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García-Cañas R, Florencio FJ, López-Maury L. Back to the future: Transplanting the chloroplast TrxF-FBPase-SBPase redox system to cyanobacteria. FRONTIERS IN PLANT SCIENCE 2022; 13:1052019. [PMID: 36518499 PMCID: PMC9742560 DOI: 10.3389/fpls.2022.1052019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/31/2022] [Indexed: 06/17/2023]
Abstract
Fructose-1,6-bisphosphatase (FBPase) and sedoheptulose-1,7-bisphosphatase (SBPase) are two essential activities in the Calvin-Benson-Bassham cycle that catalyze two irreversible reactions and are key for proper regulation and functioning of the cycle. These two activities are codified by a single gene in all cyanobacteria, although some cyanobacteria contain an additional gene coding for a FBPase. Mutants lacking the gene coding for SBP/FBPase protein are not able to grow photoautotrophically and require glucose to survive. As this protein presents both activities, we have tried to elucidate which of the two are required for photoautrophic growth in Synechocystis sp PCC 6803. For this, the genes coding for plant FBPase and SBPase were introduced in a SBP/FBPase mutant strain, and the strains were tested for growth in the absence of glucose. Ectopic expression of only a plant SBPase gene did not allow growth in the absence of glucose although allowed mutation of both Synechocystis' FBPase genes. When both plant FBPase and SBPase genes were expressed, photoautrophic growth of the SBP/FBPase mutants was restored. This complementation was partial as the strain only grew in low light, but growth was impaired at higher light intensities. Redox regulation of the Calvin-Benson-Bassham cycle is essential to properly coordinate light reactions to carbon fixation in the chloroplast. Two of the best characterized proteins that are redox-regulated in the cycle are FBPase and SBPase. These two proteins are targets of the FTR-Trx redox system with Trx f being the main reductant in vivo. Introduction of the TrxF gene improves growth of the complemented strain, suggesting that the redox state of the proteins may be the cause of this phenotype. The redox state of the plant proteins was also checked in these strains, and it shows that the cyanobacterial redox system is able to reduce all of them (SBPase, FBPase, and TrxF) in a light-dependent manner. Thus, the TrxF-FBPase-SBPase plant chloroplast system is active in cyanobacteria despite that these organisms do not contain proteins related to them. Furthermore, our system opens the possibility to study specificity of the Trx system in vivo without the complication of the different isoforms present in plants.
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Affiliation(s)
- Raquel García-Cañas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla- CSIC, Sevilla, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla- CSIC, Sevilla, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Luis López-Maury
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla- CSIC, Sevilla, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
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Mallén-Ponce MJ, Huertas MJ, Florencio FJ. Exploring the Diversity of the Thioredoxin Systems in Cyanobacteria. Antioxidants (Basel) 2022; 11:antiox11040654. [PMID: 35453339 PMCID: PMC9025218 DOI: 10.3390/antiox11040654] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 02/04/2023] Open
Abstract
Cyanobacteria evolved the ability to perform oxygenic photosynthesis using light energy to reduce CO2 from electrons extracted from water and form nutrients. These organisms also developed light-dependent redox regulation through the Trx system, formed by thioredoxins (Trxs) and thioredoxin reductases (TRs). Trxs are thiol-disulfide oxidoreductases that serve as reducing substrates for target enzymes involved in numerous processes such as photosynthetic CO2 fixation and stress responses. We focus on the evolutionary diversity of Trx systems in cyanobacteria and discuss their phylogenetic relationships. The study shows that most cyanobacteria contain at least one copy of each identified Trx, and TrxA is the only one present in all genomes analyzed. Ferredoxin thioredoxin reductase (FTR) is present in all groups except Gloeobacter and Prochlorococcus, where there is a ferredoxin flavin-thioredoxin reductase (FFTR). Our data suggest that both TRs may have coexisted in ancestral cyanobacteria together with other evolutionarily related proteins such as NTRC or DDOR, probably used against oxidative stress. Phylogenetic studies indicate that they have different evolutionary histories. As cyanobacteria diversified to occupy new habitats, some of these proteins were gradually lost in some groups. Finally, we also review the physiological relevance of redox regulation in cyanobacteria through the study of target enzymes.
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Affiliation(s)
- Manuel J. Mallén-Ponce
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
- Correspondence: (M.J.M.-P.); (M.J.H.)
| | - María José Huertas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
- Correspondence: (M.J.M.-P.); (M.J.H.)
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
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Mallén-Ponce MJ, Huertas MJ, Sánchez-Riego AM, Florencio FJ. Depletion of m-type thioredoxin impairs photosynthesis, carbon fixation, and oxidative stress in cyanobacteria. PLANT PHYSIOLOGY 2021; 187:1325-1340. [PMID: 34618018 PMCID: PMC8566235 DOI: 10.1093/plphys/kiab321] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/21/2021] [Indexed: 06/13/2023]
Abstract
Thioredoxins (Trxs) are disulfide oxidoreductases that regulate many biological processes. The m-type thioredoxin (TrxA) is the only Trx present in all oxygenic photosynthetic organisms. Extensive biochemical and proteomic analyses have identified many TrxA target proteins in different photosynthetic organisms. However, the precise function of this essential protein in vivo is still poorly known. In this study, we generated a conditional Synechocystis sp. PCC 6803 mutant strain (STXA2) using an on-off promoter that is able to survive with only 2% of the TrxA level of the wild-type (WT) strain. STXA2 characterization revealed that TrxA depletion results in growth arrest and pronounced impairment of photosynthesis and the Calvin-Benson-Bassham (CBB) cycle. Analysis of the in vivo redox state of the bifunctional enzyme fructose-1,6-bisphosphatase/sedoheptulose-1,7-bisphosphatase showed higher levels of oxidation that affected enzyme activity in STXA2. This result implies that TrxA-mediated redox regulation of the CBB cycle is conserved in both cyanobacteria and chloroplasts, although the targets have different evolutionary origins. The STXA2 strain also accumulated more reactive oxygen species and was more sensitive to oxidative stress than the WT. Analysis of the in vivo redox state of 2-Cys peroxiredoxin revealed full oxidation, corresponding with TrxA depletion. Overall, these results indicate that depletion of TrxA in STXA2 greatly alters the cellular redox state, interfering with essential processes such as photosynthetic machinery operativity, carbon assimilation, and oxidative stress response. The TrxA regulatory role appears to be conserved along the evolution of oxygenic photosynthetic organisms.
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Affiliation(s)
- Manuel J Mallén-Ponce
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
| | - María José Huertas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Ana María Sánchez-Riego
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
| | - Francisco J Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain
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Guo J, Nguyen AY, Dai Z, Su D, Gaffrey MJ, Moore RJ, Jacobs JM, Monroe ME, Smith RD, Koppenaal DW, Pakrasi HB, Qian WJ. Proteome-wide light/dark modulation of thiol oxidation in cyanobacteria revealed by quantitative site-specific redox proteomics. Mol Cell Proteomics 2014; 13:3270-85. [PMID: 25118246 DOI: 10.1074/mcp.m114.041160] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Reversible protein thiol oxidation is an essential regulatory mechanism of photosynthesis, metabolism, and gene expression in photosynthetic organisms. Herein, we present proteome-wide quantitative and site-specific profiling of in vivo thiol oxidation modulated by light/dark in the cyanobacterium Synechocystis sp. PCC 6803, an oxygenic photosynthetic prokaryote, using a resin-assisted thiol enrichment approach. Our proteomic approach integrates resin-assisted enrichment with isobaric tandem mass tag labeling to enable site-specific and quantitative measurements of reversibly oxidized thiols. The redox dynamics of ∼2,100 Cys-sites from 1,060 proteins under light, dark, and 3-(3,4-dichlorophenyl)-1,1-dimethylurea (a photosystem II inhibitor) conditions were quantified. In addition to relative quantification, the stoichiometry or percentage of oxidation (reversibly oxidized/total thiols) for ∼1,350 Cys-sites was also quantified. The overall results revealed broad changes in thiol oxidation in many key biological processes, including photosynthetic electron transport, carbon fixation, and glycolysis. Moreover, the redox sensitivity along with the stoichiometric data enabled prediction of potential functional Cys-sites for proteins of interest. The functional significance of redox-sensitive Cys-sites in NADP-dependent glyceraldehyde-3-phosphate dehydrogenase, peroxiredoxin (AhpC/TSA family protein Sll1621), and glucose 6-phosphate dehydrogenase was further confirmed with site-specific mutagenesis and biochemical studies. Together, our findings provide significant insights into the broad redox regulation of photosynthetic organisms.
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Affiliation(s)
- Jia Guo
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Amelia Y Nguyen
- ¶Department of Biology, Washington University, St. Louis, Missouri, 63130
| | - Ziyu Dai
- ‖Energy and Efficiency Division, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Dian Su
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Matthew J Gaffrey
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Ronald J Moore
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Jon M Jacobs
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Matthew E Monroe
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Richard D Smith
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352; ‡‡Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - David W Koppenaal
- ‡‡Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington, 99352
| | - Himadri B Pakrasi
- ¶Department of Biology, Washington University, St. Louis, Missouri, 63130
| | - Wei-Jun Qian
- From the ‡Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, 99352;
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Udvardy J, Borbély G, Juhász A, Farkas GL. Fe3+-chelates mediate the oxidative modulation of cyanobacterial and chloroplast enzymes. FEBS Lett 2001. [DOI: 10.1016/0014-5793(84)80862-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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6
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Juhász A, Csizmadia V, Borbély G, Udvardy J, Farkas G. The pyridine nucleotide-dependent D-glucose dehydrogenase ofNostocsp. strain Mac, a cyanobacterium, is subject to thioredoxin modulation. FEBS Lett 2001. [DOI: 10.1016/0014-5793(86)80062-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Tamoi M, Kanaboshi H, Miyasaka H, Shigeoka S. Molecular mechanisms of the resistance to hydrogen peroxide of enzymes involved in the calvin cycle from halotolerant Chlamydomonas sp. W80. Arch Biochem Biophys 2001; 390:176-85. [PMID: 11396920 DOI: 10.1006/abbi.2001.2375] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
cDNA clones encoding NADP(+)-glyceraldehyde-3-phosphate dehydrogenase (NADP(+)-GAPDH) and sedoheptulose-1,7-bisphosphatase (SBPase) were isolated and characterized from halotolerant Chlamydomonas sp. W80 (C. W80) cells. The cDNA clone for NADP(+)-GAPDH encoded 369 amino acid residues, preceded by the chloroplast transit peptide (37 amino acid residues). The cDNA clone for SBPase encoded 351 amino acids with the chloroplast transit peptide. The activities of NADP(+)-GAPDH and SBPase from C. W80 cells were resistant to H(2)O(2) up to 1 mM, as distinct from spinach chloroplastic thiol-modulated enzymes. The illumination to the dark-adapted cells and dithiothreitol treatment to the crude homogenate had little effect on the activities of NADP(+)-GAPDH and SBPase in C. W80. Modeling of the tertiary structures of NADP(+)-GAPDH and SBPase suggests that resistance of the enzymes to H(2)O(2) in C. W80 is due to the different conformational structures in the vicinity of the Cys residues of the chloroplastic enzymes between higher plant and C. W80 cells.
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Affiliation(s)
- M Tamoi
- Department of Food and Nutrition, Faculty of Agriculture, Kinki University, 3327-204 Nakamachi, Nara 631-8505, Japan
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8
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Newman J, Karakaya H, Scanlan DJ, Mann NH. A comparison of gene organization in the zwf region of the genomes of the cyanobacteria Synechococcus sp. PCC 7942 and Anabaena sp. PCC 7120. FEMS Microbiol Lett 1995; 133:187-93. [PMID: 8566707 DOI: 10.1111/j.1574-6968.1995.tb07882.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The region of the genome encoding the glucose-6-phosphate dehydrogenase gene zwf was analysed in a unicellular cyanobacterium, Synechococcus sp. PCC 7942, and a filamentous, heterocystous cyanobacterium, Anabaena sp. PCC 7120. Comparison of cyanobacterial zwf sequences revealed the presence of two absolutely conserved cysteine residues which may be implicated in the light/dark control of enzyme activity. The presence in both strains of a gene fbp, encoding fructose-1,6-bisphosphatase, upstream from zwf strongly suggests that the oxidative pentose phosphate pathway in these organisms may function to completely oxidize glucose 6-phosphate to CO2. The amino acid sequence of fructose-1,6-bisphosphatase does not support the idea of its light activation by a thiol/disulfide exchange mechanism. In the case of Anabaena sp. PCC 7120, the tal gene, encoding transaldolase, lies between zwf and fbp.
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Affiliation(s)
- J Newman
- Department of Biological Sciences, University of Warwick, Coventry, UK
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9
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Juhász A, Csizmadia V, Borbély G, Udvardy J. Redox regulation of glucose dehydrogenase from cells of the facultatively heterotrophic cyanobacterium Nostoc sp. strain MAC. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/0167-4838(87)90218-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Hermoso R, Chueca A, Lazaro JJ, Lopez-Gorge J. An immunological method for quantitative determination of photosynthetic fructose-1,6-bisphosphatase in leaf crude extracts. PHOTOSYNTHESIS RESEARCH 1987; 14:269-278. [PMID: 24430740 DOI: 10.1007/bf00032710] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/1987] [Accepted: 08/10/1987] [Indexed: 06/03/2023]
Abstract
An immunological method for quantitative determination of photosynthetic fructose-1,6-bisphosphatase in crude extracts of leaves is proposed. It is based on the ELISA technique, and offers two modifications. A non-competitive technique has a higher sensitivity and is the right option for samples of low fructose-1,6-bisphosphatase content. However, this method is not sufficiently specific when the total protein is higher than 5 μg/cm(3); so, despite its lower sensitivity, in these circumstances a competitive technique is more suitable. Thus photosynthetic fructose-1,6-bisphosphatase can be measured without interferences from the gluconeogenic cytosolic enzyme of the photosynthetic cell or from a non-specific phosphatase present in the chloroplast.
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Affiliation(s)
- R Hermoso
- Unidad de Bioquímica Vegetal, Estación Experimental del Zaidín (CSIC), Profesor Albareda 1, 18008, Granada, Spain
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Brown D, Kershaw KA. Isolation and Characterization of Two Enzymes Capable of Hydrolyzing Fructose-1,6-Bisphosphatase from the Lichen Peltigera rufescens. PLANT PHYSIOLOGY 1986; 82:462-7. [PMID: 16665052 PMCID: PMC1056141 DOI: 10.1104/pp.82.2.462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Two enzymes capable of hydrolyzing fructose-1,6-bisphosphate (FBP) have been isolated from the foliose lichen Peltigera rufescens (Weis) Mudd. These enzymes can be separated using Sephadex G-100 and DEAE Sephacel chromatography. One enzyme has a pH optimum of 6.5, and a substrate affinity of 228 micromolar FBP. This enzyme does not require MgCl(2) for activity, and is inhibited by AMP. The second enzyme has a pH optimum of 9.0, with no activity below pH 7.5. This enzyme responds sigmoidally to Mg(2+), with half-saturation concentration of 2.0 millimolar MgCl(2), and demonstrates hyperbolic kinetics for FBP (K(m) = 39 micromolar). This enzyme is activated by 20 millimolar dithiothreitol, is inhibited by AMP, but is not affected by fructose-2-6-bisphosphate. It is hypothesized that the latter enzyme is involved in the photosynthetic process, while the former enzyme is a nonspecific acid phosphatase.
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Affiliation(s)
- D Brown
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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Gerbling KP, Steup M, Latzko E. Fructose-1,6-bisphosphatase from Synechococcus leopoliensis. Substrate-dependent dimer-tetramer interconversion. EUROPEAN JOURNAL OF BIOCHEMISTRY 1985; 147:207-15. [PMID: 2982610 DOI: 10.1111/j.1432-1033.1985.tb08738.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Extracts of Synechococcus leopoliensis (Anacystis nidulans) contain two forms of D-fructose-1,6-bisphosphatase (EC 3.1.3.11) previously designated as forms A and B [Gerbling, K.-P., Steup, M., and Latzko, E. (1984) Arch. Microbiol. 137, 109-114]. Form B, which probably represents the major part of the total extractable fructose-1,6-bisphosphatase activity, has been purified to apparent homogeneity. Gel filtration, non-denaturing polyacrylamide gel electrophoresis, and cross-linking with bis(sulfosuccinimidyl)suberate revealed that the fructose-1,6-bisphosphatase B exists in either a dimeric or in a tetrameric subform, depending upon the absence or presence of fructose-1,6-bisphosphate and Mg2+. The dimer--tetramer interconversion was readily reversible. The results provide evidence for a two-step activation of fructose-1,6-bisphosphatase B involving the reduction of the dimeric subform and the subsequent substrate-dependent conversion of the reduced dimer to a reduced tetramer, which is the only catalytically active state. In contrast to form B, no substrate-dependent interconversion was detected with form A from S. leopoliensis.
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Whittaker MM, Gleason FK. Isolation and characterization of thioredoxin f from the filamentous cyanobacterium, Anabaena sp. 7119. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(18)89860-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Crawford NA, Sutton CW, Yee BC, Johnson TC, Carlson DC, Buchanan BB. Contrasting modes of photosynthetic enzyme regulation in oxygenic and anoxygenic prokaryotes. Arch Microbiol 1984; 139:124-9. [PMID: 11536590 DOI: 10.1007/bf00401986] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Enzymes that are regulated by the ferredoxin/thioredoxin system in chloroplasts--fructose-1,6-bis-phosphatase (FBPase), sedoheptulose-1,7-bisphosphatase (SBPase), and phosphoribulokinase (PRK)--were partially purified from two different types of photosynthetic prokaryotes (cyanobacteria, purple sulfur bacteria) and tested for a response to thioredoxins. Each of the enzymes from the cyanobacterium Nostoc muscorum, an oxygenic organism known to contain the ferredoxin/thioredoxin system, was activated by thioredoxins that had been reduced either chemically by dithiothreitol or photochemically by reduced ferredoxin and ferredoxin-thioredoxin reductase. Like their chloroplast counterparts, N. muscorum FBPase and SBPase were activated preferentially by reduced thioredoxin f. SBPase was also partially activated by thioredoxin m. PRK, which was present in two regulatory forms in N. muscorum, was activated similarly by thioredoxins f and m. Despite sharing the capacity for regulation by thioredoxins, the cyanobacterial FBPase and SBPase target enzymes differed antigenically from their chloroplast counterparts. The corresponding enzymes from Chromatium vinosum, an anoxygenic photosynthetic purple bacterium found recently to contain the NADP/thioredoxin system, differed from both those of cyanobacteria and chloroplasts in showing no response to reduced thioredoxin. Instead, C. vinosum FBPase, SBPase, and PRK activities were regulated by a metabolite effector, 5'-AMP. The evidence is in accord with the conclusion that thioredoxins function in regulating the reductive pentose phosphate cycle in oxygenic prokaryotes (cyanobacteria) that contain the ferredoxin/thioredoxin system, but not in anoxygenic prokaryotes (photosynthetic purple bacteria) that contain the NADP/thioredoxin system. In organisms of the latter type, enzyme effectors seem to play a dominant role in regulating photosynthetic carbon dioxide assimilation.
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Affiliation(s)
- N A Crawford
- Division of Molecular Plant Biology, University of California, Berkeley 94720, USA
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Udvardy J, Borbely G, Juhåsz A, Farkas GL. Thioredoxins and the redox modulation of glucose-6-phosphate dehydrogenase in Anabaena sp. strain PCC 7120 vegetative cells and heterocysts. J Bacteriol 1984; 157:681-3. [PMID: 6420395 PMCID: PMC215304 DOI: 10.1128/jb.157.2.681-683.1984] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Glucose-6-phosphate dehydrogenase (G6PDH) was isolated from heterocysts and vegetative cells of Anabaena sp. strain PCC 7120. Both enzyme preparations proved to be more active in their oxidized than in their reduced forms. At least one protein with thioredoxin activity was found in Anabaena sp. which, if reduced with dithiothreitol, deactivated the G6PDH preparations. The deactivated heterocyst G6PDH could be reactivated neither by O2 nor by oxidized thioredoxin. Reactivation of the enzyme was, however, achieved by oxidized glutathione or H2O2. The active form of Anabaena G6PDH was readily deactivated by heterologous thioredoxin(s). The Anabaena thioredoxin(s) modulated heterologous enzymes.
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16
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Electrophoretic and chromatographic separation of two fructose-1,6-bisphosphatase forms from Synechococcus leopoliensix. Arch Microbiol 1984. [DOI: 10.1007/bf00414449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Udvardy J, Juhász A, Farkas GL. Interaction between hysteretic regulation and redox modulation of glucose-6-phosphate dehydrogenase from Anacystis nidulans. FEBS Lett 1983; 152:97-100. [PMID: 6404651 DOI: 10.1016/0014-5793(83)80490-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The glucose-6-phosphate dehydrogenase (G6PDH) of cyanobacteria is a hysteretic enzyme which is also subject to redox modulation [FEBS Lett. 126 (1981) 85-88]. We have found that the hysteretic and redox properties of G6PDH exhibit specific interactions: (1) The hysteretic forms of G6PDH ('hypoactive' in equilibrium 'hyperactive'), obtained at pH 7.5 and 6.5, respectively, differ in their redox properties. The 'hypoactive' form is easily activated by oxidation whereas the 'hyperactive' form is easily deactivated by reduction. (2) At low G6P concentrations (greater than 1 mM) only the oxidized form of G6PDH has significant activity. An increase in G6P level diminishes the difference between the activity of oxidized and reduced G6PDH forms.
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19
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Modulation of glyceraldehyde-3-phosphate dehydrogenase inAnacystis nidulans by glutathione. Arch Microbiol 1982. [DOI: 10.1007/bf00943760] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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