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Nelson N. Investigating the Balance between Structural Conservation and Functional Flexibility in Photosystem I. Int J Mol Sci 2024; 25:5073. [PMID: 38791114 PMCID: PMC11121529 DOI: 10.3390/ijms25105073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/16/2024] [Accepted: 04/30/2024] [Indexed: 05/26/2024] Open
Abstract
Photosynthesis, as the primary source of energy for all life forms, plays a crucial role in maintaining the global balance of energy, entropy, and enthalpy in living organisms. Among its various building blocks, photosystem I (PSI) is responsible for light-driven electron transfer, crucial for generating cellular reducing power. PSI acts as a light-driven plastocyanin-ferredoxin oxidoreductase and is situated in the thylakoid membranes of cyanobacteria and the chloroplasts of eukaryotic photosynthetic organisms. Comprehending the structure and function of the photosynthetic machinery is essential for understanding its mode of action. New insights are offered into the structure and function of PSI and its associated light-harvesting proteins, with a specific focus on the remarkable structural conservation of the core complex and high plasticity of the peripheral light-harvesting complexes.
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Affiliation(s)
- Nathan Nelson
- Department of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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2
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Castell C, Rodríguez-Lumbreras LA, Hervás M, Fernández-Recio J, Navarro JA. New Insights into the Evolution of the Electron Transfer from Cytochrome f to Photosystem I in the Green and Red Branches of Photosynthetic Eukaryotes. PLANT & CELL PHYSIOLOGY 2021; 62:1082-1093. [PMID: 33772595 PMCID: PMC8557733 DOI: 10.1093/pcp/pcab044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/15/2021] [Indexed: 05/11/2023]
Abstract
In cyanobacteria and most green algae of the eukaryotic green lineage, the copper-protein plastocyanin (Pc) alternatively replaces the heme-protein cytochrome c6 (Cc6) as the soluble electron carrier from cytochrome f (Cf) to photosystem I (PSI). The functional and structural equivalence of 'green' Pc and Cc6 has been well established, representing an example of convergent evolution of two unrelated proteins. However, plants only produce Pc, despite having evolved from green algae. On the other hand, Cc6 is the only soluble donor available in most species of the red lineage of photosynthetic organisms, which includes, among others, red algae and diatoms. Interestingly, Pc genes have been identified in oceanic diatoms, probably acquired by horizontal gene transfer from green algae. However, the mechanisms that regulate the expression of a functional Pc in diatoms are still unclear. In the green eukaryotic lineage, the transfer of electrons from Cf to PSI has been characterized in depth. The conclusion is that in the green lineage, this process involves strong electrostatic interactions between partners, which ensure a high affinity and an efficient electron transfer (ET) at the cost of limiting the turnover of the process. In the red lineage, recent kinetic and structural modeling data suggest a different strategy, based on weaker electrostatic interactions between partners, with lower affinity and less efficient ET, but favoring instead the protein exchange and the turnover of the process. Finally, in diatoms the interaction of the acquired green-type Pc with both Cf and PSI may not yet be optimized.
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Affiliation(s)
- Carmen Castell
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, cicCartuja, Sevilla, Spain
| | - Luis A Rodríguez-Lumbreras
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC—Universidad de La Rioja—Gobierno de La Rioja, Logroño, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC and Universidad de Sevilla, cicCartuja, Sevilla, Spain
| | - Juan Fernández-Recio
- Instituto de Ciencias de la Vid y del Vino (ICVV), CSIC—Universidad de La Rioja—Gobierno de La Rioja, Logroño, Spain
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3
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Di Savino A, Foerster JM, Ullmann GM, Ubbink M. Enhancing the population of the encounter complex affects protein complex formation efficiency. FEBS J 2021; 289:535-548. [PMID: 34403572 PMCID: PMC9293183 DOI: 10.1111/febs.16159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/08/2021] [Accepted: 08/16/2021] [Indexed: 11/30/2022]
Abstract
Optimal charge distribution is considered to be important for efficient formation of protein complexes. Electrostatic interactions guide encounter complex formation that precedes the formation of an active protein complex. However, disturbing the optimized distribution by introduction of extra charged patches on cytochrome c peroxidase does not lead to a reduction in productive encounters with its partner cytochrome c. To test whether a complex with a high population of encounter complex is more easily affected by suboptimal charge distribution, the interactions of cytochrome c mutant R13A with wild‐type cytochrome c peroxidase and a variant with an additional negative patch were studied. The complex of the peroxidase and cytochrome c R13A was reported to have an encounter state population of 80%, compared to 30% for the wild‐type cytochrome c. NMR analysis confirms the dynamic nature of the interaction and demonstrates that the mutant cytochrome c samples the introduced negative patch. Kinetic experiments show that productive complex formation is fivefold to sevenfold slower at moderate and high ionic strength values for cytochrome c R13A but the association rate is not affected by the additional negative patch on cytochrome c peroxidase, showing that the total charge on the protein surface can compensate for less optimal charge distribution. At low ionic strength (44 mm), the association with the mutant cytochrome c reaches the same high rates as found for wild‐type cytochrome c, approaching the diffusion limit.
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4
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Teodor AH, Ooi EJ, Medina J, Alarcon M, Vaughn MD, Bruce BD, Bergkamp JJ. Aqueous-soluble bipyridine cobalt(ii/iii) complexes act as direct redox mediators in photosystem I-based biophotovoltaic devices. RSC Adv 2021; 11:10434-10450. [PMID: 35423559 PMCID: PMC8695705 DOI: 10.1039/d0ra10221k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/28/2021] [Indexed: 01/13/2023] Open
Abstract
Sustainable energy production is critical for meeting growing worldwide energy demands. Due to its stability and reduction potential, photosystem I (PSI) is attractive as the photosensitizer in biophotovoltaic devices. Herein, we characterize aqueous and organic solvent soluble synthetic bipyridine-based cobalt complexes as redox mediators for PSI-based biophotovoltaics applications. Cobalt-based complexes are not destructive to protein and have appropriate midpoint potentials for electron donation to PSI. We report on PSI stability in organic solvents commonly used in biophotovoltaics. We also show the effects of a mixed organic solvent phase on PSI reduction kinetics, slowing reduction rates approximately 8–38 fold as compared to fully aqueous systems, with implications for dye regeneration rates in PSI-based biophotovoltaics. Further, we show evidence of direct electron transfer from cobalt complexes to PSI. Finally, we report on photocurrent generation from Co mediator-PSI biophotovoltaic devices. Taken together, we discuss the development of novel Co complexes and our ability to fine-tune their characteristics via functional groups and counteranion choice to drive interaction with a biological electron acceptor on multiple levels from redox midpoints, spectral overlap, and solvent requirements, among others. This work suggests that fine-tuning of redox active species for interaction with a biological partner is possible for the creation and improvement of low cost, carbon-neutral energy production in the future. Sustainable energy production is critical for meeting growing worldwide energy demands.![]()
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Affiliation(s)
- Alexandra H Teodor
- Graduate School of Genome Science and Technology, University of Tennessee at Knoxville and Oak Ridge National Laboratory USA
| | - Eu-Jee Ooi
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
| | - Jackeline Medina
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
| | - Miguel Alarcon
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
| | | | - Barry D Bruce
- Graduate School of Genome Science and Technology, University of Tennessee at Knoxville and Oak Ridge National Laboratory USA .,Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee at Knoxville USA.,Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville USA
| | - Jesse J Bergkamp
- Department of Chemistry and Biochemistry, California State University Bakersfield USA
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5
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Castell C, Bernal-Bayard P, Ortega JM, Roncel M, Hervás M, Navarro JA. The heterologous expression of a plastocyanin in the diatom Phaeodactylum tricornutum improves cell growth under iron-deficient conditions. PHYSIOLOGIA PLANTARUM 2021; 171:277-290. [PMID: 33247466 DOI: 10.1111/ppl.13290] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
We have investigated if the heterologous expression of a functional green alga plastocyanin in the diatom Phaeodactylum tricornutum can improve photosynthetic activity and cell growth. Previous in vitro assays showed that a single-mutant of the plastocyanin from the green algae Chlamydomonas reinhardtii is effective in reducing P. tricornutum photosystem I. In this study, in vivo assays with P. tricornutum strains expressing this plastocyanin indicate that even the relatively low intracellular concentrations of holo-plastocyanin detected (≈4 μM) are enough to promote an increased growth (up to 60%) under iron-deficient conditions as compared with the WT strain, measured as higher cell densities, content in pigments and active photosystem I, global photosynthetic rates per cell, and even cell volume. In addition, the presence of plastocyanin as an additional photosynthetic electron carrier seems to decrease the over-reduction of the plastoquinone pool. Consequently, it promotes an improvement in the maximum quantum yield of both photosystem II and I, together with a decrease in the acceptor side photoinhibition of photosystem II-also associated to a reduced oxidative stress-a decrease in the peroxidation of membrane lipids in the choroplast, and a lower degree of limitation on the donor side of photosystem I. Thus the heterologous plastocyanin appears to act as a functional electron carrier, alternative to the native cytochrome c6 , under iron-limiting conditions.
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Affiliation(s)
- Carmen Castell
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - Pilar Bernal-Bayard
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - José M Ortega
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - Mercedes Roncel
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, cicCartuja, Universidad de Sevilla and CSIC, Seville, Spain
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6
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Teodor AH, Bruce BD. Putting Photosystem I to Work: Truly Green Energy. Trends Biotechnol 2020; 38:1329-1342. [PMID: 32448469 DOI: 10.1016/j.tibtech.2020.04.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 12/16/2022]
Abstract
Meeting growing energy demands sustainably is one of the greatest challenges facing the world. The sun strikes the Earth with sufficient energy in 1.5 h to meet annual world energy demands, likely making solar energy conversion part of future sustainable energy production plans. Photosynthetic organisms have been evolving solar energy utilization strategies for nearly 3.5 billion years, making reaction centers including the remarkably stable Photosystem I (PSI) especially interesting for biophotovoltaic device integration. Although these biohybrid devices have steadily improved, their output remains low compared with traditional photovoltaics. We discuss strategies and methods to improve PSI-based biophotovoltaics, focusing on PSI-surface interaction enhancement, electrolytes, and light-harvesting enhancement capabilities. Desirable features and current drawbacks to PSI-based devices are also discussed.
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Affiliation(s)
- Alexandra H Teodor
- Graduate School of Genome Science and Technology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Barry D Bruce
- Graduate School of Genome Science and Technology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA; Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Department of Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996, USA.
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7
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Bernal-Bayard P, Puerto-Galán L, Yruela I, García-Rubio I, Castell C, Ortega JM, Alonso PJ, Roncel M, Martínez JI, Hervás M, Navarro JA. The photosynthetic cytochrome c 550 from the diatom Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2017; 133:273-287. [PMID: 28032235 DOI: 10.1007/s11120-016-0327-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 12/14/2016] [Indexed: 06/06/2023]
Abstract
The photosynthetic cytochrome c 550 from the marine diatom Phaeodactylum tricornutum has been purified and characterized. Cytochrome c 550 is mostly obtained from the soluble cell extract in relatively large amounts. In addition, the protein appeared to be truncated in the last hydrophobic residues of the C-terminus, both in the soluble cytochrome c 550 and in the protein extracted from the membrane fraction, as deduced by mass spectrometry analysis and the comparison with the gene sequence. Interestingly, it has been described that the C-terminus of cytochrome c 550 forms a hydrophobic finger involved in the interaction with photosystem II in cyanobacteria. Cytochrome c 550 was almost absent in solubilized photosystem II complex samples, in contrast with the PsbO and Psb31 extrinsic subunits, thus suggesting a lower affinity of cytochrome c 550 for the photosystem II complex. Under iron-limiting conditions the amount of cytochrome c 550 decreases up to about 45% as compared to iron-replete cells, pointing to an iron-regulated synthesis. Oxidized cytochrome c 550 has been characterized using continuous wave EPR and pulse techniques, including HYSCORE, and the obtained results have been interpreted in terms of the electrostatic charge distribution in the surroundings of the heme centre.
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Affiliation(s)
- Pilar Bernal-Bayard
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - Leonor Puerto-Galán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | | | - Inés García-Rubio
- Centro Universitario de la Defensa, Zaragoza, Spain
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
| | - Carmen Castell
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - José M Ortega
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - Pablo J Alonso
- Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza & CSIC, Zaragoza, Spain
| | - Mercedes Roncel
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - Jesús I Martínez
- Centro Universitario de la Defensa, Zaragoza, Spain
- Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza & CSIC, Zaragoza, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, Centro de Investigaciones Científicas Isla de la Cartuja, Universidad de Sevilla & CSIC, Américo Vespucio 49, 41092, Sevilla, Spain.
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8
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Torrado A, Valladares A, Puerto-Galán L, Hervás M, Navarro JA, Molina-Heredia FP. Cyt c6-3: A New Isoform of Photosynthetic Cyt c6 Exclusive to Heterocyst-Forming Cyanobacteria. PLANT & CELL PHYSIOLOGY 2017; 58:256-265. [PMID: 28007969 DOI: 10.1093/pcp/pcw184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Abstract
All known cyanobacteria contain Cyt c6, a small soluble electron carrier protein whose main function is to transfer electrons from the Cyt b6f complex to PSI, although it is also involved in respiration. We have previously described a second isoform of this protein, the Cyt c6-like, whose function remains unknown. Here we describe a third isoform of Cyt c6 (here called Cytc6-3), which is only found in heterocyst-forming filamentous cyanobacteria. Cyt c6-3 is expressed in vegetative cells but is specifically repressed in heterocysts cells under diazotrophic growth conditions. Although there is a close structural similarity between Cyt c6-3 and Cyt c6 related to the general protein folding, Cyt c6-3 presents differential electrostatic surface features as compared with Cyt c6, its expression is not copper dependent and has a low reactivity towards PSI. According to the different expression pattern, functional reactivity and structural properties, Cyt c6-3 has to play an as yet to be defined regulatory role related to heterocyst differentiation.
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Affiliation(s)
- Alejandro Torrado
- School of Medicine, Department of Anatomy and Neurobiology, Medical Science Campus of the University of Puerto Rico (MCS-UPR), San Juan, PR, USA
| | - Ana Valladares
- Department of Environmental, Earth and Geospatial Sciences, North Carolina Central University, Durham, North Carolina, USA
| | - Leonor Puerto-Galán
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio, Sevilla, Spain
| | - Manuel Hervás
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas Seville, Spain
| | - José A Navarro
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas Seville, Spain
| | - Fernando P Molina-Heredia
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio, Sevilla, Spain
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Roncel M, González-Rodríguez AA, Naranjo B, Bernal-Bayard P, Lindahl AM, Hervás M, Navarro JA, Ortega JM. Iron Deficiency Induces a Partial Inhibition of the Photosynthetic Electron Transport and a High Sensitivity to Light in the Diatom Phaeodactylum tricornutum. FRONTIERS IN PLANT SCIENCE 2016; 7:1050. [PMID: 27536301 PMCID: PMC4971056 DOI: 10.3389/fpls.2016.01050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/05/2016] [Indexed: 05/09/2023]
Abstract
Iron limitation is the major factor controlling phytoplankton growth in vast regions of the contemporary oceans. In this study, a combination of thermoluminescence (TL), chlorophyll fluorescence, and P700 absorbance measurements have been used to elucidate the effects of iron deficiency in the photosynthetic electron transport of the marine diatom P. tricornutum. TL was used to determine the effects of iron deficiency on photosystem II (PSII) activity. Excitation of iron-replete P. tricornutum cells with single turn-over flashes induced the appearance of TL glow curves with two components with different peaks of temperature and contributions to the total signal intensity: the B band (23°C, 63%), and the AG band (40°C, 37%). Iron limitation did not significantly alter these bands, but induced a decrease of the total TL signal. Far red excitation did not increase the amount of the AG band in iron-limited cells, as observed for iron-replete cells. The effect of iron deficiency on the photosystem I (PSI) activity was also examined by measuring the changes in P700 redox state during illumination. The electron donation to PSI was substantially reduced in iron-deficient cells. This could be related with the important decline on cytochrome c 6 content observed in these cells. Iron deficiency also induced a marked increase in light sensitivity in P. tricornutum cells. A drastic increase in the level of peroxidation of chloroplast lipids was detected in iron-deficient cells even when grown under standard conditions at low light intensity. Illumination with a light intensity of 300 μE m(-2) s(-1) during different time periods caused a dramatic disappearance in TL signal in cells grown under low iron concentration, this treatment not affecting to the signal in iron-replete cells. The results of this work suggest that iron deficiency induces partial blocking of the electron transfer between PSII and PSI, due to a lower concentration of the electron donor cytochrome c 6. This decreased electron transfer may induce the over-reduction of the plastoquinone pool and consequently the appearance of acceptor side photoinhibition in PSII even at low light intensities. The functionality of chlororespiratory electron transfer pathway under iron restricted conditions is also discussed.
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10
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Bernal-Bayard P, Pallara C, Carmen Castell M, Molina-Heredia FP, Fernández-Recio J, Hervás M, Navarro JA. Interaction of photosystem I from Phaeodactylum tricornutum with plastocyanins as compared with its native cytochrome c6: Reunion with a lost donor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1549-59. [DOI: 10.1016/j.bbabio.2015.09.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/02/2015] [Accepted: 09/20/2015] [Indexed: 11/17/2022]
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