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Milrad Y, Mosebach L, Buchert F. Regulation of Microalgal Photosynthetic Electron Transfer. PLANTS (BASEL, SWITZERLAND) 2024; 13:2103. [PMID: 39124221 PMCID: PMC11314055 DOI: 10.3390/plants13152103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 07/24/2024] [Accepted: 07/26/2024] [Indexed: 08/12/2024]
Abstract
The global ecosystem relies on the metabolism of photosynthetic organisms, featuring the ability to harness light as an energy source. The most successful type of photosynthesis utilizes a virtually inexhaustible electron pool from water, but the driver of this oxidation, sunlight, varies on time and intensity scales of several orders of magnitude. Such rapid and steep changes in energy availability are potentially devastating for biological systems. To enable a safe and efficient light-harnessing process, photosynthetic organisms tune their light capturing, the redox connections between core complexes and auxiliary electron mediators, ion passages across the membrane, and functional coupling of energy transducing organelles. Here, microalgal species are the most diverse group, featuring both unique environmental adjustment strategies and ubiquitous protective mechanisms. In this review, we explore a selection of regulatory processes of the microalgal photosynthetic apparatus supporting smooth electron flow in variable environments.
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Affiliation(s)
- Yuval Milrad
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Laura Mosebach
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
| | - Felix Buchert
- Institute of Plant Biology and Biotechnology, University of Münster, Schlossplatz 8, 48143 Münster, Germany
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Liang W, Wei L, Wang Q, You W, Poetsch A, Du X, Lv N, Xu J. Knocking Out Chloroplastic Aldolases/Rubisco Lysine Methyltransferase Enhances Biomass Accumulation in Nannochloropsis oceanica under High-Light Stress. Int J Mol Sci 2024; 25:3756. [PMID: 38612566 PMCID: PMC11012178 DOI: 10.3390/ijms25073756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/10/2024] [Accepted: 03/12/2024] [Indexed: 04/14/2024] Open
Abstract
Rubisco large-subunit methyltransferase (LSMT), a SET-domain protein lysine methyltransferase, catalyzes the formation of trimethyl-lysine in the large subunit of Rubisco or in fructose-1,6-bisphosphate aldolases (FBAs). Rubisco and FBAs are both vital proteins involved in CO2 fixation in chloroplasts; however, the physiological effect of their trimethylation remains unknown. In Nannochloropsis oceanica, a homolog of LSMT (NoLSMT) is found. Phylogenetic analysis indicates that NoLSMT and other algae LSMTs are clustered in a basal position, suggesting that algal species are the origin of LSMT. As NoLSMT lacks the His-Ala/ProTrp triad, it is predicted to have FBAs as its substrate instead of Rubisco. The 18-20% reduced abundance of FBA methylation in NoLSMT-defective mutants further confirms this observation. Moreover, this gene (nolsmt) can be induced by low-CO2 conditions. Intriguingly, NoLSMT-knockout N. oceanica mutants exhibit a 9.7-13.8% increase in dry weight and enhanced growth, which is attributed to the alleviation of photoinhibition under high-light stress. This suggests that the elimination of FBA trimethylation facilitates carbon fixation under high-light stress conditions. These findings have implications in engineering carbon fixation to improve microalgae biomass production.
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Affiliation(s)
- Wensi Liang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wuxin You
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
| | - Ansgar Poetsch
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
| | - Xuefeng Du
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nana Lv
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
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Habibpour M, Razaghi-Moghadam Z, Nikoloski Z. Prediction and integration of metabolite-protein interactions with genome-scale metabolic models. Metab Eng 2024; 82:216-224. [PMID: 38367764 DOI: 10.1016/j.ymben.2024.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/13/2024] [Accepted: 02/14/2024] [Indexed: 02/19/2024]
Abstract
Metabolites, as small molecules, can act not only as substrates to enzymes, but also as effectors of activity of proteins with different functions, thereby affecting various cellular processes. While several experimental techniques have started to catalogue the metabolite-protein interactions (MPIs) present in different cellular contexts, characterizing the functional relevance of MPIs remains a challenging problem. Computational approaches from the constrained-based modeling framework allow for predicting MPIs and integrating their effects in the in silico analysis of metabolic and physiological phenotypes, like cell growth. Here, we provide a classification of all existing constraint-based approaches that predict and integrate MPIs using genome-scale metabolic networks as input. In addition, we benchmark the performance of the approaches to predict MPIs in a comparative study using different features extracted from the model structure and predicted metabolic phenotypes with the state-of-the-art metabolic networks of Escherichia coli and Saccharomyces cerevisiae. Lastly, we provide an outlook for future, feasible directions to expand the consideration of MPIs in constraint-based modeling approaches with wide biotechnological applications.
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Affiliation(s)
- Mahdis Habibpour
- Systems Biology and Mathematical Modeling Group, Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany
| | - Zahra Razaghi-Moghadam
- Systems Biology and Mathematical Modeling Group, Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany; Bioinformatics Department, Institute of Biochemistry and Biology, University of Potsdam, 14476, Potsdam, Germany
| | - Zoran Nikoloski
- Systems Biology and Mathematical Modeling Group, Max Planck Institute of Molecular Plant Physiology, 14476, Potsdam, Germany; Bioinformatics Department, Institute of Biochemistry and Biology, University of Potsdam, 14476, Potsdam, Germany.
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McQuillan JL, Cutolo EA, Evans C, Pandhal J. Proteomic characterization of a lutein-hyperaccumulating Chlamydomonas reinhardtii mutant reveals photoprotection-related factors as targets for increasing cellular carotenoid content. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:166. [PMID: 37925447 PMCID: PMC10625216 DOI: 10.1186/s13068-023-02421-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/28/2023] [Indexed: 11/06/2023]
Abstract
BACKGROUND Microalgae are emerging hosts for the sustainable production of lutein, a high-value carotenoid; however, to be commercially competitive with existing systems, their capacity for lutein sequestration must be augmented. Previous attempts to boost microalgal lutein production have focussed on upregulating carotenoid biosynthetic enzymes, in part due to a lack of metabolic engineering targets for expanding lutein storage. RESULTS Here, we isolated a lutein hyper-producing mutant of the model green microalga Chlamydomonas reinhardtii and characterized the metabolic mechanisms driving its enhanced lutein accumulation using label-free quantitative proteomics. Norflurazon- and high light-resistant C. reinhardtii mutants were screened to yield four mutant lines that produced significantly more lutein per cell compared to the CC-125 parental strain. Mutant 5 (Mut-5) exhibited a 5.4-fold increase in lutein content per cell, which to our knowledge is the highest fold increase of lutein in C. reinhardtii resulting from mutagenesis or metabolic engineering so far. Comparative proteomics of Mut-5 against its parental strain CC-125 revealed an increased abundance of light-harvesting complex-like proteins involved in photoprotection, among differences in pigment biosynthesis, central carbon metabolism, and translation. Further characterization of Mut-5 under varying light conditions revealed constitutive overexpression of the photoprotective proteins light-harvesting complex stress-related 1 (LHCSR1) and LHCSR3 and PSII subunit S regardless of light intensity, and increased accrual of total chlorophyll and carotenoids as light intensity increased. Although the photosynthetic efficiency of Mut-5 was comparatively lower than CC-125, the amplitude of non-photochemical quenching responses of Mut-5 was 4.5-fold higher than in CC-125 at low irradiance. CONCLUSIONS We used C. reinhardtii as a model green alga and identified light-harvesting complex-like proteins (among others) as potential metabolic engineering targets to enhance lutein accumulation in microalgae. These have the added value of imparting resistance to high light, although partially compromising photosynthetic efficiency. Further genetic characterization and engineering of Mut-5 could lead to the discovery of unknown players in photoprotective mechanisms and the development of a potent microalgal lutein production system.
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Affiliation(s)
- Josie L McQuillan
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK.
| | - Edoardo Andrea Cutolo
- Laboratory of Photosynthesis and Bioenergy, Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Caroline Evans
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK
| | - Jagroop Pandhal
- Department of Chemical and Biological Engineering, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK.
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