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Muth-Pawlak D, Kakko L, Kallio P, Aro EM. Interplay between photosynthetic electron flux and organic carbon sinks in sucrose-excreting Synechocystis sp. PCC 6803 revealed by omics approaches. Microb Cell Fact 2024; 23:188. [PMID: 38951789 PMCID: PMC11218172 DOI: 10.1186/s12934-024-02462-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Accepted: 06/17/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND Advancing the engineering of photosynthesis-based prokaryotic cell factories is important for sustainable chemical production and requires a deep understanding of the interplay between bioenergetic and metabolic pathways. Rearrangements in photosynthetic electron flow to increase the efficient use of the light energy for carbon fixation must be balanced with a strong carbon sink to avoid photoinhibition. In the cyanobacterium Synechocystis sp. PCC 6803, the flavodiiron protein Flv3 functions as an alternative electron acceptor of photosystem I and represents an interesting engineering target for reorganizing electron flow in attempts to enhance photosynthetic CO2 fixation and increase production yield. RESULTS We have shown that inactivation of Flv3 in engineered sucrose-excreting Synechocystis (S02:Δflv3) induces a transition from photoautotrophic sucrose production to mixotrophic growth sustained by sucrose re-uptake and the formation of intracellular carbon sinks such as glycogen and polyhydroxybutyrate. The growth of S02:Δflv3 exceeds that of the sucrose-producing strain (S02) and demonstrates unforeseen proteomic and metabolomic changes over the course of the nine-day cultivation. In the absence of Flv3, a down-regulation of proteins related to photosynthetic light reactions and CO2 assimilation occurred concomitantly with up-regulation of those related to glycolytic pathways, before any differences in sucrose production between S02 and S02:Δflv3 strains were observed. Over time, increased sucrose degradation in S02:Δflv3 led to the upregulation of respiratory pathway components, such as the plastoquinone reductase complexes NDH-11 and NDH-2 and the terminal respiratory oxidases Cyd and Cox, which transfer electrons to O2. While glycolytic metabolism is significantly up-regulated in S02:Δflv3 to provide energy for the cell, the accumulation of intracellular storage compounds and the increase in respiration serve as indirect sinks for photosynthetic electrons. CONCLUSIONS Our results show that the presence of strong carbon sink in the engineered sucrose-producing Synechocystis S02 strain, operating under high light, high CO2 and salt stress, cannot compensate for the lack of Flv3 by directly balancing the light transducing source and carbon fixing sink reactions. Instead, the cells immediately sense the imbalance, leading to extensive reprogramming of cellular bioenergetic, metabolic and ion transport pathways that favor mixotrophic growth rather than enhancing photoautotrophic sucrose production.
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Affiliation(s)
- Dorota Muth-Pawlak
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland.
| | - Lauri Kakko
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland
| | - Pauli Kallio
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland
| | - Eva-Mari Aro
- Department of Life Technologies, Molecular Plant Biology, University of Turku, Turku, FIN-20014, Finland
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2
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He Y, Lu C, Jiang Z, Sun Y, Liu H, Yin Z. NADH dehydrogenase-like complex L subunit improves salt tolerance by enhancing photosynthetic electron transport. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108420. [PMID: 38324953 DOI: 10.1016/j.plaphy.2024.108420] [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: 08/28/2023] [Revised: 01/17/2024] [Accepted: 02/02/2024] [Indexed: 02/09/2024]
Abstract
Cyclic electron transport (CET) around photosystem I (PSI) mediated by the NADH dehydrogenase-like (NDH) complex is closely related to plant salt tolerance. However, whether overexpression of a core subunit of the NDH complex affects the photosynthetic electron transport under salt stress is currently unclear. Here, we expressed the NDH complex L subunit (Ndhl) genes ZmNdhl1 and ZmNdhl2 from C4 plant maize (Zea mays) or OsNdhl from C3 plant rice (Oryza sativa) using a constitutive promoter in rice. Transgenic rice lines expressing ZmNdhl1, ZmNdhl2, or OsNdhl displayed enhanced salt tolerance, as indicated by greater plant height, dry weight, and leaf relative water content, as well as lower malondialdehyde content compared to wild-type plants under salt stress. Fluorescence parameters such as post-illumination rise (PIR), the prompt chlorophyll a fluorescence transient (OJIP), modulated 820-nm reflection (MR), and delayed chlorophyll a fluorescence (DF) remained relatively normal in transgenic plants during salt stress. These results indicate that expression of ZmNdhl1, ZmNdhl2, or OsNdhl increases cyclic electron transport activity, slows down damage to linear electron transport, alleviates oxidative damage to the PSI reaction center and plastocyanin, and reduces damage to electron transport on the receptor side of PSI in rice leaves under salt stress. Thus, expression of Ndhl genes from maize or rice improves salt tolerance by enhancing photosynthetic electron transport in rice. Maize and rice Ndhl genes played a similar role in enhancing salinity tolerance and avoiding photosynthetic damage.
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Affiliation(s)
- Yonghui He
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/ Jiangsu Key Laboratory of Crop Genetics and Physiology/ Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education/ Key Laboratory of Saline-alkali Soil Improvement and Utilization (Coastal Saline-alkali Lands) of the Ministry of Agriculture and Rural Affairs, Agricultural College of Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Chengcheng Lu
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/ Jiangsu Key Laboratory of Crop Genetics and Physiology/ Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education/ Key Laboratory of Saline-alkali Soil Improvement and Utilization (Coastal Saline-alkali Lands) of the Ministry of Agriculture and Rural Affairs, Agricultural College of Yangzhou University, Yangzhou, 225009, China
| | - Zifan Jiang
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/ Jiangsu Key Laboratory of Crop Genetics and Physiology/ Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education/ Key Laboratory of Saline-alkali Soil Improvement and Utilization (Coastal Saline-alkali Lands) of the Ministry of Agriculture and Rural Affairs, Agricultural College of Yangzhou University, Yangzhou, 225009, China
| | - Yu Sun
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/ Jiangsu Key Laboratory of Crop Genetics and Physiology/ Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education/ Key Laboratory of Saline-alkali Soil Improvement and Utilization (Coastal Saline-alkali Lands) of the Ministry of Agriculture and Rural Affairs, Agricultural College of Yangzhou University, Yangzhou, 225009, China
| | - Huanhuan Liu
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/ Jiangsu Key Laboratory of Crop Genetics and Physiology/ Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education/ Key Laboratory of Saline-alkali Soil Improvement and Utilization (Coastal Saline-alkali Lands) of the Ministry of Agriculture and Rural Affairs, Agricultural College of Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China
| | - Zhitong Yin
- Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Key Laboratory of Plant Functional Genomics of the Ministry of Education/ Jiangsu Key Laboratory of Crop Genetics and Physiology/ Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education/ Key Laboratory of Saline-alkali Soil Improvement and Utilization (Coastal Saline-alkali Lands) of the Ministry of Agriculture and Rural Affairs, Agricultural College of Yangzhou University, Yangzhou, 225009, China; Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou, 225009, China.
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3
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Che L, Guo Y, Huang Y, Peng L, Gao F. NDH-1L with a truncated NdhM subunit is unstable under stress conditions in cyanobacteria. PLANT DIRECT 2023; 7:e502. [PMID: 37334271 PMCID: PMC10272980 DOI: 10.1002/pld3.502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/14/2023] [Accepted: 05/19/2023] [Indexed: 06/20/2023]
Abstract
Cyanobacterial NdhM, an oxygenic photosynthesis-specific NDH-1 subunit, has been found to be essential for the formation of a large complex of NDH-1 (NDH-1L). The cryo-electron microscopic (cryo-EM) structure of NdhM from Thermosynechococcus elongatus showed that the N-terminus of NdhM contains three β-sheets, while two α-helixes are present in the middle and C-terminal part of NdhM. Here, we obtained a mutant of the unicellular cyanobacterium Synechocystis 6803 expressing a C-terminal truncated NdhM subunit designated NdhMΔC. Accumulation and activity of NDH-1 were not affected in NdhMΔC under normal growth conditions. However, the NDH-1 complex with truncated NdhM is unstable under stress. Immunoblot analyses showed that the assembly process of the cyanobacterial NDH-1L hydrophilic arm was not affected in the NdhMΔC mutant even under high temperature. Thus, our results indicate that NdhM can bind to the NDH-1 complex without its C-terminal α-helix, but the interaction is weakened. NDH-1L with truncated NdhM is more prone to dissociation, and this is particularly evident under stress conditions.
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Affiliation(s)
- Liping Che
- Development Center of Plant Germplasm Resources, College of Life SciencesShanghai Normal UniversityShanghaiChina
| | - Yuecheng Guo
- Development Center of Plant Germplasm Resources, College of Life SciencesShanghai Normal UniversityShanghaiChina
| | - Yanjie Huang
- Development Center of Plant Germplasm Resources, College of Life SciencesShanghai Normal UniversityShanghaiChina
| | - Lianwei Peng
- Development Center of Plant Germplasm Resources, College of Life SciencesShanghai Normal UniversityShanghaiChina
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life SciencesShanghai Normal UniversityShanghaiChina
| | - Fudan Gao
- Development Center of Plant Germplasm Resources, College of Life SciencesShanghai Normal UniversityShanghaiChina
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life SciencesShanghai Normal UniversityShanghaiChina
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4
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Zhang S, Zou B, Cao P, Su X, Xie F, Pan X, Li M. Structural insights into photosynthetic cyclic electron transport. MOLECULAR PLANT 2023; 16:187-205. [PMID: 36540023 DOI: 10.1016/j.molp.2022.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/17/2022] [Accepted: 12/18/2022] [Indexed: 06/17/2023]
Abstract
During photosynthesis, light energy is utilized to drive sophisticated biochemical chains of electron transfers, converting solar energy into chemical energy that feeds most life on earth. Cyclic electron transfer/flow (CET/CEF) plays an essential role in efficient photosynthesis, as it balances the ATP/NADPH ratio required in various regulatory and metabolic pathways. Photosystem I, cytochrome b6f, and NADH dehydrogenase (NDH) are large multisubunit protein complexes embedded in the thylakoid membrane of the chloroplast and key players in NDH-dependent CEF pathway. Furthermore, small mobile electron carriers serve as shuttles for electrons between these membrane protein complexes. Efficient electron transfer requires transient interactions between these electron donors and acceptors. Structural biology has been a powerful tool to advance our knowledge of this important biological process. A number of structures of the membrane-embedded complexes, soluble electron carrier proteins, and transient complexes composed of both have now been determined. These structural data reveal detailed interacting patterns of these electron donor-acceptor pairs, thus allowing us to visualize the different parts of the electron transfer process. This review summarizes the current state of structural knowledge of three membrane complexes and their interaction patterns with mobile electron carrier proteins.
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Affiliation(s)
- Shumeng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Baohua Zou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Peng Cao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
| | - Xiaodong Su
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Fen Xie
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Xiaowei Pan
- College of Life Science, Capital Normal University, Beijing, China
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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5
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Burnap RL. Cyanobacterial Bioenergetics in Relation to Cellular Growth and Productivity. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:25-64. [PMID: 36764956 DOI: 10.1007/10_2022_215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Cyanobacteria, the evolutionary originators of oxygenic photosynthesis, have the capability to convert CO2, water, and minerals into biomass using solar energy. This process is driven by intricate bioenergetic mechanisms that consist of interconnected photosynthetic and respiratory electron transport chains coupled. Over the last few decades, advances in physiochemical analysis, molecular genetics, and structural analysis have enabled us to gain a more comprehensive understanding of cyanobacterial bioenergetics. This includes the molecular understanding of the primary energy conversion mechanisms as well as photoprotective and other dissipative mechanisms that prevent photodamage when the rates of photosynthetic output, primarily in the form of ATP and NADPH, exceed the rates that cellular assimilatory processes consume these photosynthetic outputs. Despite this progress, there is still much to learn about the systems integration and the regulatory circuits that control expression levels for optimal cellular abundance and activity of the photosynthetic complexes and the cellular components that convert their products into biomass. With an improved understanding of these regulatory principles and mechanisms, it should be possible to optimally modify cyanobacteria for enhanced biotechnological purposes.
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Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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6
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Zhao J, Jiang Y, Tian Y, Mao J, Wei L, Ma W. New insights into the effect of NdhO levels on cyanobacterial cell death triggered by high temperature. FUNCTIONAL PLANT BIOLOGY : FPB 2022; 49:533-541. [PMID: 34428393 DOI: 10.1071/fp21097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
NdhO, a regulatory oxygenic photosynthesis-specific subunit, is close to the ferredoxin-binding site of cyanobacterial NDH-1, and its levels are negatively associated with the rates of cyclic electron transfer around PSI mediated by NDH-1 (NDH-CET). However, the effect of NdhO levels on cyanobacterial cell death triggered by high temperature remains elusive. Here, our results uncovered a synergistic effect of NdhO levels on the cell death and reactive oxygen species (ROS) accumulation when cyanobacterial cells grown at 30°C for 1 day were transferred to 45°C for 2 days. Such synergistic effect was found to be closely associated with the activities of NDH-CET and CO2 assimilation during high temperature. Collectively, we propose that the effect of NdhO levels on the cyanobacterial cell bleaching and cell death triggered by high temperature is a result of influencing production of ROS by NDH-CET, which is considered to be vital to balance the ATP/NADPH ratio and improve the Calvin-Benson cycle.
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Affiliation(s)
- Jiaohong Zhao
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Yuanyuan Jiang
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Yuhao Tian
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Jun Mao
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China
| | - Lanzhen Wei
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China; and Corresponding author
| | - Weimin Ma
- Shanghai Key laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai 200234, China; and Corresponding author
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7
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Su X, Cao D, Pan X, Shi L, Liu Z, Dall'Osto L, Bassi R, Zhang X, Li M. Supramolecular assembly of chloroplast NADH dehydrogenase-like complex with photosystem I from Arabidopsis thaliana. MOLECULAR PLANT 2022; 15:454-467. [PMID: 35123031 DOI: 10.1016/j.molp.2022.01.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 01/27/2022] [Accepted: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Cyclic electron transport/flow (CET/CEF) in chloroplasts is a regulatory process essential for the optimization of plant photosynthetic efficiency. A crucial CEF pathway is catalyzed by a membrane-embedded NADH dehydrogenase-like (NDH) complex that contains at least 29 protein subunits and associates with photosystem I (PSI) to form the NDH-PSI supercomplex. Here, we report the 3.9 Å resolution structure of the Arabidopsis thaliana NDH-PSI (AtNDH-PSI) supercomplex. We constructed structural models for 26 AtNDH subunits, among which 11 are unique to chloroplasts and stabilize the core part of the NDH complex. In the supercomplex, one NDH can bind up to two PSI-light-harvesting complex I (PSI-LHCI) complexes at both sides of its membrane arm. Two minor LHCIs, Lhca5 and Lhca6, each present in one PSI-LHCI, interact with NDH and contribute to supercomplex formation and stabilization. Collectively, our study reveals the structural details of the AtNDH-PSI supercomplex assembly and provides a molecular basis for further investigation of the regulatory mechanism of CEF in plants.
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Affiliation(s)
- Xiaodong Su
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China; University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Duanfang Cao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Xiaowei Pan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China; College of Life Science, Capital Normal University, Beijing 100101, P.R. China.
| | - Lifang Shi
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China
| | - Zhenfeng Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China; University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Luca Dall'Osto
- Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, 37134 Verona, Italy
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China; University of Chinese Academy of Sciences, Beijing 100049, P.R. China; Center for Biological Imaging, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China.
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, P.R. China.
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8
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Nikkanen L, Santana Sánchez A, Ermakova M, Rögner M, Cournac L, Allahverdiyeva Y. Functional redundancy between flavodiiron proteins and NDH-1 in Synechocystis sp. PCC 6803. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1460-1476. [PMID: 32394539 DOI: 10.1111/tpj.14812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 05/09/2023]
Abstract
In oxygenic photosynthetic organisms, excluding angiosperms, flavodiiron proteins (FDPs) catalyze light-dependent reduction of O2 to H2 O. This alleviates electron pressure on the photosynthetic apparatus and protects it from photodamage. In Synechocystis sp. PCC 6803, four FDP isoforms function as hetero-oligomers of Flv1 and Flv3 and/or Flv2 and Flv4. An alternative electron transport pathway mediated by the NAD(P)H dehydrogenase-like complex (NDH-1) also contributes to redox hemostasis and the photoprotection of photosynthesis. Four NDH-1 types have been characterized in cyanobacteria: NDH-11 and NDH-12 , which function in respiration; and NDH-13 and NDH-14 , which function in CO2 uptake. All four types are involved in cyclic electron transport. Along with single FDP mutants (∆flv1 and Δflv3) and the double NDH-1 mutants (∆d1d2, which is deficient in NDH-11,2 and ∆d3d4, which is deficient in NDH-13,4 ), we studied triple mutants lacking one of Flv1 or Flv3, and NDH-11,2 or NDH-13,4 . We show that the presence of either Flv1/3 or NDH-11,2 , but not NDH-13,4 , is indispensable for survival during changes in growth conditions from high CO2 /moderate light to low CO2 /high light. Our results show functional redundancy between FDPs and NDH-11,2 under the studied conditions. We suggest that ferredoxin probably functions as a primary electron donor to both Flv1/3 and NDH-11,2 , allowing their functions to be dynamically coordinated for efficient oxidation of photosystem I and for photoprotection under variable CO2 and light availability.
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Affiliation(s)
- Lauri Nikkanen
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Anita Santana Sánchez
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Maria Ermakova
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
| | - Matthias Rögner
- Plant Biochemistry, Faculty of Biology & Biotechnology, Ruhr-University Bochum, Bochum, Germany
| | - Laurent Cournac
- Eco&Sols, University of Montpellier, IRD, CIRAD, INRAE, Institut Agro, Montpellier, France
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, Finland
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9
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The plastid NAD(P)H dehydrogenase-like complex: structure, function and evolutionary dynamics. Biochem J 2020; 476:2743-2756. [PMID: 31654059 DOI: 10.1042/bcj20190365] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/27/2019] [Accepted: 09/02/2019] [Indexed: 11/17/2022]
Abstract
The thylakoid NAD(P)H dehydrogenase-like (NDH) complex is a large protein complex that reduces plastoquinone and pumps protons into the lumen generating protonmotive force. In plants, the complex consists of both nuclear and chloroplast-encoded subunits. Despite its perceived importance for stress tolerance and ATP generation, chloroplast-encoded NDH subunits have been lost numerous times during evolution in species occupying seemingly unrelated environmental niches. We have generated a phylogenetic tree that reveals independent losses in multiple phylogenetic lineages, and we use this tree as a reference to discuss possible evolutionary contexts that may have relaxed selective pressure for retention of ndh genes. While we are still yet unable to pinpoint a singular specific lifestyle that negates the need for NDH, we are able to rule out several long-standing explanations. In light of this, we discuss the biochemical changes that would be required for the chloroplast to dispense with NDH functionality with regards to known and proposed NDH-related reactions.
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10
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Structural insights into NDH-1 mediated cyclic electron transfer. Nat Commun 2020; 11:888. [PMID: 32060291 PMCID: PMC7021789 DOI: 10.1038/s41467-020-14732-z] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/21/2020] [Indexed: 02/08/2023] Open
Abstract
NDH-1 is a key component of the cyclic-electron-transfer around photosystem I (PSI CET) pathway, an important antioxidant mechanism for efficient photosynthesis. Here, we report a 3.2-Å-resolution cryo-EM structure of the ferredoxin (Fd)-NDH-1L complex from the cyanobacterium Thermosynechococcus elongatus. The structure reveals three β-carotene and fifteen lipid molecules in the membrane arm of NDH-1L. Regulatory oxygenic photosynthesis-specific (OPS) subunits NdhV, NdhS and NdhO are close to the Fd-binding site whilst NdhL is adjacent to the plastoquinone (PQ) cavity, and they play different roles in PSI CET under high-light stress. NdhV assists in the binding of Fd to NDH-1L and accelerates PSI CET in response to short-term high-light exposure. In contrast, prolonged high-light irradiation switches on the expression and assembly of the NDH-1MS complex, which likely contains no NdhO to further accelerate PSI CET and reduce ROS production. We propose that this hierarchical mechanism is necessary for the survival of cyanobacteria in an aerobic environment. NDH-1 is a key component of the cyclic-electron-transfer around photosystem I pathway, an antioxidant mechanism for efficient photosynthesis. Here, authors report a cryo-EM structure of the ferredoxin (Fd)-NDH-1L complex from the cyanobacterium Thermosynechococcus elongatus.
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11
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Pan X, Cao D, Xie F, Xu F, Su X, Mi H, Zhang X, Li M. Structural basis for electron transport mechanism of complex I-like photosynthetic NAD(P)H dehydrogenase. Nat Commun 2020; 11:610. [PMID: 32001694 PMCID: PMC6992706 DOI: 10.1038/s41467-020-14456-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 01/09/2020] [Indexed: 11/23/2022] Open
Abstract
NAD(P)H dehydrogenase-like (NDH) complex NDH-1L of cyanobacteria plays a crucial role in cyclic electron flow (CEF) around photosystem I and respiration processes. NDH-1L couples the electron transport from ferredoxin (Fd) to plastoquinone (PQ) and proton pumping from cytoplasm to the lumen that drives the ATP production. NDH-1L-dependent CEF increases the ATP/NADPH ratio, and is therefore pivotal for oxygenic phototrophs to function under stress. Here we report two structures of NDH-1L from Thermosynechococcus elongatus BP-1, in complex with one Fd and an endogenous PQ, respectively. Our structures represent the complete model of cyanobacterial NDH-1L, revealing the binding manner of NDH-1L with Fd and PQ, as well as the structural elements crucial for proper functioning of the NDH-1L complex. Together, our data provides deep insights into the electron transport from Fd to PQ, and its coupling with proton translocation in NDH-1L. NAD(P)H dehydrogenase-like complex NDH-1L couples the electron transport from ferredoxin (Fd) to plastoquinone (PQ) and proton pumping from cytoplasm to the lumen. Here authors report two structures of NDH-1L from Thermosynechococcus elongatus BP-1, in complex with one Fd and an endogenous PQ, respectively.
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Affiliation(s)
- Xiaowei Pan
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, PR China
| | - Duanfang Cao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, PR China
| | - Fen Xie
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, PR China.,University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Fang Xu
- University of Chinese Academy of Sciences, Beijing, 100049, PR China.,National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai, 200032, PR China
| | - Xiaodong Su
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, PR China
| | - Hualing Mi
- National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai, 200032, PR China.
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, PR China. .,University of Chinese Academy of Sciences, Beijing, 100049, PR China. .,Center for Biological Imaging, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, PR China.
| | - Mei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, PR China.
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12
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Ran Z, Zhao J, Tong G, Gao F, Wei L, Ma W. Ssl3451 is Important for Accumulation of NDH-1 Assembly Intermediates in the Cytoplasm of Synechocystis sp. Strain PCC 6803. PLANT & CELL PHYSIOLOGY 2019; 60:1374-1385. [PMID: 30847493 DOI: 10.1093/pcp/pcz045] [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: 06/07/2018] [Accepted: 02/25/2019] [Indexed: 06/09/2023]
Abstract
Two mutants sensitive to high light for growth and impaired in NDH-1 activity were isolated from a transposon-tagged library of Synechocystis sp. strain PCC 6803. Both mutants were tagged in the ssl3451 gene encoding a hypothetical protein, which shares a significant homology with the Arabidopsis (Arabidopsis thaliana) CHLORORESPIRATORY REDUCTION 42 (CRR42). In Arabidopsis, CRR42 associates only with an NDH-1 hydrophilic arm assembly intermediate (NAI) of about 400 kDa (NAI400), one of total three NAIs (NAI800, NAI500 and NAI400), and its deletion has little, if any, effect on accumulation of any NAIs in the stroma. In comparison, the ssl3451 product was localized mainly in the cytoplasm and associates with two NAIs of about 300 kDa (NAI300) and 130 kDa (NAI130). Deletion of Ssl3451 reduced the abundance of the NAI300 complex to levels no longer visible on gels and of the NAI130 complex to a low level, thereby impeding the assembly process of NDH-1 hydrophilic arm. Further, Ssl3451 interacts with another assembly factor Ssl3829 and they have a similar effect on accumulation of NAIs and NdhI maturation factor Slr1097 in the cytoplasm. We thus propose that Ssl3451 plays an important role in accumulation of the NAI300 and NAI130 complexes in the cytoplasm via its interacting protein Ssl3829.
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Affiliation(s)
- Zhaoxing Ran
- College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, China
| | - Jiaohong Zhao
- College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, China
| | - Guifang Tong
- College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, China
| | - Fudan Gao
- College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, China
| | - Lanzhen Wei
- College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, China
| | - Weimin Ma
- College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, China
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, 100 Guilin Road, Shanghai, China
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13
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Artier J, Holland SC, Miller NT, Zhang M, Burnap RL. Synthetic DNA system for structure-function studies of the high affinity CO2 uptake NDH-13 protein complex in cyanobacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2018; 1859:1108-1118. [DOI: 10.1016/j.bbabio.2018.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 11/26/2022]
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14
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Liran O, Shemesh E, Tchernov D. Investigation into the CO2 concentrating step rates within the carbon concentrating mechanism of Synechocystis sp. PCC6803 at various pH and light intensities reveal novel mechanistic properties. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.06.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Zhao J, Gao F, Fan DY, Chow WS, Ma W. NDH-1 Is Important for Photosystem I Function of Synechocystis sp. Strain PCC 6803 under Environmental Stress Conditions. FRONTIERS IN PLANT SCIENCE 2018; 8:2183. [PMID: 29387069 PMCID: PMC5776120 DOI: 10.3389/fpls.2017.02183] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 12/12/2017] [Indexed: 05/24/2023]
Abstract
Cyanobacterial NDH-1 interacts with photosystem I (PSI) to form an NDH-1-PSI supercomplex. Here, we observed that absence of NDH-1 had little, if any, effect on the functional fractions of PSI under growth conditions, but significantly reduced the functional fractions of PSI when cells of Synechocystis sp. strain PCC 6803 were moved to conditions of multiple stresses. The significant reduction in NDH-1-dependent functional fraction of PSI was initiated after PSII activity was impaired. This finding is consistent with our observation that the functional fraction of PSI under growth conditions was rapidly and significantly decreased with increasing concentrations of DCMU, which rapidly and significantly suppressed PSII activity by blocking the transfer of electrons from QA to QB in the PSII reaction center. Furthermore, absence of NDH-1 resulted in the PSI limitation at the functionality of PSI itself but not its donor-side and acceptor-side under conditions of multiple stresses. This was supported by the result of a significant destabilization of the PSI complex in the absence of NDH-1 but the presence of multiple stresses. Based on the above results, we propose that NDH-1 is important for PSI function of Synechocystis sp. strain PCC 6803 mainly via maintaining stabilization of PSI under conditions of environmental stresses.
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Affiliation(s)
- Jiaohong Zhao
- Department of Biology, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, China
| | - Fudan Gao
- Department of Biology, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, China
| | - Da-Yong Fan
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Wah Soon Chow
- Division of Plant Sciences, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Weimin Ma
- Department of Biology, College of Life and Environment Sciences, Shanghai Normal University, Shanghai, China
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16
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Kaplan A. On the cradle of CCM research: discovery, development, and challenges ahead. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:3785-3796. [PMID: 28520892 DOI: 10.1093/jxb/erx122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Herein, 40 years after its discovery, I briefly and critically survey the development of ideas that propelled research on CO2-concentrating mechanisms (CCMs; a term proposed by Dean Price) of phytoplankton, mainly focusing on cyanobacteria. This is not a comprehensive review on CCM research, but a personal view on the past developments and challenges that lie ahead.
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Affiliation(s)
- Aaron Kaplan
- Department of Plant and Environmental Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, 9190401, Israel
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17
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Klanchui A, Cheevadhanarak S, Prommeenate P, Meechai A. Exploring Components of the CO 2-Concentrating Mechanism in Alkaliphilic Cyanobacteria Through Genome-Based Analysis. Comput Struct Biotechnol J 2017; 15:340-350. [PMID: 28652895 PMCID: PMC5472144 DOI: 10.1016/j.csbj.2017.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 04/21/2017] [Accepted: 05/11/2017] [Indexed: 11/23/2022] Open
Abstract
In cyanobacteria, the CO2-concentrating mechanism (CCM) is a vital biological process that provides effective photosynthetic CO2 fixation by elevating the CO2 level near the active site of Rubisco. This process enables the adaptation of cyanobacteria to various habitats, particularly in CO2-limited environments. Although CCM of freshwater and marine cyanobacteria are well studied, there is limited information on the CCM of cyanobacteria living under alkaline environments. Here, we aimed to explore the molecular components of CCM in 12 alkaliphilic cyanobacteria through genome-based analysis. These cyanobacteria included 6 moderate alkaliphiles; Pleurocapsa sp. PCC 7327, Synechococcus spp., Cyanobacterium spp., Spirulina subsalsa PCC 9445, and 6 strong alkaliphiles (i.e. Arthrospira spp.). The results showed that both groups belong to β-cyanobacteria based on β-carboxysome shell proteins with form 1B of Rubisco. They also contained standard genes, ccmKLMNO cluster, which is essential for β-carboxysome formation. Most strains did not have the high-affinity Na+/HCO3- symporter SbtA and the medium-affinity ATP-dependent HCO3- transporter BCT1. Specifically, all strong alkaliphiles appeared to lack BCT1. Beside the transport systems, carboxysomal β-CA, CcaA, was absent in all alkaliphiles, except for three moderate alkaliphiles: Pleurocapsa sp. PCC 7327, Cyanobacteriumstranieri PCC 7202, and Spirulina subsalsa PCC 9445. Furthermore, comparative analysis of the CCM components among freshwater, marine, and alkaliphilic β-cyanobacteria revealed that the basic molecular components of the CCM in the alkaliphilic cyanobacteria seemed to share more degrees of similarity with freshwater than marine cyanobacteria. These findings provide a relationship between the CCM components of cyanobacteria and their habitats.
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Affiliation(s)
- Amornpan Klanchui
- Biological Engineering Program, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
| | - Supapon Cheevadhanarak
- Division of Biotechnology, School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand
| | - Peerada Prommeenate
- Biochemical Engineering and Pilot Plant Research and Development (BEC) Unit, National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency at King Mongkut's University of Technology Thonburi, Bangkok 10150, Thailand
| | - Asawin Meechai
- Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
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18
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Westermark S, Steuer R. Toward Multiscale Models of Cyanobacterial Growth: A Modular Approach. Front Bioeng Biotechnol 2016; 4:95. [PMID: 28083530 PMCID: PMC5183639 DOI: 10.3389/fbioe.2016.00095] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 12/09/2016] [Indexed: 11/29/2022] Open
Abstract
Oxygenic photosynthesis dominates global primary productivity ever since its evolution more than three billion years ago. While many aspects of phototrophic growth are well understood, it remains a considerable challenge to elucidate the manifold dependencies and interconnections between the diverse cellular processes that together facilitate the synthesis of new cells. Phototrophic growth involves the coordinated action of several layers of cellular functioning, ranging from the photosynthetic light reactions and the electron transport chain, to carbon-concentrating mechanisms and the assimilation of inorganic carbon. It requires the synthesis of new building blocks by cellular metabolism, protection against excessive light, as well as diurnal regulation by a circadian clock and the orchestration of gene expression and cell division. Computational modeling allows us to quantitatively describe these cellular functions and processes relevant for phototrophic growth. As yet, however, computational models are mostly confined to the inner workings of individual cellular processes, rather than describing the manifold interactions between them in the context of a living cell. Using cyanobacteria as model organisms, this contribution seeks to summarize existing computational models that are relevant to describe phototrophic growth and seeks to outline their interactions and dependencies. Our ultimate aim is to understand cellular functioning and growth as the outcome of a coordinated operation of diverse yet interconnected cellular processes.
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Affiliation(s)
- Stefanie Westermark
- Fachinstitut für Theoretische Biologie (ITB), Institut für Biologie, Humboldt-Universität zu Berlin , Berlin , Germany
| | - Ralf Steuer
- Fachinstitut für Theoretische Biologie (ITB), Institut für Biologie, Humboldt-Universität zu Berlin , Berlin , Germany
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19
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Holland SC, Artier J, Miller NT, Cano M, Yu J, Ghirardi ML, Burnap RL. Impacts of genetically engineered alterations in carbon sink pathways on photosynthetic performance. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.09.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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20
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Degli Esposti M, Martinez Romero E. A survey of the energy metabolism of nodulating symbionts reveals a new form of respiratory complex I. FEMS Microbiol Ecol 2016; 92:fiw084. [DOI: 10.1093/femsec/fiw084] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2016] [Indexed: 01/18/2023] Open
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21
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Degli Esposti M. Genome Analysis of Structure-Function Relationships in Respiratory Complex I, an Ancient Bioenergetic Enzyme. Genome Biol Evol 2015; 8:126-47. [PMID: 26615219 PMCID: PMC4758237 DOI: 10.1093/gbe/evv239] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Respiratory complex I (NADH:ubiquinone oxidoreductase) is a ubiquitous bioenergetic enzyme formed by over 40 subunits in eukaryotes and a minimum of 11 subunits in bacteria. Recently, crystal structures have greatly advanced our knowledge of complex I but have not clarified the details of its reaction with ubiquinone (Q). This reaction is essential for bioenergy production and takes place in a large cavity embedded within a conserved module that is homologous to the catalytic core of Ni-Fe hydrogenases. However, how a hydrogenase core has evolved into the protonmotive Q reductase module of complex I has remained unclear. This work has exploited the abundant genomic information that is currently available to deduce structure-function relationships in complex I that indicate the evolutionary steps of Q reactivity and its adaptation to natural Q substrates. The results provide answers to fundamental questions regarding various aspects of complex I reaction with Q and help re-defining the old concept that this reaction may involve two Q or inhibitor sites. The re-definition leads to a simplified classification of the plethora of complex I inhibitors while throwing a new light on the evolution of the enzyme function.
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Affiliation(s)
- Mauro Degli Esposti
- Italian Institute of Technology, Genova, Italy Center for Genomic Sciences, UNAM, Cuernavaca, Mexico
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22
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Burnap RL, Hagemann M, Kaplan A. Regulation of CO2 Concentrating Mechanism in Cyanobacteria. Life (Basel) 2015; 5:348-71. [PMID: 25636131 PMCID: PMC4390856 DOI: 10.3390/life5010348] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 01/15/2015] [Accepted: 01/21/2015] [Indexed: 12/31/2022] Open
Abstract
In this chapter, we mainly focus on the acclimation of cyanobacteria to the changing ambient CO2 and discuss mechanisms of inorganic carbon (Ci) uptake, photorespiration, and the regulation among the metabolic fluxes involved in photoautotrophic, photomixotrophic and heterotrophic growth. The structural components for several of the transport and uptake mechanisms are described and the progress towards elucidating their regulation is discussed in the context of studies, which have documented metabolomic changes in response to changes in Ci availability. Genes for several of the transport and uptake mechanisms are regulated by transcriptional regulators that are in the LysR-transcriptional regulator family and are known to act in concert with small molecule effectors, which appear to be well-known metabolites. Signals that trigger changes in gene expression and enzyme activity correspond to specific "regulatory metabolites" whose concentrations depend on the ambient Ci availability. Finally, emerging evidence for an additional layer of regulatory complexity involving small non-coding RNAs is discussed.
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Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Henry Bellmon Research Center, Oklahoma State University, Stillwater, OK 74078, USA.
| | - Martin Hagemann
- Institute Biosciences, Department Plant Physiology, University of Rostock, Albert-Einstein-Straße 3, Rostock D-18059, Germany.
| | - Aaron Kaplan
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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