1
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Ara AM, D'Haene S, van Grondelle R, Wahadoszamen M. Unveiling large charge transfer character of PSII in an iron-deficient cyanobacterial membrane: A Stark fluorescence spectroscopy study. PHOTOSYNTHESIS RESEARCH 2024; 160:77-86. [PMID: 38619701 DOI: 10.1007/s11120-024-01099-1] [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: 10/06/2023] [Accepted: 03/25/2024] [Indexed: 04/16/2024]
Abstract
In this work, we applied Stark fluorescence spectroscopy to an iron-stressed cyanobacterial membrane to reveal key insights about the electronic structures and excited state dynamics of the two important pigment-protein complexes, IsiA and PSII, both of which prevail simultaneously within the membrane during iron deficiency and whose fluorescence spectra are highly overlapped and hence often hardly resolved by conventional fluorescence spectroscopy. Thanks to the ability of Stark fluorescence spectroscopy, the fluorescence signatures of the two complexes could be plausibly recognized and disentangled. The systematic analysis of the SF spectra, carried out by employing standard Liptay formalism with a realistic spectral deconvolution protocol, revealed that the IsiA in an intact membrane retains almost identical excited state electronic structures and dynamics as compared to the isolated IsiA we reported in our earlier study. Moreover, the analysis uncovered that the excited state of the PSII subunit of the intact membrane possesses a significantly large CT character. The observed notably large magnitude of the excited state CT character may signify the supplementary role of PSII in regulative energy dissipation during iron deficiency.
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Affiliation(s)
- Anjue Mane Ara
- Department of Physics, Jagannath University, Dhaka, 1100, Bangladesh
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Sandrine D'Haene
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Md Wahadoszamen
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
- Department of Physics, University of Dhaka, Dhaka, 1000, Bangladesh.
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2
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Akhtar P, Jana S, Lambrev PH, Tan HS. Inhomogeneous energy transfer dynamics from iron-stress-induced protein A to photosystem I. FRONTIERS IN PLANT SCIENCE 2024; 15:1393886. [PMID: 38817933 PMCID: PMC11137255 DOI: 10.3389/fpls.2024.1393886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 04/30/2024] [Indexed: 06/01/2024]
Abstract
Cyanobacteria respond to iron limitation by producing the pigment-protein complex IsiA, forming rings associated with photosystem I (PSI). Initially considered a chlorophyll-storage protein, IsiA is known to act as an auxiliary light-harvesting antenna of PSI, increasing its absorption cross-section and reducing the need for iron-rich PSI core complexes. Spectroscopic studies have demonstrated efficient energy transfer from IsiA to PSI. Here we investigate the room-temperature excitation dynamics in isolated PSI-IsiA, PSI, IsiA monomer complexes and IsiA aggregates using two-dimensional electronic spectroscopy. Cross analyses of the data from these three samples allow us to resolve components of energy transfer between IsiA and PSI with lifetimes of 2-3 ps and around 20 ps. Structure-based Förster theory calculations predict a single major timescale of IsiA-PSI equilibration, that depends on multiple energy transfer routes between different IsiA subunits in the ring. Despite the experimentally observed lifetime heterogeneity, which is attributed to structural heterogeneity of the supercomplexes, IsiA is found to be a unique, highly efficient, membrane antenna complex in cyanobacteria.
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Affiliation(s)
- Parveen Akhtar
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Sanjib Jana
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore
| | - Petar H. Lambrev
- Institute of Plant Biology, HUN-REN Biological Research Centre, Szeged, Hungary
| | - Howe-Siang Tan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore
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3
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Akhtar P, Balog-Vig F, Kuntam S, Tóth SZ, Lambrev PH. Function of iron-stress-induced protein A in cyanobacterial cells with monomeric and trimeric photosystem I. PLANT PHYSIOLOGY 2024; 194:1397-1410. [PMID: 37850879 DOI: 10.1093/plphys/kiad562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/12/2023] [Accepted: 09/24/2023] [Indexed: 10/19/2023]
Abstract
The acclimation of cyanobacteria to iron deficiency is crucial for their survival in natural environments. In response to iron deficiency, many cyanobacterial species induce the production of a pigment-protein complex called iron-stress-induced protein A (IsiA). IsiA proteins associate with photosystem I (PSI) and can function as light-harvesting antennas or dissipate excess energy. They may also serve as chlorophyll storage during iron limitation. In this study, we examined the functional role of IsiA in cells of Synechocystis sp. PCC 6803 grown under iron limitation conditions by measuring the cellular IsiA content and its capability to transfer energy to PSI. We specifically tested the effect of the oligomeric state of PSI by comparing wild-type (WT) Synechocystis sp. PCC 6803 with mutants lacking specific subunits of PSI, namely PsaL/PsaI (PSI subunits XI/VIII) and PsaF/PsaJ (PSI subunits III/IX). Time-resolved fluorescence spectroscopy revealed that IsiA formed functional PSI3-IsiA18 supercomplexes, wherein IsiA effectively transfers energy to PSI on a timescale of 10 ps at room temperature-measured in isolated complexes and in vivo-confirming the primary role of IsiA as an accessory light-harvesting antenna to PSI. However, a notable fraction (40%) remained unconnected to PSI, supporting the notion of a dual functional role of IsiA. Cells with monomeric PSI under iron deficiency contained, on average, only 3 to 4 IsiA complexes bound to PSI. These results show that IsiA can transfer energy to trimeric and monomeric PSI but to varying degrees and that the acclimatory production of IsiA under iron stress is controlled by its ability to perform its light-harvesting function.
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Affiliation(s)
- Parveen Akhtar
- HUN-REN Biological Research Centre, Szeged, Institute of Plant Biology, Temesvári krt. 62, Szeged 6726, Hungary
| | - Fanny Balog-Vig
- HUN-REN Biological Research Centre, Szeged, Institute of Plant Biology, Temesvári krt. 62, Szeged 6726, Hungary
| | - Soujanya Kuntam
- HUN-REN Biological Research Centre, Szeged, Institute of Plant Biology, Temesvári krt. 62, Szeged 6726, Hungary
| | - Szilvia Z Tóth
- HUN-REN Biological Research Centre, Szeged, Institute of Plant Biology, Temesvári krt. 62, Szeged 6726, Hungary
| | - Petar H Lambrev
- HUN-REN Biological Research Centre, Szeged, Institute of Plant Biology, Temesvári krt. 62, Szeged 6726, Hungary
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4
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Harris D, Toporik H, Schlau-Cohen GS, Mazor Y. Energetic robustness to large scale structural fluctuations in a photosynthetic supercomplex. Nat Commun 2023; 14:4650. [PMID: 37532717 PMCID: PMC10397321 DOI: 10.1038/s41467-023-40146-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 07/14/2023] [Indexed: 08/04/2023] Open
Abstract
Photosynthetic organisms transport and convert solar energy with near-unity quantum efficiency using large protein supercomplexes held in flexible membranes. The individual proteins position chlorophylls to tight tolerances considered critical for fast and efficient energy transfer. The variability in protein organization within the supercomplexes, and how efficiency is maintained despite variability, had been unresolved. Here, we report on structural heterogeneity in the 2-MDa cyanobacterial PSI-IsiA photosynthetic supercomplex observed using Cryo-EM, revealing large-scale variances in the positions of IsiA relative to PSI. Single-molecule measurements found efficient IsiA-to-PSI energy transfer across all conformations, along with signatures of transiently decoupled IsiA. Structure based calculations showed that rapid IsiA-to-PSI energy transfer is always maintained, and even increases by three-fold in rare conformations via IsiA-specific chls. We postulate that antennae design mitigates structural fluctuations, providing a mechanism for robust energy transfer in the flexible membrane.
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Affiliation(s)
- Dvir Harris
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Hila Toporik
- Biodesign Institute, School of Molecular Sciences, Arizona State University, Tempe, AZ, 85801, USA
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA
- Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Gabriela S Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
| | - Yuval Mazor
- Biodesign Institute, School of Molecular Sciences, Arizona State University, Tempe, AZ, 85801, USA.
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA.
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5
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Navotnaya P, Sohoni S, Lloyd LT, Abdulhadi SM, Ting PC, Higgins JS, Engel GS. Annihilation of Excess Excitations along Phycocyanin Rods Precedes Downhill Flow to Allophycocyanin Cores in the Phycobilisome of Synechococcus elongatus PCC 7942. J Phys Chem B 2022; 126:23-29. [PMID: 34982932 PMCID: PMC8762654 DOI: 10.1021/acs.jpcb.1c06509] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Cyanobacterial phycobilisome
complexes absorb visible sunlight
and funnel photogenerated excitons to the photosystems where charge
separation occurs. In the phycobilisome complex of Synechococcus
elongatus PCC 7942, phycocyanin protein rods that absorb
bluer wavelengths are assembled on allophycocyanin cores that absorb
redder wavelengths. This arrangement creates a natural energy gradient
toward the reaction centers of the photosystems. Here, we employ broadband
pump–probe spectroscopy to observe the fate of excess excitations
in the phycobilisome complex of this organism. We show that excess
excitons are quenched through exciton–exciton annihilation
along the phycocyanin rods prior to transfer to the allophycocyanin
cores. Our observations are especially relevant in comparison to other
antenna proteins, where exciton annihilation primarily occurs in the
lowest-energy chlorophylls. The observed effect could play a limited
photoprotective role in physiological light fluences. The exciton
decay dynamics is faster in the intact phycobilisome than in isolated
C-phycocyanin trimers studied in earlier work, confirming that this
effect is an emergent property of the complex assembly. Using the
obtained annihilation data, we calculate exciton hopping times of
2.2–6.4 ps in the phycocyanin rods. This value agrees with
earlier FRET calculations of exciton hopping times along phycocyanin
hexamers by Sauer and Scheer.
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Affiliation(s)
- Polina Navotnaya
- Department of Chemistry, James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Siddhartha Sohoni
- Department of Chemistry, James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Lawson T Lloyd
- Department of Chemistry, James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Sami M Abdulhadi
- Department of Chemistry, James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Po-Chieh Ting
- Department of Chemistry, James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jacob S Higgins
- Department of Chemistry, James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Gregory S Engel
- Department of Chemistry, James Franck Institute and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
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6
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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: 13] [Impact Index Per Article: 4.3] [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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7
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Abstract
Oxygenic photosynthetic organisms have evolved a multitude of mechanisms for protection against high-light stress. IsiA, a chlorophyll a-binding cyanobacterial protein, serves as an accessory antenna complex for photosystem I. Intriguingly, IsiA can also function as an independent pigment protein complex in the thylakoid membrane and facilitate the dissipation of excess energy, providing photoprotection. The molecular basis of the IsiA-mediated excitation quenching mechanism remains poorly understood. In this study, we demonstrate that IsiA uses a novel cysteine-mediated process to quench excitation energy. The single cysteine in IsiA in the cyanobacterium Synechocystis sp. strain PCC 6803 was converted to a valine. Ultrafast fluorescence spectroscopic analysis showed that this single change abolishes the excitation energy quenching ability of IsiA, thus providing direct evidence of the crucial role of this cysteine residue in energy dissipation from excited chlorophylls. Under stress conditions, the mutant cells exhibited enhanced light sensitivity, indicating that the cysteine-mediated quenching process is critically important for photoprotection.
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8
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Schoffman H, Brown WM, Paltiel Y, Keren N, Gauger EM. Structure-based Hamiltonian model for IsiA uncovers a highly robust pigment-protein complex. J R Soc Interface 2020; 17:20200399. [PMID: 32842892 PMCID: PMC7482578 DOI: 10.1098/rsif.2020.0399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/04/2020] [Indexed: 11/12/2022] Open
Abstract
The iron stress-induced protein A (IsiA) is a source of interest and debate in biological research. The IsiA supercomplex, binding over 200 chlorophylls, assembles in multimeric rings around photosystem I (PSI). Recently, the IsiA-PSI structure from Synechocystis sp. PCC 6803 was resolved to 3.48 Å. Based on this structure, we created a model simulating a single excitation event in an IsiA monomer. This model enabled us to calculate the fluorescence and the localization of the excitation in the IsiA structure. To further examine this system, noise was introduced to the model in two forms-thermal and positional. Introducing noise highlights the functional differences in the system between cryogenic temperatures and biologically relevant temperatures. Our results show that the energetics of the IsiA pigment-protein complex are very robust at room temperature. Nevertheless, shifts in the position of specific chlorophylls lead to large changes in their optical and fluorescence properties. Based on these results, we discuss the implication of highly robust structures, with potential for serving different roles in a context-dependent manner, on our understanding of the function and evolution of photosynthetic processes.
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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, Jerusalem 91904, Israel
| | - William M. Brown
- SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Yossi Paltiel
- Applied Physics Department, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Nir Keren
- Department of Plant and Environmental Sciences, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Erik M. Gauger
- SUPA, Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
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9
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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: 14] [Impact Index Per Article: 2.8] [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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10
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Schorsch M, Kramer M, Goss T, Eisenhut M, Robinson N, Osman D, Wilde A, Sadaf S, Brückler H, Walder L, Scheibe R, Hase T, Hanke GT. A unique ferredoxin acts as a player in the low-iron response of photosynthetic organisms. Proc Natl Acad Sci U S A 2018; 115:E12111-E12120. [PMID: 30514818 PMCID: PMC6304933 DOI: 10.1073/pnas.1810379115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Iron chronically limits aquatic photosynthesis, especially in marine environments, and the correct perception and maintenance of iron homeostasis in photosynthetic bacteria, including cyanobacteria, is therefore of global significance. Multiple adaptive mechanisms, responsive promoters, and posttranscriptional regulators have been identified, which allow cyanobacteria to respond to changing iron concentrations. However, many factors remain unclear, in particular, how iron status is perceived within the cell. Here we describe a cyanobacterial ferredoxin (Fed2), with a unique C-terminal extension, that acts as a player in iron perception. Fed2 homologs are highly conserved in photosynthetic organisms from cyanobacteria to higher plants, and, although they belong to the plant type ferredoxin family of [2Fe-2S] photosynthetic electron carriers, they are not involved in photosynthetic electron transport. As deletion of fed2 appears lethal, we developed a C-terminal truncation system to attenuate protein function. Disturbed Fed2 function resulted in decreased chlorophyll accumulation, and this was exaggerated in iron-depleted medium, where different truncations led to either exaggerated or weaker responses to low iron. Despite this, iron concentrations remained the same, or were elevated in all truncation mutants. Further analysis established that, when Fed2 function was perturbed, the classical iron limitation marker IsiA failed to accumulate at transcript and protein levels. By contrast, abundance of IsiB, which shares an operon with isiA, was unaffected by loss of Fed2 function, pinpointing the site of Fed2 action in iron perception to the level of posttranscriptional regulation.
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Affiliation(s)
- Michael Schorsch
- School of Biological and Chemical Sciences, Queen Mary University of London, E1 4NS London, United Kingdom
| | - Manuela Kramer
- School of Biological and Chemical Sciences, Queen Mary University of London, E1 4NS London, United Kingdom
| | - Tatjana Goss
- Plant Biochemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Marion Eisenhut
- Plant Biochemistry, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Nigel Robinson
- Department of Biosciences, Durham University, DH1 3LE Durham, United Kingdom
| | - Deenah Osman
- Department of Biosciences, Durham University, DH1 3LE Durham, United Kingdom
| | - Annegret Wilde
- Institute of Biology III, University of Freiburg, 79104 Freiburg, Germany
| | - Shamaila Sadaf
- Institute of Chemistry of New Materials, University of Osnabrück, 49069 Osnabrück, Germany
| | - Hendrik Brückler
- Institute of Chemistry of New Materials, University of Osnabrück, 49069 Osnabrück, Germany
| | - Lorenz Walder
- Institute of Chemistry of New Materials, University of Osnabrück, 49069 Osnabrück, Germany
| | - Renate Scheibe
- Plant Physiology, University of Osnabrück, 49076 Osnabrück, Germany
| | - Toshiharu Hase
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Guy T Hanke
- School of Biological and Chemical Sciences, Queen Mary University of London, E1 4NS London, United Kingdom;
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11
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Schuurmans RM, Matthijs JCP, Hellingwerf KJ. Transition from exponential to linear photoautotrophic growth changes the physiology of Synechocystis sp. PCC 6803. PHOTOSYNTHESIS RESEARCH 2017; 132:69-82. [PMID: 28108865 PMCID: PMC5357262 DOI: 10.1007/s11120-016-0329-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 12/16/2016] [Indexed: 05/03/2023]
Abstract
Phototrophic microorganisms like cyanobacteria show growth curves in batch culture that differ from the corresponding growth curves of chemotrophic bacteria. Instead of the usual three phases, i.e., lag-, log-, and stationary phase, phototrophs display four distinct phases. The extra growth phase is a phase of linear, light-limited growth that follows the exponential phase and is often ignored as being different. Results of this study demonstrate marked growth phase-dependent alterations in the photophysiology of the cyanobacterium Synechocystis sp. PCC 6803 between cells harvested from the exponential and the linear growth phase. Notable differences are a gradual shift in the energy transfer of the light-harvesting phycobilisomes to the photosystems and a distinct change in the redox state of the plastoquinone pool. These differences will likely affect the result of physiological studies and the efficiency of product formation of Synechocystis in biotechnological applications. Our study also demonstrates that the length of the period of exponential growth can be extended by a gradually stronger incident light intensity that matches the increase of the cell density of the culture.
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Affiliation(s)
- R M Schuurmans
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - J C P Matthijs
- Aquatic Microbiology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, The Netherlands
| | - K J Hellingwerf
- Molecular Microbial Physiology Group, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
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12
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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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Schoffman H, Lis H, Shaked Y, Keren N. Iron-Nutrient Interactions within Phytoplankton. FRONTIERS IN PLANT SCIENCE 2016; 7:1223. [PMID: 27588022 PMCID: PMC4989028 DOI: 10.3389/fpls.2016.01223] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 08/02/2016] [Indexed: 05/04/2023]
Abstract
Iron limits photosynthetic activity in up to one third of the world's oceans and in many fresh water environments. When studying the effects of Fe limitation on phytoplankton or their adaptation to low Fe environments, we must take into account the numerous cellular processes within which this micronutrient plays a central role. Due to its flexible redox chemistry, Fe is indispensable in enzymatic catalysis and electron transfer reactions and is therefore closely linked to the acquisition, assimilation and utilization of essential resources. Iron limitation will therefore influence a wide range of metabolic pathways within phytoplankton, most prominently photosynthesis. In this review, we map out four well-studied interactions between Fe and essential resources: nitrogen, manganese, copper and light. Data was compiled from both field and laboratory studies to shed light on larger scale questions such as the connection between metabolic pathways and ambient iron levels and the biogeographical distribution of phytoplankton species.
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Affiliation(s)
- Hanan Schoffman
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of JerusalemJerusalem, Israel
| | - Hagar Lis
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of JerusalemJerusalem, Israel
| | - Yeala Shaked
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of JerusalemJerusalem, Israel
- Interuniversity Institute for Marine Sciences in EilatEilat, Israel
| | - Nir Keren
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of JerusalemJerusalem, Israel
- *Correspondence: Nir Keren,
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Zakar T, Laczko-Dobos H, Toth TN, Gombos Z. Carotenoids Assist in Cyanobacterial Photosystem II Assembly and Function. FRONTIERS IN PLANT SCIENCE 2016; 7:295. [PMID: 27014318 PMCID: PMC4785236 DOI: 10.3389/fpls.2016.00295] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/24/2016] [Indexed: 05/10/2023]
Abstract
Carotenoids (carotenes and xanthophylls) are ubiquitous constituents of living organisms. They are protective agents against oxidative stresses and serve as modulators of membrane microviscosity. As antioxidants they can protect photosynthetic organisms from free radicals like reactive oxygen species that originate from water splitting, the first step of photosynthesis. We summarize the structural and functional roles of carotenoids in connection with cyanobacterial Photosystem II. Although carotenoids are hydrophobic molecules, their complexes with proteins also allow cytoplasmic localization. In cyanobacterial cells such complexes are called orange carotenoid proteins, and they protect Photosystem II and Photosystem I by preventing their overexcitation through phycobilisomes (PBS). Recently it has been observed that carotenoids are not only required for the proper functioning, but also for the structural stability of PBSs.
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15
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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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Wahadoszamen M, D'Haene S, Ara AM, Romero E, Dekker JP, Grondelle RV, Berera R. Identification of common motifs in the regulation of light harvesting: The case of cyanobacteria IsiA. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:486-492. [PMID: 25615585 DOI: 10.1016/j.bbabio.2015.01.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 11/27/2014] [Accepted: 01/12/2015] [Indexed: 10/24/2022]
Abstract
When cyanobacteria are grown under iron-limited or other oxidative stress conditions the iron stress inducible pigment-protein IsiA is synthesized in variable amounts. IsiA accumulates in aggregates inside the photosynthetic membrane that strongly dissipate chlorophyll excited state energy. In this paper we applied Stark fluorescence (SF) spectroscopy at 77K to IsiA aggregates to gain insight into the nature of the emitting and energy dissipating state(s). Our study shows that two emitting states are present in the system, one emitting at 684 nm and the other emitting at about 730 nm. The new 730 nm state exhibits strongly reduced fluorescence (F) together with a large charge transfer character. We discuss these findings in the light of the energy dissipation mechanisms involved in the regulation of photosynthesis in plants, cyanobacteria and diatoms. Our results suggest that photosynthetic organisms have adopted common mechanisms to cope with the deleterious effects of excess light under unfavorable growth conditions.
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Affiliation(s)
- Md Wahadoszamen
- Biophysics of Photosynthesis/Physics of Energy, Department of Physics Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands; Department of Physics, University of Dhaka, Dhaka 1000, Bangladesh.
| | - Sandrine D'Haene
- Biophysics of Photosynthesis/Physics of Energy, Department of Physics Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands
| | - Anjue Mane Ara
- Biophysics of Photosynthesis/Physics of Energy, Department of Physics Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands; Department of Physics, Jagannath University, Dhaka 1100, Bangladesh
| | - Elisabet Romero
- Biophysics of Photosynthesis/Physics of Energy, Department of Physics Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands
| | - Jan P Dekker
- Biophysics of Photosynthesis/Physics of Energy, Department of Physics Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Biophysics of Photosynthesis/Physics of Energy, Department of Physics Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands
| | - Rudi Berera
- Biophysics of Photosynthesis/Physics of Energy, Department of Physics Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands.
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Behrenfeld MJ, Milligan AJ. Photophysiological expressions of iron stress in phytoplankton. ANNUAL REVIEW OF MARINE SCIENCE 2013; 5:217-46. [PMID: 22881354 DOI: 10.1146/annurev-marine-121211-172356] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Iron is essential for all life, but it is particularly important to photoautotrophs because of the many iron-dependent electron transport components in photosynthetic membranes. Since the proliferation of oxygenic photosynthesis in the Archean ocean, iron has been a scarce commodity, and it is now recognized as a limiting resource for phytoplankton over broad expanses of the open ocean and even in some coastal/continental shelf waters. Iron stress does not impair photochemical or carbon fixation efficiencies, and in this respect it resembles the highly tuned photosynthetic systems of steady-state macronutrient-limited phytoplankton. However, iron stress does present unique photophysiological challenges, and phytoplankton have responded to these challenges through major architectural changes in photosynthetic membranes. These evolved responses include overexpression of photosynthetic pigments and iron-economic pathways for ATP synthesis, and they result in diagnostic fluorescence properties that allow a broad appraisal of iron stress in the field and even the detection of iron stress from space.
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Affiliation(s)
- Michael J Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331-2902, USA.
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18
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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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19
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Goss R, Jakob T. Regulation and function of xanthophyll cycle-dependent photoprotection in algae. PHOTOSYNTHESIS RESEARCH 2010; 106:103-22. [PMID: 20224940 DOI: 10.1007/s11120-010-9536-x] [Citation(s) in RCA: 217] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Accepted: 02/05/2010] [Indexed: 05/18/2023]
Abstract
The xanthophyll cycle represents one of the important photoprotection mechanisms in plant cells. In the present review, we summarize current knowledge about the violaxanthin cycle of vascular plants, green and brown algae, and the diadinoxanthin cycle of the algal classes Bacillariophyceae, Xanthophyceae, Haptophyceae, and Dinophyceae. We address the biochemistry of the xanthophyll cycle enzymes with a special focus on protein structure, co-substrate requirements and regulation of enzyme activity. We present recent ideas regarding the structural basis of xanthophyll cycle-dependent photoprotection, including different models for the mechanism of non-photochemical quenching of chlorophyll a fluorescence. In a dedicated chapter, we also describe the unique violaxanthin antheraxanthin cycle of the Prasinophyceae, together with its implication for the mechanism of xanthophyll cycle-dependent heat dissipation. The interaction between the diadinoxanthin cycle and alternative electron flow pathways in the chloroplasts of diatoms is an additional topic of this review, and in the last chapter we cover aspects of the importance of xanthophyll cycle-dependent photoprotection for different algal species in their natural environments.
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Affiliation(s)
- Reimund Goss
- Institute of Biology I, Plant Physiology, University of Leipzig, Johannisallee 21-23, 04103 Leipzig, Germany.
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20
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A mechanism of energy dissipation in cyanobacteria. Biophys J 2009; 96:2261-7. [PMID: 19289052 DOI: 10.1016/j.bpj.2008.12.3905] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2008] [Revised: 12/03/2008] [Accepted: 12/05/2008] [Indexed: 11/21/2022] Open
Abstract
When grown under a variety of stress conditions, cyanobacteria express the isiA gene, which encodes the IsiA pigment-protein complex. Overexpression of the isiA gene under iron-depletion stress conditions leads to the formation of large IsiA aggregates, which display remarkably short fluorescence lifetimes and thus a strong capacity to dissipate energy. In this work we investigate the underlying molecular mechanism responsible for chlorophyll fluorescence quenching. Femtosecond transient absorption spectroscopy allowed us to follow the process of energy dissipation in real time. The light energy harvested by chlorophyll pigments migrated within the system and eventually reaches a quenching site where the energy is transferred to a carotenoid-excited state, which dissipates it by decaying to the ground state. We compare these findings with those obtained for the main light-harvesting complex in green plants (light-harvesting complex II) and artificial light-harvesting antennas, and conclude that all of these systems show the same mechanism of energy dissipation, i.e., one or more carotenoids act as energy dissipators by accepting energy via low-lying singlet-excited S(1) states and dissipating it as heat.
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21
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Karapetyan NV. Protective dissipation of excess absorbed energy by photosynthetic apparatus of cyanobacteria: role of antenna terminal emitters. PHOTOSYNTHESIS RESEARCH 2008; 97:195-204. [PMID: 18720026 DOI: 10.1007/s11120-008-9336-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 07/17/2008] [Indexed: 05/26/2023]
Abstract
Two mechanisms of photoprotective dissipation of the excessively absorbed energy by photosynthetic apparatus of cyanobacteria are described that divert energy from reaction centers. Energy dissipation, monitored as nonphotochemical fluorescence quenching, occurs at different steps of energy transfer within the phycobilisomes or core antenna of photosystem I. Although these mechanisms differ significantly, in both cases, energy dissipates mainly from terminal emitters: allophycocyanin B or core membrane linker protein (L(CM)) in phycobilisomes, or the longest-wavelength chlorophylls in photosystem I antenna. It is supposed that carotenoid-induced energy dissipation in phycobilisomes is triggered by light-induced transformation of the nonquenched state of antenna into quenched state due to conformation changes caused by orange carotinoid-binding protein (OCP)-phycobilisome interaction. Fluorescence of the longest-wavelength chlorophylls of photosystem I antenna is strongly quenched by P700 cation radical or by P700 triplet state, dependent on redox state of the acceptor side cofactors of photosystem I.
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Affiliation(s)
- Navassard V Karapetyan
- A.N. Bakh Institute of Biochemistry, Russian Academy of Sciences, Leninsky pr. 33, Moscow, 119071, Russia.
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