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Utschig LM, Zaluzec NJ, Malavath T, Ponomarenko NS, Tiede DM. Solar water splitting Pt-nanoparticle photosystem I thylakoid systems: Catalyst identification, location and oligomeric structure. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - BIOENERGETICS 2023; 1864:148974. [PMID: 37001790 DOI: 10.1016/j.bbabio.2023.148974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/10/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023]
Abstract
Photosynthetic conversion of light energy into chemical energy occurs in sheet-like membrane-bound compartments called thylakoids and is mediated by large integral membrane protein-pigment complexes called reaction centers (RCs). Oxygenic photosynthesis of higher plants, cyanobacteria and algae requires the symbiotic linking of two RCs, photosystem II (PSII) and photosystem I (PSI), to split water and assimilate carbon dioxide. Worldwide there is a large research investment in developing RC-based hybrids that utilize the highly evolved solar energy conversion capabilities of RCs to power catalytic reactions for solar fuel generation. Of particular interest is the solar-powered production of H2, a clean and renewable energy source that can replace carbon-based fossil fuels and help provide for ever-increasing global energy demands. Recently, we developed thylakoid membrane hybrids with abiotic catalysts and demonstrated that photosynthetic Z-scheme electron flow from the light-driven water oxidation at PSII can drive H2 production from PSI. One of these hybrid systems was created by self-assembling Pt-nanoparticles (PtNPs) with the stromal subunits of PSI that extend beyond the membrane plane in both spinach and cyanobacterial thylakoids. Using PtNPs as site-specific probe molecules, we report the electron microscopic (EM) imaging of oligomeric structure, location and organization of PSI in thylakoid membranes and provide the first direct visualization of photosynthetic Z-scheme solar water-splitting biohybrids for clean H2 production.
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Jia A, Zheng Y, Chen H, Wang Q. Regulation and Functional Complexity of the Chlorophyll-Binding Protein IsiA. Front Microbiol 2021; 12:774107. [PMID: 34867913 PMCID: PMC8635728 DOI: 10.3389/fmicb.2021.774107] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
As the oldest known lineage of oxygen-releasing photosynthetic organisms, cyanobacteria play the key roles in helping shaping the ecology of Earth. Iron is an ideal transition metal for redox reactions in biological systems. Cyanobacteria frequently encounter iron deficiency due to the environmental oxidation of ferrous ions to ferric ions, which are highly insoluble at physiological pH. A series of responses, including architectural changes to the photosynthetic membranes, allow cyanobacteria to withstand this condition and maintain photosynthesis. Iron-stress-induced protein A (IsiA) is homologous to the cyanobacterial chlorophyll (Chl)-binding protein, photosystem II core antenna protein CP43. IsiA is the major Chl-containing protein in iron-starved cyanobacteria, binding up to 50% of the Chl in these cells, and this Chl can be released from IsiA for the reconstruction of photosystems during the recovery from iron limitation. The pigment–protein complex (CPVI-4) encoded by isiA was identified and found to be expressed under iron-deficient conditions nearly 30years ago. However, its precise function is unknown, partially due to its complex regulation; isiA expression is induced by various types of stresses and abnormal physiological states besides iron deficiency. Furthermore, IsiA forms a range of complexes that perform different functions. In this article, we describe progress in understanding the regulation and functions of IsiA based on laboratory research using model cyanobacteria.
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Affiliation(s)
- Anqi Jia
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Yanli Zheng
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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Zhao LS, Huokko T, Wilson S, Simpson DM, Wang Q, Ruban AV, Mullineaux CW, Zhang YZ, Liu LN. Structural variability, coordination and adaptation of a native photosynthetic machinery. NATURE PLANTS 2020; 6:869-882. [PMID: 32665651 DOI: 10.1038/s41477-020-0694-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 05/14/2020] [Indexed: 05/12/2023]
Abstract
Cyanobacterial thylakoid membranes represent the active sites for both photosynthetic and respiratory electron transport. We used high-resolution atomic force microscopy to visualize the native organization and interactions of photosynthetic complexes within the thylakoid membranes from the model cyanobacterium Synechococcus elongatus PCC 7942. The thylakoid membranes are heterogeneous and assemble photosynthetic complexes into functional domains to enhance their coordination and regulation. Under high light, the chlorophyll-binding proteins IsiA are strongly expressed and associate with Photosystem I (PSI), forming highly variable IsiA-PSI supercomplexes to increase the absorption cross-section of PSI. There are also tight interactions of PSI with Photosystem II (PSII), cytochrome b6f, ATP synthase and NAD(P)H dehydrogenase complexes. The organizational variability of these photosynthetic supercomplexes permits efficient linear and cyclic electron transport as well as bioenergetic regulation. Understanding the organizational landscape and environmental adaptation of cyanobacterial thylakoid membranes may help inform strategies for engineering efficient photosynthetic systems and photo-biofactories.
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Affiliation(s)
- Long-Sheng Zhao
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, China
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
- College of Marine Life Sciences and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Tuomas Huokko
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Sam Wilson
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Deborah M Simpson
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Conrad W Mullineaux
- School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Yu-Zhong Zhang
- State Key Laboratory of Microbial Technology, and Marine Biotechnology Research Center, Shandong University, Qingdao, China.
- College of Marine Life Sciences and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China.
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.
| | - Lu-Ning Liu
- Institute of Integrative Biology, University of Liverpool, Liverpool, UK.
- College of Marine Life Sciences and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China.
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Schoffman H, Keren N. Function of the IsiA pigment-protein complex in vivo. PHOTOSYNTHESIS RESEARCH 2019; 141:343-353. [PMID: 30929163 DOI: 10.1007/s11120-019-00638-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
The acclimation of cyanobacterial photosynthetic apparatus to iron deficiency is crucial for their performance under limiting conditions. In many cyanobacterial species, one of the major responses to iron deficiency is the induction of isiA. The function of the IsiA pigment-protein complex has been the subject of intensive research. In this study of the model Synechocystis sp. PCC 6803 strain, we probe the accumulation of the pigment-protein complex and its effects on in vivo photosynthetic performance. We provide evidence that in this organism the dominant factor controlling IsiA accumulation is the intracellular iron concentration and not photo-oxidative stress or redox poise. These findings support the use of IsiA as a tool for assessing iron bioavailability in environmental studies. We also present evidence demonstrating that the IsiA pigment-protein complex exerts only small effects on the performance of the reaction centers. We propose that its major function is as a storage depot able to hold up to 50% of the cellular chlorophyll content during transition into iron limitation. During recovery from iron limitation, chlorophyll is released from the complex and used for the reconstruction of photosystems. Therefore, the IsiA pigment-protein complex can play a critical role not only when cells transition into iron limitation, but also in supporting efficient recovery of the photosynthetic apparatus in the transition back out of the iron-limited state.
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Affiliation(s)
- Hanan Schoffman
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel
| | - Nir Keren
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, Israel.
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5
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Ma F, Zhang X, Zhu X, Li T, Zhan J, Chen H, He C, Wang Q. Dynamic Changes of IsiA-Containing Complexes during Long-Term Iron Deficiency in Synechocystis sp. PCC 6803. MOLECULAR PLANT 2017; 10:143-154. [PMID: 27777125 DOI: 10.1016/j.molp.2016.10.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/05/2016] [Accepted: 10/13/2016] [Indexed: 05/26/2023]
Abstract
Iron stress-induced protein A (IsiA), a major chlorophyll-binding protein in the thylakoid membrane, is significantly induced under iron deficiency conditions. Using immunoblot analysis and 77 K fluorescence spectroscopy combined with sucrose gradient fractionation, we monitored dynamic changes of IsiA-containing complexes in Synechocystis sp. PCC 6803 during exposure to long-term iron deficiency. Within 3 days of exposure to iron deficiency conditions, the initially induced free IsiA proteins preferentially conjugated to PS I trimer to form IsiA18-PS I trimers, which serve as light energy collectors for efficiently transmitting energy to PS I. With prolonged iron deficiency, IsiA proteins assembled either into IsiA aggregates or into two other types of IsiA-PS I supercomplexes, namely IsiA-PS I high fluorescence supercomplex (IHFS) and IsiA-PS I low fluorescence supercomplex (ILFS). Further analysis revealed a role for IsiA as an energy dissipater in the IHFS and as an energy collector in the ILFS. The trimeric structure of PS I mediated by PsaL was found to be indispensable for the formation of IHFS/ILFS. Dynamic changes in IsiA-containing complexes in cyanobacteria during long-term iron deficiency may represent an adaptation to iron limitation stress for flexible light energy distribution, which balances electron transfer between PS I and PS II, thus minimizing photooxidative damage.
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Affiliation(s)
- Fei Ma
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Xin Zhang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Xi Zhu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Tianpei Li
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing 100039, China
| | - Jiao Zhan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Hui Chen
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Chenliu He
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Qiang Wang
- Key Laboratory of Algal Biology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan, Hubei 430072, China.
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Sun J, Golbeck JH. The Presence of the IsiA-PSI Supercomplex Leads to Enhanced Photosystem I Electron Throughput in Iron-Starved Cells of Synechococcus sp. PCC 7002. J Phys Chem B 2015; 119:13549-59. [DOI: 10.1021/acs.jpcb.5b02176] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Junlei Sun
- Department of Biochemistry and Molecular Biology and ‡Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 United States
| | - John H. Golbeck
- Department of Biochemistry and Molecular Biology and ‡Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 United States
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7
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Salomon E, Keren N. Acclimation to environmentally relevant Mn concentrations rescues a cyanobacterium from the detrimental effects of iron limitation. Environ Microbiol 2015; 17:2090-8. [DOI: 10.1111/1462-2920.12826] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/13/2015] [Accepted: 02/22/2015] [Indexed: 11/26/2022]
Affiliation(s)
- Eitan Salomon
- Department of Plant and Environmental Sciences; The Alexander Silberman Institute of Life Sciences; The Hebrew University of Jerusalem; Jerusalem Israel
| | - Nir Keren
- Department of Plant and Environmental Sciences; The Alexander Silberman Institute of Life Sciences; The Hebrew University of Jerusalem; Jerusalem Israel
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8
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Cheng D, He Q. PfsR is a key regulator of iron homeostasis in Synechocystis PCC 6803. PLoS One 2014; 9:e101743. [PMID: 25010795 PMCID: PMC4092027 DOI: 10.1371/journal.pone.0101743] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 06/10/2014] [Indexed: 02/04/2023] Open
Abstract
Iron is an essential cofactor in numerous cellular processes. The iron deficiency in the oceans affects the primary productivity of phytoplankton including cyanobacteria. In this study, we examined the function of PfsR, a TetR family transcriptional regulator, in iron homeostasis of the cyanobacterium Synechocystis PCC 6803. Compared with the wild type, the pfsR deletion mutant displayed stronger tolerance to iron limitation and accumulated significantly more chlorophyll a, carotenoid, and phycocyanin under iron-limiting conditions. The mutant also maintained more photosystem I and photosystem II complexes than the wild type after iron deprivation. In addition, the activities of photosystem I and photosystem II were much higher in pfsR deletion mutant than in wild-type cells under iron-limiting conditions. The transcripts of pfsR were enhanced by iron limitation and inactivation of the gene affected pronouncedly expression of fut genes (encoding a ferric iron transporter), feoB (encoding a ferrous iron transporter), bfr genes (encoding bacterioferritins), ho genes (encoding heme oxygenases), isiA (encoding a chlorophyll-binding protein), and furA (encoding a ferric uptake regulator). The iron quota in pfsR deletion mutant cells was higher than in wild-type cells both before and after exposure to iron limitation. Electrophoretic mobility shift assays showed that PfsR bound to its own promoter and thereby auto-regulated its own expression. These data suggest that PfsR is a critical regulator of iron homeostasis.
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Affiliation(s)
- Dan Cheng
- Department of Applied Science, University of Arkansas at Little Rock, Little Rock, Arkansas, United States of America
| | - Qingfang He
- Department of Applied Science, University of Arkansas at Little Rock, Little Rock, Arkansas, United States of America
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9
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Fraser JM, Tulk SE, Jeans JA, Campbell DA, Bibby TS, Cockshutt AM. Photophysiological and photosynthetic complex changes during iron starvation in Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942. PLoS One 2013; 8:e59861. [PMID: 23527279 PMCID: PMC3602374 DOI: 10.1371/journal.pone.0059861] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 02/19/2013] [Indexed: 12/13/2022] Open
Abstract
Iron is an essential component in many protein complexes involved in photosynthesis, but environmental iron availability is often low as oxidized forms of iron are insoluble in water. To adjust to low environmental iron levels, cyanobacteria undergo numerous changes to balance their iron budget and mitigate the physiological effects of iron depletion. We investigated changes in key protein abundances and photophysiological parameters in the model cyanobacteria Synechococcus PCC 7942 and Synechocystis PCC 6803 over a 120 hour time course of iron deprivation. The iron stress induced protein (IsiA) accumulated to high levels within 48 h of the onset of iron deprivation, reaching a molar ratio of ∼42 IsiA : Photosystem I in Synechococcus PCC 7942 and ∼12 IsiA : Photosystem I in Synechocystis PCC 6803. Concomitantly the iron-rich complexes Cytochrome b6f and Photosystem I declined in abundance, leading to a decrease in the Photosystem I : Photosystem II ratio. Chlorophyll fluorescence analyses showed a drop in electron transport per Photosystem II in Synechococcus, but not in Synechocystis after iron depletion. We found no evidence that the accumulated IsiA contributes to light capture by Photosystem II complexes.
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Affiliation(s)
- Jared M Fraser
- Department of Chemistry & Biochemistry, Mount Allison University, Sackville, New Brunswick, Canada
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10
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Ryan-Keogh TJ, Macey AI, Cockshutt AM, Moore CM, Bibby TS. THE CYANOBACTERIAL CHLOROPHYLL-BINDING-PROTEIN ISIA ACTS TO INCREASE THE IN VIVO EFFECTIVE ABSORPTION CROSS-SECTION OF PSI UNDER IRON LIMITATION(1). JOURNAL OF PHYCOLOGY 2012; 48:145-54. [PMID: 27009659 DOI: 10.1111/j.1529-8817.2011.01092.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Iron availability limits primary production in >30% of the world's oceans; hence phytoplankton have developed acclimation strategies. In particular, cyanobacteria express IsiA (iron-stress-induced) under iron stress, which can become the most abundant chl-binding protein in the cell. Within iron-limited oceanic regions with significant cyanobacterial biomass, IsiA may represent a significant fraction of the total chl. We spectroscopically measured the effective cross-section of the photosynthetic reaction center PSI (σPSI ) in vivo and biochemically quantified the absolute abundance of PSI, PSII, and IsiA in the model cyanobacterium Synechocystis sp. PCC 6803. We demonstrate that accumulation of IsiA results in a ∼60% increase in σPSI , in agreement with the theoretical increase in cross-section based on the structure of the biochemically isolated IsiA-PSI supercomplex from cyanobacteria. Deriving a chl budget, we suggest that IsiA plays a primary role as a light-harvesting antenna for PSI. On progressive iron-stress in culture, IsiA continues to accumulate without a concomitant increase in σPSI , suggesting that there may be a secondary role for IsiA. In natural populations, the potential physiological significance of the uncoupled pool of IsiA remains to be established. However, the functional role as a PSI antenna suggests that a large fraction of IsiA-bound chl is directly involved in photosynthetic electron transport.
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Affiliation(s)
- Thomas J Ryan-Keogh
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UKDepartment of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G7, CanadaSchool of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK
| | - Anna I Macey
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UKDepartment of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G7, CanadaSchool of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK
| | - Amanda M Cockshutt
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UKDepartment of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G7, CanadaSchool of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK
| | - C Mark Moore
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UKDepartment of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G7, CanadaSchool of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK
| | - Thomas S Bibby
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UKDepartment of Chemistry and Biochemistry, Mount Allison University, Sackville, NB E4L 1G7, CanadaSchool of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, European Way, Southampton, SO14 3ZH, UK
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Feng X, Neupane B, Acharya K, Zazubovich V, Picorel R, Seibert M, Jankowiak R. Spectroscopic Study of the CP43′ Complex and the PSI–CP43′ Supercomplex of the Cyanobacterium Synechocystis PCC 6803. J Phys Chem B 2011; 115:13339-49. [DOI: 10.1021/jp206054b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ximao Feng
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Bhanu Neupane
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Khem Acharya
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Valter Zazubovich
- Department of Physics, Concordia University, Montreal, Quebec, Canada
| | - Rafael Picorel
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
- Estación Experimental de Aula Dei (CSIC), Zaragoza, Spain
| | - Michael Seibert
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
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12
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Zhang Y, Chen M, Church WB, Lau KW, Larkum AWD, Jermiin LS. The molecular structure of the IsiA–Photosystem I supercomplex, modelled from high-resolution, crystal structures of Photosystem I and the CP43 protein. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:457-65. [PMID: 20064486 DOI: 10.1016/j.bbabio.2010.01.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 12/31/2009] [Accepted: 01/05/2010] [Indexed: 11/30/2022]
Affiliation(s)
- Yinan Zhang
- School of Biological Sciences, University of Sydney, Sydney, NSW, Australia
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13
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Herbstová M, Litvín R, Gardian Z, Komenda J, Vácha F. Localization of Pcb antenna complexes in the photosynthetic prokaryote Prochlorothrix hollandica. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:89-97. [DOI: 10.1016/j.bbabio.2009.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 09/01/2009] [Accepted: 09/08/2009] [Indexed: 11/26/2022]
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14
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Singh AK, Sherman LA. Reflections on the function of IsiA, a cyanobacterial stress-inducible, Chl-binding protein. PHOTOSYNTHESIS RESEARCH 2007; 93:17-25. [PMID: 17375369 DOI: 10.1007/s11120-007-9151-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Accepted: 02/19/2007] [Indexed: 05/14/2023]
Abstract
The isiA gene encodes a protein that is similar to the Photosystem II chlorophyll-binding protein CP43, but lacks the entire large lumenal loop of over 100 amino acids. What is the function of this IsiA protein? Research on IsiA has traveled a long and interesting path since it was first discovered by its large accumulation during growth under iron-limited conditions. What appeared to be a simple on-off switch for isiA based on iron concentration has developed into a much richer and more intriguing set of possibilities that involve its expression and function. We provide an overview of isiA transcriptional regulation by many environmental factors and its proposed functions. We also describe the response to oxidative stress by cells that lack the IsiA protein. It is now clear that isiA expression can be de-repressed in the presence of normal iron levels and that the regulatory mechanisms can be linked to the inter-relationship between iron homeostasis and oxidative stress. The de facto transcriptional control of isiA expression has expanded to include regulation at both the transcriptional and post-transcriptional levels.
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Affiliation(s)
- Abhay K Singh
- Department of Biological Sciences, Purdue University, Hansen Hall, West Lafayette, IN 47907, USA
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15
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Rakhimberdieva MG, Vavilin DV, Vermaas WFJ, Elanskaya IV, Karapetyan NV. Phycobilin/chlorophyll excitation equilibration upon carotenoid-induced non-photochemical fluorescence quenching in phycobilisomes of the cyanobacterium Synechocystis sp. PCC 6803. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:757-65. [PMID: 17240350 DOI: 10.1016/j.bbabio.2006.12.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2006] [Revised: 11/24/2006] [Accepted: 12/14/2006] [Indexed: 11/26/2022]
Abstract
To determine the mechanism of carotenoid-sensitized non-photochemical quenching in cyanobacteria, the kinetics of blue-light-induced quenching and fluorescence spectra were studied in the wild type and mutants of Synechocystis sp. PCC 6803 grown with or without iron. The blue-light-induced quenching was observed in the wild type as well as in mutants lacking PS II or IsiA confirming that neither IsiA nor PS II is required for carotenoid-triggered fluorescence quenching. Both fluorescence at 660 nm (originating from phycobilisomes) and at 681 nm (which, upon 440 nm excitation originates mostly from chlorophyll) was quenched. However, no blue-light-induced changes in the fluorescence yield were observed in the apcE(-) mutant that lacks phycobilisome attachment. The results are interpreted to indicate that interaction of the Slr1963-associated carotenoid with--presumably--allophycocyanin in the phycobilisome core is responsible for non-photochemical energy quenching, and that excitations on chlorophyll in the thylakoid equilibrate sufficiently with excitations on allophycocyanin in wild type to contribute to quenching of chlorophyll fluorescence.
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16
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Ivanov AG, Krol M, Sveshnikov D, Selstam E, Sandström S, Koochek M, Park YI, Vasil'ev S, Bruce D, Oquist G, Huner NPA. Iron deficiency in cyanobacteria causes monomerization of photosystem I trimers and reduces the capacity for state transitions and the effective absorption cross section of photosystem I in vivo. PLANT PHYSIOLOGY 2006; 141:1436-45. [PMID: 16798943 PMCID: PMC1533926 DOI: 10.1104/pp.106.082339] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The induction of the isiA (CP43') protein in iron-stressed cyanobacteria is accompanied by the formation of a ring of 18 CP43' proteins around the photosystem I (PSI) trimer and is thought to increase the absorption cross section of PSI within the CP43'-PSI supercomplex. In contrast to these in vitro studies, our in vivo measurements failed to demonstrate any increase of the PSI absorption cross section in two strains (Synechococcus sp. PCC 7942 and Synechocystis sp. PCC 6803) of iron-stressed cells. We report that iron-stressed cells exhibited a reduced capacity for state transitions and limited dark reduction of the plastoquinone pool, which accounts for the increase in PSII-related 685 nm chlorophyll fluorescence under iron deficiency. This was accompanied by lower abundance of the NADP-dehydrogenase complex and the PSI-associated subunit PsaL, as well as a reduced amount of phosphatidylglycerol. Nondenaturating polyacrylamide gel electrophoresis separation of the chlorophyll-protein complexes indicated that the monomeric form of PSI is favored over the trimeric form of PSI under iron stress. Thus, we demonstrate that the induction of CP43' does not increase the PSI functional absorption cross section of whole cells in vivo, but rather, induces monomerization of PSI trimers and reduces the capacity for state transitions. We discuss the role of CP43' as an effective energy quencher to photoprotect PSII and PSI under unfavorable environmental conditions in cyanobacteria in vivo.
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Affiliation(s)
- Alexander G Ivanov
- Department of Biology and The Biotron, University of Western Ontario, London, Ontario, Canada N6A 5B7
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Melkozernov AN, Barber J, Blankenship RE. Light Harvesting in Photosystem I Supercomplexes,. Biochemistry 2005; 45:331-45. [PMID: 16401064 DOI: 10.1021/bi051932o] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In photosynthetic membranes of cyanobacteria, algae, and higher plants, photosystem I (PSI) mediates light-driven transmembrane electron transfer from plastocyanin or cytochrome c6 to the ferredoxin-NADP complex. The oxidoreductase function of PSI is sensitized by a reversible photooxidation of primary electron donor P700, which launches a multistep electron transfer via a series of redox cofactors of the reaction center (RC). The excitation energy for the functioning of the primary electron donor in the RC is delivered via the chlorophyll core antenna in the complex with peripheral light-harvesting antennas. Supermolecular complexes of the PSI acquire remarkably different structural forms of the peripheral light-harvesting antenna complexes, including distinct pigment types and organizational principles. The PSI core antenna, being the main functional unit of the supercomplexes, provides an increased functional connectivity in the chlorophyll antenna network due to dense pigment packing resulting in a fast spread of the excitation among the neighbors. Functional connectivity within the network as well as the spectral overlap of antenna pigments allows equilibration of the excitation energy in the depth of the whole membrane within picoseconds and loss-free delivery of the excitation to primary donor P700 within 20-40 ps. Low-light-adapted cyanobacteria under iron-deficiency conditions extend this capacity via assembly of efficiently energy coupled rings of CP43-like complexes around the PSI trimers. In green algae and higher plants, less efficient energy coupling in the eukaryotic PSI-LHCI supercomplexes is probably a result of the structural adaptation of the Chl a/b binding LHCI peripheral antenna that not only extends the absorption cross section of the PSI core but participates in regulation of excitation flows between the two photosystems as well as in photoprotection.
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Affiliation(s)
- Alexander N Melkozernov
- Department of Chemistry and Biochemistry and Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, USA.
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Chen M, Bibby TS. Photosynthetic apparatus of antenna-reaction centres supercomplexes in oxyphotobacteria: insight through significance of Pcb/IsiA proteins. PHOTOSYNTHESIS RESEARCH 2005; 86:165-73. [PMID: 16172936 DOI: 10.1007/s11120-005-1330-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2004] [Accepted: 01/27/2005] [Indexed: 05/04/2023]
Abstract
In this Review we give an overview of the structure and function of the membrane-bound photosynthetic antenna reaction centre complexes present in oxyphotobacteria. We summarise how variations in the organisation of these complexes have enabled oxyphotobacteria to exploit different ecological niches and discuss the evolutionary relationships of the IsiA/Pcb family of pigment-binding proteins.
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Affiliation(s)
- Min Chen
- School of Biological Sciences, University of Sydney, NSW 2006, Australia. minchen@bio. usyd.edu.au
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Kouril R, Yeremenko N, D'Haene S, Oostergetel GT, Matthijs HCP, Dekker JP, Boekema EJ. Supercomplexes of IsiA and photosystem I in a mutant lacking subunit PsaL. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1706:262-6. [PMID: 15694354 DOI: 10.1016/j.bbabio.2004.11.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2004] [Revised: 11/22/2004] [Accepted: 11/22/2004] [Indexed: 11/30/2022]
Abstract
The cyanobacterium Synechocystis PCC 6803 grown under short-term iron-deficient conditions assembles a supercomplex consisting of a trimeric Photosystem I (PSI) complex encircled by a ring of 18 IsiA complexes. Furthermore, it has been shown that single or double rings of IsiA with up to 35 copies in total can surround monomeric PSI. Here we present an analysis by electron microscopy and image analysis of the various PSI-IsiA supercomplexes from a Synechocystis PCC 6803 mutant lacking the PsaL subunit after short- and long-term iron-deficient growth. In the absence of PsaL, the tendency to form complexes with IsiA is still strong, but the average number of complete rings is lower than in the wild type. The majority of IsiA copies binds into partial double rings at the side of PsaF/J subunits rather than in complete single or double rings, which also cover the PsaL side of the PSI monomer. This indicates that PsaL facilitates the formation of IsiA rings around PSI monomers but is not an obligatory structural component in the formation of PSI-IsiA complexes.
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Affiliation(s)
- Roman Kouril
- Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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Kouril R, Arteni AA, Lax J, Yeremenko N, D'Haene S, Rögner M, Matthijs HCP, Dekker JP, Boekema EJ. Structure and functional role of supercomplexes of IsiA and Photosystem I in cyanobacterial photosynthesis. FEBS Lett 2005; 579:3253-7. [PMID: 15943969 DOI: 10.1016/j.febslet.2005.03.051] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2005] [Indexed: 10/25/2022]
Abstract
Cyanobacteria express large quantities of the iron stress-inducible protein IsiA under iron deficiency. IsiA can assemble into numerous types of single or double rings surrounding Photosystem I. These supercomplexes are functional in light-harvesting, empty IsiA rings are effective energy dissipaters. Electron microscopy studies of these supercomplexes show that Photosystem I trimers bind 18 IsiA copies in a single ring, whereas monomers may bind up to 35 copies in two rings. Work on mutants indicates that the PsaF/J and PsaL subunits facilitate the formation of closed rings around Photosystem I monomers but are not obligatory components in the formation of Photosystem I-IsiA supercomplexes.
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Affiliation(s)
- Roman Kouril
- Department of Biophysical Chemistry, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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