1
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Chen Z, Guo Z, Han M, Feng Y, Ma J. Integrated physiological and transcriptomic analyzes reveal the duality of TiO 2 nanoparticles on alfalfa (Medicago sativa L.). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 272:116059. [PMID: 38309235 DOI: 10.1016/j.ecoenv.2024.116059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 12/29/2023] [Accepted: 01/29/2024] [Indexed: 02/05/2024]
Abstract
Alfalfa (Medicago sativa L.) is a feed crop due to its rich nutrition and high productivity. The utilization of titanium oxide nanoparticles (TiO2 NPs) brings benefits to agricultural production but also has potential hazards. To investigate the duality and related mechanism of TiO2 NPs on alfalfa, its different doses including 0, 50, 100, 200, 500, and 1000 mg L- 1 (CK, Ti-50, Ti-100, Ti-200, Ti-500, and Ti-1000) were sprayed on leaves. The results showed that greater doses of TiO2 NPs (500 and 1000 mg L-1) negatively affected the physiological parameters, including morphology, biomass, leaf ultrastructure, stomata, photosynthesis, pigments, and antioxidant ability. However, 100 mg L-1 TiO2 NPs revealed an optimal positive effect; compared with the CK, it dramatically increased plant height, fresh weight, and dry weight by 22%, 21%, and 41%, respectively. Additionally, TiO2 NPs at low doses significantly protected leaf tissue, promoted stomatal opening, and enhanced the antioxidant system; while higher doses had phytotoxicity. Hence, TiO2 NPs are dose-dependent on alfalfa. The transcriptomic analysis identified 4625 and 2121 differentially expressed genes (DEGs) in the comparison of CK vs. Ti-100 and CK vs. Ti-500, respectively. They were mainly enriched in photosynthesis, chlorophyll metabolism, and energy metabolism. Notably, TiO2 NPs-induced phytotoxicity on photosynthetic parameters happened concurrently with the alterations of the genes involved in the porphyrin and chlorophyll metabolism and carbon fixation in photosynthetic organisms in the KEGG analysis. Similarly, it affected the efficiency of alfalfa energy transformation processes, including pyruvate metabolism and chlorophyll synthesis. Several key related genes in these pathways were validated. Therefore, TiO2 NPs have positive and toxic effects by regulating morphology, leaf ultrastructure, stomata, photosynthesis, redox homeostasis, and genes related to key pathways. It is significant to understand the duality of TiO2 NPs and cultivate varieties resistant to nanomaterial pollution.
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Affiliation(s)
- Zhao Chen
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Zhipeng Guo
- College of Grassland Agriculture, Northwest A&F University, Yangling 712100, Shaanxi Province, China
| | - Mengli Han
- College of Animal science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Yuxi Feng
- College of Animal science and Technology, Yangzhou University, Yangzhou 225009, China
| | - Jin Ma
- School of Landscape Architecture, Zhejiang Agriculture & Forestry University, Hangzhou 311300, China.
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2
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Chen GE, Hunter CN. Engineering Chlorophyll, Bacteriochlorophyll, and Carotenoid Biosynthetic Pathways in Escherichia coli. ACS Synth Biol 2023; 12:2236-2244. [PMID: 37531642 PMCID: PMC10443036 DOI: 10.1021/acssynbio.3c00237] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Indexed: 08/04/2023]
Abstract
The biosynthesis of chlorophylls (Chls) and bacteriochlorophylls (BChls) represents a key aspect of photosynthesis research. Our previous work assembled the complete pathway for the synthesis of Chl a in Escherichia coli; here we engineer the more complex BChl a pathway in the same heterotrophic host. Coexpression of 18 genes enabled E. coli to produce BChl a, verifying that we have identified the minimum set of genes for the BChl a biosynthesis pathway. The protochlorophyllide reduction step was mediated by the bchNBL genes, and this same module was used to modify the Chl a pathway previously constructed in E. coli, eliminating the need for the light-dependent protochlorophyllide reductase. Furthermore, we demonstrate the feasibility of synthesizing more than one family of photosynthetic pigments in one host by engineering E. coli strains that accumulate the carotenoids neurosporene and β-carotene in addition to BChl a.
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Affiliation(s)
- Guangyu E. Chen
- State
Key Laboratory of Microbial Metabolism, School of Life Sciences and
Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - C. Neil Hunter
- School
of Biosciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
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3
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Yuning L, Xianmei Y, Jingjing Z, Jinghua D, Luyang L, Jintian L, Benshui S. Transcriptome analyses reveal the potential mechanisms for color changes of a sweet orange peel induced by Candidatus Liberibacter asiaticus. Gene 2022; 839:146736. [PMID: 35835404 DOI: 10.1016/j.gene.2022.146736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/22/2022] [Accepted: 07/08/2022] [Indexed: 11/04/2022]
Abstract
'Shatangju' mandarin (Citrus reticulate Blanco cv. Shatangju) is a Chinese citrus specialty in southern China with a delicious taste and an attractive appearance. Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus (CLas) threatens the Shatangju industry seriously. Fruits from citrus trees with HLB show 'red nose' peels with a serious reduction in fruit value. Differentially expressed genes (DEGs) have been identified in the leaves of several citrus species with HLB infection. However, similar studies on the fruit peels of citrus trees with HLB infection are very limited. In this study, the pathogen CLas was diagnosed in the 'red nose' fruit peels of Shatangju. The chlorophyll and carotenoid contents in different peels were also analyzed. Besides, we identified DEGs in the comparison between peels from normal red-colored and 'red nose' fruits via RNA-seq. A total of 1922 unigenes were identified as DEGs, of which 434 were up-regulated and 1488 were down-regulated in the 'red nose' fruit peels. DEGs involved in chlorophyll and carotenoids biosynthesis, photosynthesis, and transcription factors could be responsible for fruit color changes after HLB infection. Our findings provide a preliminary understanding of the mechanism underlying the formation of a 'red nose' on fruit peel from HLB-infected trees.
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Affiliation(s)
- Li Yuning
- Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Yang Xianmei
- Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Zhang Jingjing
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangdong Provincial Key Laboratory of Plant Molecular Breeding, South China Agricultural University, Guangzhou 510642, China
| | - Dai Jinghua
- Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Liu Luyang
- Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China
| | - Lin Jintian
- Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Shu Benshui
- Guangzhou City Key Laboratory of Subtropical Fruit Trees Outbreak Control, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
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4
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Tang X, Zhang Y, Wang G, Zhang C, Wang F, Shi J, Zhang T, Ding J. Molecular mechanism of S-adenosylmethionine sensing by SAMTOR in mTORC1 signaling. SCIENCE ADVANCES 2022; 8:eabn3868. [PMID: 35776786 PMCID: PMC10883374 DOI: 10.1126/sciadv.abn3868] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The mechanistic target of rapamycin-mLST8-raptor complex (mTORC1) functions as a central regulator of cell growth and metabolism in response to changes in nutrient signals such as amino acids. SAMTOR is an S-adenosylmethionine (SAM) sensor, which regulates the mTORC1 activity through its interaction with the GTPase-activating protein activity toward Rags-1 (GATOR1)-KPTN, ITFG2, C12orf66 and SZT2-containing regulator (KICSTOR) complex. In this work, we report the crystal structures of Drosophila melanogaster SAMTOR in apo form and in complex with SAM. SAMTOR comprises an N-terminal helical domain and a C-terminal SAM-dependent methyltransferase (MTase) domain. The MTase domain contains the SAM-binding site and the potential GATOR1-KICSTOR-binding site. The helical domain functions as a molecular switch, which undergoes conformational change upon SAM binding and thereby modulates the interaction of SAMTOR with GATOR1-KICSTOR. The functional roles of the key residues and the helical domain are validated by functional assays. Our structural and functional data together reveal the molecular mechanism of the SAM sensing of SAMTOR and its functional role in mTORC1 signaling.
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Affiliation(s)
- Xin Tang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
| | - Yifan Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Guanchao Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Chunxiao Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Fang Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Jiawen Shi
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, Nantong 226011, China
| | - Tianlong Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
- Institute of Geriatrics, Affiliated Nantong Hospital of Shanghai University, Sixth People's Hospital of Nantong, Shanghai Engineering Research Center of Organ Repair, School of Medicine, Shanghai University, Nantong 226011, China
| | - Jianping Ding
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
- School of Life Science and Technology, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
- School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Xiangshan Road, Hangzhou 310024, China
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5
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Proctor MS, Sutherland GA, Canniffe DP, Hitchcock A. The terminal enzymes of (bacterio)chlorophyll biosynthesis. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211903. [PMID: 35573041 PMCID: PMC9066304 DOI: 10.1098/rsos.211903] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/29/2022] [Indexed: 05/03/2023]
Abstract
(Bacterio)chlorophylls are modified tetrapyrroles that are used by phototrophic organisms to harvest solar energy, powering the metabolic processes that sustain most of the life on Earth. Biosynthesis of these pigments involves enzymatic modification of the side chains and oxidation state of a porphyrin precursor, modifications that differ by species and alter the absorption properties of the pigments. (Bacterio)chlorophylls are coordinated by proteins that form macromolecular assemblies to absorb light and transfer excitation energy to a special pair of redox-active (bacterio)chlorophyll molecules in the photosynthetic reaction centre. Assembly of these pigment-protein complexes is aided by an isoprenoid moiety esterified to the (bacterio)chlorin macrocycle, which anchors and stabilizes the pigments within their protein scaffolds. The reduction of the isoprenoid 'tail' and its addition to the macrocycle are the final stages in (bacterio)chlorophyll biosynthesis and are catalysed by two enzymes, geranylgeranyl reductase and (bacterio)chlorophyll synthase. These enzymes work in conjunction with photosynthetic complex assembly factors and the membrane biogenesis machinery to synchronize delivery of the pigments to the proteins that coordinate them. In this review, we summarize current understanding of the catalytic mechanism, substrate recognition and regulation of these crucial enzymes and their involvement in thylakoid biogenesis and photosystem repair in oxygenic phototrophs.
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Affiliation(s)
- Matthew S. Proctor
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - George A. Sutherland
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Daniel P. Canniffe
- Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK
| | - Andrew Hitchcock
- Plants, Photosynthesis and Soil, School of Biosciences, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
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6
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Heyes DJ, Zhang S, Taylor A, Johannissen LO, Hardman SJO, Hay S, Scrutton NS. Photocatalysis as the 'master switch' of photomorphogenesis in early plant development. NATURE PLANTS 2021; 7:268-276. [PMID: 33686224 DOI: 10.1038/s41477-021-00866-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Enzymatic photocatalysis is seldom used in biology. Photocatalysis by light-dependent protochlorophyllide oxidoreductase (LPOR)-one of only a few natural light-dependent enzymes-is an exception, and is responsible for the conversion of protochlorophyllide to chlorophyllide in chlorophyll biosynthesis. Photocatalysis by LPOR not only regulates the biosynthesis of the most abundant pigment on Earth but it is also a 'master switch' in photomorphogenesis in early plant development. Following illumination, LPOR promotes chlorophyll production, plastid membranes are transformed and the photosynthetic apparatus is established. Given these remarkable, light-induced pigment and morphological changes, the LPOR-catalysed reaction has been extensively studied from catalytic, physiological and plant development perspectives, highlighting vital, and multiple, cellular roles of this intriguing enzyme. Here, we offer a perspective in which the link between LPOR photocatalysis and plant photomorphogenesis is explored. Notable breakthroughs in LPOR structural biology have uncovered the structural-mechanistic basis of photocatalysis. These studies have clarified how photon absorption by the pigment protochlorophyllide-bound in a ternary LPOR-protochlorophyllide-NADPH complex-triggers photocatalysis and a cascade of complex molecular and cellular events that lead to plant morphological changes. Photocatalysis is therefore the master switch responsible for early-stage plant development and ultimately life on Earth.
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Affiliation(s)
- Derren J Heyes
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK.
| | - Shaowei Zhang
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Aoife Taylor
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Linus O Johannissen
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Samantha J O Hardman
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Sam Hay
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology, Department of Chemistry, School of Natural Sciences, The University of Manchester, Manchester, UK.
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7
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Zhang H, Hu Y, Yang L, Lin Z, Zhao X, Chen J, Tang X, Wang Y. Transcriptome aberration in marine microalgae Phaeodactylum tricornutum induced by commercial naphthenic acids. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 268:115735. [PMID: 33068844 DOI: 10.1016/j.envpol.2020.115735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 09/17/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
Naphthenic acids (NAs) are cycloalkyl linear carboxylic acids primarily originating from oil sand tailings water (OSTW), and the exposure to NAs affects the photosynthesis of marine microalgaes. However, the transcriptional response upon the stress of NAs remains unclear. Herein, we investigate the transcriptome alterations of marine Phaeodactylum tricornutum induced by NAs using RNA-sequencing. In total 70 differentially expressed genes (DEGs) are enriched in seven biological process pathways, and 48 DEGs are enriched in four molecular functions. Differentially expressed genes of P. tricornutum are primarily concentrated in three photosynthesis-related pathways including the porphyrin and chlorophyll metabolism pathway, the photosynthesis pathway, and the carbon fixation pathway in photosynthetic organisms. Five DEGs such as hemE, chlM, TPI/GapC3, FbaC5, and CHLH are validated using quantitative real-time PCR assay. NAs at low concentrations affect the material energy conversion efficiency of P. tricornutum, such as chlorophyll synthesis, electron transfer efficiency, and carbon assimilation.
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Affiliation(s)
- Huanxin Zhang
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266100, China; College of Geography and Environment, Shandong Normal University, Jinan, 250000, China
| | - Yanran Hu
- School of Life Science, Central South University, Changsha, 410000, China
| | - Likun Yang
- Emory School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Zhihao Lin
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266100, China
| | - Xinyu Zhao
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266100, China
| | - Jun Chen
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266100, China
| | - Xuexi Tang
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
| | - Ying Wang
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
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8
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Wittmann D, Sinha N, Grimm B. Thioredoxin-dependent control balances the metabolic activities of tetrapyrrole biosynthesis. Biol Chem 2020; 402:379-397. [PMID: 33068374 DOI: 10.1515/hsz-2020-0308] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 10/13/2020] [Indexed: 11/15/2022]
Abstract
Plastids are specialized organelles found in plants, which are endowed with their own genomes, and differ in many respects from the intracellular compartments of organisms belonging to other kingdoms of life. They differentiate into diverse, plant organ-specific variants, and are perhaps the most versatile organelles known. Chloroplasts are the green plastids in the leaves and stems of plants, whose primary function is photosynthesis. In response to environmental changes, chloroplasts use several mechanisms to coordinate their photosynthetic activities with nuclear gene expression and other metabolic pathways. Here, we focus on a redox-based regulatory network composed of thioredoxins (TRX) and TRX-like proteins. Among multiple redox-controlled metabolic activities in chloroplasts, tetrapyrrole biosynthesis is particularly rich in TRX-dependent enzymes. This review summarizes the effects of plastid-localized reductants on several enzymes of this pathway, which have been shown to undergo dithiol-disulfide transitions. We describe the impact of TRX-dependent control on the activity, stability and interactions of these enzymes, and assess its contribution to the provision of adequate supplies of metabolic intermediates in the face of diurnal and more rapid and transient changes in light levels and other environmental factors.
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Affiliation(s)
- Daniel Wittmann
- Humboldt-Universität zu Berlin, Faculty of Life Science, Institute of Biology/Plant Physiology, Philippstraße 13 (Building 12), 10115Berlin, Germany
| | - Neha Sinha
- Humboldt-Universität zu Berlin, Faculty of Life Science, Institute of Biology/Plant Physiology, Philippstraße 13 (Building 12), 10115Berlin, Germany
| | - Bernhard Grimm
- Humboldt-Universität zu Berlin, Faculty of Life Science, Institute of Biology/Plant Physiology, Philippstraße 13 (Building 12), 10115Berlin, Germany
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9
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Zhang C, Zhang B, Mu B, Zheng X, Zhao F, Lan W, Fu A, Luan S. A Thylakoid Membrane Protein Functions Synergistically with GUN5 in Chlorophyll Biosynthesis. PLANT COMMUNICATIONS 2020; 1:100094. [PMID: 33367259 PMCID: PMC7747962 DOI: 10.1016/j.xplc.2020.100094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/24/2020] [Accepted: 07/02/2020] [Indexed: 05/21/2023]
Abstract
Chlorophyll (Chl) is essential for photosynthetic reactions and chloroplast development. While the enzymatic pathway for Chl biosynthesis is well established, the regulatory mechanism underlying the homeostasis of Chl levels remains largely unknown. In this study, we identified CBD1 (Chlorophyll Biosynthetic Defect1), which functions in the regulation of chlorophyll biosynthesis. The CBD1 gene was expressed specifically in green tissues and its protein product was embedded in the thylakoid membrane. Furthermore, CBD1 was precisely co-expressed and functionally correlated with GUN5 (Genome Uncoupled 5). Analysis of chlorophyll metabolic intermediates indicated that cbd1 and cbd1gun5 mutants over-accumulated magnesium protoporphyrin IX (Mg-Proto IX). In addition, the cbd1 mutant thylakoid contained less Mg than the wild type not only as a result of lower Chl content, but also implicating CBD1 in Mg transport. This was supported by the finding that CBD1 complemented a Mg2+ uptake-deficient Salmonella strain under low Mg conditions. Taken together, these results indicate that CBD1 functions synergistically with CHLH/GUN5 in Mg-Proto IX processing, and may serve as a Mg-transport protein to maintain Mg homeostasis in the chloroplast.
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Affiliation(s)
- Chi Zhang
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Bin Zhang
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Baicong Mu
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
- Temasek Life Sciences Laboratory, Singapore 117604, Republic of Singapore
| | - Xiaojiang Zheng
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Fugeng Zhao
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
| | - Wenzhi Lan
- Nanjing University-Nanjing Forestry University Joint Institute for Plant Molecular Biology, College of Life Sciences, Nanjing University, Nanjing 210093, China
- Corresponding author
| | - Aigen Fu
- The Key Laboratory of Western Resources Biology and Biological Technology, College of Life Sciences, Northwest University, Xi'an 710069, China
- Corresponding author
| | - Sheng Luan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
- Corresponding author
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10
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Abstract
Modified tetrapyrroles are large macrocyclic compounds, consisting of diverse conjugation and metal chelation systems and imparting an array of colors to the biological structures that contain them. Tetrapyrroles represent some of the most complex small molecules synthesized by cells and are involved in many essential processes that are fundamental to life on Earth, including photosynthesis, respiration, and catalysis. These molecules are all derived from a common template through a series of enzyme-mediated transformations that alter the oxidation state of the macrocycle and also modify its size, its side-chain composition, and the nature of the centrally chelated metal ion. The different modified tetrapyrroles include chlorophylls, hemes, siroheme, corrins (including vitamin B12), coenzyme F430, heme d1, and bilins. After nearly a century of study, almost all of the more than 90 different enzymes that synthesize this family of compounds are now known, and expression of reconstructed operons in heterologous hosts has confirmed that most pathways are complete. Aside from the highly diverse nature of the chemical reactions catalyzed, an interesting aspect of comparative biochemistry is to see how different enzymes and even entire pathways have evolved to perform alternative chemical reactions to produce the same end products in the presence and absence of oxygen. Although there is still much to learn, our current understanding of tetrapyrrole biogenesis represents a remarkable biochemical milestone that is summarized in this review.
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Affiliation(s)
- Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Martin J Warren
- School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom
- Quadram Institute Bioscience, Norwich Research Park, Norwich NR4 7UQ, United Kingdom
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11
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Da Q, Wang P, Wang M, Sun T, Jin H, Liu B, Wang J, Grimm B, Wang HB. Thioredoxin and NADPH-Dependent Thioredoxin Reductase C Regulation of Tetrapyrrole Biosynthesis. PLANT PHYSIOLOGY 2017; 175:652-666. [PMID: 28827456 PMCID: PMC5619880 DOI: 10.1104/pp.16.01500] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 08/18/2017] [Indexed: 05/23/2023]
Abstract
In chloroplasts, thioredoxin (TRX) isoforms and NADPH-dependent thioredoxin reductase C (NTRC) act as redox regulatory factors involved in multiple plastid biogenesis and metabolic processes. To date, less is known about the functional coordination between TRXs and NTRC in chlorophyll biosynthesis. In this study, we aimed to explore the potential functions of TRX m and NTRC in the regulation of the tetrapyrrole biosynthesis (TBS) pathway. Silencing of three genes, TRX m1, TRX m2, and TRX m4 (TRX ms), led to pale-green leaves, a significantly reduced 5-aminolevulinic acid (ALA)-synthesizing capacity, and reduced accumulation of chlorophyll and its metabolic intermediates in Arabidopsis (Arabidopsis thaliana). The contents of ALA dehydratase, protoporphyrinogen IX oxidase, the I subunit of Mg-chelatase, Mg-protoporphyrin IX methyltransferase (CHLM), and NADPH-protochlorophyllide oxidoreductase were decreased in triple TRX m-silenced seedlings compared with the wild type, although the transcript levels of the corresponding genes were not altered significantly. Protein-protein interaction analyses revealed a physical interaction between the TRX m isoforms and CHLM. 4-Acetoamido-4-maleimidylstilbene-2,2-disulfonate labeling showed the regulatory impact of TRX ms on the CHLM redox status. Since CHLM also is regulated by NTRC (Richter et al., 2013), we assessed the concurrent functions of TRX m and NTRC in the control of CHLM. Combined deficiencies of three TRX m isoforms and NTRC led to a cumulative decrease in leaf pigmentation, TBS intermediate contents, ALA synthesis rate, and CHLM activity. We discuss the coordinated roles of TRX m and NTRC in the redox control of CHLM stability with its corollary activity in the TBS pathway.
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Affiliation(s)
- Qingen Da
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
| | - Peng Wang
- Humboldt-University Berlin, Institute of Biology, Plant Physiology, 10115 Berlin, Germany
| | - Menglong Wang
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
| | - Ting Sun
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
| | - Honglei Jin
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
| | - Bing Liu
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
| | - Jinfa Wang
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
| | - Bernhard Grimm
- Humboldt-University Berlin, Institute of Biology, Plant Physiology, 10115 Berlin, Germany
| | - Hong-Bin Wang
- State Key Laboratory of Biocontrol and Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Sun Yat-sen University, 510275 Guangzhou, People's Republic of China
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12
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Wang Z, Hong X, Hu K, Wang Y, Wang X, Du S, Li Y, Hu D, Cheng K, An B, Li Y. Impaired Magnesium Protoporphyrin IX Methyltransferase (ChlM) Impedes Chlorophyll Synthesis and Plant Growth in Rice. FRONTIERS IN PLANT SCIENCE 2017; 8:1694. [PMID: 29033966 PMCID: PMC5626950 DOI: 10.3389/fpls.2017.01694] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/14/2017] [Indexed: 05/05/2023]
Abstract
Magnesium protoporphyrin IX methyltransferase (ChlM) catalyzes the formation of magnesium protoporphyrin IX monomethylester (MgPME) from magnesium protoporphyrin IX (MgP) in the chlorophyll synthesis pathway. However, no ChlM gene has yet been identified and studied in monocotyledonous plants. In this study, a spontaneous mutant, yellow-green leaf 18 (ygl18), was isolated from rice (Oryza sativa). This mutant showed yellow-green leaves, decreased chlorophyll level, and climate-dependent growth differences. Map-based cloning of this mutant identified the YGL18 gene LOC_Os06g04150. YGL18 is expressed in green tissues, especially in leaf organs, where it functions in chloroplasts. YGL18 showed an amino-acid sequence similarity to that of ChlM from different photosynthetic organisms. In vitro enzymatic assays demonstrated that YGL18 performed ChlM enzymatic activity, but ygl18 had nearly lost all ChlM activity. Correspondingly, the substrate MgP was largely accumulated while the product MgPME was reduced in ygl18 leaves. YGL18 is required for light-dependent and photoperiod-regulated chlorophyll synthesis. The retarded growth of ygl18 mutant plants was caused by the high light intensity. Moreover, the higher light intensity and longer exposure in high light intensity even made the ygl18 plants be more susceptible to death. Based on these results, it is suggested that YGL18 plays essential roles in light-related chlorophyll synthesis and light intensity-involved plant growth.
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Affiliation(s)
- Zhaohai Wang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
- The Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, School of Agricultural Sciences, Jiangxi Agricultural University, Nanchang, China
| | - Xiao Hong
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Keke Hu
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ya Wang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaoxin Wang
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Shiyun Du
- Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, China
| | - Yang Li
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Dandan Hu
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Kexin Cheng
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Baoguang An
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yangsheng Li
- State Key Laboratory of Hybrid Rice, Key Laboratory for Research and Utilization of Heterosis in Indica Rice, Ministry of Agriculture, The Yangtze River Valley Hybrid Rice Collaboration Innovation Center, College of Life Sciences, Wuhan University, Wuhan, China
- *Correspondence: Yangsheng Li
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13
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Richter AS, Wang P, Grimm B. Arabidopsis Mg-Protoporphyrin IX Methyltransferase Activity and Redox Regulation Depend on Conserved Cysteines. PLANT & CELL PHYSIOLOGY 2016; 57:519-27. [PMID: 26759408 DOI: 10.1093/pcp/pcw007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 01/06/2016] [Indexed: 05/10/2023]
Abstract
Redox regulation is an essential post-translational regulatory mechanism in prokaryotes and eukaryotes. The reversible oxidation and reduction of cysteine residues of proteins is also important in photosynthetic organisms to control enzymatic activities, protein stability and the interaction with other proteins of chloroplast-localized proteins. Several enzymes of the plant tetrapyrrole biosynthesis pathway have been identified to be redox regulated by thioredoxins (TRXs) and NADPH-dependent thioredoxin reductase C (NTRC). Among these proteins, Mg protoporphyrin IX methyltransferase (encoded by CHLM) was identified to be activated and stabilized by interaction with NTRC. CHLM catalyzes a methyl group transfer by using S-adenosylmethionine (SAM). Here we demonstrate that three conserved cysteine residues of Arabidopsis CHLM are essential for catalytic function and redox-dependent activation of the enzyme. In vitro and in planta biochemical assays of recombinant CHLM and the Arabidopsis chlm knockout mutant overexpressing wild-type and cysteine substitution mutants of CHLM revealed modified methyltransferase activity, when the conserved cysteine residues of CHLM are replaced by serine. While C177 is responsible for redox-dependent enzyme activation, exchange of the two cysteine residues, C111 and C115, has a strong impact on enzyme activity. The modified CHLM activity of single and double mutants with cysteine substitution is presented, and the role of each cysteine residue is discussed based on a modeled structure of CHLM. These studies contribute to enhanced understanding of the physiological and enzymatic significance of redox-regulated CHLM.
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Affiliation(s)
- Andreas S Richter
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, D-10115 Berlin, Germany
| | - Peng Wang
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, D-10115 Berlin, Germany
| | - Bernhard Grimm
- Institute of Biology/Plant Physiology, Humboldt-University Berlin, D-10115 Berlin, Germany
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14
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Chen X, Pu H, Fang Y, Wang X, Zhao S, Lin Y, Zhang M, Dai HE, Gong W, Liu L. Crystal structure of the catalytic subunit of magnesium chelatase. NATURE PLANTS 2015; 1:15125. [PMID: 27250678 DOI: 10.1038/nplants.2015.125] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2015] [Accepted: 07/30/2015] [Indexed: 05/20/2023]
Abstract
Tetrapyrroles, including haem and chlorophyll, play vital roles for various biological processes, such as respiration and photosynthesis, and their biosynthesis is critical for virtually all organisms. In photosynthetic organisms, magnesium chelatase (MgCh) catalyses insertion of magnesium into the centre of protoporphyrin IX, the branch-point precursor for both haem and chlorophyll, leading tetrapyrrole biosynthesis into the magnesium branch(1,2). This reaction needs a cooperated action of the three subunits of MgCh: the catalytic subunit ChlH and two AAA(+) subunits, ChlI and ChlD (refs 3-5). To date, the mechanism of MgCh awaits further elucidation due to a lack of high-resolution structures, especially for the ∼150 kDa catalytic subunit. Here we report the crystal structure of ChlH from the photosynthetic cyanobacterium Synechocystis PCC 6803, solved at 2.5 Å resolution. The active site is buried deeply inside the protein interior, and the surrounding residues are conserved throughout evolution. This structure helps to explain the loss of function reported for the cch and gun5 mutations of the ChlH subunit, and to provide the molecular basis of substrate channelling during the magnesium-chelating process. The structure advances our understanding of the holoenzyme of MgCh, a metal chelating enzyme other than ferrochelatase.
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Affiliation(s)
- Xuemin Chen
- Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hua Pu
- Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying Fang
- Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao Wang
- Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shun Zhao
- Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yajing Lin
- Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Min Zhang
- School of Life Sciences, Anhui University, Hefei, Anhui 230601, China
| | - Huai-En Dai
- Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Weimin Gong
- Laboratory of Non-coding RNA, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
- Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230027, China
| | - Lin Liu
- Photosynthesis Research Centre, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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15
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Regulation and function of tetrapyrrole biosynthesis in plants and algae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:968-85. [PMID: 25979235 DOI: 10.1016/j.bbabio.2015.05.007] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/21/2015] [Accepted: 05/07/2015] [Indexed: 12/20/2022]
Abstract
Tetrapyrroles are macrocyclic molecules with various structural variants and multiple functions in Prokaryotes and Eukaryotes. Present knowledge about the metabolism of tetrapyrroles reflects the complex evolution of the pathway in different kingdoms of organisms, the complexity of structural and enzymatic variations of enzymatic steps, as well as a wide range of regulatory mechanisms, which ensure adequate synthesis of tetrapyrrole end-products at any time of development and environmental condition. This review intends to highlight new findings of research on tetrapyrrole biosynthesis in plants and algae. In the course of the heme and chlorophyll synthesis in these photosynthetic organisms, glutamate, one of the central and abundant metabolites, is converted into highly photoreactive tetrapyrrole intermediates. Thereby, several mechanisms of posttranslational control are thought to be essential for a tight regulation of each enzymatic step. Finally, we wish to discuss the potential role of tetrapyrroles in retrograde signaling and point out perspectives of the formation of macromolecular protein complexes in tetrapyrrole biosynthesis as an efficient mechanism to ensure a fine-tuned metabolic flow in the pathway. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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