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Stevenson DK, Vreman HJ, Wong RJ. Heme, Heme Oxygenase-1, Statins, and SARS-CoV-2. Antioxidants (Basel) 2023; 12:antiox12030614. [PMID: 36978862 PMCID: PMC10044896 DOI: 10.3390/antiox12030614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Heme, a metalloporphyrin, or more specifically, a tetrapyrrole containing ferrous iron, is an ancient molecule [...]
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Zheng T, Zhan J, Yang M, Wang M, Sun W, Shan Z, Chen H. Hemin-induced increase in saponin content contributes to the alleviation of osmotic and cold stress damage to Conyza blinii in a heme oxygenase 1-dependent manner. J Zhejiang Univ Sci B 2021; 22:682-694. [PMID: 34414702 DOI: 10.1631/jzus.b2000697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Hemin can improve the stress resistance of plants through the heme oxygenase system. Additionally, substances contained in plants, such as secondary metabolites, can improve stress resistance. However, few studies have explored the effects of hemin on secondary metabolite content. Therefore, the effects of hemin on saponin synthesis and the mechanism of plant injury relief by hemin in Conyza blinii were investigated in this study. Hemin treatment promoted plant growth and increased the antioxidant enzyme activity and saponin content of C. blinii under osmotic stress and cold stress. Further study showed that hemin could provide sufficient precursors for saponin synthesis by improving the photosynthetic capacity of C. blinii and increasing the gene expression of key enzymes in the saponin synthesis pathway, thus increasing the saponin content. Moreover, the promotion effect of hemin on saponin synthesis is dependent on heme oxygenase-1 and can be reversed by the inhibitor Zn-protoporphyrin-IX (ZnPPIX). This study revealed that hemin can increase the saponin content of C. blinii and alleviate the damage caused by abiotic stress, and it also broadened the understanding of the relationship between hemin and secondary metabolites in plant abiotic stress relief.
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Affiliation(s)
- Tianrun Zheng
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.,Chongqing Academy of Chinese Materia Medica, Chongqing 400065, China
| | - Junyi Zhan
- College of Life Science, Nanjing Agricultural University, Nanjing 210095, China
| | - Ming Yang
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China
| | - Maojia Wang
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China
| | - Wenjun Sun
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China
| | - Zhi Shan
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China
| | - Hui Chen
- College of Life Science, Sichuan Agricultural University, Ya'an 625014, China.
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Zheng T, Wang M, Zhan J, Sun W, Yang Q, Lin Z, Bu T, Tang Z, Li C, Yan J, Shan Z, Chen H. Ferrous iron-induced increases in capitate glandular trichome density and upregulation of CbHO-1 contributes to increases in blinin content in Conyza blinii. PLANTA 2020; 252:81. [PMID: 33037484 DOI: 10.1007/s00425-020-03492-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/04/2020] [Indexed: 06/11/2023]
Abstract
Ferrous iron can promote the development of glandular trichomes and increase the content of blinin, which depends on CbHO-1 expression. Conyza blinii (C. blinii) is a unique Chinese herbal medicine that grows in Sichuan Province, China. Because the habitat of C. blinii is an iron ore mining area with abundant iron content, this species can be used as one of the best materials to study the mechanism of plant tolerance to iron. In this study, C. blinii was treated with ferrous-EDTA solutions at different concentrations, and it was found that the tolerance value of C. blinii to iron was 200 μM. Under this concentration, the plant height, root length, biomass, and iron content of C. blinii increased to the maximum values, and the effect was dependent on the upregulated expression of CbHO-1. At the same time, under ferrous iron, the photosynthetic capacity and capitate glandular trichome density of C. blinii also significantly increased, providing precursors and sites for the synthesis of blinin, thus significantly increasing the content of blinin. These processes were also dependent on the high expression of CbHO-1. Correlation analysis showed that there were strong positive correlations between iron content, capitate glandular trichome density, CbHO-1 gene expression, and blinin content. This study explored the effects of ferrous iron on the physiology and biochemistry of C. blinii, greatly improving our understanding of the mechanism of iron tolerance in C. blinii.
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Affiliation(s)
- Tianrun Zheng
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Maojia Wang
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Junyi Zhan
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Wenjun Sun
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Qin Yang
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Zhiyi Lin
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Tongliang Bu
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Zizhong Tang
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Chenglei Li
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Jun Yan
- Key Laboratory of Coarse Cereal Processing, Ministry of Agriculture Rural Affairs, School of Food and Bioengineering, Chengdu University, Chengdu, China
| | - Zhi Shan
- College of Life Science, Sichuan Agricultural University, Ya'an, China
| | - Hui Chen
- College of Life Science, Sichuan Agricultural University, Ya'an, China.
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Biochemical composition and in vitro digestibility of Galdieria sulphuraria grown on spent cherry-brine liquid. N Biotechnol 2019; 53:9-15. [PMID: 31195159 DOI: 10.1016/j.nbt.2019.06.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 06/06/2019] [Accepted: 06/08/2019] [Indexed: 01/25/2023]
Abstract
The aim of this work was to valorise an industrial food by-product and to produce a microalgal biomass rich in phytochemicals at high added value for food and nutraceutical applications. The biochemical composition, in vitro digestibility and antioxidant activity of Galdieria sulphuraria biomass grown heterotrophically on standard medium (SM) and on spent Cherry-Brine Liquid (sCBL) were assessed and compared. The biomass produced in sCBL was characterized by a lower content of proteins and lipids, while showing an increase in carbohydrates and polyphenols (5.3 vs 1.6 mg g-1). The sCBL biomass lipid moiety had a lower palmitic and linoleic acid content and a higher oleic acid concentration than SM. The total protein digestibility of Galdieria grown in SM and sCBL was 79% and 63% respectively. The antioxidant activity (AA) of G. sulphuraria biomass grown in sCBL was significantly higher than that grown in SM. Studying the AA release for sCBL biomass during the digestion, the highest value was found in the intestinal phase. In conclusion, G. sulphuraria has a valuable nutritional profile and could become a valuable source of phytochemicals, depending on the cultivation media. Cultivation on sCBL would allow an environmentally and economically sustainable process, valorising the food by-product and producing a microalgal biomass rich in cherry anthocyanins with high AA released at the intestinal level.
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Regulation of the heme biosynthetic pathway for combinational biosynthesis of phycocyanobilin in Escherichia coli. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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6
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Muneer S, Kim TH, Choi BC, Lee BS, Lee JH. Effect of CO, NOx and SO2 on ROS production, photosynthesis and ascorbate-glutathione pathway to induce Fragaria×annasa as a hyperaccumulator. Redox Biol 2013; 2:91-8. [PMID: 25460723 PMCID: PMC4297940 DOI: 10.1016/j.redox.2013.12.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 12/06/2013] [Accepted: 12/07/2013] [Indexed: 12/23/2022] Open
Abstract
A study was conducted to determine the effect of carbon monoxide (CO), nitroxide (NOx) and sulfur dioxide (SO2) on ROS production, photosynthesis and ascorbate-glutathione pathway in strawberry plants. The results showed that both singlet oxygen (O2(-1)) and hydrogen peroxide (H2O2) content increased in CO, NOx and SO2 treated strawberry leaves. A drastic reduction of primary metabolism of plants (photosynthesis), with the closure of stomata, resulted in a reduction of protein, carbohydrate and sucrose content due to production of reactive oxygen species (ROS) under prolonged exposure of gas stress. The resulting antioxidant enzymes were increased under a low dose of gas stress, whereas they were decreased due to a high dose of gas stress. Our results indicate that increased ROS may act as a signal to induce defense responses to CO, NOx and SO2 gas stress. The increased level of antioxidant enzymes plays a significant role in plant protection due to which strawberry plants can be used as a hyperaccumulator to maintain environmental pollution, however, the defense capacity cannot sufficiently alleviate oxidative damage under prolonged exposure of CO, NOx and SO2 stress.
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Affiliation(s)
- Sowbiya Muneer
- Department of Horticulture, College of Agricultural Life Sciences, Chonnam National University, 300 Young Bong-Dong Buk-Gu, Gwangju 500-757, Republic of Korea
| | - Tae Hwan Kim
- Department of Animal Science, Institute of Agricultural Science and Technology, College of Agriculture & Life Science, Chonnam National University, 300 YoungBong-Dong Buk-Gu, Gwangju 500-757, Republic of Korea
| | - Byung Chul Choi
- School of Mechanical Systems Engineering, College of Engineering, Chonnam National, University, 300 Young Bong-Dong Buk-Gu, Gwangju 500-757, Republic of Korea
| | - Beom Seon Lee
- Dayung GS Co., Ltd., Damyang, Jeonnam 517-922, Republic of Korea
| | - Jeong Hyun Lee
- Department of Horticulture, College of Agricultural Life Sciences, Chonnam National University, 300 Young Bong-Dong Buk-Gu, Gwangju 500-757, Republic of Korea.
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Vreman HJ, Wong RJ, Stevenson DK. Quantitating carbon monoxide production from heme by vascular plant preparations in vitro. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2011; 49:61-68. [PMID: 21055958 DOI: 10.1016/j.plaphy.2010.09.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 09/28/2010] [Accepted: 09/30/2010] [Indexed: 05/30/2023]
Abstract
Heme in animals is mainly degraded enzymatically, producing a predictable amount of carbon monoxide (CO). Under some conditions, alternative sources of CO production are important, such as lipid peroxidation and photo-oxidation. Less is known about CO production in plants as a reflection of enzymatic activity or coupled oxidation, but a sensitive assay for CO production in plants would be a valuable tool to explore the various sources in plants as the conditions of the reactions and mechanisms are defined. Using gas chromatography, we determined the requirements for heme-supported in vitro CO generation by exogenous reactants (NADPH, tissue supernatant, oxygen), optimum reaction conditions (time, temperature, pH, light), and effects of various cofactors and substrates using supernatants from Spinacia oleracea (spinach) leaf and Solanum tuberosa (potato) tuber homogenates. We then determined the CO production rate distribution between organ (root, stem, leaf, flower, fruit) supernatants in a number of commercially available plant species. CO production ranged from 4-65 nmol CO/h/g fresh weight and occurred in all vascular plant tissues examined, with the highest rates in chloroplast-containing tissues. In spinach leaves, CO production was concentrated (>2-fold) in the particulate fraction, whereas in potato tubers, the particulate fraction accounted for <50% of the rates in homogenates. We conclude that gas chromatography is uniquely suited for the determination of CO production in pigmented, heterogeneous plant tissue preparations.
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Affiliation(s)
- Hendrik J Vreman
- Department of Pediatrics, Division of Neonatal and Developmental Medicine, Stanford University School of Medicine, 300 Pasteur Dr, Stanford, CA 94305-5208, USA.
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8
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Csatorday K, Maccoll R, Berns DS. Accumulation of protoporphyrin IX and Zn protoporphyrin IX in Cyanidium caldarium. Proc Natl Acad Sci U S A 2010; 78:1700-2. [PMID: 16592992 PMCID: PMC319200 DOI: 10.1073/pnas.78.3.1700] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In vivo fluorescence studies of Cyanidium caldarium mutants grown in the dark in dextrose-containing media have shown that these organisms accumulate protoporphyrin IX. In the dark the accumulated protoporphyrin IX is gradually turned into a metalloporphyrin, Zn protoporphyrin. In the light, in the chlorophyll-lacking mutant GGB, both compounds are degraded and phycobiliproteins are formed. These results implicate protoporphyrin IX in situ as the general precursor to tetrapyrrole pigments and Zn protoporphyrin IX as a possible intermediate or regulator in the biosynthesis of phycobilins.
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Affiliation(s)
- K Csatorday
- Division of Laboratories and Research, New York State Department of Health, Albany, New York 12201
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Conrad R, Seiler W. Role of microorganisms in the consumption and production of atmospheric carbon monoxide by soil. Appl Environ Microbiol 2010; 40:437-45. [PMID: 16345624 PMCID: PMC291601 DOI: 10.1128/aem.40.3.437-445.1980] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Consumption and production of atmospheric CO was measured under field conditions in three different types of soil. CO was consumed by an apparent first-order reaction and produced by an apparent zero-order reaction, resulting in a dynamic equilibrium with the consumption of atmospheric CO as the net reaction. CO consumption was higher in summer than in winter. Laboratory experiments on five different soil types showed that CO consumption was strongly inhibited by the presence of streptomycin or cycloheximide (Actidione), or both. Thus, eucaryotic as well as procaryotic microorganisms were apparently responsible for the observed CO consumption. The aerobic carboxydobacterium Pseudomonas carboxydovorans added to sterile soil was able to utilize the low amounts (ca. 0.7 ppmv) of CO present in laboratory air. CO was consumed by soil under aerobic as well as anaerobic conditions. Anaerobic preincubation of the soil stimulated the anaerobic CO consumption and reduced the aerobic CO consumption. In contrast to CO consumption, CO production was stimulated by autoclaving, by ultraviolet-irradiation, by fumigation with NH(3) or CHCl(3), by treatment with streptomycin or cycloheximide or both, by addition of NaCN, NaN(3), or Na(2)HAsO(4) (or all three) in the presence of glucose under an atmosphere of pure oxygen, or by a drying and rewetting procedure. The consumption of atmospheric CO by soil is a microbial process, but the production of CO is apparently not a metabolic process.
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Affiliation(s)
- R Conrad
- Max-Planck-Institut für Chemie, D-6500 Mainz, West Germany
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Alvey RM, Bezy RP, Frankenberg-Dinkel N, Kehoe DM. A light regulated OmpR-class promoter element co-ordinates light-harvesting protein and chromophore biosynthetic enzyme gene expression. Mol Microbiol 2007; 64:319-32. [PMID: 17381552 DOI: 10.1111/j.1365-2958.2007.05656.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Co-ordination of chromophore and apoprotein biosynthesis is required during photosynthetic light-harvesting antennae production, such as occurs during complementary chromatic adaptation (CCA). This response to ambient light colour changes is controlled by a phytochrome-class photoreceptor and involves changes in the synthesis of cyanobacterial light-harvesting antennae. During growth in red light, CCA activates cpc2 transcription, an operon that encodes the light-harvesting protein phycocyanin. In order to function, this apoprotein must have covalently attached phycocyanobilin chromophores, which are synthesized by PcyA. We show that pcyA is also transcriptionally activated by CCA during red light growth and is not regulated via feedback that senses cpc2 RNA levels. The pcyA and cpc2 promoters contain a common regulatory element, a direct repeat typical of OmpR-class transcription factor binding sites, at similar positions relative to their red light-controlled transcription start sites. Deletion of this element from the pcyA promoter eliminated CCA-regulated transcription, and insertion of the element into a non-light responsive promoter conferred CCA regulation. We conclude that this element is necessary and sufficient to confer CCA transcriptional regulation and that it co-ordinates phycocyanin and phycocyanobilin biosynthesis in red light.
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MESH Headings
- Adaptation, Physiological/radiation effects
- Bacterial Proteins/genetics
- Base Sequence
- Cluster Analysis
- Cyanobacteria/genetics
- Cyanobacteria/radiation effects
- Feedback, Physiological/radiation effects
- Gene Expression Regulation, Bacterial/radiation effects
- Genes, Bacterial
- Light
- Light-Harvesting Protein Complexes/genetics
- Light-Harvesting Protein Complexes/radiation effects
- Models, Genetic
- Molecular Sequence Data
- Oxidoreductases/metabolism
- Phycobilins/biosynthesis
- Phycobilisomes/metabolism
- Phycobilisomes/radiation effects
- Phycocyanin/biosynthesis
- Promoter Regions, Genetic/genetics
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- Repetitive Sequences, Nucleic Acid/genetics
- Trans-Activators/genetics
- Transcription Initiation Site
- Transcription, Genetic/radiation effects
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Affiliation(s)
- Richard M Alvey
- Department of Biology, 1001 East Third Street, Indiana University, Bloomington, IN47405, USA
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11
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Granick S, Beale SI. Hemes, chlorophylls, and related compounds: biosynthesis and metabolic regulation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 46:33-203. [PMID: 345768 DOI: 10.1002/9780470122914.ch2] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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12
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Croft MT, Lawrence AD, Raux-Deery E, Warren MJ, Smith AG. Algae acquire vitamin B12 through a symbiotic relationship with bacteria. Nature 2005; 438:90-3. [PMID: 16267554 DOI: 10.1038/nature04056] [Citation(s) in RCA: 755] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Accepted: 07/15/2005] [Indexed: 11/08/2022]
Abstract
Vitamin B12 (cobalamin) was identified nearly 80 years ago as the anti-pernicious anaemia factor in liver, and its importance in human health and disease has resulted in much work on its uptake, cellular transport and utilization. Plants do not contain cobalamin because they have no cobalamin-dependent enzymes. Deficiencies are therefore common in strict vegetarians, and in the elderly, who are susceptible to an autoimmune disorder that prevents its efficient uptake. In contrast, many algae are rich in vitamin B12, with some species, such as Porphyra yezoensis (Nori), containing as much cobalamin as liver. Despite this, the role of the cofactor in algal metabolism remains unknown, as does the source of the vitamin for these organisms. A survey of 326 algal species revealed that 171 species require exogenous vitamin B12 for growth, implying that more than half of the algal kingdom are cobalamin auxotrophs. Here we show that the role of vitamin B12 in algal metabolism is primarily as a cofactor for vitamin B12-dependent methionine synthase, and that cobalamin auxotrophy has arisen numerous times throughout evolution, probably owing to the loss of the vitamin B12-independent form of the enzyme. The source of cobalamin seems to be bacteria, indicating an important and unsuspected symbiosis.
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Affiliation(s)
- Martin T Croft
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
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13
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Gossauer A, Nydegger F, Benedikt E, Köst HP. Syntheses of Bile Pigments. Part 16. Synthesis of a vinyl-substituted 2,3-Dihydrobilinedione: Possible role of this new class of bile pigments in phycobilin biosynthesis. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19890720315] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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14
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Tarr MA, Miller WL, Zepp RG. Direct carbon monoxide photoproduction from plant matter. ACTA ACUST UNITED AC 1995. [DOI: 10.1029/94jd03324] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Rhie G, Beale S. Regulation of heme oxygenase activity in Cyanidium caldarium by light, glucose, and phycobilin precursors. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36926-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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16
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Grossman AR, Schaefer MR, Chiang GG, Collier JL. The phycobilisome, a light-harvesting complex responsive to environmental conditions. Microbiol Rev 1993; 57:725-49. [PMID: 8246846 PMCID: PMC372933 DOI: 10.1128/mr.57.3.725-749.1993] [Citation(s) in RCA: 242] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Photosynthetic organisms can acclimate to their environment by changing many cellular processes, including the biosynthesis of the photosynthetic apparatus. In this article we discuss the phycobilisome, the light-harvesting apparatus of cyanobacteria and red algae. Unlike most light-harvesting antenna complexes, the phycobilisome is not an integral membrane complex but is attached to the surface of the photosynthetic membranes. It is composed of both the pigmented phycobiliproteins and the nonpigmented linker polypeptides; the former are important for absorbing light energy, while the latter are important for stability and assembly of the complex. The composition of the phycobilisome is very sensitive to a number of different environmental factors. Some of the filamentous cyanobacteria can alter the composition of the phycobilisome in response to the prevalent wavelengths of light in the environment. This process, called complementary chromatic adaptation, allows these organisms to efficiently utilize available light energy to drive photosynthetic electron transport and CO2 fixation. Under conditions of macronutrient limitation, many cyanobacteria degrade their phycobilisomes in a rapid and orderly fashion. Since the phycobilisome is an abundant component of the cell, its degradation may provide a substantial amount of nitrogen to nitrogen-limited cells. Furthermore, degradation of the phycobilisome during nutrient-limited growth may prevent photodamage that would occur if the cells were to absorb light under conditions of metabolic arrest. The interplay of various environmental parameters in determining the number of phycobilisomes and their structural characteristics and the ways in which these parameters control phycobilisome biosynthesis are fertile areas for investigation.
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Affiliation(s)
- A R Grossman
- Department of Plant Biology, Carnegie Institution of Washington, Stanford, California 94305
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17
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Beale SI, Weinstein JD. Chapter 5 Biochemistry and regulation of photosynthetic pigment formation in plants and algae. BIOSYNTHESIS OF TETRAPYRROLES 1991. [DOI: 10.1016/s0167-7306(08)60112-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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18
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Brown SB, Houghton JD, Vernon DI. Biosynthesis of phycobilins. Formation of the chromophore of phytochrome, phycocyanin and phycoerythrin. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1990; 5:3-23. [PMID: 2111391 DOI: 10.1016/1011-1344(90)85002-e] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phycobiliproteins play important roles in photomorphogenesis and photosynthesis. The light-absorbing chromophores of the phycobiliproteins are linear tetrapyrroles (bilins) very similar in structure to the mammalian bile pigments. 5-Aminolaevulinate (5-ALA) is the first committed intermediate in phycobilin synthesis. The biosynthesis of 5-ALA, destined for phycobilins, occurs via the five-carbon pathway, now well established for tetrapyrrole synthesis in plants and distinct from the mammalian pathway. The phycobilins are formed by reduction of biliverdin which results from the synthesis and degradation of haem. This haem is an essential intermediate in the biosynthesis of phycobilins. Phycocyanobilin, the blue-green pigment found in certain algae and cyanobacteria, is formed from biliverdin via phytochromobilin, the chromophore of phytochrome. This leads to the likelihood that phytochromobilin is formed as an end product, or intermediate, in the synthesis of all phycobilins.
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Affiliation(s)
- S B Brown
- Department of Biochemistry, University of Leeds, U.K
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19
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Heme regulates expression of phycobiliprotein photogenes in the unicellular rhodophyte, Cyanidium caldarium. J Biol Chem 1989. [DOI: 10.1016/s0021-9258(19)47104-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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20
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Houghton JD, Turner L, Brown SB. The effect of gabaculine on tetrapyrrole biosynthesis and heterotrophic growth in Cyanidium caldarium. Biochem J 1988; 254:907-10. [PMID: 3196303 PMCID: PMC1135170 DOI: 10.1042/bj2540907] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Pigment synthesis in four strains of the unicellular red alga Cyanidium caldarium with different pigment-synthesizing patterns was inhibited in the presence of gabaculine (3-amino-2,3-dihydrobenzoic acid). Parallel inhibition of light-induced chlorophyll and phycocyanin synthesis was observed in strain III-D-2, which only synthesizes pigments in the light. Similar parallel inhibition was observed in the dark in mutant CPD, which is able to synthesize chlorophyll and phycocyanin in the absence of light. Inhibition of pigment synthesis in all strains was overcome by addition of 5-aminolaevulinic acid. Inhibition of phycocyanin synthesis in mutant GGB (unable to synthesize chlorophyll) and inhibition of chlorophyll synthesis in mutant III-C (unable to synthesize phycocyanin) were also observed. Gabaculine also inhibited the heterotrophic growth of C. caldarium in the dark. However, inhibition was overcome after an extended lag period, following which cell growth proceeded at a similar rate to that of control cells not exposed to gabaculine. Heterotrophic growth in cells pre-exposed to gabaculine was not inhibited by subsequent exposure. Possible mechanisms for this adaptation are discussed.
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Affiliation(s)
- J D Houghton
- Department of Biochemistry, University of Leeds, U.K
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Algal heme oxygenase from Cyanidium caldarium. Partial purification and fractionation into three required protein components. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37873-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Beale SI, Cornejo J. Enzymatic heme oxygenase activity in soluble extracts of the unicellular red alga, Cyanidium caldarium. Arch Biochem Biophys 1984; 235:371-84. [PMID: 6549121 DOI: 10.1016/0003-9861(84)90210-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Extracts of the phycocyanin-containing unicellular red alga, Cyanidium caldarium, catalyzed enzymatic cleavage of the heme macrocycle to form the linear tetrapyrrole bilin structure. This is the key first step in the branch of the tetrapyrrole biosynthetic pathway leading to phycobilin photosynthetic accessory pigments. A mixed-function oxidase mechanism, similar to the biliverdin-forming reaction catalyzed by animal cell-derived microsomal heme oxygenase, was indicated by requirements for O2 and a reduced pyridine nucleotide. To avoid enzymatic conversion of the bilin product to phycocyanobilins and subsequent degradation during incubation, mesoheme IX was substituted for the normal physiological substrate, protoheme IX. Mesobiliverdin IX alpha was identified as the primary incubation product by comparative reverse-phase high-pressure liquid chromatography and absorption spectrophotometry. The enzymatic nature of the reaction was indicated by the requirement for cell extract, absence of activity in boiled cell extract, high specificity for NADPH as cosubstrate, formation of the physiologically relevant IX alpha bilin isomer, and over 75% inhibition by 1 microM Sn-protoporphyrin, which has been reported to be a competitive inhibitor of animal microsomal heme oxygenase. On the other hand, coupled oxidation of mesoheme, catalyzed by ascorbate plus pyridine or myoglobin, yielded a mixture of ring-opening mesobiliverdin IX isomers, was not inhibited by Sn-protoporphyrin, and could not use NADPH as the reductant. Unlike the animal microsomal heme oxygenase, the algal reaction appeared to be catalyzed by a soluble enzyme that was not sedimentable by centrifugation for 1 h at 200,000g. Although NADPH was the preferred reductant, small amounts of activity were obtained with NADH or ascorbate. A portion of the activity was retained after gel filtration of the cell extract to remove low-molecular-weight components. Considerable stimulation of activity, particularly in preparations that had been subjected to gel filtration, was obtained by addition of ascorbate to the incubation mixture containing NADPH. The results indicate that C. caldarium possesses a true heme oxygenase system, with properties somewhat different from that catalyzing heme degradation in animals. Taken together with previous results indicating that biliverdin is a precursor to phycocyanobilin, the results suggest that algal heme oxygenase is a component of the phycobilin biosynthetic pathway.
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Brown SB, Holroyd JA, Vernon DI, Jones OT. Ferrochelatase activity in the photosynthetic alga Cyanidium caldarium. Development of the enzyme during biosynthesis of photosynthetic pigments. Biochem J 1984; 220:861-3. [PMID: 6466309 PMCID: PMC1153708 DOI: 10.1042/bj2200861] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Dark-grown cells of the photosynthetic alga Cyanidium caldarium were shown to contain ferrochelatase activity, which increased markedly when the cells were induced to form pigments by exposure to light. Km values for the crude enzyme preparation were 14.8 microM and 6.5 microM for binding of Co2+ and deuteroporphyrin IX respectively.
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Primary structure of allophycocyanin from the unicellular rhodophyte, Cyanidium caldarium. The complete amino acid sequences of the alpha and beta subunits. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44587-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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27
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Phycobiliprotein synthesis in the unicellular rhodophyte, Cyanidium caldarium. Cell-free translation of the mRNAs for the alpha and beta subunit polypeptides of phycocyanin. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)32652-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Schuster A, K�st HP, R�diger W, Eder J. Investigations on the apoprotein of phycocyanin from Cyanidium caldarium. Arch Microbiol 1983. [DOI: 10.1007/bf00419478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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30
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Brown SB, Holroyd JA, Vernon DI, Troxler RF, Smith KM. The effect of N-methylprotoporphyrin IX on the synthesis of photosynthetic pigments in Cyanidium caldarium. Further evidence for the role of haem in the biosynthesis of plant billins. Biochem J 1982; 208:487-91. [PMID: 6760860 PMCID: PMC1153988 DOI: 10.1042/bj2080487] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
N-Methylprotoporphyrin IX strongly inhibits synthesis of phycocyanobilin, but not chlorophyll a, in the dark. In the light, both phycocyanin and chlorophyll a synthesis are inhibited in parallel. These results are consistent with the intermediacy of haem in algal bilin synthesis and suggest a control mechanism for chlorophyll a synthesis, previously unknown.
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31
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Yoshida T, Noguchi M, Kikuchi G. The step of carbon monoxide liberation in the sequence of heme degradation catalyzed by the reconstituted microsomal heme oxygenase system. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34075-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Troxler R, Ehrhardt M, Brown-Mason A, Offner G. Primary structure of phycocyanin from the unicellular rhodophyte Cyanidium caldarium. II. Complete amino acid sequence of the beta subunit. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(18)43250-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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34
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Offner G, Brown-Mason A, Ehrhardt M, Troxler R. Primary structure of phycocyanin from the unicellular rhodophyte Cyanidium caldarium. I. Complete amino acid sequence of the alpha subunit. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(18)43249-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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35
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36
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The fate of 18O in guanosine monophosphate during enzymic transformations leading to guanosine 3‘,5‘-monophosphate generation. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69756-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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37
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Brown SB, Holroyd JA, Troxler RF, Offner GD. Bile pigment synthesis in plants. Incorporation of haem into phycocyanobilin and phycobiliproteins in Cyanidium caldarium. Biochem J 1981; 194:137-47. [PMID: 7305974 PMCID: PMC1162726 DOI: 10.1042/bj1940137] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A procedure was developed whereby haem was taken up by dark-grown cells of the unicellular rhodophyte Cyanidium caldarium. These cells were subsequently incubated either in the dark with 5-aminolaevulinate, which results in excretion of phycocyanobilin into the suspending medium or incubated in the light, which results in synthesis and accumulation of phycocyanin and chlorophyll a within the cells. Phycocyanobilin was isolated from phycocyanin by cleavage from apoprotein in methanol. Phycocyanobilin prepared from phycocyanin or excreted from cells given 5-aminolaevulinate was methylated and purified by t.l.c. By using 14C labelling either in the haem or in 5-aminolaevulinate administered, haem incorporation into phycocyanobilin was demonstrated in both dark and light systems. Since chlorophyll a synthesized in the light in the presence of labelled haem contained no radioactivity, it was clear that haem was directly incorporated into phycocyanobilin and not first converted into protoporphyrin IX. These results clearly demonstrate phycocyanobilin synthesis via haem and not via magnesium protoporphyrin IX as has also been postulated.
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Brown SB, Holroyd AJ, Troxler RF. Mechanism of bile-pigment synthesis in algae. 18O incorporation into phycocyanobilin in the unicellular rhodophyte, Cyanidium caldarium. Biochem J 1980; 190:445-9. [PMID: 7470059 PMCID: PMC1162110 DOI: 10.1042/bj1900445] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The origin of the lactam oxygen atoms of phycocyanobilin from Cyanidium caldarium was studied using 18O labelling. By inhibiting photosynthesis, a high 18O enrichment was maintained in the gas phase and the resulting incorporation of label showed that the lactam oxygen atoms were derived from two oxygen molecules. Slow exchange of these oxygen atoms with water was demonstrated directly by using H218O.
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Nakajima R, Yamazaki I. The conversion of horseradish peroxidase C to a verdohemoprotein by a hydroperoxide derived enzymatically from indole-3-acetic acid and by m-nitroperoxybenzoic acid. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)85994-x] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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40
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Bauer K, Conrad R, Seiler W. Photooxidative production of carbon monoxide by phototrophic microorganisms. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 589:46-55. [PMID: 7356978 DOI: 10.1016/0005-2728(80)90131-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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41
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Gantt E. Structure and Function of Phycobilisomes: Light Harvesting Pigment Complexes in Red and Blue-Green Algae. INTERNATIONAL REVIEW OF CYTOLOGY 1980. [DOI: 10.1016/s0074-7696(08)61971-3] [Citation(s) in RCA: 168] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Troxler RF, Brown AS, Brown SB. Bile pigment synthesis in plants. Mechanism of 18O incorporation into phycocyanobilin in the unicellular rhodophyte. Cyanidium caldarium. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(18)50775-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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44
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Cosner JC, Troxler RF. Phycobiliprotein synthesis in protoplasts of the unicellular cyanophyte, Anacystis nidulans. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 519:474-88. [PMID: 96857 DOI: 10.1016/0005-2787(78)90100-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Stable and metabolically active protoplasts were prepared from the unicellular cyanophyte, Anacystis nidulans, by enzymatic digestion of the cell wall with 0.1% lysozyme. The yield of protoplasts from intact algal cells was approx. 50%. Incorporation of L-[U-14C]leucine into cold trichloroacetic acid-insoluble material from protoplasts preparations was linear for 1.5 h and continued for an additional 2.5 h. Incorporation of radiolabeled leucine into hot trichloroacetic acid-insoluble material from protoplast preparations demonstrated protein synthesis in protoplasts in vitro. Phycocyanin is the principal phycobiliprotein and allophycocyanin is a minor phycobiliprotein in A. nidulans cells. The light-absorbing chromophore of both of these phycobiliproteins is the linear tetrapyrrole (bile pigment), phycocyanobilin. Radiolabeled phycocyanin and allophycocyanin were isolated from protoplast preparations which had been incubated with L-[U-14]leucine or delta-amino[4-14C] levulinic acid (a precursor of phycocyanobilin). The radio-labeled phycobiliproteins were purified by ammonium sulfate fractionation and ion-exchange chromatography on brushite columns. The specific radioactivity of phycocyanin and allophycocyanin in brushite column eluates (protoplasts incubated with radiolabeled leucine) was 106 000 and 82 000 dpm/mg, respectively. The specific radioactivity of phycocyanin and allophycocyanin in brushite column eluates (protoplasts incubated with radiolabeled delta-aminolevulinic acid) was 33 000 and 38 000 dpm/mg, respectively. Phycobiliproteins from protoplasts incubated with radiolabeled leucine were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 25% of the incorporated radioactivity in protoplast lysates and approx. 60% of the incorporated radioactivity in protoplast lysates and approx. 60% of the incorporated ratioactivity in phycocyanin and allophycocyanin (in brushite column eluates) comigrated with the subunits of these phycobiliproteins on sodium dodecyl sulfate-polyacrylamide gels. Chromic acid degradation of phycobiliproteins from protoplast preparations incubated with delta-amino[4-14C] levulinic acid yielded radiolabeled imides which were derived from the phycocyanobilin chromophore. Imides from radiolabeled phycobiliproteins isolated from protoplast preparations incubated with L-[U-14C]leucine did not contain radioactivity. These results show that both the apoprotein and tetrapyrrolic moieties of phycocyanin and allophycocyanin were synthesized in A. nidulans protoplasts in vitro.
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Troxler RF, Kelly P, Brown SB. Phycocyanobilin synthesis in the unicellular rhodophyte Cyanidium caldarium. Biochem J 1978; 172:569-76. [PMID: 687359 PMCID: PMC1185732 DOI: 10.1042/bj1720569] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Light is required for synthesis of the accessory photosynethetic pigment phycocyanin in cells of the unicellular rhodophyte Cyanidium caldarium. Phycocyanin is a conjugated protein composed of polypeptide subunits to which the light-absorbing bile pigment chromophore phycocyanobilin is covalently attached. Dark-grown cells of C. caldarium are unable to make phycocyanin, but when incubated in the dark with 5-aminolaevulinate the cells synthesize and excrete a protein-free phycobilin (algal bile pigment) into the suspending medium. The electronic absorption spectrum, electron impact mass spectrum, chromatographic properties and imide products obtained after chronic acid degradation of the excreted phycobilin were identical with those of phycocyanobilin cleaved from phycocyanin in boiling methanol. This establishes the structural identity between the excreted phycobilin, which is the end product of bile-pigment synthesis in vivo, and the chromophore cleaved from phycocyanin in boiling methanol. The significance of the structure of the excreted phycobilin with respect to the events surrounding the assembly of the phycocyanin molecule in vivo is discussed.
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Jurgenson JE, Beale SI, Troxler RF. Biosynthesis of delta-aminolevulinic acid in the unicellular rhodophyte, cyanidium caldarium. Biochem Biophys Res Commun 1976; 69:149-57. [PMID: 1259751 DOI: 10.1016/s0006-291x(76)80285-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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48
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Kao OH, Edwards MR, Coll RM, Berns DS. Thermophilic phycocyanin. EXPERIENTIA. SUPPLEMENTUM 1976; 26:291-305. [PMID: 820565 DOI: 10.1007/978-3-0348-7675-9_24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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49
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Brown AS, Foster JA, Voynow PV, Franzblau C, Troxler RF. Allophycocyanin from the filamentous cyanophyte, Phormidium luridum. Biochemistry 1975; 14:3581-8. [PMID: 809053 DOI: 10.1021/bi00687a011] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Allophycocyanin from the filamentous cyanophyte, Phormidium luridum, was purified by ammonium sulfate fractionation and ion exchange chromatography on brushite columns. The specific absorption coefficient (E 0.1% 1cm) of purified allophycocyanin was 6.1 in distilled water and 7.3 in 0.05 M potassium phosphate buffer (pH 7). Absorption maxima of allophycocyanin occurred at 650, 618 (shoulder), 350, and 275 nm. Circular dichroic spectra displayed positive ellipticity bands at 655 and 625 nm, and a major negative ellipticity band at 340 nm. Computer analysis of the circular dichroic spectrum of allophycocyanin from 207 to 243 nm indicated that the secondary structure contained 60% alpha helix and 40% beta form. The estimated molecular weight of allophycocyanin on Sephadex G-200 columns at pH 7.0 was 155,000. Electrophoretic examination of allophycocyanin on sodium dodecyl sulfate polyacrylamide gels revealed two subunits, alpha and beta, with apparent molecular weights of 17,300 and 19,000, respectively. Densitometric analysis of unstained gels at 600 nm indicated that one phycocyanobilin chromophore was associated with each subunit. Treatment of allophycocyanin with 12% formic acid or 8 M urea and subsequent removal of the denaturant yielded a derivative with spectroscopic characteristics similar to phycocyanin. Subsequent incubation in phosphate buffer (pH 7), but not in acetate buffer (pH 5) or in water, was accompanied by a progressive reappearance of absorption maxima at 650 and 618 nm (shoulder), and positive ellipticity bands at 655 and 617 nm. Automated sequence analysis of allophycocyanin (a) showed that the sequence of amino acids at the amino terminus of the alpha and beta subunits is different, (b) showed that the subunits occur in a ratio of 1:1, and (c) demonstrated sequence homology at the amino terminus of allophycocyanin, phycocyanin, and phycoerythrin.
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Troxler RF, Foster JA, Brown AS, Franzblau C. The alpha and beta subunits of Cyanidium caldarium phycocyanin: properties and amino acid sequences at the amino terminus. Biochemistry 1975; 14:268-74. [PMID: 1120102 DOI: 10.1021/bi00673a012] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Phycocyanin was isolated and purified from the unicellular alga, Cyanidium caldarium. Subunits were prepared on a Bio-Rex-70 column developed stepwise with urea solutions (pH 1.9). The alpha subunit eluted in 8 M urea and the beta subunit eluted in 9 M urea. The alpha and beta subunits displayed absorption maxima at 660, 354, and 277 nm in 8 M and 9 M urea. The alpha:beta ratio of total absorbance under the 660-nm peak was 0.56 suggesting an alpha:beta phycocyanobilin chromophore ration of 1:2. On calibrated sodium dodecyl sulfate gels, the alphs subunit had an estimated molecular weight of 15,500 plus or minus 1100 and the beta subunit has an estimated molecular weight of 18,300 plus or minus 300. Minimum molecular weights based on one histidine residue per subunit were 16,300 for the alpha subunit and 18,750 for the beta subunit. Phycocyanin displayed a single visible absorption maximum at 625 nm and two positive circular dichroic bands at 632 and 610 nm. The alpha and beta subunits displayed single visible absorption maxima at 618 and 600 nm and single positive circular dichroic peaks at 620 and 585 nm, respectively. Two-dimensional maps of tryptic digests of the alpha and beta subunits revealed distinct patterns of peptides each of which was consistent with the lysine and arginine composition of these polypeptides. Maps of tryptic digests of phycocyanin contained 25 major peptides (a total of 27 lysine and arginine residues). Automated sequence analysis of separated subunits revealed a 70% homology within the first 27 residues at the amino terminus of the alpha and beta subunits of C. caldarium phycocyanin.
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