardon Lane, Maricopa, AZ 85138 USA
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12
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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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13
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Jiang Y, Wang J, Tao X, Zhang Y. Characterization and expression of Rubisco activase genes in Ipomoea batatas. Mol Biol Rep 2013; 40:6309-21. [PMID: 24065541 PMCID: PMC3824211 DOI: 10.1007/s11033-013-2744-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 09/14/2013] [Indexed: 11/27/2022]
Abstract
Two-dimensional electrophoresis, coupled with MALDI-TOF-MS, was used to identify differentially expressed proteins between young and mature leaves of sweet potato [Ipomoea batatas (L.) Lam]. The results showed that there were 25 differential proteins between young and mature leaves. The Rubisco activase (RCA) that catalyzes the activation of Rubisco in vivo and plays a crucial role in photosynthesis was among these 25 proteins. So far, little was known about the molecular biology of RCA in sweet potato. Here, this research reports the cloning and characterization of two genes encoding the short isoform and the long isoform of sweet potato RCAs. Analysis of DNA sequences of RCA suggested that the corresponding mRNAs were transcribed from two different genes. To study the roles of these two RCA isoforms in photosynthesis, we investigated the expression patterns of these RCA genes at the mRNA and protein levels every 2 h in a photoperiod and under different temperatures conditions. The results indicated that these two RCA isoforms may play different roles in regulating photosynthesis and they may be regulated by light, heat or both. In addition, there were interactions between Rubisco large subunit (RBCl) and short isoform RCA (RCAs) as well as RCAs and long isoform RCA (RCAl), but no interaction between RBCl and RCAl, implying they might form a sandwich-like structure (RBCl–RCAs–RCAl), at least in yeast cells. These results provided new information on the modulation of RCA genes in sweet potato, which could be useful in improving photosynthesis and plant growth in sweet potato.
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Affiliation(s)
- Yusong Jiang
- Key Laboratory of Resource Biology and Eco-environment of Ministry of Education, Sichuan Key Laboratory of Molecular Biology and Biotechnology, College of Life Science, Sichuan University, Chengdu, 610064 People’s Republic of China
| | - Jianxi Wang
- Key Laboratory of Resource Biology and Eco-environment of Ministry of Education, Sichuan Key Laboratory of Molecular Biology and Biotechnology, College of Life Science, Sichuan University, Chengdu, 610064 People’s Republic of China
| | - Xiang Tao
- Key Laboratory of Resource Biology and Eco-environment of Ministry of Education, Sichuan Key Laboratory of Molecular Biology and Biotechnology, College of Life Science, Sichuan University, Chengdu, 610064 People’s Republic of China
| | - Yizheng Zhang
- Key Laboratory of Resource Biology and Eco-environment of Ministry of Education, Sichuan Key Laboratory of Molecular Biology and Biotechnology, College of Life Science, Sichuan University, Chengdu, 610064 People’s Republic of China
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