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Arshad F, Eaton-Rye JJ. Indirect interactions involving the PsbM or PsbT subunits and the PsbO, PsbU and PsbV proteins stabilize assembly and activity of Photosystem II in Synechocystis sp. PCC 6803. PHOTOSYNTHESIS RESEARCH 2024; 160:61-75. [PMID: 38488942 PMCID: PMC11108944 DOI: 10.1007/s11120-024-01091-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 03/05/2024] [Indexed: 03/17/2024]
Abstract
The low-molecular-weight PsbM and PsbT proteins of Photosystem II (PS II) are both located at the monomer-monomer interface of the mature PS II dimer. Since the extrinsic proteins are associated with the final step of assembly of an active PS II monomer and, in the case of PsbO, are known to impact the stability of the PS II dimer, we have investigated the potential cooperativity between the PsbM and PsbT subunits and the PsbO, PsbU and PsbV extrinsic proteins. Blue-native polyacrylamide electrophoresis and western blotting detected stable PS II monomers in the ∆PsbM:∆PsbO and ∆PsbT:∆PsbO mutants that retained sufficient oxygen-evolving activity to support reduced photoautotrophic growth. In contrast, the ∆PsbM:∆PsbU and ∆PsbT:∆PsbU mutants assembled dimeric PS II at levels comparable to wild type and supported photoautotrophic growth at rates similar to those obtained with the corresponding ∆PsbM and ∆PsbT cells. Removal of PsbV was more detrimental than removal of PsbO. Only limited levels of dimeric PS II were observed in the ∆PsbM:∆PsbV mutant and the overall reduced level of assembled PS II in this mutant resulted in diminished rates of photoautotrophic growth and PS II activity below those obtained in the ∆PsbM:∆PsbO and ∆PsbT:∆PsbO strains. In addition, the ∆PsbT:∆PsbV mutant did not assemble active PS II centers although inactive monomers could be detected. The inability of the ∆PsbT:∆PsbV mutant to grow photoautotrophically, or to evolve oxygen, suggested a stable oxygen-evolving complex could not assemble in this mutant.
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Affiliation(s)
- Faiza Arshad
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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2
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Liang H, Chen H, Liu X, Wang Z, Li P, Lu S. Heterologous Production in the Synechocystis Chassis Suggests the Biosynthetic Pathway of Astaxanthin in Cyanobacteria. Antioxidants (Basel) 2023; 12:1826. [PMID: 37891905 PMCID: PMC10604110 DOI: 10.3390/antiox12101826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/24/2023] [Accepted: 10/01/2023] [Indexed: 10/29/2023] Open
Abstract
Astaxanthin is a carotenoid species with the highest antioxidant capability. Its natural resource is very rare. The biosynthesis of astaxanthin from β-carotene includes a hydroxylation step and a ketolation step, for which the corresponding enzymes have been characterized in a few species. However, the sequence of these two reactions is unclear, and may vary with different organisms. In this study, we aimed to elucidate this sequence in Synechocystis, which is an ideal cyanobacterial synthetic biology chassis. We first silenced the endogenous carotene oxygenase gene SyneCrtO to avoid its possible interference in the carotenoid metabolic network. We then introduced the β-carotene ketolase gene from Haematococcus pluvialis (HpBKT) and the CrtZ-type carotene β-hydroxylase gene from Pantoea agglomerans (PaCrtZ) to this δCrtO strain. Our pigment analysis demonstrated that both the endogenous CrtR-type carotene hydroxylase SyneCrtR and HpBKT have the preference to use β-carotene as their substrate for hydroxylation and ketolation reactions to produce zeaxanthin and canthaxanthin, respectively. However, the endogenous SyneCrtR is not able to further catalyze the 3,3'-hydroxylation of canthaxanthin to generate astaxanthin. From our results, a higher accumulation of canthaxanthin and a much lower level of astaxanthin, as confirmed using liquid chromatography-tandem mass spectrometry analysis, were detected in our transgenic BKT+/CrtZ+/δCrtO cells. Therefore, we proposed that the bottleneck for the heterologous production of astaxanthin in Synechocystis might exist at the hydroxylation step, which requires a comprehensive screening or genetic engineering for the corresponding carotene hydroxylase to enable the industrial production of astaxanthin.
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Affiliation(s)
- Hanyu Liang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
- Shenzhen Research Institute of Nanjing University, Shenzhen 518000, China
| | - Hongjuan Chen
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Xinya Liu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Zihan Wang
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Pengfu Li
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
- Shenzhen Research Institute of Nanjing University, Shenzhen 518000, China
| | - Shan Lu
- State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210023, China
- Shenzhen Research Institute of Nanjing University, Shenzhen 518000, China
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Sheridan KJ, Brown TJ, Eaton-Rye JJ, Summerfield TC. Expression of the far-red D1 protein or introduction of conserved far-red D1 residues into Synechocystis sp. PCC 6803 impairs Photosystem II. PHYSIOLOGIA PLANTARUM 2023; 175:e13997. [PMID: 37882270 DOI: 10.1111/ppl.13997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 10/27/2023]
Abstract
The wavelengths of light harvested in oxygenic photosynthesis are ~400-700 nm. Some cyanobacteria respond to far-red light exposure via a process called far-red light photoacclimation which enables absorption of light at wavelengths >700 nm and its use to support photosynthesis. Far-red-light-induced changes include up-regulation of alternative copies of multiple proteins of Photosystem II (PS II). This includes an alternative copy of the D1 protein, D1FR . Here, we show that D1FR introduced into Synechocystis sp. PCC 6803 (hereafter Synechocystis 6803) can be incorporated into PS II centres that evolve oxygen at low rates but cannot support photoautotrophic growth. Using mutagenesis to modify the psbA2 gene of Synechocystis 6803, we modified residues in helices A, B, and C to be characteristic of D1FR residues. Modification of the Synechocystis 6803 helix A to resemble the D1FR helix A, with modifications in the region of the bound ß-carotene (CarD1 ) and the accessory chlorophyll, ChlZD1 , produced a strain with a similar phenotype to the D1FR strain. In contrast, the D1FR changes in helices B and C had minor impacts on photoautotrophy but impacted the function of PS II, possibly through a change in the equilibrium for electron sharing between the primary and secondary plastoquinone electron acceptors QA and QB in favour of QA - . The addition of combinations of residue changes in helix C indicates compensating effects may occur and highlight the need to experimentally determine the impact of multiple residue changes.
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Affiliation(s)
- Kevin J Sheridan
- Department of Botany, University of Otago, Dunedin, New Zealand
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Toby J Brown
- Department of Botany, University of Otago, Dunedin, New Zealand
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Bahavar N, Shokravi S. Acclimation response and ability of growth and photosynthesis of terrestrial cyanobacterium Cylindrospermum sp. strain FS 64 under combined environmental factors. Arch Microbiol 2022; 204:165. [PMID: 35122519 PMCID: PMC8818005 DOI: 10.1007/s00203-022-02772-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 11/28/2022]
Abstract
This investigation tested the hypothesis that the native cyanobacteria can acclimatize and grow under the combination of environmental factors and/or how does their process change with the age of culture? Here, we tried to combine multiple factors to simulated what happens in natural ecosystems. We analyzed the physiological response of terrestrial cyanobacterium, Cylindrospermum sp. FS 64 under combination effect of different salinity (17, 80, and 160 mM) and alkaline pHs (9 and 11) at extremely limited carbon dioxide concentration (no aeration) up to 96 h. Our evidence showed that growth, biomass, photosystem II, and phycobilisome activity significantly increased under 80 mM salinity and pH 11. In addition, this combined condition led to a significant increase in maximum light-saturated photosynthesis activity and photosynthetic efficiency. While phycobilisomes and photosystem activity decreased by increasing salinity (160 mM) which caused decreased growth rates after 96 h. The single-cell study (CLMS microscopy) which illustrated the physiological state of the individual and active-cell confirmed the efficiency and effectiveness of both photosystems and phycobilisome under the combined effect of 80 mM salinity and pH 11.
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Affiliation(s)
- Nadia Bahavar
- Plant Physiology Laboratory, Bioscience Faculty, Universidad Autónoma de Barcelona, 08193, Bellaterra, Spain.
| | - Shadman Shokravi
- Department of Biology, Gorgan Branch, Islamic Azad University, Gorgan, Iran
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Choo P, Forsman JA, Hui L, Khaing EP, Summerfield TC, Eaton-Rye JJ. The PsbJ protein is required for photosystem II activity in centers lacking the PsbO and PsbV lumenal subunits. PHOTOSYNTHESIS RESEARCH 2022; 151:103-111. [PMID: 34273062 DOI: 10.1007/s11120-021-00862-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Photosystem II (PS II) of oxygenic photosynthesis is found in the thylakoid membranes of plastids and cyanobacteria. The mature PS II complex comprises a central core of four membrane proteins that bind the majority of the redox-active cofactors. In cyanobacteria the central core is surrounded by 13 low-molecular-weight (LMW) subunits which each consist of one or two transmembrane helices. Three additional hydrophilic subunits known as PsbO, PsbU and PsbV are found associated with hydrophilic loops belonging to the core proteins protruding into the thylakoid lumen. During biogenesis the majority of the LMW subunits are known to initially associate with individual pre-assembly complexes consisting of one or more of the core proteins; however, the point at which the PsbJ LMW subunit binds to PS II is not known. The majority of models for PS II biogenesis propose that the three extrinsic proteins and PsbJ bind in the final stages of PS II assembly. We have investigated the impact of creating the double mutants ∆PsbJ:∆PsbO, ∆PsbJ:∆PsbU and ∆PsbJ:∆PsbV to investigate potential cooperation between these subunits in the final stages of biogenesis. Our results indicate that PsbJ can bind to PS II in the absence of any one of the extrinsic proteins. However, unlike their respective single mutants, the ∆PsbJ:∆PsbO and ∆PsbJ:∆PsbV strains were not photoautotrophic and were unable to support oxygen evolution suggesting a functional oxygen-evolving complex could not assemble in these strains. In contrast, the PS II centers formed in the ∆PsbJ:∆PsbU strain were capable of photoautotrophic growth and could support oxygen evolution when whole-chain electron transport was supported by the addition of bicarbonate.
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Affiliation(s)
- Priscilla Choo
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Jack A Forsman
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- Department of Botany, University of Otago, Dunedin, New Zealand
| | - Liangliang Hui
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Ei Phyo Khaing
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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Morris JN, Kovács S, Vass I, Summerfield TC, Eaton-Rye JJ. Environmental pH and a Glu364 to Gln mutation in the chlorophyll-binding CP47 protein affect redox-active TyrD and charge recombination in Photosystem II. FEBS Lett 2018; 593:163-174. [PMID: 30485416 DOI: 10.1002/1873-3468.13307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/19/2018] [Accepted: 11/19/2018] [Indexed: 12/16/2022]
Abstract
In Photosystem II, loop E of the chlorophyll-binding CP47 protein is located near a redox-active tyrosine, YD , forming a symmetrical analog to loop E in CP43, which provides a ligand to the oxygen-evolving complex (OEC). A Glu364 to Gln substitution in CP47, near YD , does not affect growth in the cyanobacterium Synechocystis sp. PCC 6803; however, deletion of the extrinsic protein PsbV in this mutant leads to a strain displaying a pH-sensitive phenotype. Using thermoluminescence, chlorophyll fluorescence, and flash-induced oxygen evolution analyses, we demonstrate that Glu364 influences the stability of YD and the redox state of the OEC, and highlight the effects of external pH on photosynthetic electron transfer in intact cyanobacterial cells.
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Affiliation(s)
- Jaz N Morris
- Department of Botany, University of Otago, Dunedin, New Zealand.,Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Sándor Kovács
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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Eaton-Rye JJ, Sobotka R. Editorial: Assembly of the Photosystem II Membrane-Protein Complex of Oxygenic Photosynthesis. FRONTIERS IN PLANT SCIENCE 2017; 8:884. [PMID: 28603539 PMCID: PMC5445156 DOI: 10.3389/fpls.2017.00884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 05/11/2017] [Indexed: 05/08/2023]
Affiliation(s)
- Julian J. Eaton-Rye
- Department of Biochemistry, University of OtagoDunedin, New Zealand
- *Correspondence: Julian J. Eaton-Rye
| | - Roman Sobotka
- Laboratory of Photosynthesis, Center Algatech, Institute of Microbiology, Czech Academy of SciencesTřeboň, Czechia
- Faculty of Science, University of South BohemiaČeské Budějovice, Czechia
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Morris JN, Eaton-Rye JJ, Summerfield TC. Environmental pH and the Requirement for the Extrinsic Proteins of Photosystem II in the Function of Cyanobacterial Photosynthesis. FRONTIERS IN PLANT SCIENCE 2016; 7:1135. [PMID: 27555848 PMCID: PMC4977308 DOI: 10.3389/fpls.2016.01135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
In one of the final stages of cyanobacterial Photosystem II (PS II) assembly, binding of up to four extrinsic proteins to PS II stabilizes the oxygen-evolving complex (OEC). Growth of cyanobacterial mutants deficient in certain combinations of these thylakoid-lumen-associated polypeptides is sensitive to changes in environmental pH, despite the physical separation of the membrane-embedded PS II complex from the external environment. In this perspective we discuss the effect of environmental pH on OEC function and photoautotrophic growth in cyanobacteria with reference to pH-sensitive PS II mutants lacking extrinsic proteins. We consider the possibilities that, compared to pH 10.0, pH 7.5 increases susceptibility to PS II-generated reactive oxygen species (ROS) causing photoinhibition and reducing PS II assembly in some mutants, and that perturbations to channels in the lumenal regions of PS II might alter the accessibility of water to the active site as well as egress of oxygen and protons to the thylakoid lumen. Reduced levels of PS II in these mutants, and reduced OEC activity arising from the disruption of substrate/product channels, could reduce the trans-thylakoid pH gradient (ΔpH), leading to the impairment of photosynthesis. Growth of some PS II mutants at pH 7.5 can be rescued by elevating CO2 levels, suggesting that the pH-sensitive phenotype might primarily be an indirect result of back-pressure in the electron transport chain that results in heightened production of ROS by the impaired photosystem.
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Affiliation(s)
- Jaz N. Morris
- Department of Botany, University of OtagoDunedin, New Zealand
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9
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Crawford TS, Hanning KR, Chua JPS, Eaton-Rye JJ, Summerfield TC. Comparison of D1´- and D1-containing PS II reaction centre complexes under different environmental conditions in Synechocystis sp. PCC 6803. PLANT, CELL & ENVIRONMENT 2016; 39:1715-26. [PMID: 26991994 DOI: 10.1111/pce.12738] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 02/22/2016] [Accepted: 03/03/2016] [Indexed: 05/24/2023]
Abstract
In oxygenic photosynthesis, the D1 protein of Photosystem II is the primary target of photodamage and environmental stress can accelerate this process. The cyanobacterial response to stress includes transcriptional regulation of genes encoding D1, including low-oxygen-induction of psbA1 encoding the D1´ protein in Synechocystis sp. PCC 6803. The psbA1 gene is also transiently up-regulated in high light, and its deletion has been reported to increase ammonium-induced photoinhibition. Therefore we investigated the role of D1´-containing PS II centres under different environmental conditions. A strain containing only D1´-PS II centres under aerobic conditions exhibited increased sensitivity to ammonium chloride and high light compared to a D1-containing strain. Additionally a D1´-PS II strain was outperformed by a D1-PS II strain under normal conditions; however, a strain containing low-oxygen-induced D1´-PS II centres was more resilient under high light than an equivalent D1 strain. These D1´-containing centres had chlorophyll a fluorescence characteristics indicative of altered forward electron transport and back charge recombination with the donor side of PS II. Our results indicate D1´-PS II centres are important in the reconfiguration of thylakoid electron transport in response to high light and low oxygen.
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Affiliation(s)
- Tim S Crawford
- Department of Botany, University of Otago, Dunedin, 9054, New Zealand
- Department of Biochemistry, University of Otago, Dunedin, 9054, New Zealand
| | - Kyrin R Hanning
- Department of Botany, University of Otago, Dunedin, 9054, New Zealand
| | - Jocelyn P S Chua
- Department of Botany, University of Otago, Dunedin, 9054, New Zealand
| | - Julian J Eaton-Rye
- Department of Biochemistry, University of Otago, Dunedin, 9054, New Zealand
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Roose JL, Frankel LK, Mummadisetti MP, Bricker TM. The extrinsic proteins of photosystem II: update. PLANTA 2016; 243:889-908. [PMID: 26759350 DOI: 10.1007/s00425-015-2462-6] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 12/25/2015] [Indexed: 05/24/2023]
Abstract
Recent investigations have provided important new insights into the structures and functions of the extrinsic proteins of Photosystem II. This review is an update of the last major review on the extrinsic proteins of Photosystem II (Bricker et al., Biochemistry 31:4623-4628 2012). In this report, we will examine advances in our understanding of the structure and function of these components. These proteins include PsbO, which is uniformly present in all oxygenic organisms, the PsbU, PsbV, CyanoQ, and CyanoP proteins, found in the cyanobacteria, and the PsbP, PsbQ and PsbR proteins, found in the green plant lineage. These proteins serve to stabilize the Mn4CaO5 cluster and optimize oxygen evolution at physiological calcium and chloride concentrations. The mechanisms used to perform these functions, however, remain poorly understood. Recently, important new findings have significantly advanced our understanding of the structures, locations and functions of these important subunits. We will discuss the biochemical, structural and genetic studies that have been used to elucidate the roles played by these proteins within the photosystem and their locations within the photosynthetic complex. Additionally, we will examine open questions needing to be addressed to provide a coherent picture of the role of these components within the photosystem.
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Affiliation(s)
- Johnna L Roose
- Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Laurie K Frankel
- Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Manjula P Mummadisetti
- Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Terry M Bricker
- Division of Biochemistry and Molecular Biology, Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, 70803, USA.
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Crawford TS, Eaton-Rye JJ, Summerfield TC. Mutation of Gly195 of the ChlH Subunit of Mg-chelatase Reduces Chlorophyll and Further Disrupts PS II Assembly in a Ycf48-Deficient Strain of Synechocystis sp. PCC 6803. FRONTIERS IN PLANT SCIENCE 2016; 7:1060. [PMID: 27489555 PMCID: PMC4951491 DOI: 10.3389/fpls.2016.01060] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 07/06/2016] [Indexed: 05/09/2023]
Abstract
Biogenesis of the photosystems in oxygenic phototrophs requires co-translational insertion of chlorophyll a. The first committed step of chlorophyll a biosynthesis is the insertion of a Mg(2+) ion into the tetrapyrrole intermediate protoporphyrin IX, catalyzed by Mg-chelatase. We have identified a Synechocystis sp. PCC 6803 strain with a spontaneous mutation in chlH that results in a Gly195 to Glu substitution in a conserved region of the catalytic subunit of Mg-chelatase. Mutant strains containing the ChlH Gly195 to Glu mutation were generated using a two-step protocol that introduced the chlH gene into a putative neutral site in the chromosome prior to deletion of the native gene. The Gly195 to Glu mutation resulted in strains with decreased chlorophyll a. Deletion of the PS II assembly factor Ycf48 in a strain carrying the ChlH Gly195 to Glu mutation did not grow photoautotrophically. In addition, the ChlH-G195E:ΔYcf48 strain showed impaired PS II activity and decreased assembly of PS II centers in comparison to a ΔYcf48 strain. We suggest decreased chlorophyll in the ChlH-G195E mutant provides a background to screen for the role of assembly factors that are not essential under optimal growth conditions.
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Affiliation(s)
- Tim S. Crawford
- Department of Biochemistry, University of OtagoDunedin, New Zealand
- Department of Botany, University of OtagoDunedin, New Zealand
| | | | - Tina C. Summerfield
- Department of Botany, University of OtagoDunedin, New Zealand
- *Correspondence: Tina C. Summerfield,
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12
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Touloupakis E, Cicchi B, Benavides AMS, Torzillo G. Effect of high pH on growth of Synechocystis sp. PCC 6803 cultures and their contamination by golden algae (Poterioochromonas sp.). Appl Microbiol Biotechnol 2015; 100:1333-1341. [PMID: 26541331 PMCID: PMC4717179 DOI: 10.1007/s00253-015-7024-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/31/2015] [Accepted: 09/08/2015] [Indexed: 11/29/2022]
Abstract
Culturing cyanobacteria in a highly alkaline environment is a possible strategy for controlling contamination by other organisms. Synechocystis PCC 6803 cells were grown in continuous cultures to assess their growth performance at different pH values. Light conversion efficiency linearly decreased with the increase in pH and ranged between 12.5 % (PAR) at pH 7.5 (optimal) and decreased to 8.9 % at pH 11.0. Photosynthetic activity, assessed by measuring both chlorophyll fluorescence and photosynthesis rate, was not much affected going from pH 7.5 to 11.0, while productivity, growth yield, and biomass yield on light energy declined by 32, 28, and 26 % respectively at pH 11.0. Biochemical composition of the biomass did not change much within pH 7 and 10, while when grown at pH 11.0, carbohydrate content increased by 33 % while lipid content decreased by about the same amount. Protein content remained almost constant (average 65.8 % of dry weight). Cultures maintained at pH above 11.0 could grow free of contaminants (protozoa and other competing microalgae belonging to the species of Poterioochromonas).
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Affiliation(s)
- Eleftherios Touloupakis
- Istituto per lo Studio degli Ecosistemi, CNR, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Italy
| | - Bernardo Cicchi
- Istituto per lo Studio degli Ecosistemi, CNR, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Italy
| | - Ana Margarita Silva Benavides
- Escuela de Biología, Universidad de Costa Rica, San Pedro, San José, 2060, Costa Rica
- Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), Universidad de Costa Rica, San Pedro, San José, 2060, Costa Rica
| | - Giuseppe Torzillo
- Istituto per lo Studio degli Ecosistemi, CNR, Via Madonna del Piano 10, I-50019, Sesto Fiorentino, Italy.
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13
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Effects of light intensity and carbon dioxide on lipids and fatty acids produced by Synechocystis sp. PCC6803 during continuous flow. ALGAL RES 2015. [DOI: 10.1016/j.algal.2015.07.018] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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14
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Pigolev AV, Klimov VV. The green alga Chlamydomonas reinhardtii as a tool for in vivo study of site-directed mutations in PsbO protein of photosystem II. BIOCHEMISTRY (MOSCOW) 2015; 80:662-73. [DOI: 10.1134/s0006297915060036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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