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Liu YL, Zheng HL. Physiological and Proteomic Analyses of Two Acanthus Species to Tidal Flooding Stress. Int J Mol Sci 2021; 22:ijms22031055. [PMID: 33494455 PMCID: PMC7865619 DOI: 10.3390/ijms22031055] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 12/16/2022] Open
Abstract
The mangrove plant Acanthus ilicifolius and its relative, Acanthus mollis, have been previously proved to possess diverse pharmacological effects. Therefore, evaluating the differentially expressed proteins of these species under tidal flooding stress is essential to fully exploit and benefit from their medicinal values. The roots of A. ilicifolius and A. mollis were exposed to 6 h of flooding stress per day for 10 days. The dry weight, hydrogen peroxide (H2O2) content, anatomical characteristics, carbon and energy levels, and two-dimensional electrophoresis coupled with MALDI-TOF/TOF MS technology were used to reveal the divergent flooding resistant strategies. A. ilicifolius performed better under tidal flooding stress, which was reflected in the integrity of the morphological structure, more efficient use of carbon and energy, and a higher percentage of up-regulated proteins associated with carbon and energy metabolism. A. mollis could not survive in flooding conditions for a long time, as revealed by disrupting cell structures of the roots, less efficient use of carbon and energy, and a higher percentage of down-regulated proteins associated with carbon and energy metabolism. Energy provision and flux balance played a role in the flooding tolerance of A. ilicifolius and A. mollis.
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Li JW, Chen XD, Hu XY, Ma L, Zhang SB. Comparative physiological and proteomic analyses reveal different adaptive strategies by Cymbidium sinense and C. tracyanum to drought. PLANTA 2018; 247:69-97. [PMID: 28871432 DOI: 10.1007/s00425-017-2768-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/28/2017] [Indexed: 06/07/2023]
Abstract
A terrestrial orchid, Cymbidium sinense appears to utilizes "remedy strategy", while an epiphytic orchid, C. tracyanum , employs a "precaution strategy" to drought stress based on morphological, physiological and proteomic analysis. Drought condition influences plant growth and productivity. Although the mechanism by which plants adapt to this abiotic stress has been studied extensively, the water-adaptive strategies of epiphytes grown in water-limited habitats remain undefined. Here, root and leaf anatomies, dynamic changes in physiological and proteomic responses during periods of drought stress and recovery studied in an epiphytic orchid (Cymbidium tracyanum) and a terrestrial orchid (C. sinense) to investigate their strategies for coping with drought. Compared with C. sinense, C. tracyanum showed stronger drought-resistant adaptive characteristics to drought because its leaves had more negative water potential at turgor loss point and roots had higher proportion of velamen radicum thickness. Although both species demonstrated quick recovery of photosynthesis after stress treatment, they differed in physiological and proteomic responses. We detected and functionally characterized 103 differentially expressed proteins in C. sinense and 104 proteins in C. tracyanum. These proteins were mainly involved in carbon and energy metabolism, photosynthesis, and defense responses. The up-regulated expression of plastid fibrillin may have contributed to the marked accumulation of jasmonates only in stressed C. sinense, while ferredoxin-NADP reductase up-regulation was only found in C. tracyanum which possibly related to the stimulation of cyclic electron flow that is linked with photoprotection. These physiological and proteomic performances suggest distinct adaptive strategies to drought stress between C. sinense (remedy strategy) and C. tracyanum (precaution strategy). Our findings may help improve our understanding about the ecological adaptation of epiphytic orchids.
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Affiliation(s)
- Jia-Wei Li
- Key Laboratory for Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, Yunnan, China
- Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
- College of Life Science, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiao-Dong Chen
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Xiang-Yang Hu
- College of Life Science, Shanghai University, Shanghai, 200444, China
| | - Lan Ma
- Key Laboratory for Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, Yunnan, China
- Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China
| | - Shi-Bao Zhang
- Key Laboratory for Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming, 650201, Yunnan, China.
- Yunnan Key Laboratory for Wild Plant Resources, Kunming, 650201, China.
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Midorikawa T, Endow JK, Dufour J, Zhu J, Inoue K. Plastidic type I signal peptidase 1 is a redox-dependent thylakoidal processing peptidase. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:592-603. [PMID: 25182596 DOI: 10.1111/tpj.12655] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/08/2014] [Accepted: 08/21/2014] [Indexed: 05/09/2023]
Abstract
Thylakoids are the photosynthetic membranes in chloroplasts and cyanobacteria. The aqueous phase inside the thylakoid known as the thylakoid lumen plays an essential role in the photosynthetic electron transport. The presence and significance of thiol-disulfide exchange in this compartment have been recognized but remain poorly understood. All proteins found free in the thylakoid lumen and some proteins associated to the thylakoid membrane require an N-terminal targeting signal, which is removed in the lumen by a membrane-bound serine protease called thylakoidal processing peptidase (TPP). TPP is homologous to Escherichia coli type I signal peptidase (SPI) called LepB. Genetic data indicate that plastidic SPI 1 (Plsp1) is the main TPP in Arabidopsis thaliana (Arabidopsis) although biochemical evidence had been lacking. Here we demonstrate catalytic activity of bacterially produced Arabidopsis Plsp1. Recombinant Plsp1 showed processing activity against various TPP substrates at a level comparable to that of LepB. Plsp1 and LepB were also similar in the pH optima, sensitivity to arylomycin variants and a preference for the residue at -3 to the cleavage site within a substrate. Plsp1 orthologs found in angiosperms contain two unique Cys residues located in the lumen. Results of processing assays suggested that these residues were redox active and formation of a disulfide bond between them was necessary for the activity of recombinant Arabidopsis Plsp1. Furthermore, Plsp1 in Arabidopsis and pea thylakoids migrated faster under non-reducing conditions than under reducing conditions on SDS-PAGE. These results underpin the notion that Plsp1 is a redox-dependent signal peptidase in the thylakoid lumen.
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Affiliation(s)
- Takafumi Midorikawa
- Department of Plant Sciences, University of California, One Shields Avenue, Davis, CA, 95616, USA
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Endow JK, Ruppel NJ, Inoue K. Keep the balloon deflated: the significance of protein maturation for thylakoid flattening. PLANT SIGNALING & BEHAVIOR 2010; 5:721-3. [PMID: 21135574 PMCID: PMC3001570 DOI: 10.4161/psb.5.6.11662] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 02/25/2010] [Indexed: 05/24/2023]
Abstract
Thylakoidal processing peptidase (TPP) catalyzes the removal of signal peptide which leads to maturation of a subset of proteins including photosynthetic electron transport components in thylakoids. The biochemical properties of TPP were highly defined during the 1980's and 1990's, but the physiological significance of the TPP activity had remained undefined. Completion of genome sequencing revealed the presence of three TPP isoforms in the model plant Arabidopsis thaliana. A recent genetic study demonstrated that one isoform, plastidic type I signal peptidase 1 (Plsp1), is necessary for proper thylakoid assembly. Interestingly, Plsp1 was found in both the chloroplast envelope and thylakoids, being responsible for maturation of an outer membrane protein Toc75 and a lumenal protein OE33. A more recent study has shown that Plsp1 is involved in maturation of two additional lumenal proteins, OE23 and plastocyanin, and that accumulation of unprocessed Toc75 does not disrupt normal chloroplast development. The study also revealed that plsp1-null plastids accumulate balloon-like vesicles that appear to be the remnants of thylakoids as they contain unprocessed OE33 in the peripheral regions. These findings suggest that proper maturation of lumenal proteins is required for correct assembly and/or maintenance of thylakoids, but may not be necessary for initiation of membrane development. The ballooned thylakoids in plsp1-null plastids may be a useful tool to elucidate the mechanism of thylakoid flattening, which correlates with the energized state of the membranes.
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Affiliation(s)
- Joshua K Endow
- Department of Plant Sciences, University of California, Davis, California, USA
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Cain P, Hall M, Schröder WP, Kieselbach T, Robinson C. A novel extended family of stromal thioredoxins. PLANT MOLECULAR BIOLOGY 2009; 70:273-81. [PMID: 19259774 DOI: 10.1007/s11103-009-9471-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Accepted: 02/10/2009] [Indexed: 05/08/2023]
Abstract
Thioredoxins play key regulatory roles in chloroplasts by linking photosynthetic light reactions to a series of plastid functions. In addition to the established groups of thioredoxins, f, m, x, and y, novel plant thioredoxins were also considered to include WCRKC motif proteins, CDSP32, the APR proteins, the lilium proteins and HCF164. Despite their important roles, the subcellular locations of many novel thioredoxins has remained unknown. Here, we report a study of their subcellular location using the cDNA clone resources of TAIR. In addition to filling all gaps in the subcellular map of the established chloroplast thioredoxins f, m, x and y, we show that the members of the WCRKC family are targeted to the stroma and provide evidence for a stromal location of the lilium proteins. The combined data from this and related studies indicate a consistent stromal location of the known Arabidopsis chloroplast thioredoxins except for thylakoid-bound HCF164.
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Affiliation(s)
- Peter Cain
- Department of Biological Sciences, University of Warwick, Coventry, UK
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6
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Puthiyaveetil S, Kavanagh TA, Cain P, Sullivan JA, Newell CA, Gray JC, Robinson C, van der Giezen M, Rogers MB, Allen JF. The ancestral symbiont sensor kinase CSK links photosynthesis with gene expression in chloroplasts. Proc Natl Acad Sci U S A 2008; 105:10061-6. [PMID: 18632566 PMCID: PMC2474565 DOI: 10.1073/pnas.0803928105] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2008] [Indexed: 11/18/2022] Open
Abstract
We describe a novel, typically prokaryotic, sensor kinase in chloroplasts of green plants. The gene for this chloroplast sensor kinase (CSK) is found in cyanobacteria, prokaryotes from which chloroplasts evolved. The CSK gene has moved, during evolution, from the ancestral chloroplast to the nuclear genomes of eukaryotic algae and green plants. The CSK protein is now synthesised in the cytosol of photosynthetic eukaryotes and imported into their chloroplasts as a protein precursor. In the model higher plant Arabidopsis thaliana, CSK is autophosphorylated and required for control of transcription of chloroplast genes by the redox state of an electron carrier connecting photosystems I and II. CSK therefore provides a redox regulatory mechanism that couples photosynthesis to gene expression. This mechanism is inherited directly from the cyanobacterial ancestor of chloroplasts, is intrinsic to chloroplasts, and is targeted to chloroplast genes.
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Affiliation(s)
- Sujith Puthiyaveetil
- *School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
| | | | - Peter Cain
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - James A. Sullivan
- *School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
| | - Christine A. Newell
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom; and
| | - John C. Gray
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, United Kingdom; and
| | - Colin Robinson
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Mark van der Giezen
- Centre for Eukaryotic Evolutionary Microbiology, School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - Matthew B. Rogers
- Centre for Eukaryotic Evolutionary Microbiology, School of Biosciences, University of Exeter, Exeter EX4 4QD, United Kingdom
| | - John F. Allen
- *School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, United Kingdom
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Srivastava S, Rahman MH, Shah S, Kav NNV. Constitutive expression of the pea ABA-responsive 17 (ABR17) cDNA confers multiple stress tolerance in Arabidopsis thaliana. PLANT BIOTECHNOLOGY JOURNAL 2006; 4:529-49. [PMID: 17309728 DOI: 10.1111/j.1467-7652.2006.00201.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
The constitutive expression of the pea ABR17 (abscisic acid-responsive 17) cDNA, which is a member of the group 10 family of pathogenesis-related proteins (PR 10), in Arabidopsis thaliana is reported. The presence of ABR17 transcripts and the protein in the three transgenic lines is demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) and two-dimensional electrophoresis followed by tandem mass spectrometry, respectively. Three independently derived transgenic lines containing ABR17 germinated better in the presence of salt, cold temperature or both. Furthermore, the transgenic plants also exhibited enhanced tolerance to freezing temperature, suggesting the potential utility of the ABR17 gene to engineer multiple stress tolerance. In order to obtain insights into the mechanism underlying ABR17-mediated stress tolerance, we have compared the proteome of a transgenic line with that of its wild-type counterpart. Several proteins were observed to be significantly altered in the transgenic line, including some with a role(s) in photosynthesis, stress tolerance and the regulation of gene expression. Our findings are discussed within the context of available genes to engineer multiple stress tolerance as well as the biological activities of the ABR17 protein.
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Affiliation(s)
- Sanjeeva Srivastava
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada, T6G 2P5
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Kessler F, Schnell DJ. The function and diversity of plastid protein import pathways: a multilane GTPase highway into plastids. Traffic 2006; 7:248-57. [PMID: 16497220 DOI: 10.1111/j.1600-0854.2005.00382.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photosynthetic chloroplast is the hallmark organelle of green plants. During the endosymbiotic evolution of chloroplasts, the vast majority of genes from the original cyanobacterial endosymbiont were transferred to the host cell nucleus. Chloroplast biogenesis therefore requires the import of nucleus-encoded proteins from their site of synthesis in the cytosol. The majority of proteins are imported by the activity of Toc and Tic complexes located within the chloroplast envelope. In addition to chloroplasts, plants have evolved additional, non-photosynthetic plastid types that are essential components of all cells. Recent studies indicate that the biogenesis of various plastid types relies on distinct but homologous Toc-Tic import pathways that have specialized in the import of specific classes of substrates. These different import pathways appear to be necessary to balance the essential physiological role of plastids in cellular metabolism with the demands of cellular differentiation and plant development.
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Affiliation(s)
- Felix Kessler
- Laboratoire de Physiologie Végétale, Institut de Botanique, Université de Neuchâtel, Rue Emile-Argand 11, 2007 Neuchâtel, Switzerland.
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9
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Yang EJ, Oh YA, Lee ES, Park AR, Cho SK, Yoo YJ, Park OK. Oxygen-evolving enhancer protein 2 is phosphorylated by glycine-rich protein 3/wall-associated kinase 1 in Arabidopsis. Biochem Biophys Res Commun 2003; 305:862-8. [PMID: 12767910 DOI: 10.1016/s0006-291x(03)00851-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The Arabidopsis wall-associated receptor kinase, WAK1, is a member of WAK family that links the plasma membrane to the extracellular matrix. A glycine-rich secreted protein, AtGRP-3, was previously shown to regulate WAK1 functions through binding to the extracellular domain of WAK1. In this study, we sought to determine the downstream molecules of the AtGRP-3/WAK1 signaling pathway, by using two-dimensional gel electrophoresis combined with Edman sequencing and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). We report here that a chloroplast protein, oxygen-evolving enhancer protein 2 (OEE2), specifically interacts with the cytoplasmic kinase domain of WAK1 and becomes phosphorylated in an AtGRP-3-dependent manner. The phosphorylation of OEE2 is also induced in Arabidopsis by treatment with avirulent Pseudomonas syringae. Taken together, these results suggest that OEE2 activity is regulated by AtGRP-3/WAK1.
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Affiliation(s)
- Eun Ju Yang
- Kumho Life and Environmental Science Laboratory, 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea
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10
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Cleary SP, Tan FC, Nakrieko KA, Thompson SJ, Mullineaux PM, Creissen GP, von Stedingk E, Glaser E, Smith AG, Robinson C. Isolated plant mitochondria import chloroplast precursor proteins in vitro with the same efficiency as chloroplasts. J Biol Chem 2002; 277:5562-9. [PMID: 11733507 DOI: 10.1074/jbc.m106532200] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Most chloroplast and mitochondrial proteins are synthesized with N-terminal presequences that direct their import into the appropriate organelle. In this report we have analyzed the specificity of standard in vitro assays for import into isolated pea chloroplasts and mitochondria. We find that chloroplast protein import is highly specific because mitochondrial proteins are not imported to any detectable levels. Surprisingly, however, pea mitochondria import a range of chloroplast protein precursors with the same efficiency as chloroplasts, including those of plastocyanin, the 33-kDa photosystem II protein, Hcf136, and coproporphyrinogen III oxidase. These import reactions are dependent on the Deltaphi across the inner mitochondrial membrane, and furthermore, marker enzyme assays and Western blotting studies exclude any import by contaminating chloroplasts in the preparation. The pea mitochondria specifically recognize information in the chloroplast-targeting presequences, because they also import a fusion comprising the presequence of coproporphyrinogen III oxidase linked to green fluorescent protein. However, the same construct is targeted exclusively into chloroplasts in vivo indicating that the in vitro mitochondrial import reactions are unphysiological, possibly because essential specificity factors are absent in these assays. Finally, we show that disruption of potential amphipathic helices in one presequence does not block import into pea mitochondria, indicating that other features are recognized.
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Affiliation(s)
- Suzanne P Cleary
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
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11
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Chloroplast and Mitochondrial Type I Signal Peptidases. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1874-6047(02)80006-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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12
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Mant A, Woolhead CA, Moore M, Henry R, Robinson C. Insertion of PsaK into the thylakoid membrane in a "Horseshoe" conformation occurs in the absence of signal recognition particle, nucleoside triphosphates, or functional albino3. J Biol Chem 2001; 276:36200-6. [PMID: 11451950 DOI: 10.1074/jbc.m102914200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The photosystem I subunit PsaK spans the thylakoid membrane twice, with the N and C termini both located in the lumen. The insertion mechanism of a thylakoid membrane protein adopting this type of topology has not been studied before, and we have used in vitro assays to determine the requirements for PsaK insertion into thylakoids. PsaK inserts with high efficiency and we show that one transmembrane span (the C-terminal region) can insert independently of the other, indicating that a "hairpin"-type mechanism is not essential. Insertion of PsaK does not require stromal extract, indicating that signal recognition particle (SRP) is not involved. Removal of nucleoside triphosphates inhibits insertion only slightly, both in the presence and absence of stroma, suggesting a mild stimulatory effect of a factor in the translation system and again ruling out an involvement of SRP or its partner protein, FtsY. We, furthermore, find no evidence for the involvement of known membrane-bound translocation apparatus; proteolysis of thylakoids destroys the Sec and Tat translocons but does not block PsaK insertion, and antibodies against the Oxa1/YidC homolog, Alb3, block the SRP-dependent insertion of Lhcb1 but again have no effect on PsaK insertion. Because YidC is required for the efficient insertion of every membrane protein tested in Escherichia coli (whether SRP-dependent or -independent), PsaK is the first protein identified as being independent of YidC/Alb3-type factors in either thylakoids or bacteria. The data raise the possibility of a wholly spontaneous insertion pathway.
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Affiliation(s)
- A Mant
- Department of Biological Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom
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Koussevitzky S, Ne'eman E, Sommer A, Steffens JC, Harel E. Purification and properties of a novel chloroplast stromal peptidase. Processing of polyphenol oxidase and other imported precursors. J Biol Chem 1998; 273:27064-9. [PMID: 9765221 DOI: 10.1074/jbc.273.42.27064] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Polyphenol oxidases (PPOs) are nuclear-encoded chloroplast proteins that are targeted to the thylakoid lumen by a bipartite presequence. The N-terminal part of this sequence is removed by a stromal processing peptidase (SPP), and the resulting intermediate is translocated across the thylakoid and processed to the mature protein. A 4800-fold-purified SPP processed a PPO precursor (pPPO) at a site identical to that occurring in organelle. The in vitro product of SPP action on pPPO was further processed and translocated by thylakoids. This SPP processed other precursors but was inactive toward those of light-harvesting chlorophyll binding proteins. The enzyme appeared to be a metalloendopeptidase, like previously reported SPPs. However, it differed in substrate specificity, apparent size, and, most significantly, cleavage site of pPPO. Whereas the processing sites of lumen proteins determined so far were relatively distant from the hydrophobic core of the thylakoid targeting domain, pPPO was cleaved immediately before this domain. Cleavage removed the twin arginine motif characteristic of thylakoid targeting domains of lumen proteins, which are translocated by the DeltapH-dependent pathway. The possible significance of these observations to PPO translocation mechanism is discussed. It is suggested that several SPPs may exist in chloroplasts with preferences for different subsets of precursors.
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Affiliation(s)
- S Koussevitzky
- Department of Plant Sciences, the Hebrew University, Jerusalem 91904, Israel
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Richter S, Lamppa GK. A chloroplast processing enzyme functions as the general stromal processing peptidase. Proc Natl Acad Sci U S A 1998; 95:7463-8. [PMID: 9636172 PMCID: PMC22651 DOI: 10.1073/pnas.95.13.7463] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A highly specific stromal processing activity is thought to cleave a large diversity of precursors targeted to the chloroplast, removing an N-terminal transit peptide. The identity of this key component of the import machinery has not been unequivocally established. We have previously characterized a chloroplast processing enzyme (CPE) that cleaves the precursor of the light-harvesting chlorophyll a/b binding protein of photosystem II (LHCPII). Here we report the overexpression of active CPE in Escherichia coli. Examination of the recombinant enzyme in vitro revealed that it cleaves not only preLHCPII, but also the precursors for an array of proteins essential for different reactions and destined for different compartments of the organelle. CPE also processes its own precursor in trans. Neither the recombinant CPE nor the native CPE of chloroplasts process a preLHCPII mutant with an altered cleavage site demonstrating that both forms of the enzyme are sensitive to the same structural modification of the substrate. The transit peptide of the precursor of ferredoxin is released by a single cleavage event and found intact after processing by recombinant CPE and a chloroplast extract as well. These results provide the first direct demonstration that CPE is the general stromal processing peptidase that acts as an endopeptidase. Significantly, recombinant CPE cleaves in the absence of other chloroplast proteins, and this activity depends on metal cations, such as zinc.
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Affiliation(s)
- S Richter
- Department of Molecular Genetics and Cell Biology, University of Chicago, 920 E. 58th Street, Chicago, IL 60637, USA
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Abstract
▪ Abstract The assembly of the photosynthetic apparatus at the thylakoid begins with the targeting of proteins from their site of synthesis in the cytoplasm or stroma to the thylakoid membrane. Plastid-encoded proteins are targeted directly to the thylakoid during or after synthesis on plastid ribosomes. Nuclear-encoded proteins undergo a two-step targeting process requiring posttranslational import into the organelle from the cytoplasm and subsequent targeting to the thylakoid membrane. Recent investigations have revealed a single general import machinery at the envelope that mediates the direct transport of preproteins from the cytoplasm to the stroma. In contrast, at least four distinct pathways exist for the targeting of proteins to the thylakoid membrane. At least two of these systems are homologous to translocation systems that operate in bacteria and at the endoplasmic reticulum, indicating that elements of the targeting mechanisms have been conserved from the original prokaryotic endosymbiont.
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Affiliation(s)
- Danny J. Schnell
- Department of Biological Sciences, Rutgers, The State University of New Jersey, Newark, New Jersey 07102; e-mail:
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16
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Itzhaki H, Naveh L, Lindahl M, Cook M, Adam Z. Identification and characterization of DegP, a serine protease associated with the luminal side of the thylakoid membrane. J Biol Chem 1998; 273:7094-8. [PMID: 9507020 DOI: 10.1074/jbc.273.12.7094] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proteases involved in proteolytic degradation in the thylakoid lumen are largely unknown. Western analysis with an antibody against the Escherichia coli periplasmic serine protease DegP suggested that pea chloroplasts contain a homologue of this protease. This homologue was peripherally bound to the luminal side of the thylakoid membrane and could only be removed by a combination of high salt and non-ionic detergent. Its level increased almost 2-fold in pea seedlings exposed to elevated temperature for 4 h, suggesting this protease's role in the chloroplast's heat response. Isolated thylakoid membranes containing the chloroplastic homologue of DegP degraded beta-casein, an in vitro substrate of the bacterial protease. This activity was partially inhibited by a serine protease inhibitor, suggesting that at least part of the casein-degrading activity in the thylakoid membrane is attributable to DegP. The existence of chloroplastic DegP was further supported by isolating a full-length Arabidopsis cDNA (designated AtDegP) encoding a protein that is 37% identical and 60% similar to the E. coli protease. The amino terminus of the deduced amino acid sequence contained a bipartite transit peptide, typical of proteins targeted to the thylakoid lumen, and the mature portion of the protein contained the highly conserved serine protease catalytic triad His-Asp-Ser. The possible physiological roles of chloroplastic DegP protease are discussed.
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Affiliation(s)
- H Itzhaki
- Department of Agricultural Botany, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel
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17
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Chaal BK, Mould RM, Barbrook AC, Gray JC, Howe CJ. Characterization of a cDNA encoding the thylakoidal processing peptidase from Arabidopsis thaliana. Implications for the origin and catalytic mechanism of the enzyme. J Biol Chem 1998; 273:689-92. [PMID: 9422718 DOI: 10.1074/jbc.273.2.689] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
We have identified and sequenced a cDNA containing a complete open reading frame for a putative 340-amino acid precursor of the thylakoidal processing peptidase from Arabidopsis thaliana. The predicted amino acid sequence of the protein includes regions highly conserved among Type I leader peptidases and indicates that the enzyme uses a serine-lysine catalytic dyad mechanism. Phylogenetic analysis indicated a common ancestry of the enzyme with those from oxygenic photosynthetic prokaryotes, suggesting that the cDNA encoded the chloroplast enzyme. The catalytic domain was overexpressed in Escherichia coli, generating a product capable of cleaving the thylakoid-transfer domain from a chloroplast protein. Antibodies to the overexpressed polypeptide cross-reacted with a 30-kDa thylakoid membrane protein.
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Affiliation(s)
- B K Chaal
- Cambridge Center for Molecular Recognition, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, United Kingdom
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18
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Protein transport into and across the thylakoid membrane. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1997. [DOI: 10.1016/s1011-1344(96)07408-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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19
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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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20
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Halperin T, Adam Z. Degradation of mistargeted OEE33 in the chloroplast stroma. PLANT MOLECULAR BIOLOGY 1996; 30:925-933. [PMID: 8639751 DOI: 10.1007/bf00020804] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
OEE33, a component of the oxygen-evolving enzyme in chloroplasts, normally resides in the thylakoid lumen. In an attempt to study the fate of mistargeted proteins in chloroplasts, we substituted the bipartite transit peptide of OEE33 with that of CAB7, an integral thylakoid-membrane protein. As a result, when imported into isolated chloroplasts, the chimeric protein protein was targeted to the stroma instead of the thylakoid lumen. Whereas the wild-type OEE33 was totally stable for at least 2 h, the chimeric protein was rapidly degraded, with a half-life of 60 min. Degradation of the chimeric protein was stimulated by ATP supplementation. Degradation could also be observed in lysed chloroplasts, in an ATP-stimulated manner. When lysates were fractionated, the proteolytic activity was found to be associated mainly with the stromal fraction. This activity was very effectively inhibited by all tested inhibitors of serine proteases. Western blot analysis demonstrated that the stromal fraction active in degrading the chimeric OEE33 contains ClpC and ClpP, homologues of the regulatory and proteolytic subunits, respectively, of the bacterial, ATP-dependent, serine-type Clp protease.
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Affiliation(s)
- T Halperin
- Department of Agricultural Botany, Faculty of Agriculture, Hebrew University, Rehovot, Israel
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21
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Mant A, Schmidt I, Herrmann RG, Robinson C, Klösgen RB. Sec-dependent thylakoid protein translocation. Delta pH requirement is dictated by passenger protein and ATP concentration. J Biol Chem 1995; 270:23275-81. [PMID: 7559481 DOI: 10.1074/jbc.270.40.23275] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A Sec-type system is responsible for the translocation of a subset of proteins across the thylakoid membrane in higher plant chloroplasts. Previous studies have suggested that the thylakoidal delta pH plays a minor role in this translocation mechanism, but we show here that it can be essential for the translocation process, depending on the identity of the passenger protein and the concentration of ATP. Studies using chimeric proteins show that, whereas the presequence dictates the translocation pathway, the delta pH requirement is dictated exclusively by the passenger protein; some passenger proteins are virtually delta pH-independent whereas others are absolutely dependent. delta pH requirement is not related to charge characteristics of the passenger proteins, ruling out an electrophoretic effect. Analysis of the 33-kDa photosystem II protein reveals an inverse relationship between delta pH requirement and ATP concentration; import into isolated thylakoids is inhibited 14-fold by nigericin at moderate ATP concentrations, and totally inhibited when the ATP concentration is reduced to 2 microM. The results indicate that the roles of the delta pH and ATP overlap and suggest that the delta pH may be obligatory when the passenger protein is abnormally difficult to translocate, possibly due to the folding of the polypeptide chain. We compare the energetics of this system with those of prokaryotic systems from which the chloroplast system is believed to have evolved.
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Affiliation(s)
- A Mant
- Department of Biological Sciences, University of Warwick, Coventry, United Kingdom
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22
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Berghöfer J, Karnauchov I, Herrmann RG, Klösgen RB. Isolation and characterization of a cDNA encoding the SecA protein from spinach chloroplasts. Evidence for azide resistance of Sec-dependent protein translocation across thylakoid membranes in spinach. J Biol Chem 1995; 270:18341-6. [PMID: 7629156 DOI: 10.1074/jbc.270.31.18341] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Thylakoid membranes of chloroplasts in higher plants harbor different pathways for the translocation of proteins. One of these routes is related to the prokaryotic Sec pathway, which mediates the secretion of particular proteins into the periplasmic space and involves the SecA protein as an essential component. We have isolated a full size cDNA of 3739 nucleotides encoding the SecA homologue from spinach. It contains an open reading frame of 1036 codons corresponding to a polypeptide with a calculated mass of 117 kDa. The deduced amino acid sequence shows between 43 and 49% identity to SecA proteins from bacteria and lower algae and 62% identity to SecA of the cyanobacterium Synechococcus sp. PCC7942. Compared with the Escherichia coli protein, spinach SecA carries an amino-terminal extension of approximately 80 residues. In organello experiments performed with the protein made in vitro by transcription of the cDNA and cell-free translation of the resulting RNA showed that this extension comprises a transit peptide that mediates the import of the protein into the chloroplast. The processed product of approximately 107 kDa accumulates predominantly in the stroma and to a lower extent associates with the thylakoid membrane. Comparably to E. coli, in which SecA activity can be inhibited by sodium azide, thylakoid translocation of a subset of lumenal proteins is sensitive to sodium azide in pea but not in spinach chloroplasts, suggesting that the latter contain an azide-resistant SecA variant.
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Affiliation(s)
- J Berghöfer
- Botanisches Institut, Ludwig-Maximilians-Universität, München, Germany
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23
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Laidler V, Chaddock AM, Knott TG, Walker D, Robinson C. A SecY homolog in Arabidopsis thaliana. Sequence of a full-length cDNA clone and import of the precursor protein into chloroplasts. J Biol Chem 1995; 270:17664-7. [PMID: 7629062 DOI: 10.1074/jbc.270.30.17664] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Proteins are translocated across the thylakoid membrane by two distinct pathways in higher plant chloroplasts, one of which is related to prokaryotic Sec-dependent translocation mechanisms. SecY is an essential, hydrophobic component of the membrane-bound translocase complex in bacteria, and we report here the nucleotide sequence of a full-length cDNA encoding a homolog of SecY from Arabidopsis thaliana. The predicted protein of 551 residues includes an amino-terminal extension of approximately 120 residues when compared with other SecY proteins. The deduced sequence of the mature protein, cpSecY, is 41% identical with SecY from Synechococcus and 33% identical with the Escherichia coli protein. The extension serves to target the protein into chloroplasts; transcription-translation of the cDNA yields a 58-kDa precursor protein which is imported into pea chloroplasts, processed to a product of 46 kDa, and targeted into the thylakoid membrane.
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Affiliation(s)
- V Laidler
- Department of Biological Sciences, University of Warwick, Coventry, United Kingdom
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24
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Kapazoglou A, Sagliocco F, Dure L. PSII-T, a new nuclear encoded lumenal protein from photosystem II. Targeting and processing in isolated chloroplasts. J Biol Chem 1995; 270:12197-202. [PMID: 7744870 DOI: 10.1074/jbc.270.20.12197] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
An intronless nuclear gene, psbT, isolated from cotton, encodes a putative 11-kDa protein (PSII-T) highly homologous in its C terminus to the N terminus of the partially sequenced PSII-T protein from spinach photosystem II. Analysis of the deduced amino acid sequence of cotton PSII-T revealed the presence of potential chloroplast stroma and thylakoid targeting domains and a putative mature PSII protein of 3.0 kDa, composed of only 28 amino acid residues. The cotton PSII-T 11-kDa precursor was synthesized in vitro in a wheat germ extract translation system, and the translation product was used in assays for protein imports into isolated pea chloroplasts. It was shown that the cotton PSII-T precursor was imported into the chloroplasts, processed to a mature form of approximately 3.0 kDa, agreeing with the predicted size from amino acid sequence analysis, and localized to the lumenal side of the thylakoid membrane, thus defining a new nuclear encoded lumenal protein and the smallest polypeptide of PSII reported to date. Processing of the PSII-T precursor occurred in two steps and involved the formation of a stromal intermediate of approximately 7.5 kDa, as predicted from primary structure analysis.
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Affiliation(s)
- A Kapazoglou
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA
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25
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Cohen Y, Yalovsky S, Nechushtai R. Integration and assembly of photosynthetic protein complexes in chloroplast thylakoid membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1241:1-30. [PMID: 7742345 DOI: 10.1016/0304-4157(94)00012-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Y Cohen
- Department of Botany, Hebrew University of Jerusalem, Israel
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26
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Creighton AM, Hulford A, Mant A, Robinson D, Robinson C. A monomeric, tightly folded stromal intermediate on the delta pH-dependent thylakoidal protein transport pathway. J Biol Chem 1995; 270:1663-9. [PMID: 7829500 DOI: 10.1074/jbc.270.4.1663] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Two distinct mechanisms have been previously identified for the transport of proteins across the chloroplast thylakoid membrane, one of which is unusual in that neither soluble factors nor ATP are required; the system requires only the transthylakoidal delta pH. We have examined this mechanism by studying the properties of one of its substrates: the extrinsic 23-kDa protein (23K) of photosystem II. Previous work has shown that this protein can be transported into isolated thylakoids as the full-length precursor protein; we show that the stromal import intermediate form of this protein is similarly translocation-competent. Gel filtration tests indicate that the stromal intermediate is probably monomeric. Protease sensitivity tests on both the initial in vitro translation product and the stromal import intermediate show that the presequence is highly susceptible to digestion whereas the mature protein is resistant to high concentrations of trypsin. The mature protein becomes very sensitive to digestion if unfolded in urea, or after heating, and we therefore propose that the natural substrate for this translocation system consists of a relatively unfolded presequence together with a tightly folded passenger protein. The ability of thylakoids to import pre-23K is destroyed by prior treatment of the thylakoids with low concentrations of trypsin, demonstrating the involvement of surface-exposed proteins in the import process. However, we can find no evidence for the binding of pre-23K or i23K to the thylakoid surface, and we therefore propose that the initial interaction of these substrates with the thylakoidal translocase is weak, reversible, and probably delta pH-independent. In the second phase of the translocation mechanism, the delta pH drives either the translocation and unfolding of proteins, or the translocation of a fully folded protein.
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Affiliation(s)
- A M Creighton
- Department of Biological Sciences, University of Warwick, Coventry, United Kingdom
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27
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Scott MP, Nielsen VS, Knoetzel J, Andersen R, Møller BL. Import of the barley PSI-F subunit into the thylakoid lumen of isolated chloroplasts. PLANT MOLECULAR BIOLOGY 1994; 26:1223-1229. [PMID: 7811981 DOI: 10.1007/bf00040704] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A full-length cDNA clone encoding the PSI-F subunit of barley photosystem I has been isolated and sequenced. The open reading frame encodes a precursor polypeptide with a deduced molecular mass of 24837 Da. The barley PSI-F precursor contains a bipartite presequence with characteristics similar to the presequences of proteins destined to the thylakoid lumen. In vitro import studies demonstrate that an in vitro synthesized precursor is transported across the chloroplast envelope and directed to the thylakoid membrane, where it accumulates in a protease-resistant form. Incubation of the precursor with a chloroplast stromal extract results in processing to a form intermediate in size between the precursor and mature forms. Hydrophobicity analysis of the barley PSI-F protein reveals a hydrophobic region predicted to be a membrane spanning alpha-helix. The hydrophobic nature of PSI-F combined with a bipartite presequence is unusual. We postulate that the second domain in the bipartite presequence of the PSI-F precursor proteins is required to ensure the proper orientation of PSI-F in the thylakoid membrane. The expression of the PsaF gene is light-induced similar to other barley photosystem I genes.
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Affiliation(s)
- M P Scott
- Department of Plant Biology, Royal Veterinary and Agricultural University, Frederiksberg, Copenhagen, Denmark
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28
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Mant A, Nielsen VS, Knott TG, Møller BL, Robinson C. Multiple mechanisms for the targeting of photosystem I subunits F, H, K, L, and N into and across the thylakoid membrane. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)46985-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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29
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Robinson C, Klösgen RB. Targeting of proteins into and across the thylakoid membrane--a multitude of mechanisms. PLANT MOLECULAR BIOLOGY 1994; 26:15-24. [PMID: 7948865 DOI: 10.1007/bf00039516] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- C Robinson
- Department of Biological Sciences, University of Warwick, Coventry, UK
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30
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Madueño F, Bradshaw S, Gray J. The thylakoid-targeting domain of the chloroplast Rieske iron-sulfur protein is located in the N-terminal hydrophobic region of the mature protein. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32462-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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31
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Bassham D, Creighton A, Karnauchov I, Herrmann R, Klösgen R, Robinson C. Mutations at the stromal processing peptidase cleavage site of a thylakoid lumen protein precursor affect the rate of processing but not the fidelity. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)33973-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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32
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Bassham DC, Creighton AM, Arretz M, Brunner M, Robinson C. Efficient but aberrant cleavage of mitochondrial precursor proteins by the chloroplast stromal processing peptidase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 221:523-8. [PMID: 8168539 DOI: 10.1111/j.1432-1033.1994.tb18764.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cytosol-synthesized chloroplast and mitochondrial precursor proteins are proteolytically processed after import by highly specific, metal-dependent soluble enzymes: the stromal processing peptidase (SPP) and the matrix processing peptidase (MPP), respectively. We have used in vitro processing assays to compare the reaction specificities of highly purified preparations of pea SPP and Neurospora crassa MPP, both of which are unable to cleave a variety of 'foreign' proteins. We show that SPP can cleave all five mitochondrial precursor proteins tested, namely cyclophilin, the beta subunit of the F1-ATPase complex, the Rieske FeS protein, the alpha-MPP subunit and cytochrome b2. In contrast, MPP is unable to cleave any chloroplast precursor proteins tested. Several of the mitochondrial precursor proteins are cleaved more efficiently by SPP than are many authentic chloroplast precursor proteins but, in each case, cleavage takes place at a site or sites which are N-terminal to the authentic MPP site; pre-cyclophilin is cleaved 5 residues upstream of the MPP site and the precursor of the beta subunit of the F1-ATPase complex is cleaved at sites 5 and 12 residues upstream. We discuss the implications of these data for the SPP reaction mechanism.
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Affiliation(s)
- D C Bassham
- Department of Biological Sciences, University of Warwick, England
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33
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Knott T, Robinson C. The secA inhibitor, azide, reversibly blocks the translocation of a subset of proteins across the chloroplast thylakoid membrane. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37125-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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34
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Hulford A, Hazell L, Mould R, Robinson C. Two distinct mechanisms for the translocation of proteins across the thylakoid membrane, one requiring the presence of a stromal protein factor and nucleotide triphosphates. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)41855-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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35
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Import of barley photosystem I subunit N into the thylakoid lumen is mediated by a bipartite presequence lacking an intermediate processing site. Role of the delta pH in translocation across the thylakoid membrane. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)41925-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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36
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Translocation of Proteins Across Chloroplast Membranes. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/s1569-2558(08)60403-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
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37
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Abstract
During the last five or six years there has been a shift in focus in the field of chloroplast protein transport, with greater emphasis being placed on understanding the sorting of proteins to the thylakoids and the envelope membranes. As a result, we have a much-improved understanding of the variety of important pathways that function during chloroplast biogenesis. It is now clear that a considerable number of distinct intraorganellar sorting mechanisms operate to direct imported proteins to their correct destinations. Some of the underlying mechanisms are also beginning to emerge, although it is accurate to say that we are still a long way from understanding in genuine detail how proteins are translocated across chloroplast membranes. However, the availability of such a range of efficient in vitro import assays should ensure that rapid progress is made in coming years. The major gaps in this field now concern the identities and roles of the elements of the important apparatus: Although at least two distinct translocation systems operate during chloroplast biogenesis, none of these components has been identified, purified, or cloned. This is primarily because these proteins are often difficult to assay individually, and they are usually of very low abundance. Nevertheless, it is essential that progress is made in this area soon in order to maintain the present momentum.
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Affiliation(s)
- C Robinson
- Department of Biological Sciences, University of Warwick, Coventry, England
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38
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Creighton AM, Bassham DC, Robinson C. The stromal processing peptidase activities from Chlamydomonas reinhardtii and Pisum sativum: unexpected similarities in reaction specificity. PLANT MOLECULAR BIOLOGY 1993; 23:1291-1296. [PMID: 8292793 DOI: 10.1007/bf00042363] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We have partially purified the stromal processing peptidase from Chlamydomonas reinhardtii and compared the properties of this activity with those of the pea counterpart. Whereas previous studies have suggested that the two enzymes may have significantly different reaction specificities, we find that they are in fact very similar. Both enzymes process precursors of two higher-plant thylakoid lumen proteins, and one C. reinhardtii lumenal protein, to similar intermediate-size forms. However, whereas the algal enzyme processes the precursor of C. reinhardtii Rubisco small subunit to the correct mature size, this precursor is cleaved only to an intermediate size by the pea enzyme. The small subunit precursor from pea appears to be cleaved by both enzymes in a similar manner. In terms of sensitivity to inhibitors, the two activities are notably different; the pea enzyme has previously been shown to be inhibited by several types of heavy-metal chelator, but we have found that none of these compounds affect the algal activity.
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Affiliation(s)
- A M Creighton
- Department of Biological Sciences, University of Warwick, Coventry, UK
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39
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Brock IW, Hazell L, Michl D, Nielsen VS, Møller BL, Herrmann RG, Klösgen RB, Robinson C. Precursors of one integral and five lumenal thylakoid proteins are imported by isolated pea and barley thylakoids: optimisation of in vitro assays. PLANT MOLECULAR BIOLOGY 1993; 23:717-725. [PMID: 8251625 DOI: 10.1007/bf00021527] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In vitro assays for the import of proteins by isolated pea thylakoids have been refined and optimised with respect to (a) the method of thylakoid preparation, (b) the concentration of thylakoids in the import assay, and (c) the pH and temperature of the import assay. As a result, the 23 kDa and 16 kDa proteins of the photosynthetic oxygen-evolving complex are imported with efficiencies approaching 100%; import of the third oxygen-evolving complex protein is also observed, albeit with lower efficiencies. We have also demonstrated import of three further thylakoid proteins: plastocyanin, the CFoII subunit of the ATP synthase, and the photosystem I subunit, PSI-N, using this import assay. Import of plastocyanin, PSI-N and the 33 kDa oxygen-evolving complex protein subunit requires the presence of stromal extract whereas the other three proteins are efficiently imported in the absence of added soluble proteins. Import into isolated barley thylakoids was achieved under identical assay conditions, although with somewhat lower efficiency than into pea thylakoids.
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Affiliation(s)
- I W Brock
- Department of Biological Sciences, University of Warwick, Coventry, UK
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40
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Robinson C, Klösgen RB, Herrmann RG, Shackleton JB. Protein translocation across the thylakoid membrane--a tale of two mechanisms. FEBS Lett 1993; 325:67-9. [PMID: 8513895 DOI: 10.1016/0014-5793(93)81415-v] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In vitro reconstitution assays have been used in recent years to probe the mechanisms by which a variety of cytosolically synthesised proteins are transported across the thylakoid membrane within higher plant chloroplasts. The emerging data suggest that two distinct mechanisms operate. Translocation of a subset of lumenal proteins, namely the 23 kDa and 16 kDa proteins of the oxygen-evolving complex, and of the CFo2 protein (an integral membrane protein), requires only the presence of the thylakoidal delta pH. In contrast, two other lumenal proteins, the 33 kDa oxygen-evolving complex protein and plastocyanin, require also the presence of ATP and at least one stromal factor for efficient transport into isolated thylakoids to take place.
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Affiliation(s)
- C Robinson
- Department of Biological Sciences, University of Warwick, Coventry, UK
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41
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Valentin K. SecA is plastid-encoded in a red alga: implications for the evolution of plastid genomes and the thylakoid protein import apparatus. MOLECULAR & GENERAL GENETICS : MGG 1993; 236:245-50. [PMID: 8437571 DOI: 10.1007/bf00277119] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Partial sequence analysis of the plastid DNA (ptDNA) from a red alga, Antithamnion sp., revealed the presence of a homologue to the Escherichia coli secA gene as well as two open reading frames (ORF 510, ORF 179). In addition a sec Y homologue has been detected on the plastid genome by heterologous hybridization. None of these genes has been found in completely sequenced chlorophytic plastid genomes. SecA and secY gene copies were also detected in the ptDNA of a chromophytic alga, indicating that secA Y may be ubiquitous in rhodophytes and chromophytes. The significance of these findings for the evolution of plastid genomes and the thylakoid protein import mechanism is discussed.
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Affiliation(s)
- K Valentin
- Department of Botany, University of Washington, Seattle 98195
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42
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Kuroda I, Inagaki J, Yamamoto Y. Precursor of the nuclear-encoded extrinsic 30 kDa protein in photosystem II of Euglena gracilis Z is not a polyprotein. PLANT MOLECULAR BIOLOGY 1993; 21:171-176. [PMID: 7678760 DOI: 10.1007/bf00039627] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Polyprotein-type precursors have been reported for the nuclear-encoded proteins such as the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and the apoproteins of light-harvesting chlorophyll-protein (LHC) in Euglena. We report here that the precursor of the extrinsic 30 kDa protein of photosystem II (PS II) encoded by nuclear DNA is not a polyprotein. The precursor was identified as a 45 kDa protein by immunoprecipitation of in vitro translation products of mRNA and by a pulse-chase experiment. It is probable that the structure of the precursor of the nuclear-encoded protein in Euglena chloroplast is closely related to the feature of assembly, as well as of transport, of the protein in chloroplast.
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Affiliation(s)
- I Kuroda
- Department of Biology, Faculty of Science, Okayama University, Japan
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Bowyer J, Packer J, McCormack B, Whitelegge J, Robinson C, Taylor M. Carboxyl-terminal processing of the D1 protein and photoactivation of water-splitting in photosystem II. Partial purification and characterization of the processing enzyme from Scenedesmus obliquus and Pisum sativum. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42783-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Cline K, Ettinger WF, Theg SM. Protein-specific energy requirements for protein transport across or into thylakoid membranes. Two lumenal proteins are transported in the absence of ATP. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)45935-2] [Citation(s) in RCA: 108] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Bassham D, Bartling D, Mould R, Dunbar B, Weisbeek P, Herrmann R, Robinson C. Transport of proteins into chloroplasts. Delineation of envelope “transit” and thylakoid “transfer” signals within the pre-sequences of three imported thylakoid lumen proteins. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54326-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Abstract
A chimaeric gene was constructed encoding the pre-sequence of the 33 kDa oxygen-evolving complex protein from wheat (a thylakoid lumen protein) linked to ricin A chain. The fusion protein is efficiently imported by isolated pea chloroplasts and localised partly in the stroma, with the remainder bound to the stromal surface of the thylakoids. The imported protein is fully processed by both the stromal and thylakoidal processing peptidases, indicating that partial or complete translocation across the thylakoid membrane has taken place.
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Affiliation(s)
- L M Roberts
- Department of Biological Sciences, University of Warwick, Coventry, UK
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Douwe de Boer A, Weisbeek PJ. Chloroplast protein topogenesis: import, sorting and assembly. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1071:221-53. [PMID: 1958688 DOI: 10.1016/0304-4157(91)90015-o] [Citation(s) in RCA: 172] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- A Douwe de Boer
- Department of Molecular Cell Biology, University of Utrecht, The Netherlands
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Mould R, Shackleton J, Robinson C. Transport of proteins into chloroplasts. Requirements for the efficient import of two lumenal oxygen-evolving complex proteins into isolated thylakoids. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(19)47371-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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