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Dai JL, He YJ, Chen HH, Jiang JG. Dual Roles of Two Malic Enzymes in Lipid Biosynthesis and Salt Stress Response in Dunaliella salina. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023. [PMID: 37906521 DOI: 10.1021/acs.jafc.3c04810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Triacylglycerols (TAG) from microalgae can be used as feedstocks for biofuel production to address fuel shortages. Most of the current research has focused on the enzymes involved in TAG biosynthesis. In this study, the effects of malic enzyme (ME), which provides precursor and reducing power for TAG biosynthesis, on biomass and lipid accumulation and its response to salt stress in Dunaliella salina were investigated. The overexpression of DsME1 and DsME2 improved the lipid production, which reached 0.243 and 0.253 g/L and were 30.5 and 36.3% higher than wild type, respectively. The transcript levels of DsME1 and DsME2 increased with increasing salt concentration (0, 1, 2, 3, and 4.5 mol/L NaCl), indicating that DsMEs participated in the salt stress response in D. salina. It was found that cis-acting elements associated with the salt stress response were present on the promoters of two DsMEs. The deletion of the MYB binding site (MBS) on the DsME2 promoter confirmed that MBS drives the expression of DsME2 to participate in osmotic regulation in D. salina. In conclusion, MEs are the critical enzymes that play pivotal roles in lipid accumulation and osmotic regulation.
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Affiliation(s)
- Jv-Liang Dai
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Yu-Jing He
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Hao-Hong Chen
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jian-Guo Jiang
- School of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China
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2
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Li J, Chen H, Chang L, Wu C, Zhang H, Chen YQ, Chen W. Functions and substrate selectivity of diacylglycerol acyltransferases from Mortierella alpina. Appl Microbiol Biotechnol 2023; 107:5761-5774. [PMID: 37498333 DOI: 10.1007/s00253-023-12694-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 07/07/2023] [Accepted: 07/18/2023] [Indexed: 07/28/2023]
Abstract
Mortierella alpina produces various polyunsaturated fatty acids in the form of triacylglycerols (TAG). Diacylglycerol acyltransferase (DGAT) catalyzes the binding of acyl-CoA to diacylglycerol to form TAG and is the key enzyme involved in TAG synthesis. A variety of DGATs are present in M. alpina; however, comparative analysis of the functional properties and substrate selectivity of these DGATs is insufficient. In this study, DGAT1 (MaDGAT1A/1B/1C) and DGAT2 (MaDGAT2A/2B) isoforms from M. alpina were analyzed and heterologously expressed in S. cerevisiae H1246. The results showed that MaDGAT1A/1B/2A/2B were able to restore TAG synthesis, and the corresponding TAG content in recombinant yeasts was 2.92 ± 0.42%, 3.62 ± 0.22%, 0.86 ± 0.34%, and 0.18 ± 0.09%, respectively. In S. cerevisiae H1246, MaDGAT1A preferred C16:1 among monounsaturated fatty acids, MaDGAT1B preferred C16:0 among saturated fatty acids (SFAs), and MaDGAT2A/2B preferred C18:0 among SFAs. Under exogenous addition of polyunsaturated fatty acids (PUFAs), MaDGAT1A and 2A preferentially assembled linoleic acid into TAG, and MaDGAT2B had substrate selectivity for eicosapentaenoic and linoleic acids in ω-6 PUFAs. In vitro, MaDGAT1A showed no obvious acyl-CoA selectivity and MaDGAT1B preferred C20:5-CoA. MaDGAT1A/1B preferred C18:1/C18:1-DAG compared with C20:4/C20:4-DAG. This study indicates that MaDGATs have the potential to be used in the production of LA/EPA-rich TAG and provide a reference for improving the production of TAGs in oleaginous fungi. KEY POINTS: • MaDGAT1A preferred C16:1 among MUFAs, MaDGAT1B and MaDGAT2A/2B preferred C16:0 and C18:0 among SFAs, respectively • MaDGAT1A/2A preferentially assembled linoleic acid into TAG, and MaDGAT2B has substrate selectivity for eicosapentaenoic acid and linoleic acid in ω-6 PUFAs • MaDGAT1A showed no obvious acyl-CoA selectivity, and MaDGAT1B preferred C20:5-CoA. MaDGAT1A/1B preferred to select C18:1/C18:1-DAG compared with C20:4/C20:4-DAG.
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Affiliation(s)
- Jun Li
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China.
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China.
| | - Lulu Chang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Chen Wu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Hao Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
| | - Yong Q Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC, 27157, USA
| | - Wei Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, Jiangsu, 214122, People's Republic of China
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Liu K, Li J, Xing C, Yuan H, Yang J. Characterization of Auxenochlorella protothecoides acyltransferases and potential of their protein interactions to promote the enrichment of oleic acid. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:69. [PMID: 37085915 PMCID: PMC10120206 DOI: 10.1186/s13068-023-02318-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/10/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND After centuries of heavy reliance on fossil fuel energy, the world suffers from an energy crisis and global warming, calling for carbon emission reduction and a transition to clean energy. Microalgae have attracted much attention as a potential feedstock for biofuel production due to their high triacylglycerol content and CO2 sequestration ability. Many diacylglycerol acyltransferases (DGAT) species have been characterized, which catalyze the final committed step in triacylglycerol biosynthesis. However, the detailed structure-function features of DGATs and the role of the interactions among DGAT proteins in lipid metabolism remained largely unknown. RESULTS In this study, the three characterized DGATs of Auxenochlorella protothecoides 2341 showed distinct structural and functional conservation. Functional complementation analyses showed that ApDGAT1 had higher activity than ApDGAT2b in yeast and model microalgae, and ApDGAT2a had no activity in yeast. The N-terminus was not essential to the catalysis function of ApDGAT1 but was crucial to ApDGAT2b as its enzyme activity was sensitive to any N-terminus modifications. Similarly, when acyl-CoA binding proteins (ACBPs) were fused to the N-terminus of ApDGAT1 and ApDGAT2b, zero and significant activity changes were observed, respectively. Interestingly, the ApACBP3 + ApDGAT1 variant contributed to higher oil accumulation than the original DGAT1, and ApACBP1 + ApDGAT1 fusion boosted oleic acid content in yeast. Overexpression of the three DGATs and the variation of ApACBP3 + ApDGAT1 increased the content of C18:1 of Chlamydomonas reinhardtii CC-5235. Significantly, ApDGAT1 interacted with itself, ApDGAT2b, and ApACBP1, which indicated that these three lipid metabolic proteins might have been a part of a dynamic protein interactome that facilitated the enrichment of oleic acid. CONCLUSIONS This study provided new insights into the functional and structural characteristics of DGATs and elucidated the importance of these physical interactions in potential lipid channeling.
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Affiliation(s)
- Kui Liu
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinyu Li
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Chao Xing
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Hongli Yuan
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinshui Yang
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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Xin F, Wang R, Chang Y, Gao M, Xie Z, Yang W, Chen M, Zhang H, Song Y. Homologous Overexpression of Diacylglycerol Acyltransferase in Oleaginous Fungus Mucor circinelloides WJ11 Enhances Lipid Accumulation under Static Solid Cultivation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:9073-9083. [PMID: 35844180 DOI: 10.1021/acs.jafc.2c03489] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Diacylglycerol acyltransferase (DGAT) catalyzes the binding of acyl-CoA to diacylglycerol to form triacylglycerol (TAG). Previous studies strongly indicate that DGAT2, rather than DGAT1, is crucial for TAG accumulation in the oleaginous fungus Mucor circinelloides. To increase the lipid content of M. circinelloides WJ11, McDGAT2 was overexpressed by homologous recombination; compared to the control strain Mc2075, transformants McDGAT2d showed a significant increase in biomass for both spores and mycelia (from 87.7 to 101.2 mg/g in spores and from 75.6 to 93.1 mg/g in mycelia). McDGAT2 overexpression under static solid fermentation gave a greater boost to lipid accumulation in mycelia than in spores. Total fatty acid content in mycelia increased by 68.0% (from 13.6 to 22.8%) and in spores by 26.3% (from 10.6 to 13.4%). However, under submerged fermentation, the lipid content of McDGAT2d was the same as the control, while biomass was slightly reduced. Transcriptomics showed that NADPH was derived mainly from the pentose phosphate pathway, acetyl-CoA was from multiple pathways, and leucine metabolism played an important role in substrate supply for fatty acid biosynthesis. Static solid fermentation may be the more suitable fermentation method for microbial oil production by filamentous fungi due to its lower fermentation costs.
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Affiliation(s)
- Feifei Xin
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Ruixue Wang
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Yufei Chang
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Meng Gao
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Zhike Xie
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Wu Yang
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Meiling Chen
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Huaiyuan Zhang
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
| | - Yuanda Song
- Colin Ratledge Center for Microbial Lipids, School of Agriculture Engineering and Food Science, Shandong University of Technology, 266 Xincun West Road, Zibo, Shandong 255000, People's Republic of China
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5
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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Yang J, Liu J, Pan Y, Maréchal E, Amato A, Liu M, Gong Y, Li Y, Hu H. PDAT regulates PE as transient carbon sink alternative to triacylglycerol in Nannochloropsis. PLANT PHYSIOLOGY 2022; 189:1345-1362. [PMID: 35385114 PMCID: PMC9237688 DOI: 10.1093/plphys/kiac160] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/14/2022] [Indexed: 05/21/2023]
Abstract
Triacylglycerols (TAGs) are the main storage lipids in photosynthetic organisms under stress. In the oleaginous alga Nannochloropsis oceanica, while multiple acyl CoA:diacylglycerol (DAG) acyltransferases (NoDGATs) are involved in TAG production, the role of the unique phospholipid:DAG acyltransferase (NoPDAT) remains unknown. Here, we performed a functional complementation assay in TAG-deficient yeast (Saccharomyces cerevisiae) and an in vitro assay to probe the acyltransferase activity of NoPDAT. Subcellular localization, overexpression, and knockdown (KD) experiments were also conducted to elucidate the role of NoPDAT in N. oceanica. NoPDAT, residing at the outermost plastid membrane, does not phylogenetically fall into the clades of algae or plants and uses phosphatidylethanolamine (PE) and phosphatidylglycerol with 16:0, 16:1, and 18:1 at position sn-2 as acyl-donors in vivo. NoPDAT KD, not triggering any compensatory mechanism via DGATs, led to an ∼30% decrease of TAG content, accompanied by a vast accumulation of PEs rich in 16:0, 16:1, and 18:1 fatty acids (referred to as "LU-PE") that was positively associated with CO2 availability. We conclude that the NoPDAT pathway is parallel to and independent of the NoDGAT pathway for oil production. LU-PE can serve as an alternative carbon sink for photosynthetically assimilated carbon in N. oceanica when PDAT-mediated TAG biosynthesis is compromised or under stress in the presence of high CO2 levels.
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Affiliation(s)
| | | | - Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG‐LPCV, 38054 Grenoble Cedex 9, France
| | - Alberto Amato
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG‐LPCV, 38054 Grenoble Cedex 9, France
| | - Meijing Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yangmin Gong
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Yantao Li
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, Maryland 21202, USA
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7
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Interactions between plant lipid-binding proteins and their ligands. Prog Lipid Res 2022; 86:101156. [DOI: 10.1016/j.plipres.2022.101156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 10/05/2021] [Accepted: 01/14/2022] [Indexed: 01/11/2023]
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8
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Xu Y, Pan X, Lu J, Wang J, Shan Q, Stout J, Chen G. Evolutionary and biochemical characterization of a Chromochloris zofingiensis MBOAT with wax synthase and diacylglycerol acyltransferase activity. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5584-5598. [PMID: 34037747 DOI: 10.1093/jxb/erab236] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
Wax synthase (WS) catalyzes the last step in wax ester biosynthesis in green plants. Two unrelated sub-families of WS, including the bifunctional acyltransferase and plant-like WS have been reported, but the latter is largely uncharacterized in microalgae. Here, we functionally characterized a putative plant-like WS (CzWS1) from the emerging model green microalga Chromochloris zofingiensis. Our results showed that plant-like WS evolved under different selection constraints in plants and microalgae, with positive selection likely contributing to functional divergence. Unlike jojoba with high amounts of wax ester in seeds and a highly active WS enzyme, C. zofingiensis has no detectable wax ester but a high abundance of WS transcripts. Co-expression analysis showed that C. zofingiensis WS has different expression correlation with lipid biosynthetic genes from jojoba, and may have a divergent function. In vitro characterization indicated that CzWS1 had diacylglycerol acyltransferase activity along with WS activity, and overexpression of CzWS1 in yeast and Chlamydomonas reinhardtii affected triacylglycerol accumulation. Moreover, biochemical and bioinformatic analyses revealed the relevance of the C-terminal region of CzWS1 in enzyme function. Taken together, our results indicated a functional divergence of plant-like WS in plants and microalgae, and the importance of its C-terminal region in specialization of enzyme function.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Xue Pan
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, and Department of Botany and Plant Sciences, University of California, Riverside, CA, USA
| | - Junhao Lu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Juli Wang
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Qiyuan Shan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
- School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, China
| | - Jake Stout
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
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9
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Chen H, Wang Q. Regulatory mechanisms of lipid biosynthesis in microalgae. Biol Rev Camb Philos Soc 2021; 96:2373-2391. [PMID: 34101323 DOI: 10.1111/brv.12759] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/01/2023]
Abstract
Microalgal lipids are highly promising feedstocks for biofuel production. Microalgal lipids, especially triacylglycerol, and practical applications of these compounds have received increasing attention in recent years. For the commercial use of microalgal lipids to be feasible, many fundamental biological questions must be addressed based on detailed studies of algal biology, including how lipid biosynthesis occurs and is regulated. Here, we review the current understanding of microalgal lipid biosynthesis, with a focus on the underlying regulatory mechanisms. We also present possible solutions for overcoming various obstacles to understanding the basic biology of microalgal lipid biosynthesis and the practical application of microalgae-based lipids. This review will provide a theoretical reference for both algal researchers and decision makers regarding the future directions of microalgal research, particularly pertaining to microalgal-based lipid biosynthesis.
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Affiliation(s)
- Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
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10
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Zhang Y, Ye Y, Bai F, Liu J. The oleaginous astaxanthin-producing alga Chromochloris zofingiensis: potential from production to an emerging model for studying lipid metabolism and carotenogenesis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:119. [PMID: 33992124 PMCID: PMC8126118 DOI: 10.1186/s13068-021-01969-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/07/2021] [Indexed: 05/05/2023]
Abstract
The algal lipids-based biodiesel, albeit having advantages over plant oils, still remains high in the production cost. Co-production of value-added products with lipids has the potential to add benefits and is thus believed to be a promising strategy to improve the production economics of algal biodiesel. Chromochloris zofingiensis, a unicellular green alga, has been considered as a promising feedstock for biodiesel production because of its robust growth and ability of accumulating high levels of triacylglycerol under multiple trophic conditions. This alga is also able to synthesize high-value keto-carotenoids and has been cited as a candidate producer of astaxanthin, the strongest antioxidant found in nature. The concurrent accumulation of triacylglycerol and astaxanthin enables C. zofingiensis an ideal cell factory for integrated production of the two compounds and has potential to improve algae-based production economics. Furthermore, with the advent of chromosome-level whole genome sequence and genetic tools, C. zofingiensis becomes an emerging model for studying lipid metabolism and carotenogenesis. In this review, we summarize recent progress on the production of triacylglycerol and astaxanthin by C. zofingiensis. We also update our understanding in the distinctive molecular mechanisms underlying lipid metabolism and carotenogenesis, with an emphasis on triacylglycerol and astaxanthin biosynthesis and crosstalk between the two pathways. Furthermore, strategies for trait improvements are discussed regarding triacylglycerol and astaxanthin synthesis in C. zofingiensis.
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Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Ying Ye
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Fan Bai
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China.
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11
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Bhunia RK, Sinha K, Chawla K, Randhawa V, Sharma TR. Functional characterization of two type-1 diacylglycerol acyltransferase (DGAT1) genes from rice (Oryza sativa) embryo restoring the triacylglycerol accumulation in yeast. PLANT MOLECULAR BIOLOGY 2021; 105:247-262. [PMID: 33089420 DOI: 10.1007/s11103-020-01085-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Two OsDGAT1 genes showed the ability to restore TAG and LB synthesis in yeast H1246. Alterations in the N-terminal region of OsDGAT1-1 gene revealed its regulatory role in gene function. Accumulation of triacylglycerol (TAG) or oil in vegetative tissues has emerged as a promising approach to meet the global needs of food, feed, and fuel. Rice (Oryza sativa) has been recognized as an important cereal crop containing nutritional rice bran oil with high economic value for renewable energy production. To identify the key component involved in storage lipid biosynthesis, two type-1 diacylglycerol acyltransferases (DGAT1) from rice were characterized for its in vivo function in the H1246 (dga1, lro1, are1 and are2) yeast quadruple mutant. The ectopic expression of rice DGAT1 (designated as OsDGAT1-1 and OsDGAT1-2) genes restored the capability of TAG synthesis and lipid body (LB) formation in H1246. OsDGAT1-1 showed nearly equal substrate preferences to C16:0-CoA and 18:1-CoA whereas OsDGAT1-2 displayed substrate selectivity for C16:0-CoA over 18:1-CoA, indicating that these enzymes have contrasting substrate specificities. In parallel, we have identified the intrinsically disordered region (IDR) at the N-terminal domains of OsDGAT1 proteins. The regulatory role of the N-terminal domain was dissected. Single point mutations at the phosphorylation sites and truncations of the N-terminal region highlighted reduced lipid accumulation capabilities among different OsDGAT1-1 variants.
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Affiliation(s)
- Rupam Kumar Bhunia
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India.
| | - Kshitija Sinha
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India
| | - Kirti Chawla
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India
| | - Vinay Randhawa
- Department of Biochemistry, Panjab University, Chandigarh, 160014, India
| | - Tilak Raj Sharma
- Plant Tissue Culture and Genetic Engineering, National Agri-Food Biotechnology Institute (NABI), Mohali, Punjab, 140306, India
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12
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Cui H, Zhao C, Xu W, Zhang H, Hang W, Zhu X, Ji C, Xue J, Zhang C, Li R. Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis. BMC PLANT BIOLOGY 2021; 21:20. [PMID: 33407140 PMCID: PMC7788937 DOI: 10.1186/s12870-020-02794-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 12/09/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous. RESULTS Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. CONCLUSIONS Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Hongjiang Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wei Hang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Xiaoli Zhu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
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13
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Cui H, Xu W, Zhu X, Zhao C, Cui Y, Ji C, Zhang C, Xue J, Qin S, Jia X, Li R. Characterization of a Haematococcus pluvialis Diacylglycerol Acyltransferase 1 and Its Potential in Unsaturated Fatty Acid-Rich Triacylglycerol Production. FRONTIERS IN PLANT SCIENCE 2021; 12:771300. [PMID: 34950166 PMCID: PMC8688921 DOI: 10.3389/fpls.2021.771300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/08/2021] [Indexed: 05/17/2023]
Abstract
The unicellular green alga Haematococcus pluvialis has been recognized as an industry strain to produce simultaneously esterified astaxanthin (EAST) and triacylglycerol (TAG) under stress induction. It is necessary to identify the key enzymes involving in synergistic accumulation of EAST and TAG in H. pluvialis. In this study, a novel diacylglycerol acyltransferase 1 was systematically characterized by in vivo and in silico assays. The upregulated expression of HpDGAT1 gene was positively associated with the significant increase of TAG and EAST contents under stress conditions. Functional complementation by overexpressing HpDGAT1 in a TAG-deficient yeast strain H1246 revealed that HpDGAT1 could restore TAG biosynthesis and exhibited a high substrate preference for monounsaturated fatty acyl-CoAs (MUFAs) and polyunsaturated fatty acyl-CoAs (PUFAs). Notably, heterogeneous expression of HpDGAT1 in Chlamydomonas reinhardtii and Arabidopsis thaliana resulted in a significant enhancement of total oils and concurrently a high accumulation of MUFAs- and PUFAs-rich TAGs. Furthermore, molecular docking analysis indicated that HpDGAT1 contained AST-binding sites. These findings evidence a possible dual-function role for HpDGAT1 involving in TAG and EAST synthesis, demonstrating that it is a potential target gene to enrich AST accumulation in this alga and to design oil production in both commercial algae and oil crops.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Xiaoli Zhu
- College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Yulin Cui
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Song Qin
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Xiaoyun Jia
- College of Life Sciences, Shanxi Agricultural University, Taigu, China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
- *Correspondence: Runzhi Li,
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14
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Xu Y, Caldo KMP, Falarz L, Jayawardhane K, Chen G. Kinetic improvement of an algal diacylglycerol acyltransferase 1 via fusion with an acyl-CoA binding protein. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:856-871. [PMID: 31991039 DOI: 10.1111/tpj.14708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/26/2019] [Accepted: 01/21/2020] [Indexed: 05/03/2023]
Abstract
Microalgal oils in the form of triacylglycerols (TAGs) are broadly used as nutritional supplements and biofuels. Diacylglycerol acyltransferase (DGAT) catalyzes the final step of acyl-CoA-dependent biosynthesis of TAG, and is considered a key target for manipulating oil production. Although a growing number of DGAT1s have been identified and over-expressed in some algal species, the detailed structure-function relationship, as well as the improvement of DGAT1 performance via protein engineering, remain largely untapped. Here, we explored the structure-function features of the hydrophilic N-terminal domain of DGAT1 from the green microalga Chromochloris zofingiensis (CzDGAT1). The results indicated that the N-terminal domain of CzDGAT1 was less disordered than those of the higher eukaryotic enzymes and its partial truncation or complete removal could substantially decrease enzyme activity, suggesting its possible role in maintaining enzyme performance. Although the N-terminal domains of animal and plant DGAT1s were previously found to bind acyl-CoAs, replacement of CzDGAT1 N-terminus by an acyl-CoA binding protein (ACBP) could not restore enzyme activity. Interestingly, the fusion of ACBP to the N-terminus of the full-length CzDGAT1 could enhance the enzyme affinity for acyl-CoAs and augment protein accumulation levels, which ultimately drove oil accumulation in yeast cells and tobacco leaves to higher levels than the full-length CzDGAT1. Overall, our findings unravel the distinct features of the N-terminus of algal DGAT1 and provide a strategy to engineer enhanced performance in DGAT1 via protein fusion, which may open a vista in generating improved membrane-bound acyl-CoA-dependent enzymes and boosting oil biosynthesis in plants and oleaginous microorganisms.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Lucas Falarz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Kethmi Jayawardhane
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
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15
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Wu T, Fu Y, Shi Y, Li Y, Kou Y, Mao X, Liu J. Functional Characterization of Long-Chain Acyl-CoA Synthetase Gene Family from the Oleaginous Alga Chromochloris zofingiensis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:4473-4484. [PMID: 32208653 DOI: 10.1021/acs.jafc.0c01284] [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] [Indexed: 05/03/2023]
Abstract
Long-chain acyl-coenzyme A (CoA) synthetase (LACS) catalyzes the formation of acyl-CoAs from free fatty acids, which is pivotal for lipid metabolism. Here, we confirmed the presence of six CzLACS genes in Chromochloris zofingiensis. Functional complementation and in vitro enzymatic assay indicated that CzLACS2 through CzLACS5 rather than CzLACS1 or CzLACS6 are bona fide LACS enzymes and they have overlapping yet distinct substrate preference. The results of the subcellular colocalization experiment and different expression patterns under three triacylglycerol (TAG)-inducing conditions showed that CzLACS2 through CzLACS4 reside at endoplasmic reticulum (ER) and are involved in TAG biosynthesis, while CzLACS5 resides in peroxisome and participates in fatty acid β-oxidation. The yeast one-hybrid assay using a library of 50 transcription factors (TFs) constructed in our study identified 12 TFs potentially involved in regulating the expression of CzLACSs. Moreover, heterologous expression of CzLACSs demonstrated their engineering potential for modulating TAG synthesis in yeast and algal cells.
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Affiliation(s)
- Tao Wu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Yunlei Fu
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Ying Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yuelian Li
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Yaping Kou
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
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16
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Nguyen T, Xu Y, Abdel-Hameed M, Sorensen JL, Singer SD, Chen G. Characterization of a Type-2 Diacylglycerol Acyltransferase from Haematococcus pluvialis Reveals Possible Allostery of the Recombinant Enzyme. Lipids 2019; 55:425-433. [PMID: 31879987 DOI: 10.1002/lipd.12210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/09/2019] [Accepted: 12/13/2019] [Indexed: 12/24/2022]
Abstract
Haematococcus pluvialis is a green microalga used in the algal biotechnology industry that can accumulate considerable amounts of storage triacylglycerol (TAG) and astaxanthin, which is a high-value carotenoid with strong antioxidant activity, under stress conditions. Diacylglycerol acyltransferase (DGAT) catalyzes the last step of the acyl-CoA-dependent TAG biosynthesis and appears to represent a bottleneck in algal TAG formation. In this study, putative H. pluvialis DGAT2 cDNA (HpDGAT2A, B, D and E) were identified from a transcriptome database and were subjected to sequence-based in silico analyses. The coding sequences of HpDGAT2B, D, and E were then isolated and characterized through heterologous expression in a TAG-deficient Saccharomyces cerevisiae strain H1246. The expression of HpDGAT2D allowed the recovery of TAG biosynthesis in this yeast mutant, and further in vitro enzymatic assays confirmed that the recombinant HpDGAT2D possessed strong DGAT activity. Interestingly, the recombinant HpDGAT2D displayed sigmoidal kinetics in response to increasing acyl-CoA concentrations, which has not been reported in plant or algal DGAT2 in previous studies.
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Affiliation(s)
- Trinh Nguyen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
| | - Mona Abdel-Hameed
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - John L Sorensen
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Stacy D Singer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, T1J 4B1, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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17
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Guo Z, Ye Z, Haslam RP, Michaelson LV, Napier JA, Chye M. Arabidopsis cytosolic acyl-CoA-binding proteins function in determining seed oil composition. PLANT DIRECT 2019; 3:e00182. [PMID: 31844833 PMCID: PMC6892995 DOI: 10.1002/pld3.182] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 10/14/2019] [Accepted: 10/24/2019] [Indexed: 05/04/2023]
Abstract
As plant seed oils provide animals with essential fatty acids (FAs), genes that regulate plant lipid metabolism have been used in genetic manipulation to improve dietary seed oil composition and benefit human health. Herein, the Arabidopsis thaliana cytosolic acyl-CoA-binding proteins (AtACBPs), AtACBP4, AtACBP5, and AtACBP6 were shown to play a role in determining seed oil content by analysis of atacbp (atacbp4, atacbp5, atacbp6, atacbp4atacbp5, atacbp4atacbp6, atacbp5atacbp6, and atacbp4atacbp5atacbp6) seed oil content in comparison with the Col-0 wild type (WT). Triacylglycerol (TAG) composition in electrospray ionization-mass spectrometer (ESI-MS) analysis on atacbp6 seed oil showed a reduction (-50%) of C58-TAGs in comparison with the WT. Investigations on fatty acid composition of atacbp mutants indicated that 18:2-FA accumulated in atacbp6 and 18:3-FA in atacbp4, both at the expense of 20:1-FA. As TAG composition can be modified by acyl editing through phosphatidylcholines (PC) and lysophosphatidylcholines (LPC), total PC and LPC content in atacbp6 mature seeds was determined and ESI-MS analysis revealed that LPC had increased (+300%) at the expense of PC. Among all the 14 tested PC species, all (34:1-, 34:2-, 34:3-, 34:4-, 34:5-, 34:6-, 36:2-, 36:3-, 36:5-, 36:6-, 38:2-, 38:3-, and 38:4-PCs) but 36:4-PC were lower in atacbp6 than the WT. In contrast, all LPC species (16:0-, 18:1-, 18:2-, 18:3-, and 20:1-LPC) examined were elevated in atacbp6. LPC abundance also increased in atacbp4atacbp5, but not atacbp4 and atacbp5. Interestingly, when LPC composition in atacbp4atacbp5 was compared with atacbp4 and atacbp5, significant differences were observed between atacbp4atacbp5 and each single mutant, implying that AtACBP4 and AtACBP5 play combinatory roles by affecting LPC (but not PC) biosynthesis. Furthermore, PC-related genes such as those encoding acyl-CoA:lysophphosphatidylcholine acyltransferase (LPCAT1) and phospholipase A2 alpha (PLA2α) were upregulated in atacbp6 developing seeds. A model on the role of AtACBP6 in modulating TAG through regulating LPCAT1 and PLA2α expression is proposed. Taken together, cytosolic AtACBPs appear to affect unsaturated TAG content and are good candidates for engineering oil crops to enhance seed oil composition.
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Affiliation(s)
- Ze‐Hua Guo
- School of Biological SciencesThe University of Hong KongHong KongChina
| | - Zi‐Wei Ye
- School of Biological SciencesThe University of Hong KongHong KongChina
| | | | | | | | - Mee‐Len Chye
- School of Biological SciencesThe University of Hong KongHong KongChina
- State Key Laboratory of AgrobiotechnologyThe Chinese University of Hong KongHong KongChina
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18
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Wu T, Mao X, Kou Y, Li Y, Sun H, He Y, Chen F. Characterization of Microalgal Acetyl-CoA Synthetases with High Catalytic Efficiency Reveals Their Regulatory Mechanism and Lipid Engineering Potential. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:9569-9578. [PMID: 31385495 DOI: 10.1021/acs.jafc.9b03370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Acetyl-CoA synthetase (ACS) plays a key role in microalgal lipid biosynthesis and acetyl-CoA industrial production. In the present study, two ACSs were cloned and characterized from the oleaginous microalga Chromochloris zofingiensis. In vitro kinetic analysis showed that the Km values of CzACS1 and CzACS2 for potassium acetate were 0.99 and 0.81 mM, respectively. Moreover, CzACS1 and CzACS2 had outstanding catalytic efficiencies (kcat/Km), which were 70.67 and 79.98 s-1 mM-1, respectively, and these values were higher than that of other reported ACSs. CzACS1 and CzACS2 exhibited differential expression patterns at the transcriptional level under various conditions. Screening a recombinant library of 52 transcription factors (TFs) constructed in the present study via yeast one-hybrid assay pointed to seven TFs with potential involvement in the regulation of the two ACS genes. Expression correlation analysis implied that GATA20 was likely an important regulator of CzACS2 and that ERF9 could regulate two CzACSs simultaneously.
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Affiliation(s)
| | | | | | | | - Han Sun
- Institute for Advanced Study , Shenzhen University , Shenzhen 518060 , China
| | | | - Feng Chen
- Institute for Advanced Study , Shenzhen University , Shenzhen 518060 , China
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