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le Roux MSL, Burger NFV, Vlok M, Kunert KJ, Cullis CA, Botha AM. Wheat Line "RYNO3936" Is Associated With Delayed Water Stress-Induced Leaf Senescence and Rapid Water-Deficit Stress Recovery. FRONTIERS IN PLANT SCIENCE 2020; 11:1053. [PMID: 32760414 PMCID: PMC7372113 DOI: 10.3389/fpls.2020.01053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 06/25/2020] [Indexed: 06/11/2023]
Abstract
Random mutagenesis was applied to produce a new wheat mutant (RYNO3926) with superior characteristics regarding tolerance to water deficit stress induced at late booting stage. The mutant also displays rapid recovery from water stress conditions. Under water stress conditions mutant plants reached maturity faster and produced more seeds than its wild type wheat progenitor. Wild-type Tugela DN plants died within 7 days after induction of water stress induced at late booting stage, while mutant plants survived by maintaining a higher relative moisture content (RMC), increased total chlorophyll, and a higher photosynthesis rate and stomatal conductance. Analysis of the proteome of mutant plants revealed that they better regulate post-translational modification (SUMOylation) and have increased expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) proteins. Mutant plants also expressed unique proteins associated with dehydration tolerance including abscisic stress-ripening protein, cold induced protein, cold-responsive protein, dehydrin, Group 3 late embryogenesis, and a lipoprotein (LAlv9) belonging to the family of lipocalins. Overall, our results suggest that our new mutant RYNO3936 has a potential for inclusion in future breeding programs to improve drought tolerance under dryland conditions.
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Affiliation(s)
| | | | - Maré Vlok
- Proteomics Unit, Central Analytical Facilities, University of Stellenbosch, Stellenbosch, South Africa
| | - Karl J. Kunert
- Department of Plant and Soil Sciences, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Christopher A. Cullis
- Department of Biology, Case Western Reserve University, Cleveland, OH, United States
| | - Anna-Maria Botha
- Department of Genetics, University of Stellenbosch, Stellenbosch, South Africa
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Majeran W, Wostrikoff K, Wollman FA, Vallon O. Role of ClpP in the Biogenesis and Degradation of RuBisCO and ATP Synthase in Chlamydomonas reinhardtii. PLANTS (BASEL, SWITZERLAND) 2019; 8:E191. [PMID: 31248038 PMCID: PMC6681370 DOI: 10.3390/plants8070191] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 06/17/2019] [Accepted: 06/19/2019] [Indexed: 01/17/2023]
Abstract
Ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO) associates a chloroplast- and a nucleus-encoded subunit (LSU and SSU). It constitutes the major entry point of inorganic carbon into the biosphere as it catalyzes photosynthetic CO2 fixation. Its abundance and richness in sulfur-containing amino acids make it a prime source of N and S during nutrient starvation, when photosynthesis is downregulated and a high RuBisCO level is no longer needed. Here we show that translational attenuation of ClpP1 in the green alga Chlamydomonas reinhardtii results in retarded degradation of RuBisCO during S- and N-starvation, suggesting that the Clp protease is a major effector of RubisCO degradation in these conditions. Furthermore, we show that ClpP cannot be attenuated in the context of rbcL point mutations that prevent LSU folding. The mutant LSU remains in interaction with the chloroplast chaperonin complex. We propose that degradation of the mutant LSU by the Clp protease is necessary to prevent poisoning of the chaperonin. In the total absence of LSU, attenuation of ClpP leads to a dramatic stabilization of unassembled SSU, indicating that Clp is responsible for its degradation. In contrast, attenuation of ClpP in the absence of SSU does not lead to overaccumulation of LSU, whose translation is controlled by assembly. Altogether, these results point to RuBisCO degradation as one of the major house-keeping functions of the essential Clp protease. In addition, we show that non-assembled subunits of the ATP synthase are also stabilized when ClpP is attenuated. In the case of the atpA-FUD16 mutation, this can even allow the assembly of a small amount of CF1, which partially restores phototrophy.
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Affiliation(s)
- Wojciech Majeran
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, Université Paris-Diderot, Université Paris-Sud, INRA, Université Evry, Université Paris-Saclay, Rue de Noetzlin, 91190 Gif-sur-Yvette, France.
| | - Katia Wostrikoff
- UMR7141 CNRS/Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Francis-André Wollman
- UMR7141 CNRS/Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | - Olivier Vallon
- UMR7141 CNRS/Sorbonne Université, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
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3
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DFT and TD-DFT Studies of Mg-Substitution in Chlorophyll by Cr(II), Fe(II) and Ni(II). CHEMISTRY AFRICA-A JOURNAL OF THE TUNISIAN CHEMICAL SOCIETY 2018. [DOI: 10.1007/s42250-018-0003-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Carlos Ruiz-Ruiz J, Ramón-Sierra J, Arias-Argaez C, Magaña-Ortiz D, Ortiz-Vázquez E. Antibacterial activity of proteins extracted from the pulp of wild edible fruit of Bromelia pinguin L. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2016. [DOI: 10.1080/10942912.2016.1154572] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Jorge Carlos Ruiz-Ruiz
- División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Mérida, Mérida, Yucatán, México
| | - Jesús Ramón-Sierra
- División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Mérida, Mérida, Yucatán, México
| | - Carolina Arias-Argaez
- División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Mérida, Mérida, Yucatán, México
| | - Denis Magaña-Ortiz
- División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Mérida, Mérida, Yucatán, México
| | - Elizabeth Ortiz-Vázquez
- División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Mérida, Mérida, Yucatán, México
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Girondé A, Poret M, Etienne P, Trouverie J, Bouchereau A, Le Cahérec F, Leport L, Niogret MF, Avice JC. A Comparative Study of Proteolytic Mechanisms during Leaf Senescence of Four Genotypes of Winter Oilseed Rape Highlighted Relevant Physiological and Molecular Traits for NRE Improvement. PLANTS (BASEL, SWITZERLAND) 2015; 5:E1. [PMID: 27135221 PMCID: PMC4844419 DOI: 10.3390/plants5010001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/07/2015] [Accepted: 12/14/2015] [Indexed: 11/21/2022]
Abstract
Winter oilseed rape is characterized by a low N use efficiency related to a weak leaf N remobilization efficiency (NRE) at vegetative stages. By investigating the natural genotypic variability of leaf NRE, our goal was to characterize the relevant physiological traits and the main protease classes associated with an efficient proteolysis and high leaf NRE in response to ample or restricted nitrate supply. The degradation rate of soluble proteins and D1 protein (a thylakoid-bound protein) were correlated to N remobilization, except for the genotype Samouraï which showed a low NRE despite high levels of proteolysis. Under restricted nitrate conditions, high levels of soluble protein degradation were associated with serine, cysteine and aspartic proteases at acidic pH. Low leaf NRE was related to a weak proteolysis of both soluble and thylakoid-bound proteins. The results obtained on the genotype Samouraï suggest that the timing between the onset of proteolysis and abscission could be a determinant. The specific involvement of acidic proteases suggests that autophagy and/or senescence-associated vacuoles are implicated in N remobilization under low N conditions. The data revealed that the rate of D1 degradation could be a relevant indicator of leaf NRE and might be used as a tool for plant breeding.
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Affiliation(s)
- Alexandra Girondé
- UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France.
| | - Marine Poret
- UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France.
| | - Philippe Etienne
- UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France.
| | - Jacques Trouverie
- UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France.
| | - Alain Bouchereau
- INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
| | - Françoise Le Cahérec
- INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
| | - Laurent Leport
- INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
| | - Marie-Françoise Niogret
- INRA, UMR 1349 Institut de Génétique, Environnement et Protection des Plantes, Agrocampus Ouest, Université de Rennes 1, F-35653 Le Rheu, France.
| | - Jean-Christophe Avice
- UMR INRA-UCBN 950 Ecophysiologie Végétale, Agronomie & Nutritions N.C.S., Université de Caen Normandie, F-14032 Caen, France.
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Ishida H, Izumi M, Wada S, Makino A. Roles of autophagy in chloroplast recycling. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:512-21. [PMID: 24269172 DOI: 10.1016/j.bbabio.2013.11.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 11/01/2013] [Accepted: 11/07/2013] [Indexed: 01/04/2023]
Abstract
Chloroplasts are the primary energy suppliers for plants, and much of the total leaf nitrogen is distributed to these organelles. During growth and reproduction, chloroplasts in turn represent a major source of nitrogen to be recovered from senescing leaves and used in newly-forming and storage organs. Chloroplast proteins also can be an alternative substrate for respiration under suboptimal conditions. Autophagy is a process of bulk degradation and nutrient sequestration that is conserved in all eukaryotes. Autophagy can selectively target chloroplasts as whole organelles and or as Rubisco-containing bodies that are enclosed by the envelope and specifically contain the stromal portion of the chloroplast. Although information is still limited, recent work indicates that chloroplast recycling via autophagy plays important roles not only in developmental processes but also in organelle quality control and adaptation to changing environments. This article is part of a Special Issue entitled: Dynamic and ultrastructure of bioenergetic membranes and their components.
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Affiliation(s)
- Hiroyuki Ishida
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
| | - Masanori Izumi
- Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Shinya Wada
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
| | - Amane Makino
- Graduate School of Agricultural Sciences, Tohoku University, Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0076, Japan
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Lee TA, Vande Wetering SW, Brusslan JA. Stromal protein degradation is incomplete in Arabidopsis thaliana autophagy mutants undergoing natural senescence. BMC Res Notes 2013; 6:17. [PMID: 23327451 PMCID: PMC3724497 DOI: 10.1186/1756-0500-6-17] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/15/2013] [Indexed: 02/08/2023] Open
Abstract
Background Degradation of highly abundant stromal proteins plays an important role in the nitrogen economy of the plant during senescence. Lines of evidence supporting proteolysis within the chloroplast and outside the chloroplast have been reported. Two extra-plastidic degradation pathways, chlorophagy and Rubisco Containing Bodies, rely on cytoplasmic autophagy. Results In this work, levels of three stromal proteins (Rubisco large subunit, chloroplast glutamine synthetase and Rubisco activase) and one thylakoid protein (the major light harvesting complex protein of photosystem II) were measured during natural senescence in WT and in two autophagy T-DNA insertion mutants (atg5 and atg7). Thylakoid-localized protein decreased similarly in all genotypes, but stromal protein degradation was incomplete in the two atg mutants. In addition, degradation of two stromal proteins was observed in chloroplasts isolated from mid-senescence leaves. Conclusions These data suggest that autophagy does contribute to the complete proteolysis of stromal proteins, but does not play a major degenerative role. In addition, support for in organello degradation is provided.
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Affiliation(s)
- Travis A Lee
- Department of Biological Sciences, California State University, Long Beach, 1250 Bellflower Boulevard, Long Beach, CA 90840-9502, USA
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8
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Fukayama H, Abe R, Uchida N. SDS-dependent proteases induced by ABA and its relation to Rubisco and Rubisco activase contents in rice leaves. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2010; 48:808-812. [PMID: 20829052 DOI: 10.1016/j.plaphy.2010.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 06/22/2010] [Accepted: 08/13/2010] [Indexed: 05/29/2023]
Abstract
Protease activities and its relation to the contents of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and Rubisco activase were investigated in detached leaves of rice (Oryza sativa L.) floated on the solutions containing abscisic acid (ABA) or benzyladenine (BA). Rubisco and Rubisco activase contents were decreased during the time course and the decreases were enhanced by ABA and suppressed by BA. The decrease in Rubisco activase was faster than that in Rubisco. SDS-dependent protease activities at 50-70 kDa (rice SDS-dependent protease: RSP) analyzed by the gelatin containing PAGE were significantly enhanced by ABA. RSPs were also increased in attached leaves during senescence. RSPs had the pH optimum of 5.5, suggesting that RSPs are vacuolar protease. Both decrease in Rubisco and Rubisco activase contents and increase in RSPs activities were suppressed by cycloheximide. These findings indicate that the activities of RSPs are well correlated with the decrease in these protein contents. Immunoblotting analysis showed that Rubisco in the leaf extracts was completely degraded by 5h at pH 5.5 with SDS where it was optimal condition for RSPs. However, the degradation of Rubisco did not proceed at pH 7.5 without SDS where it is near physiological condition for stromal proteins. Rubisco activase was degraded at similar rate under both conditions. These results suggest that RSPs can functions in a senescence related degradation system of chloroplast protein in rice leaves. Rubisco activase would be more susceptible to proteolysis than Rubisco under physiological condition and this could affect the contents of these proteins in leaves.
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Affiliation(s)
- Hiroshi Fukayama
- Graduate School of Agricultural Science, Kobe University, Nada-ku, Kobe 657-8501, Japan.
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Gregersen PL, Holm PB, Krupinska K. Leaf senescence and nutrient remobilisation in barley and wheat. PLANT BIOLOGY (STUTTGART, GERMANY) 2008; 10 Suppl 1:37-49. [PMID: 18721310 DOI: 10.1111/j.1438-8677.2008.00114.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Extensive studies have been undertaken on senescence processes in barley and wheat and their importance for the nitrogen use efficiency of these crop plants. During the senescence processes, proteins are degraded and nutrients are re-mobilised from senescing leaves to other organs, especially the developing grain. Most of the proteins degraded reside in the chloroplasts, with Rubisco constituting the most dominant protein fraction. Despite intensive studies, the proteases responsible for Rubisco degradation have not yet been identified. Evidence for degradation of stromal proteins outside of chloroplasts is summarised. Rubisco is thought to be released from chloroplasts into vesicles containing stroma material (RCB = Rubisco-containing bodies). These vesicles may then take different routes for their degradation. Transcriptome analyses on barley and wheat senescence have identified genes involved in degradative, metabolic and regulatory processes that could be used in future strategies aimed at modifying the senescence process. The breeding of crops for characters related to senescence processes, e.g. higher yields and better nutrient use efficiency, is complex. Such breeding has to cope with the dilemma that delayed senescence, which could lead to higher yields, is correlated with a decrease in nutrient use efficiency. Pinpointing regulatory genes involved in senescence might lead to tools that could effectively overcome this dilemma.
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Affiliation(s)
- P L Gregersen
- Department of Genetics and Biotechnology, DJF, University of Aarhus, Research Center Flakkebjerg, Slagelse, Denmark
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Kingston-Smith AH, Davies TE, Edwards JE, Theodorou MK. From plants to animals; the role of plant cell death in ruminant herbivores. JOURNAL OF EXPERIMENTAL BOTANY 2008; 59:521-32. [PMID: 18252704 DOI: 10.1093/jxb/erm326] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plant cell death occurring as a result of adverse environmental conditions is known to limit crop production. It is less well recognized that plant cell death processes can also contribute to the poor environmental footprint of ruminant livestock production. Although the forage cells ingested by grazing ruminant herbivores will ultimately die, the lack of oxygen, elevated temperature, and challenge by microflora experienced in the rumen induce regulated plant stress responses resulting in DNA fragmentation and autolytic protein breakdown during the cell death process. Excessive ruminal proteolysis contributes to the inefficient conversion of plant to microbial and animal protein which results in up to 70% of the ingested nitrogen being returned to the land as the nitrogenous pollutants ammonia and urea. This constitutes a significant challenge for sustainable livestock production. As it is estimated that 25% of cultivated land worldwide is assigned to livestock production, it is clear that understanding the fundamental biology underlying cell death in ingested forage will have a highly significant role in minimizing the impact of human activities. This review examines our current understanding of plant metabolism in the rumen and explores opportunities for exploitation of plant genetics to advance sustainable land use.
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Affiliation(s)
- Alison H Kingston-Smith
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth SY23 3EB, UK.
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Zhang LF, Rui Q, Zhang P, Wang XY, Xu LL. A novel 51-kDa fragment of the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase formed in the stroma of chloroplasts in dark-induced senescing wheat leaves. PHYSIOLOGIA PLANTARUM 2007; 131:64-71. [PMID: 18251925 DOI: 10.1111/j.1399-3054.2007.00928.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The degradation of large subunit (LSU) of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in wheat (Triticum aestivum L. cv. Yangmai 158) leaves was studied. A novel 51-kDa fragment was detected in leaf crude extracts and in chloroplast lysates from leaves with dark-induced senescence. Further studies showed that the 51-kDa fragment was found in the reaction solution with stroma fraction but not in that with the chloroplast membrane fraction and in the chloroplast lysates from mature wheat leaves. The reaction of producing the 51-kDa fragment was inhibited by 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride (AEBSF), 1,10-phenanthroline and EDTA. The N-terminal sequence analysis indicated that the LSU was cleaved at the peptide bond between Lys-14 and Ala-15. In addition, a 50-kDa fragment of LSU formed obviously at pH 6.0-6.5 was detected in the crude extracts of leaves with dark-induced senescence but was not found in lysates of chloroplasts. The degradation was prevented by AEBSF, leupeptin and transepoxysuccinyl-l-leucylamido (4-guanidino) butane (E-64). The results obtained in this study imply that the appearance of the 51-kDa fragment could be because of the involvement of a new senescence-associated protease that is located in the stroma of chloroplasts in senescing wheat leaves.
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Affiliation(s)
- Lie-Feng Zhang
- Department of Biochemistry and Molecular Biology, College of Life Science, Nanjing Agricultural University, 210095 Nanjing, China
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Nakano R, Ishida H, Makino A, Mae T. In vivo fragmentation of the large subunit of ribulose-1,5-bisphosphate carboxylase by reactive oxygen species in an intact leaf of cucumber under chilling-light conditions. PLANT & CELL PHYSIOLOGY 2006; 47:270-6. [PMID: 16373381 DOI: 10.1093/pcp/pci245] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Previous studies have demonstrated that the large subunit (LSU) of ribulose-1,5-bisphosphate carboxylase (Rubisco) is site-specifically cleaved by a hydroxyl radical (*OH) generated in the illuminated chloroplast lysates or by an artificial *OH-generating system. However, it is not known whether such cleavage of the LSU by reactive oxygen species (ROS) actually occurs in an intact leaf. When leaf discs of chilling-sensitive cucumber (Cucumis sativus L.) were illuminated at 4 degrees C, five major fragments of the LSU were observed. This fragmentation was completely inhibited by ROS scavengers, such as n-propyl gallate (for *OH) and 1,2-dihydroxybenzene-3,5-disulfonic acid (Tiron) (for superoxide). FeSO4 stimulated this fragmentation, whereas an iron-specific chelator, deferoxamine, suppressed it. Furthermore, such fragments were identical to those generated from the purified Rubisco by an *OH-generating system in vitro on two-dimensional PAGE. These results indicate that the direct fragmentation of the LSU by reactive oxygen species also occurs in an intact leaf.
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Affiliation(s)
- Ryouhei Nakano
- Department of Applied Plant Science, Graduate School of Agricultural Science, Tohoku University, Tsutsumidori-Amamiyamachi, Sendai, 981-8555 Japan
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Carvalho LC, Esquível MG, Martins I, Ricardo CP, Amâncio S. Monitoring the stability of Rubisco in micropropagated grapevine (Vitis vinifera L.) by two-dimensional electrophoresis. JOURNAL OF PLANT PHYSIOLOGY 2005; 162:365-74. [PMID: 15900878 DOI: 10.1016/j.jplph.2004.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Plants cultured in vitro suffer from several physiological and biochemical impairments due to the artificial conditions of growth, namely the composition of the heterotrophic media. Upon transfer to ex vitro, the higher irradiances, compared to in vitro, can lead to oxidative stress symptoms, which can be counteracted by CO2 concentrations above atmospheric levels. Here we analyse the stability of Rubisco in in vitro grapevine plantlets, and after transfer to ex vitro under four acclimatization treatments: low irradiance (LL, 150 micromol m(-2)s(-1)) and high irradiance (HL, 300 micromol m(-2)s(-1)) in association with CO2 concentrations of 350 (LCO2) and 700 (HCO2) microL L(-1). Proteins were separated with SDS polyacrylamide gel electrophoresis and two-dimensional electrophoresis and Rubisco degradation peptides were analysed by immunoblotting with anti-LSU antibodies. These degradation products were present in the leaves of plantlets under both in vitro and ex vitro treatments. Under LCO2 they were maintained for almost all of the 28 days of the acclimatization period, while becoming scarcely detected after 14 days under HCO2 and after 7 days when HCO2 was associated with HL. These results appear to confirm the counteraction of HCO2 concentrations over the oxidative stress eventually caused by HL. The patterns of soluble sugars in acclimatizing leaves under HLHCO2 also gave an indication of a faster acquisition of autotrophic characteristics.
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Affiliation(s)
- Luísa C Carvalho
- DBEB/CBAA, Instituto Superior de Agronomia, UTL, Tapada da Ajuda, 1349-017 Lisboa, Portugal
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Kingston-Smith AH, Merry RJ, Leemans DK, Thomas H, Theodorou MK. Evidence in support of a role for plant-mediated proteolysis in the rumens of grazing animals. Br J Nutr 2005; 93:73-9. [PMID: 15705228 DOI: 10.1079/bjn20041303] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The present work aimed to differentiate between proteolytic activities of plants and micro-organisms during the incubation of grass in cattle rumens. Freshly cut ryegrass was placed in bags of varying permeability and incubated for 16 h in the rumens of dairy cows that had previously grazed a ryegrass sward, supplemented with 4 kg dairy concentrate daily. Woven polyester bags (50 microm pore size) permitted direct access of the micro-organisms and rumen fluid enzymes to the plant material. The polythene was impermeable even to small molecules such as NH(3). Dialysis tubing excluded micro-organisms and rumen enzymes/metabolites larger than 10 kDa. DM loss was 46.3 % in polyester, 36.2 % in polythene and 38.1 % in dialysis treatments. It is possible that the DM loss within polythene bags occurred due to a solubilisation of plant constituents (e.g. water-soluble carbohydrates) rather than microbial attachment/degradation processes. The final protein content of the herbage residues was not significantly different between treatments. Regardless of bag permeability, over 97 % of the initial protein content was lost during incubations in situ. Electrophoretic separation showed that Rubisco was extensively degraded in herbage residues whereas the membrane-associated, light-harvesting protein remained relatively undegraded. Protease activity was detected in herbage residues and bathing liquids after all incubation in situ treatments. Although rumen fluid contains proteases (possibly of plant and microbial origin), our results suggest that, owing to cell compartmentation, their activity against the proteins of intact plant cells is limited, supporting the view that plant proteases are involved in the degradation of proteins in freshly ingested herbage.
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Affiliation(s)
- A H Kingston-Smith
- Department of Plant, Animal and Microbial Science, Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth SY23 3EB, UK.
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15
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Lim PO, Nam HG. The molecular and genetic control of leaf senescence and longevity in Arabidopsis. Curr Top Dev Biol 2005; 67:49-83. [PMID: 15949531 DOI: 10.1016/s0070-2153(05)67002-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The life of a leaf initiated from a leaf primordium ends with senescence, the final step of leaf development. Leaf senescence is a developmentally programmed degeneration process that is controlled by multiple developmental and environmental signals. It is a highly regulated and complex process that involves orderly, sequential changes in cellular physiology, biochemistry, and gene expression. Elucidating molecular mechanisms underlying such a complex, yet delicate process of leaf senescence is a challenging and important biological task. For the past decade, impressive progress has been achieved on the molecular processes of leaf senescence through identification of genes that show enhanced expression during senescence. In addition, Arabidopsis has been established as a model plant for genetic analysis of leaf senescence. The progress on the characterization of genetic mutants of leaf senescence in Arabidopsis has firmly shown that leaf senescence is a genetically controlled developmental phenomenon involving numerous regulatory elements. Especially, employment of global expression analysis as well as genomic resources in Arabidopsis has been very fruitful in revealing the molecular genetic nature and mechanisms underlying leaf senescence. This progress, including molecular characterization of some of the genetic regulatory elements, are revealing that senescence is composed of a complex regulatory network. In this review, we will present current understanding of the molecular genetic mechanisms by which leaf senescence is regulated and processed, focusing mostly on the regulatory factors of senescence in Arabidopsis. We also present a potential biotechnological implication of leaf senescence studies on the improvement of important agronomic traits such as crop yield and post-harvest shelf life. We further provide future research prospects to better understand the complex regulatory network of senescence.
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Affiliation(s)
- Pyung Ok Lim
- National Research Laboratory of Plant Molecular Genetics, Division of Molecular and Life Sciences, Pohang University of Science and Technology Pohang, Kyungbuk, 790-784, Korea
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16
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Coffeen WC, Wolpert TJ. Purification and characterization of serine proteases that exhibit caspase-like activity and are associated with programmed cell death in Avena sativa. THE PLANT CELL 2004; 16:857-73. [PMID: 15020745 PMCID: PMC412861 DOI: 10.1105/tpc.017947] [Citation(s) in RCA: 124] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2003] [Accepted: 01/27/2004] [Indexed: 05/18/2023]
Abstract
Victoria blight of Avena sativa (oat) is caused by the fungus Cochliobolus victoriae, which is pathogenic because of the production of the toxin victorin. The victorin-induced response in sensitive A. sativa has been characterized as a form of programmed cell death (PCD) and displays morphological and biochemical features similar to apoptosis, including chromatin condensation, DNA laddering, cell shrinkage, altered mitochondrial function, and ordered, substrate-specific proteolytic events. Victorin-induced proteolysis of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is shown to be prevented by caspase-specific and general protease inhibitors. Evidence is presented for a signaling cascade leading to Rubisco proteolysis that involves multiple proteases. Furthermore, two proteases that are apparently involved in the Rubisco proteolytic cascade were purified and characterized. These proteases exhibit caspase specificity and display amino acid sequences homologous to plant subtilisin-like Ser proteases. The proteases are constitutively present in an active form and are relocalized to the extracellular fluid after induction of PCD by either victorin or heat shock. The role of the enzymes as processive proteases involved in a signal cascade during the PCD response is discussed.
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Affiliation(s)
- Warren C Coffeen
- Department of Botany and Plant Pathology and Center for Gene Research and Biotechnology, Oregon State University, Corvallis 97331-2902, USA
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17
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Richter S, Lamppa GK. Determinants for removal and degradation of transit peptides of chloroplast precursor proteins. J Biol Chem 2002; 277:43888-94. [PMID: 12235143 DOI: 10.1074/jbc.m206020200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The stromal processing peptidase (SPP) cleaves a large diversity of chloroplast precursor proteins, removing an N-terminal transit peptide. We predicted previously that this key step of the import pathway is mediated by features of the transit peptide that determine precursor binding and cleavage followed by transit peptide conversion to a degradable substrate. Here we performed competition experiments using synthesized oligopeptides of the transit peptide of ferredoxin precursor to investigate the mechanism of these processes. We found that binding and processing of ferredoxin precursor depend on specific interactions of SPP with the region consisting of the C-terminal 12 residues of the transit peptide. Analysis of four other precursors suggests that processing depends on the same region, although their transit peptides are highly divergent in primary sequence and length. Upon processing, SPP terminates its interaction with the transit peptide by a second cleavage, converting it to a subfragment form. From the competition experiments we deduce that SPP releases a subfragment consisting of the transit peptide without its original C terminus. Interestingly, examination of the ATP-dependent metallopeptidase activity responsible for degradation of transit peptide subfragments suggests that it may recognize other unrelated peptides and, hence, act separately from SPP as a novel stromal oligopeptidase.
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Affiliation(s)
- Stefan Richter
- Department of Molecular Genetics and Cell Biology, University of Chicago, Illinois 60637, USA
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Kokubun N, Ishida H, Makino A, Mae T. The degradation of the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase into the 44-kDa fragment in the lysates of chloroplasts incubated in darkness. PLANT & CELL PHYSIOLOGY 2002; 43:1390-1395. [PMID: 12461140 DOI: 10.1093/pcp/pcf159] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Lysates of chloroplasts isolated from naturally senescing wheat leaves were incubated in darkness. The 44-kDa fragment, lacking the N-terminal-side portion of the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (LSU), was found by immunoblotting with the LSU site-specific antibodies. Analysis of its N-terminal amino acid sequence indicated that the LSU was specifically cleaved at the peptide bond between Phe-40 and Arg-41. The site was located on the surface of the molecule and faced outward. Such cleavage of the LSU has not been previously reported. It is indicated that the cleavage was triggered by an unknown protease existing in chloroplasts.
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Affiliation(s)
- Norimoto Kokubun
- Laboratory of Plant Nutrition and Function, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Sendai, 981-8555 Japan
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19
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Yamauchi Y, Ejiri Y, Tanaka K. Glycation by ascorbic acid causes loss of activity of ribulose-1,5-bisphosphate carboxylase/oxygenase and its increased susceptibility to proteases. PLANT & CELL PHYSIOLOGY 2002; 43:1334-1341. [PMID: 12461133 DOI: 10.1093/pcp/pcf162] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Glycation is a process whereby sugar molecules form a covalent adduct with protein amino groups. In this study, we used ascorbic acid (AsA) as a glycating agent and purified cucumber (Cucumis sativus L.) ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) as a model protein in chloroplast tissues, and examined effects of glycation on the activity and susceptibility of Rubisco to proteases. Glycation proceeded via two phases during incubation with AsA and Rubisco in vitro at physiological conditions (10 mM AsA, pH 7.5, 25 degrees C in the presence of atmospheric oxygen). At the early stage of glycation (phase 1), the amount of AsA attaching to Rubisco increased at an almost linear rate (0.5-0.7 mol AsA incorporated (mol Rubisco)(-1) d(-1)). By Western blotting using monoclonal antibodies recognizing glycation adducts, a major glycation adduct, N( epsilon )-(carboxymethyl)lysine was detected. At the late stage of glycation (phase 2), incorporation of AsA reached saturation, and a glycation adduct, pentosidine mediating intramolecular cross-linking, was detected corresponding to formation of high molecular weight aggregates cross-linked between subunits. Glycation led to a decrease in Rubisco activity (half-life about 7-8 d). Furthermore, glycated Rubisco of phase 2 drastically increased protease susceptibility in contrast to unchanged susceptibility of glycated Rubisco of phase 1 compared to that of native Rubisco. Results obtained here suggest that AsA is possibly an important factor in the loss of activity and turnover of Rubisco.
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Affiliation(s)
- Yasuo Yamauchi
- Laboratory of Plant Biotechnology, Faculty of Agriculture, Tottori University, Koyama, Tottori, 680-8553 Japan.
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20
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Hanaoka H, Noda T, Shirano Y, Kato T, Hayashi H, Shibata D, Tabata S, Ohsumi Y. Leaf senescence and starvation-induced chlorosis are accelerated by the disruption of an Arabidopsis autophagy gene. PLANT PHYSIOLOGY 2002; 129:1181-93. [PMID: 12114572 PMCID: PMC166512 DOI: 10.1104/pp.011024] [Citation(s) in RCA: 453] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Autophagy is an intracellular process for vacuolar bulk degradation of cytoplasmic components. The molecular machinery responsible for yeast and mammalian autophagy has recently begun to be elucidated at the cellular level, but the role that autophagy plays at the organismal level has yet to be determined. In this study, a genome-wide search revealed significant conservation between yeast and plant autophagy genes. Twenty-five plant genes that are homologous to 12 yeast genes essential for autophagy were discovered. We identified an Arabidopsis mutant carrying a T-DNA insertion within AtAPG9, which is the only ortholog of yeast Apg9 in Arabidopsis (atapg9-1). AtAPG9 is transcribed in every wild-type organ tested but not in the atapg9-1 mutant. Under nitrogen or carbon-starvation conditions, chlorosis was observed earlier in atapg9-1 cotyledons and rosette leaves compared with wild-type plants. Furthermore, atapg9-1 exhibited a reduction in seed set when nitrogen starved. Even under nutrient growth conditions, bolting and natural leaf senescence were accelerated in atapg9-1 plants. Senescence-associated genes SEN1 and YSL4 were up-regulated in atapg9-1 before induction of senescence, unlike in wild type. All of these phenotypes were complemented by the expression of wild-type AtAPG9 in atapg9-1 plants. These results imply that autophagy is required for maintenance of the cellular viability under nutrient-limited conditions and for efficient nutrient use as a whole plant.
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Affiliation(s)
- Hideki Hanaoka
- Department of Cell Biology, National Institute for Basic Biology, Nishigonaka 38, Myodaiji-cho, Okazaki 444-8585, Japan
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21
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Hörtensteiner S, Feller U. Nitrogen metabolism and remobilization during senescence. JOURNAL OF EXPERIMENTAL BOTANY 2002; 53:927-37. [PMID: 11912235 DOI: 10.1093/jexbot/53.370.927] [Citation(s) in RCA: 318] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Senescence is a highly organized and well-regulated process. As much as 75% of total cellular nitrogen may be located in mesophyll chloroplasts of C(3)-plants. Proteolysis of chloroplast proteins begins in an early phase of senescence and the liberated amino acids can be exported to growing parts of the plant (e.g. maturing fruits). Rubisco and other stromal enzymes can be degraded in isolated chloroplasts, implying the involvement of plastidial peptide hydrolases. Whether or not ATP is required and if stromal proteins are modified (e.g. by reactive oxygen species) prior to their degradation are questions still under debate. Several proteins, in particular cysteine proteases, have been demonstrated to be specifically expressed during senescence. Their contribution to the general degradation of chloroplast proteins is unclear. The accumulation in intact cells of peptide fragments and inhibitor studies suggest that multiple degradation pathways may exist for stromal proteins and that vacuolar endopeptidases might also be involved under certain conditions. The breakdown of chlorophyll-binding proteins associated with the thylakoid membrane is less well investigated. The degradation of these proteins requires the simultaneous catabolism of chlorophylls. The breakdown of chlorophylls has been elucidated during the last decade. Interestingly, nitrogen present in chlorophyll is not exported from senescencing leaves, but remains within the cells in the form of linear tetrapyrrolic catabolites that accumulate in the vacuole. The degradation pathways for chlorophylls and chloroplast proteins are partially interconnected.
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Affiliation(s)
- Stefan Hörtensteiner
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland
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22
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Yamauchi Y, Sugimoto T, Sueyoshi K, Oji Y, Tanaka K. A serine endopeptidase from cucumber leaves is inhibited by L-arginine, guanidino compounds and divalent cations. PHYTOCHEMISTRY 2001; 58:677-82. [PMID: 11672731 DOI: 10.1016/s0031-9422(01)00309-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
An endopeptidase was purified and characterized from green leaves of cucumber (Cucumis sativus L. suyo). The purified enzyme, a basic amino acid-specific endopeptidase with a pI of 5.0, was a monomeric protein of 80 kDa whose pH optimum was 9.5. Inhibitor analysis suggested that it was a serine endopeptidase and contained sulfhydryl groups essential for catalytic activity. Analysis of internal amino acid sequences of the endopeptidase showed no significant similarity to other proteins. Its activity was inhibited by L-Arg and guanidino compounds having high hydrophobicity, as well as divalent cations such as Mg2+ and Ca2+. The K(i) values of L-Arg and Mg2+, which are also likely in vivo inhibitors, were 3.5 and 10 mM, respectively. Inhibition by L-Arg and Mg2+ was additive, and more than 70% of the activity was reversibly inhibited under their physiologically significant concentrations. These results suggest that the enzyme is possibly regulated by L-Arg and/or guanidino compounds, and by divalent cations in vivo.
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Affiliation(s)
- Y Yamauchi
- Laboratory of Plant Biotechnology, Faculty of Agriculture, Tottori University, Koyama, 680-8553, Tottori, Japan.
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23
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Minamikawa T, Toyooka K, Okamoto T, Hara-Nishimura I, Nishimura M. Degradation of ribulose-bisphosphate carboxylase by vacuolar enzymes of senescing French bean leaves: immunocytochemical and ultrastructural observations. PROTOPLASMA 2001; 218:144-153. [PMID: 11770431 DOI: 10.1007/bf01306604] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The possible involvement of vacuolar cysteine proteinases in degradation of ribulose-bisphosphate carboxylase (Rubisco) in senescing French bean leaves was studied by ultrastructural and immunocytochemical analyses with antibodies raised against the large subunit (LSU) of Rubisco and SH-EP, a cysteine proteinase from Vigna mungo that is immunologically identical to one of the major proteinases of French bean plants. Primary leaves of 10-day-old plants were detached and placed at 25 degrees C in darkness for 0, 4, and 8 days to allow their senescence to proceed. The leaves at each senescence stage were subjected to the conventional electron microscopic and immunocytochemical studies. The results indicated that the chloroplasts of senescing French bean leaves were separated from the cytoplasm of the cell periphery and taken into the central vacuole and that the Rubisco LSU in the chloroplasts was degraded by vacuolar enzymes such as an SH-EP-related cysteine proteinase that developed in senescing leaves. The present results together with the results of previous biochemical studies using vacuolar lysates support the view that Rubisco is degraded through the association of chloroplasts with the central vacuole during the senescence of leaves that were detached and placed in darkness.
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Affiliation(s)
- T Minamikawa
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji, Tokyo 192-0397, Japan
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24
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Beers EP, Woffenden BJ, Zhao C. Plant proteolytic enzymes: possible roles during programmed cell death. PLANT MOLECULAR BIOLOGY 2000; 44:399-415. [PMID: 11199397 DOI: 10.1023/a:1026556928624] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Proteolytic enzymes are known to be associated with developmentally programmed cell death during organ senescence and tracheary element differentiation. Recent evidence also links proteinases with some types of pathogen- and stress-induced cell suicide. The precise roles of proteinases in these and other plant programmed cell death processes are not understood, however. To provide a framework for consideration of the importance of proteinases during plant cell suicide, characteristics of the best-known proteinases from plants including subtilisin-type and papain-type enzymes, phytepsins, metalloproteinases and the 26S proteasome are summarized. Examples of serine, cysteine, aspartic, metallo- and threonine proteinases linked to animal programmed cell death are cited and the potential for plant proteinases to act as mediators of signal transduction and as effectors of programmed cell death is discussed.
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Affiliation(s)
- E P Beers
- Department of Horticulture, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
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25
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Khan S, Andralojc PJ, Lea PJ, Parry MA. 2'-carboxy-D-arabitinol 1-phosphate protects ribulose 1, 5-bisphosphate carboxylase/oxygenase against proteolytic breakdown. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 266:840-7. [PMID: 10583377 DOI: 10.1046/j.1432-1327.1999.00913.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Trypsin-catalysed cleavage of purified ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) and the resultant irreversible loss of carboxylase activity were prevented by prior incubation with the naturally occurring nocturnal Rubisco inhibitor 2'-carboxy-D-arabitinol 1-phosphate (CA1P), as well as with ribulose 1,5-bisphosphate (RuBP), Mg2+ and CO2. CA1P also protected Rubisco from loss of activity caused by carboxypeptidase A. When similar experiments were carried out using soluble chloroplast proteases, CA1P was again able to protect Rubisco against proteolytic degradation and the consequent irreversible loss of catalytic activity. Thus, CA1P prevents the proteolytic breakdown of Rubisco by endogenous and exogenous proteases. In this way, CA1P may affect the amounts of Rubisco protein available for photosynthetic CO2 assimilation. Rubisco turnover (in the presence of RuBP, Mg2+ and CO2) may confer similar protection against proteases in the light.
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Affiliation(s)
- S Khan
- Department of Biochemistry, IACR-Rothamsted, Harpenden, Hertfordshire, UK
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26
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Navarre DA, Wolpert TJ. Victorin induction of an apoptotic/senescence-like response in oats. THE PLANT CELL 1999; 11:237-49. [PMID: 9927641 PMCID: PMC144174 DOI: 10.1105/tpc.11.2.237] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Victorin is a host-selective toxin produced by Cochliobolus victoriae, the causal agent of victoria blight of oats. Previously, victorin was shown to be bound specifically by two proteins of the mitochondrial glycine decarboxylase complex, at least one of which binds victorin only in toxin-sensitive genotypes in vivo. This enzyme complex is involved in the photorespiratory cycle and is inhibited by victorin, with an effective concentration for 50% inhibition of 81 pM. The photorespiratory cycle begins with ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and victorin was found to induce a specific proteolytic cleavage of the Rubisco large subunit (LSU). Leaf slices incubated with victorin for 4 hr in the dark accumulated a form of the LSU that is cleaved after the 14th amino acid. This proteolytic cleavage was prevented by the protease inhibitors E-64 and calpeptin. Another primary symptom of victorin treatment is chlorophyll loss, which along with the specific LSU cleavage is suggestive of a victorin-induced, senescence-like response. DNA from victorin-treated leaf slices showed a pronounced laddering effect, which is typical of apoptosis. Calcium appeared to play a role in mediating the plant response to victorin because LaCl3 gave near-complete protection against victorin, preventing both leaf symptoms and LSU cleavage. The ethylene inhibitors aminooxyacetic acid and silver thiosulfate also gave significant protection against victorin-induced leaf symptoms and prevented LSU cleavage. The symptoms resulting from victorin treatment suggest that victorin causes premature senescence of leaves.
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Affiliation(s)
- D A Navarre
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon 97331-2902, USA
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27
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Barakat S, Pearce DA, Sherman F, Rapp WD. Maize contains a Lon protease gene that can partially complement a yeast pim1-deletion mutant. PLANT MOLECULAR BIOLOGY 1998; 37:141-154. [PMID: 9620272 DOI: 10.1023/a:1005912831051] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We have identified a gene in maize that encodes a product belonging to the Lon protease family. In yeast and mammals, Lon-type proteases catalyze the ATP-dependent degradation of mitochondrial matrix proteins. The maize gene, which we have designated LON1, is predicted to encode a protein with a molecular mass of 97.7 kDa. Lon1p is more similar in sequence to bacterial Lon proteases than to the yeast and human mitochondrial Lon proteases. LON1 transcripts are present in shoots of 4-day-old etiolated maize seedlings, and transcript levels decrease when these seedlings are heat-shocked. LON1 transcripts are also present at comparable levels in leaves and roots of 2-week-old greenhouse-grown seedlings. In yeast, the mitochondrial Lon-type protease, Pim1p, has been implicated in mitochondrial protein turnover, the assembly of mitochondrial enzyme complexes, and mitochondrial DNA maintenance, and it is essential for respiratory function. We show that maize Lon1p can replace the Pim1p function in yeast for maintaining mitochondrial DNA integrity, but not in the assembly of cytochrome a x a3 complexes.
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Affiliation(s)
- S Barakat
- Department of Biology, University of Missouri-St. Louis 63121, USA
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28
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Laing WA, Christeller JT. A Plant Chloroplast Glutamyl Proteinase. PLANT PHYSIOLOGY 1997; 114:715-722. [PMID: 12223739 PMCID: PMC158356 DOI: 10.1104/pp.114.2.715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A glutamyl proteinase was partially purified from Percoll gradient-purified spinach (Spinacia oleracea) chloroplast preparations and appeared to be predominantly localized in the chloroplast stroma. The enzyme degraded casein, but of the 11 synthetic endopeptidase substrates tested, only benzyloxycarbonyl-leucine-leucine-glutamic acid-[beta]-napthylamide was hydrolyzed at measurable rates. In addition, the enzyme cleaved the oxidized [beta]-chain of insulin after a glutamic acid residue. There was no evidence that native ribulose-1,5-bisphosphate carboxylase/oxygenase was cleaved by this proteinase. The apparent Km for benzyloxycarbonyl-leucine-leucine-glutamic acid-[beta]NA at the pH optimum of 8.0 was about 1 mM. Cl-ions were required for both activity and stability. Of the proteinase inhibitors covering all four classes of the endopeptidases, only 4-(2-aminoethyl)-benzenesulfonyl-fluoride HCl and L-1-chloro-3-[4-tosylamido]-4-phenyl-2-butanone significantly inhibited the proteinase. The partially purified enzyme had a molecular weight of about 350,000 to 380,000, based on size-exclusion chromatography. The enzyme has both similar and distinctive properties to those of the bacterial glutamyl proteinases. To our knowledge, this is the first description of a plant glutamyl proteinase found predominantly or exclusively in the chloroplast.
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Affiliation(s)
- W. A. Laing
- HortResearch, Private Bag 92169, Auckland, New Zealand (W.A.L.)
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29
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Adam Z. Protein stability and degradation in chloroplasts. PLANT MOLECULAR BIOLOGY 1996; 32:773-783. [PMID: 8980530 DOI: 10.1007/bf00020476] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- Z Adam
- Department of Agricultural Botany, Faculty of Agriculture, Hebrew University, Rehovot, Israel
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30
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Abstract
Proteolysis is essential for many aspects of plant physiology and development. It is responsible for cellular housekeeping and the stress response by removing abnormal/misfolded proteins, for supplying amino acids needed to make new proteins, for assisting in the maturation of zymogens and peptide hormones by limited cleavages, for controlling metabolism, homeosis, and development by reducing the abundance of key enzymes and regulatory proteins, and for the programmed cell death of specific plant organs or cells. It also has potential biotechnological ramifications in attempts to improve crop plants by modifying protein levels. Accumulating evidence indicates that protein degradation in plants is a complex process involving a multitude of proteolytic pathways with each cellular compartment likely to have one or more. Many of these have homologous pathways in bacteria and animals. Examples include the chloroplast ClpAP protease, vacuolar cathepsins, the KEX2-like proteases of the secretory system, and the ubiquitin/26S proteasome system in the nucleus and cytoplasm. The ubiquitin-dependent pathway requires that proteins targeted for degradation become conjugated with chains of multiple ubiquitins; these chains then serve as recognition signals for selective degradation by the 26S proteasome, a 1.5 MDa multisubunit protease complex. The ubiquitin pathway is particularly important for developmental regulation by selectively removing various cell-cycle effectors, transcription factors, and cell receptors such as phytochrome A. From insights into this and other proteolytic pathways, the use of phosphorylation/dephosphorylation and/or the addition of amino acid tags to selectively mark proteins for degradation have become recurring themes.
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Affiliation(s)
- R D Vierstra
- Department of Horticulture, University of Wisconsin-Madison 53706, USA
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31
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Desimone M, Henke A, Wagner E. Oxidative Stress Induces Partial Degradation of the Large Subunit of Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase in Isolated Chloroplasts of Barley. PLANT PHYSIOLOGY 1996; 111:789-796. [PMID: 12226330 PMCID: PMC157896 DOI: 10.1104/pp.111.3.789] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The effects of oxidative stress on the degradation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39) were studied in isolated chloroplasts from barley (Hordeum vulgare L. cv Angora). Active oxygen (AO) was generated by varying the light intensity, the oxygen concentration, or the addition of herbicides or ADP-FeCl3-ascorbate to the medium. Oxidative treatments stimulated association of Rubisco with the insoluble fraction of chloroplasts and partial proteolysis of the large subunit (LSU). The most prominent degradation product of the LSU of Rubisco showed an apparent molecular mass of 36 kD. The data suggest that an increase in the amount of AO photogenerated by O2 reduction at photosystem I triggers Rubisco degradation. A possible relationship between AO-mediated denaturation of Rubisco and proteolysis of the LSU is discussed.
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Affiliation(s)
- M. Desimone
- Institut fur Biologie II, Universitat Freiburg, Schanzlestrasse 1, D-79104 Freiburg, Germany
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32
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Yoshida T, Minamikawa T. Successive amino-terminal proteolysis of the large subunit of ribulose 1,5-biphosphate carboxylase/oxygenase by vacuolar enzymes from French bean leaves. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 238:317-24. [PMID: 8681940 DOI: 10.1111/j.1432-1033.1996.0317z.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Mainly using the protein immunoblot technique, we observed the decrease in amounts of the large subunit (LSU) and the small subunit (SSU) of ribulose 1,5-biphosphate carboxylase/oxygenase (Rubisco) in detached primary leaves of French bean plants during senescence under the light or in darkness, but detected no significant degradation products of these subunits. Treatment of the detached leaves with 0.6% (mass/vol.) dimethyl sulfoxide, 0.05% (mass/vol.) Tween 80 considerably promoted the senescence, as estimated by the reduction in content of the soluble protein, and also in the amounts of LSU and SSU, but no degradation product of either subunit was found. When extracts prepared from the primary leaves were incubated at pH 5.4 or pH 7.4, the amount of LSU of 53 kDa decreased and concurrently 50-kDa and 42-kDa polypeptides were formed. Since the results suggested that Rubisco may be degraded by vacuolar enzymes, we incubated Rubisco with vacuolar lysates prepared from the senescing primary leaves and found that the LSU, but not SSU, was degraded to a 41-kDa polypeptide through three intermediates of 50 kDa, 48 kDa and 42 kDa. Determination of amino-terminal amino acid sequences of these fragments indicated that each of the proteolysis steps occurred by removal of a small amino-terminal peptide. Experiments with various inhibitors of proteases as well as with a purified Vigna mungo vacuolar protease, termed SH-EP [Mitsuhashi, W. & Minamikawa, T. (1989) Plant Physiol. 89, 274-279] suggested the involvement of two types of proteases in these steps: a cysteine protease that is the same type of enzyme as SH-EP catalyzes the steps from the LSU to the 48-kDa polypeptide through the 50-kDa polypeptide, and a serine protease catalyzes the steps from the 48-kDa polypeptide to the 41-kDa polypeptide through the 42-kDa polypeptide.
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Affiliation(s)
- T Yoshida
- Department of Biology, Tokyo Metropolitan University, Japan
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Ostersetzer O, Tabak S, Yarden O, Shapira R, Adam Z. Immunological detection of proteins similar to bacterial proteases in higher plant chloroplasts. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 236:932-6. [PMID: 8665915 DOI: 10.1111/j.1432-1033.1996.00932.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Despite numerous demonstrations of protein degradation in chloroplasts of higher plants, little is known about the identity of the proteases involved in these reactions. To identify chloroplast proteases by immunological means, we investigated two proteins: ClpP, a protein similar to the proteolytic subunit of the bacterial ATP-dependent Clp protease, for which a gene is found in the chloroplast genome [Maurizi, M.R., Clark, W.P., Kim, S. H. & Gottesman, S. (1990) J. Biol. Chem. 265, 12546-12552] and PrcA, a cyanobacterial Ca2+-stimulated protease [Maldener, I., Lockau, W., Cai, Y. & Wolk, P. (1991) Mol. & Gen. Genet. 225, 113-120]. We expressed the clpP gene from rice in Escherichia coli, purified its product, and generated antibodies against the product. Western blot analysis revealed the ClpP protein in different leaf extracts. Analysis of fractionated barley chloroplasts revealed that the protein was associated with the stromal fraction. The expression of ClpP is light independent and tissue specific, as it was found in green and etiolated barley leaves, but not in roots. A second protein, similar to the cyanobacterial protease PrcA, was also detected in chloroplasts. Antibody against this protease recognized proteins in various leaf extracts. When pea chloroplasts were fractionated, the antibody only recognized a stromal protein. The expression of this protein is regulated by light, as it was found in green leaves, but not in etiolated leaves. The tissue specificity of PrcA was similar to that of ClpP in that it could not be detected in root extracts.
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Affiliation(s)
- O Ostersetzer
- Department of Agricultural Botany, The Hebrew University of Jerusalem, Rehovot, Israel
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Crafts-Brandner SJ, Klein RR, Klein P, Hölzer R, Feller U. Coordination of protein and mRNA abundances of stromal enzymes and mRNA abundances of the Clp protease subunits during senescence of Phaseolus vulgaris (L.) leaves. PLANTA 1996; 200:312-318. [PMID: 8931351 DOI: 10.1007/bf00200298] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Our objective was to determine the coordination of transcript and/or protein abundances of stromal enzymes during leaf senescence. First trifolioliate leaves of Phaseolus vulgaris L. plants were sampled beginning at the time of full leaf expansion; at this same time, half of the plants were switched to a nutrient solution lacking N. Total RNA and soluble protein abundances decreased after full leaf expansion whereas chlorophyll abundance remained constant; N stress enhanced the decline in these traits. Abundances of ribulose-1,5-bisposphate carboxylase/oxygenase (Rubisco; EC 4.1.1.39), Rubisco activase and phosphoribulokinase (Ru5P kinase; EC 2.7.1.19) decreased after full leaf expansion in a coordinated manner for both treatments. In contrast, adenosine diphosphate glucose (ADPGlc) pyrophosphorylase (EC 2.7.7.27) abundance was relatively constant during natural senescence but did decline similar to the other enzymes under N stress. Northern analyses indicated that transcript abundances for all enzymes declined markedly on a fresh-weight basis just after full leaf expansion. This rapid decline was particularly strong for the Rubisco small subunit (rbcS) transcript. The decline was enhanced by N stress for rbcS and Rubisco activase (rca), but not for Ru5P kinase (prk) and ADPGlc pyrophosphorylase (agp). Transcripts of the Clp protease subunits clpC and clpP declined in abundance just after full leaf expansion, similar to the other mRNA species. When Northern blots were analyzed using equal RNA loads, rbcS transcripts still declined markedly just after full leaf expansion whereas rca and clpC transcripts increased over time. The results indicated that senescence was initiated near the time of full leaf expansion, was accelerated by N stress, and was characterized by large decline in transcripts of stromal enzymes. The decreased mRNA abundances were in general associated with steadily declining stromal protein abundances, with ADPGlc pyrophosphorylase being the notable exception. Transcript analyses for the Clp subunits supported a recent report (Shanklin et al., 1995, Plant Cell 7: 1713-1722) indicating that the Clp protease subunits were constitutive throughout development and suggested that ClpC and ClpP do not function as a senescence-specific proteolytic system in Phaseolus.
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Li HH, Merchant S. Degradation of plastocyanin in copper-deficient Chlamydomonas reinhardtii. Evidence for a protease-susceptible conformation of the apoprotein and regulated proteolysis. J Biol Chem 1995; 270:23504-10. [PMID: 7559514 DOI: 10.1074/jbc.270.40.23504] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In the green alga Chlamydomonas reinhardtii, the copper-dependent accumulation of plastocyanin is effected via the altered stability of the protein in copper-deficient versus copper-sufficient medium (t1/2) < 20 min versus several hours). To understand the mechanism of plastocyanin degradation in vivo, the purified apoprotein was characterized relative to the holoprotein with respect to conformation and protease susceptibility. Circular dichroism spectroscopy revealed that the apoprotein in solution did not display the characteristic secondary structure displayed by the native or reconstituted holoprotein. The apoprotein was also susceptible to digestion in vitro by chymotrypsin whereas the holoprotein was resistant. High ionic conditions, which stabilize the folded structure of apoplastocyanin, also inhibit its degradation by chymotrypsin. These results suggest that one explanation for plastocyanin degradation in copper-deficient cells in vivo might be the increased susceptibility of the apo form to a lumenal protease. Since apoplastocyanin is a normal biosynthetic intermediate for the formation of holoplastocyanin, the increased susceptibility of apoplastocyanin to proteolysis implies that degradative and biosynthetic activities would compete for the same substrate. However, characterization of an apoplastocyanin-accumulating mutant suggests that a plastocyanin-degrading protease is active only in copper-deficient cells. Thus, apoplastocyanin is rapidly degraded in copper-deficient cells, whereas its major fate in copper-supplemented cells is holoplastocyanin formation.
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Affiliation(s)
- H H Li
- Department of Chemistry and Biochemistry, University of California at Los Angeles 90095-1569, USA
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