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Gisriel CJ. Recent structural discoveries of photosystems I and II acclimated to absorb far-red light. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149032. [PMID: 38401604 PMCID: PMC11162955 DOI: 10.1016/j.bbabio.2024.149032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/22/2024] [Accepted: 02/09/2024] [Indexed: 02/26/2024]
Abstract
Photosystems I and II are the photooxidoreductases central to oxygenic photosynthesis and canonically absorb visible light (400-700 nm). Recent investigations have revealed that certain cyanobacteria can acclimate to environments enriched in far-red light (700-800 nm), yet can still perform oxygenic photosynthesis in a process called far-red light photoacclimation, or FaRLiP. During this process, the photosystem subunits and pigment compositions are altered. Here, the current structural understanding of the photosystems expressed during FaRLiP is described. The design principles may be useful for guiding efforts to engineer shade tolerance in organisms that typically cannot utilize far-red light.
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Elias E, Oliver TJ, Croce R. Oxygenic Photosynthesis in Far-Red Light: Strategies and Mechanisms. Annu Rev Phys Chem 2024; 75:231-256. [PMID: 38382567 DOI: 10.1146/annurev-physchem-090722-125847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Oxygenic photosynthesis, the process that converts light energy into chemical energy, is traditionally associated with the absorption of visible light by chlorophyll molecules. However, recent studies have revealed a growing number of organisms capable of using far-red light (700-800 nm) to drive oxygenic photosynthesis. This phenomenon challenges the conventional understanding of the limits of this process. In this review, we briefly introduce the organisms that exhibit far-red photosynthesis and explore the different strategies they employ to harvest far-red light. We discuss the modifications of photosynthetic complexes and their impact on the delivery of excitation energy to photochemical centers and on overall photochemical efficiency. Finally, we examine the solutions employed to drive electron transport and water oxidation using relatively low-energy photons. The findings discussed here not only expand our knowledge of the remarkable adaptation capacities of photosynthetic organisms but also offer insights into the potential for enhancing light capture in crops.
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Affiliation(s)
- Eduard Elias
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands;
| | - Thomas J Oliver
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands;
| | - Roberta Croce
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands;
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3
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Shen L, Gao Y, Tang K, Qi R, Fu L, Chen JH, Wang W, Ma X, Li P, Chen M, Kuang T, Zhang X, Shen JR, Wang P, Han G. Structure of a unique PSII-Pcb tetrameric megacomplex in a chlorophyll d-containing cyanobacterium. SCIENCE ADVANCES 2024; 10:eadk7140. [PMID: 38394197 PMCID: PMC10889353 DOI: 10.1126/sciadv.adk7140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
Acaryochloris marina is a unique cyanobacterium using chlorophyll d (Chl d) as its major pigment and thus can use far-red light for photosynthesis. Photosystem II (PSII) of A. marina associates with a number of prochlorophyte Chl-binding (Pcb) proteins to act as the light-harvesting system. We report here the cryo-electron microscopic structure of a PSII-Pcb megacomplex from A. marina at a 3.6-angstrom overall resolution and a 3.3-angstrom local resolution. The megacomplex is organized as a tetramer consisting of two PSII core dimers flanked by sixteen symmetrically related Pcb proteins, with a total molecular weight of 1.9 megadaltons. The structure reveals the detailed organization of PSII core consisting of 15 known protein subunits and an unknown subunit, the assembly of 4 Pcb antennas within each PSII monomer, and possible pathways of energy transfer within the megacomplex, providing deep insights into energy transfer and dissipation mechanisms within the PSII-Pcb megacomplex involved in far-red light utilization.
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Affiliation(s)
- Liangliang Shen
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
| | - Yuanzhu Gao
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Kailu Tang
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Ruxi Qi
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lutang Fu
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jing-Hua Chen
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wenda Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
| | - Xiaomin Ma
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Peiyao Li
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Min Chen
- School of Life and Environmental Science, Faculty of Science, University of Sydney, Sydney NSW 2006, Australia
| | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
| | - Xing Zhang
- Department of Biophysics, and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Center of Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou 310058, China
- Zhejiang Laboratory for System and Precision Medicine, Zhejiang University Medical Center, 1369 West Wenyi Road, Hangzhou 311121, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
- Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Peiyi Wang
- Cryo-EM Centre, Southern University of Science and Technology, Shenzhen 518055, China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- China National Botanical Garden, Beijing 100093, China
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4
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Gisriel CJ, Shen G, Brudvig GW, Bryant DA. Structure of the antenna complex expressed during far-red light photoacclimation in Synechococcus sp. PCC 7335. J Biol Chem 2024; 300:105590. [PMID: 38141759 PMCID: PMC10810746 DOI: 10.1016/j.jbc.2023.105590] [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: 10/22/2023] [Revised: 11/28/2023] [Accepted: 12/12/2023] [Indexed: 12/25/2023] Open
Abstract
Far-red light photoacclimation, or FaRLiP, is a facultative response exhibited by some cyanobacteria that allows them to absorb and utilize lower energy light (700-800 nm) than the wavelengths typically used for oxygenic photosynthesis (400-700 nm). During this process, three essential components of the photosynthetic apparatus are altered: photosystem I, photosystem II, and the phycobilisome. In all three cases, at least some of the chromophores found in these pigment-protein complexes are replaced by chromophores that have red-shifted absorbance relative to the analogous complexes produced in visible light. Recent structural and spectroscopic studies have elucidated important features of the two photosystems when altered to absorb and utilize far-red light, but much less is understood about the modified phycobiliproteins made during FaRLiP. We used single-particle, cryo-EM to determine the molecular structure of a phycobiliprotein core complex comprising allophycocyanin variants that absorb far-red light during FaRLiP in the marine cyanobacterium Synechococcus sp. PCC 7335. The structure reveals the arrangement of the numerous red-shifted allophycocyanin variants and the probable locations of the chromophores that serve as the terminal emitters in this complex. It also suggests how energy is transferred to the photosystem II complexes produced during FaRLiP. The structure additionally allows comparisons with other previously studied allophycocyanins to gain insights into how phycocyanobilin chromophores can be tuned to absorb far-red light. These studies provide new insights into how far-red light is harvested and utilized during FaRLiP, a widespread cyanobacterial photoacclimation mechanism.
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Affiliation(s)
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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Battistuzzi M, Morlino MS, Cocola L, Trainotti L, Treu L, Campanaro S, Claudi R, Poletto L, La Rocca N. Transcriptomic and photosynthetic analyses of Synechocystis sp. PCC6803 and Chlorogloeopsis fritschii sp. PCC6912 exposed to an M-dwarf spectrum under an anoxic atmosphere. FRONTIERS IN PLANT SCIENCE 2024; 14:1322052. [PMID: 38304456 PMCID: PMC10830646 DOI: 10.3389/fpls.2023.1322052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 12/29/2023] [Indexed: 02/03/2024]
Abstract
Introduction Cyanobacteria appeared in the anoxic Archean Earth, evolving for the first time oxygenic photosynthesis and deeply changing the atmosphere by introducing oxygen. Starting possibly from UV-protected environments, characterized by low visible and far-red enriched light spectra, cyanobacteria spread everywhere on Earth thanks to their adaptation capabilities in light harvesting. In the last decade, few cyanobacteria species which can acclimate to far-red light through Far-Red Light Photoacclimation (FaRLiP) have been isolated. FaRLiP cyanobacteria were thus proposed as model organisms to study the origin of oxygenic photosynthesis as well as its possible functionality around stars with high far-red emission, the M-dwarfs. These stars are astrobiological targets, as their longevity could sustain life evolution and they demonstrated to host rocky terrestrial-like exoplanets within their Habitable Zone. Methods We studied the acclimation responses of the FaRLiP strain Chlorogloeopsis fritschii sp. PCC6912 and the non-FaRLiP strain Synechocystis sp. PCC6803 to the combination of three simulated light spectra (M-dwarf, solar and far-red) and two atmospheric compositions (oxic, anoxic). We first checked their growth, O2 production and pigment composition, then we studied their transcriptional responses by RNA sequencing under each combination of light spectrum and atmosphere conditions. Results and discussion PCC6803 did not show relevant differences in gene expression when comparing the responses to M-dwarf and solar-simulated lights, while far-red caused a variation in the transcriptional level of many genes. PCC6912 showed, on the contrary, different transcriptional responses to each light condition and activated the FaRLiP response under the M-dwarf simulated light. Surprisingly, the anoxic atmosphere did not impact the transcriptional profile of the 2 strains significantly. Results show that both cyanobacteria seem inherently prepared for anoxia and to harvest the photons emitted by a simulated M-dwarf star, whether they are only visible (PCC6803) or also far-red photons (PCC6912). They also show that visible photons in the simulated M-dwarf are sufficient to keep a similar metabolism with respect to solar-simulated light. Conclusion Results prove the adaptability of the cyanobacterial metabolism and enhance the plausibility of finding oxygenic biospheres on exoplanets orbiting M-dwarf stars.
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Affiliation(s)
- Mariano Battistuzzi
- National Council of Research of Italy, Institute for Photonics and Nanotechnologies (CNR-IFN), Padua, Italy
- Department of Biology, University of Padua, Padua, Italy
- Center for Space Studies and Activities (CISAS), University of Padua, Padua, Italy
| | | | - Lorenzo Cocola
- National Council of Research of Italy, Institute for Photonics and Nanotechnologies (CNR-IFN), Padua, Italy
| | | | - Laura Treu
- Department of Biology, University of Padua, Padua, Italy
| | | | - Riccardo Claudi
- National Institute for Astrophysics, Astronomical Observatory of Padua (INAF-OAPD), Padua, Italy
- Department of Mathematics and Physics, University Roma Tre, Rome, Italy
| | - Luca Poletto
- National Council of Research of Italy, Institute for Photonics and Nanotechnologies (CNR-IFN), Padua, Italy
| | - Nicoletta La Rocca
- Department of Biology, University of Padua, Padua, Italy
- Center for Space Studies and Activities (CISAS), University of Padua, Padua, Italy
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Ko JT, Li YY, Chen PY, Liu PY, Ho MY. Use of 16S rRNA gene sequences to identify cyanobacteria that can grow in far-red light. Mol Ecol Resour 2024; 24:e13871. [PMID: 37772760 DOI: 10.1111/1755-0998.13871] [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: 05/26/2023] [Revised: 09/10/2023] [Accepted: 09/18/2023] [Indexed: 09/30/2023]
Abstract
Although most cyanobacteria use visible light (VL; λ = 400-700 nm) for photosynthesis, some have evolved strategies to use far-red light (FRL; λ = 700-800 nm). These cyanobacteria are defined as far-red light-utilizing cyanobacteria (FRLCyano), including two groups: (1) chlorophyll d-producing Acaryochloris spp. and (2) polyphyletic cyanobacteria that produce chlorophylls d and f in response to FRL. Numerous ecological studies examine pigments, such as chlorophylls d and f, to investigate the presence of FRLCyano in the environment. This method is not ideal because it can only detect FRLCyano that have made chlorophylls d or f. Here we develop a new method, far-red cyanobacteria identification (FRCI), to identify FRLCyano based on 16S rRNA gene sequences. From public databases and published articles, 62 16S rRNA gene sequences of FRLCyano were extracted. Comparing with related lineages, we determined that 97% sequence identity is the optimal cut-off for distinguishing FRLCyano from other cyanobacteria. To test the method experimentally, we collected samples from 17 sites in Taipei, Taiwan, and conducted VL and FRL enrichments. Our results demonstrate that FRCI can detect FRLCyano during FRL enrichments more sensitively than pigment analysis. FRCI can also resolve the composition of FRLCyano at the genus level, which pigment analysis cannot do. In addition, we applied FRCI to published datasets and discovered putative FRLCyano in diverse environments, including soils, hot springs and deserts. Overall, our results indicate that FRCI is a sensitive and high-resolution method using 16S rRNA gene sequences to identify FRLCyano.
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Affiliation(s)
- Jui-Tse Ko
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Ying-Yang Li
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
| | - Pa-Yu Chen
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Po-Yu Liu
- School of Medicine, College of Medicine, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Ming-Yang Ho
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan
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7
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Ranepura GA, Mao J, Vermaas JV, Wang J, Gisriel CJ, Wei RJ, Ortiz-Soto J, Uddin MR, Amin M, Brudvig GW, Gunner MR. Computing the Relative Affinity of Chlorophylls a and b to Light-Harvesting Complex II. J Phys Chem B 2023; 127:10974-10986. [PMID: 38097367 DOI: 10.1021/acs.jpcb.3c06273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
In plants and algae, the primary antenna protein bound to photosystem II is light-harvesting complex II (LHCII), a pigment-protein complex that binds eight chlorophyll (Chl) a molecules and six Chl b molecules. Chl a and Chl b differ only in that Chl a has a methyl group (-CH3) on one of its pyrrole rings, while Chl b has a formyl group (-CHO) at that position. This blue-shifts the Chl b absorbance relative to Chl a. It is not known how the protein selectively binds the right Chl type at each site. Knowing the selection criteria would allow the design of light-harvesting complexes that bind different Chl types, modifying an organism to utilize the light of different wavelengths. The difference in the binding affinity of Chl a and Chl b in pea and spinach LHCII was calculated using multiconformation continuum electrostatics and free energy perturbation. Both methods have identified some Chl sites where the bound Chl type (a or b) has a significantly higher affinity, especially when the protein provides a hydrogen bond for the Chl b formyl group. However, the Chl a sites often have little calculated preference for one Chl type, so they are predicted to bind a mixture of Chl a and b. The electron density of the spinach LHCII was reanalyzed, which, however, confirmed that there is negligible Chl b in the Chl a-binding sites. It is suggested that the protein chooses the correct Chl type during folding, segregating the preferred Chl to the correct binding site.
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Affiliation(s)
- Gehan A Ranepura
- Ph.D. Program in Physics, The Graduate Center, City University of New York, New York, New York 10016, United States
- Department of Physics, City College of New York, New York, New York 10031, United States
| | - Junjun Mao
- Benjamin Levich Institute for Physico-Chemical Hydrodynamics, City College of New York, New York, New York 10031, United States
| | - Josh V Vermaas
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, 612 Wilson Road, East Lansing, Michigan 48824, United States
| | - Jimin Wang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Christopher J Gisriel
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Rongmei Judy Wei
- Department of Physics, City College of New York, New York, New York 10031, United States
- Ph.D. Program in Chemistry, The Graduate Center, City University of New York, New York, New York 10016, United States
| | - Jose Ortiz-Soto
- Department of Physics, City College of New York, New York, New York 10031, United States
- Ph.D. Program in Chemistry, The Graduate Center, City University of New York, New York, New York 10016, United States
| | - Md Raihan Uddin
- Department of Physics, City College of New York, New York, New York 10031, United States
- Ph.D. Program in Biochemistry, The Graduate Center, City University of New York, New York, New York 10016, United States
| | - Muhamed Amin
- Laboratory of Computational Biology, National Heart, Lung and Blood, Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Gary W Brudvig
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, United States
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - M R Gunner
- PhD Program in Physics, in Chemistry and in Biochemistry at the Graduate Center, City University of New York, New York, New York 10016, United States
- Department of Physics, City College of New York, New York, New York 10031, United States
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8
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Gisriel CJ, Bryant DA, Brudvig GW, Cardona T. Molecular diversity and evolution of far-red light-acclimated photosystem I. FRONTIERS IN PLANT SCIENCE 2023; 14:1289199. [PMID: 38053766 PMCID: PMC10694217 DOI: 10.3389/fpls.2023.1289199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023]
Abstract
The need to acclimate to different environmental conditions is central to the evolution of cyanobacteria. Far-red light (FRL) photoacclimation, or FaRLiP, is an acclimation mechanism that enables certain cyanobacteria to use FRL to drive photosynthesis. During this process, a well-defined gene cluster is upregulated, resulting in changes to the photosystems that allow them to absorb FRL to perform photochemistry. Because FaRLiP is widespread, and because it exemplifies cyanobacterial adaptation mechanisms in nature, it is of interest to understand its molecular evolution. Here, we performed a phylogenetic analysis of the photosystem I subunits encoded in the FaRLiP gene cluster and analyzed the available structural data to predict ancestral characteristics of FRL-absorbing photosystem I. The analysis suggests that FRL-specific photosystem I subunits arose relatively late during the evolution of cyanobacteria when compared with some of the FRL-specific subunits of photosystem II, and that the order Nodosilineales, which include strains like Halomicronema hongdechloris and Synechococcus sp. PCC 7335, could have obtained FaRLiP via horizontal gene transfer. We show that the ancestral form of FRL-absorbing photosystem I contained three chlorophyll f-binding sites in the PsaB2 subunit, and a rotated chlorophyll a molecule in the A0B site of the electron transfer chain. Along with our previous study of photosystem II expressed during FaRLiP, these studies describe the molecular evolution of the photosystem complexes encoded by the FaRLiP gene cluster.
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Affiliation(s)
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, CT, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Tanai Cardona
- Department of Life Sciences, Imperial College London, London, United Kingdom
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
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9
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Chen M, Sawicki A, Wang F. Modeling the Characteristic Residues of Chlorophyll f Synthase (ChlF) from Halomicronema hongdechloris to Determine Its Reaction Mechanism. Microorganisms 2023; 11:2305. [PMID: 37764149 PMCID: PMC10535343 DOI: 10.3390/microorganisms11092305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/07/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Photosystem II (PSII) is a quinone-utilizing photosynthetic system that converts light energy into chemical energy and catalyzes water splitting. PsbA (D1) and PsbD (D2) are the core subunits of the reaction center that provide most of the ligands to redox-active cofactors and exhibit photooxidoreductase activities that convert quinone and water into quinol and dioxygen. The performed analysis explored the putative uncoupled electron transfer pathways surrounding P680+ induced by far-red light (FRL) based on photosystem II (PSII) complexes containing substituted D1 subunits in Halomicronema hongdechloris. Chlorophyll f-synthase (ChlF) is a D1 protein paralog. Modeling PSII-ChlF complexes determined several key protein motifs of ChlF. The PSII complexes included a dysfunctional Mn4CaO5 cluster where ChlF replaced the D1 protein. We propose the mechanism of chlorophyll f synthesis from chlorophyll a via free radical chemistry in an oxygenated environment created by over-excited pheophytin a and an inactive water splitting reaction owing to an uncoupled Mn4CaO5 cluster in PSII-ChlF complexes. The role of ChlF in the formation of an inactive PSII reaction center is under debate, and putative mechanisms of chlorophyll f biosynthesis are discussed.
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Affiliation(s)
- Min Chen
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
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10
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Sheridan KJ, Brown TJ, Eaton-Rye JJ, Summerfield TC. Expression of the far-red D1 protein or introduction of conserved far-red D1 residues into Synechocystis sp. PCC 6803 impairs Photosystem II. PHYSIOLOGIA PLANTARUM 2023; 175:e13997. [PMID: 37882270 DOI: 10.1111/ppl.13997] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 10/27/2023]
Abstract
The wavelengths of light harvested in oxygenic photosynthesis are ~400-700 nm. Some cyanobacteria respond to far-red light exposure via a process called far-red light photoacclimation which enables absorption of light at wavelengths >700 nm and its use to support photosynthesis. Far-red-light-induced changes include up-regulation of alternative copies of multiple proteins of Photosystem II (PS II). This includes an alternative copy of the D1 protein, D1FR . Here, we show that D1FR introduced into Synechocystis sp. PCC 6803 (hereafter Synechocystis 6803) can be incorporated into PS II centres that evolve oxygen at low rates but cannot support photoautotrophic growth. Using mutagenesis to modify the psbA2 gene of Synechocystis 6803, we modified residues in helices A, B, and C to be characteristic of D1FR residues. Modification of the Synechocystis 6803 helix A to resemble the D1FR helix A, with modifications in the region of the bound ß-carotene (CarD1 ) and the accessory chlorophyll, ChlZD1 , produced a strain with a similar phenotype to the D1FR strain. In contrast, the D1FR changes in helices B and C had minor impacts on photoautotrophy but impacted the function of PS II, possibly through a change in the equilibrium for electron sharing between the primary and secondary plastoquinone electron acceptors QA and QB in favour of QA - . The addition of combinations of residue changes in helix C indicates compensating effects may occur and highlight the need to experimentally determine the impact of multiple residue changes.
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Affiliation(s)
- Kevin J Sheridan
- Department of Botany, University of Otago, Dunedin, New Zealand
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Toby J Brown
- Department of Botany, University of Otago, Dunedin, New Zealand
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
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11
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Gisriel CJ, Shen G, Flesher DA, Kurashov V, Golbeck JH, Brudvig GW, Amin M, Bryant DA. Structure of a dimeric photosystem II complex from a cyanobacterium acclimated to far-red light. J Biol Chem 2023; 299:102815. [PMID: 36549647 PMCID: PMC9843442 DOI: 10.1016/j.jbc.2022.102815] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Photosystem II (PSII) is the water-splitting enzyme central to oxygenic photosynthesis. To drive water oxidation, light is harvested by accessory pigments, mostly chlorophyll (Chl) a molecules, which absorb visible light (400-700 nm). Some cyanobacteria facultatively acclimate to shaded environments by altering their photosynthetic machinery to additionally absorb far-red light (FRL, 700-800 nm), a process termed far-red light photoacclimation or FaRLiP. During far-red light photoacclimation, FRL-PSII is assembled with FRL-specific isoforms of the subunits PsbA, PsbB, PsbC, PsbD, and PsbH, and some Chl-binding sites contain Chls d or f instead of the usual Chl a. The structure of an apo-FRL-PSII monomer lacking the FRL-specific PsbH subunit has previously been determined, but visualization of the dimeric complex has remained elusive. Here, we report the cryo-EM structure of a dimeric FRL-PSII complex. The site assignments for Chls d and f are consistent with those assigned in the previous apo-FRL-PSII monomeric structure. All sites that bind Chl d or Chl f at high occupancy exhibit a FRL-specific interaction of the formyl moiety of the Chl d or Chl f with the protein environment, which in some cases involves a phenylalanine sidechain. The structure retains the FRL-specific PsbH2 subunit, which appears to alter the energetic landscape of FRL-PSII, redirecting energy transfer from the phycobiliprotein complex to a Chl f molecule bound by PsbB2 that acts as a bridge for energy transfer to the electron transfer chain. Collectively, these observations extend our previous understanding of the structure-function relationship that allows PSII to function using lower energy FRL.
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Affiliation(s)
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - David A Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Muhamed Amin
- Department of Sciences, University College Groningen, University of Groningen, Groningen, the Netherlands; Rijksuniversiteit Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands; Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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12
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Vergara-Barros P, Alcorta J, Casanova-Katny A, Nürnberg DJ, Díez B. Compensatory Transcriptional Response of Fischerella thermalis to Thermal Damage of the Photosynthetic Electron Transfer Chain. Molecules 2022; 27:8515. [PMID: 36500606 PMCID: PMC9740203 DOI: 10.3390/molecules27238515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 12/11/2022] Open
Abstract
Key organisms in the environment, such as oxygenic photosynthetic primary producers (photosynthetic eukaryotes and cyanobacteria), are responsible for fixing most of the carbon globally. However, they are affected by environmental conditions, such as temperature, which in turn affect their distribution. Globally, the cyanobacterium Fischerella thermalis is one of the main primary producers in terrestrial hot springs with thermal gradients up to 60 °C, but the mechanisms by which F. thermalis maintains its photosynthetic activity at these high temperatures are not known. In this study, we used molecular approaches and bioinformatics, in addition to photophysiological analyses, to determine the genetic activity associated with the energy metabolism of F. thermalis both in situ and in high-temperature (40 °C to 65 °C) cultures. Our results show that photosynthesis of F. thermalis decays with temperature, while increased transcriptional activity of genes encoding photosystem II reaction center proteins, such as PsbA (D1), could help overcome thermal damage at up to 60 °C. We observed that F. thermalis tends to lose copies of the standard G4 D1 isoform while maintaining the recently described D1INT isoform, suggesting a preference for photoresistant isoforms in response to the thermal gradient. The transcriptional activity and metabolic characteristics of F. thermalis, as measured by metatranscriptomics, further suggest that carbon metabolism occurs in parallel with photosynthesis, thereby assisting in energy acquisition under high temperatures at which other photosynthetic organisms cannot survive. This study reveals that, to cope with the harsh conditions of hot springs, F. thermalis has several compensatory adaptations, and provides emerging evidence for mixotrophic metabolism as being potentially relevant to the thermotolerance of this species. Ultimately, this work increases our knowledge about thermal adaptation strategies of cyanobacteria.
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Affiliation(s)
- Pablo Vergara-Barros
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago 8370186, Chile
| | - Jaime Alcorta
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
| | - Angélica Casanova-Katny
- Laboratory of Plant Ecophysiology, Faculty of Natural Resources, Campus Luis Rivas del Canto, Catholic University of Temuco, Temuco 4780000, Chile
| | - Dennis J. Nürnberg
- Institute of Experimental Physics, Freie Universität Berlin, 14195 Berlin, Germany
- Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany
| | - Beatriz Díez
- Department of Molecular Genetics and Microbiology, Biological Sciences Faculty, Pontifical Catholic University of Chile, Santiago 8331150, Chile
- Millennium Institute Center for Genome Regulation (CGR), Santiago 8370186, Chile
- Center for Climate and Resilience Research (CR)2, Santiago 8370449, Chile
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13
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Pinevich AV, Averina SG. On the Edge of the Rainbow: Red-Shifted Chlorophylls and Far-Red Light Photoadaptation in Cyanobacteria. Microbiology (Reading) 2022. [DOI: 10.1134/s0026261722602019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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