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Uphill energy transfer mechanism for photosynthesis in an Antarctic alga. Nat Commun 2023; 14:730. [PMID: 36792917 PMCID: PMC9931709 DOI: 10.1038/s41467-023-36245-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 01/20/2023] [Indexed: 02/17/2023] Open
Abstract
Prasiola crispa, an aerial green alga, forms layered colonies under the severe terrestrial conditions of Antarctica. Since only far-red light is available at a deep layer of the colony, P. crispa has evolved a molecular system for photosystem II (PSII) excitation using far-red light with uphill energy transfer. However, the molecular basis underlying this system remains elusive. Here, we purified a light-harvesting chlorophyll (Chl)-binding protein complex from P. crispa (Pc-frLHC) that excites PSII with far-red light and revealed its ring-shaped structure with undecameric 11-fold symmetry at 3.13 Å resolution. The primary structure suggests that Pc-frLHC evolved from LHCI rather than LHCII. The circular arrangement of the Pc-frLHC subunits is unique among eukaryote LHCs and forms unprecedented Chl pentamers at every subunit‒subunit interface near the excitation energy exit sites. The Chl pentamers probably contribute to far-red light absorption. Pc-frLHC's unique Chl arrangement likely promotes PSII excitation with entropy-driven uphill excitation energy transfer.
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Giovagnetti V, Ruban AV. The mechanism of regulation of photosystem I cross-section in the pennate diatom Phaeodactylum tricornutum. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:561-575. [PMID: 33068431 DOI: 10.1093/jxb/eraa478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/12/2020] [Indexed: 06/11/2023]
Abstract
Photosystems possess distinct fluorescence emissions at low (77K) temperature. PSI emits in the long-wavelength region at ~710-740 nm. In diatoms, a successful clade of marine primary producers, the contribution of PSI-associated emission (710-717 nm) has been shown to be relatively small. However, in the pennate diatom Phaeodactylum tricornutum, the source of the long-wavelength emission at ~710 nm (F710) remains controversial. Here, we addressed the origin and modulation of F710 fluorescence in this alga grown under continuous and intermittent light. The latter condition led to a strong enhancement in F710. Biochemical and spectral properties of the photosynthetic complexes isolated from thylakoid membranes were investigated for both culture conditions. F710 emission appeared to be associated with PSI regardless of light acclimation. To further assess whether PSII could also contribute to this emission, we decreased the concentration of PSII reaction centres and core antenna by growing cells with lincomycin, a chloroplast protein synthesis inhibitor. The treatment did not diminish F710 fluorescence. Our data suggest that F710 emission originates from PSI under the conditions tested and is enhanced in intermittent light-grown cells due to increased energy flow from the FCP antenna to PSI.
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Affiliation(s)
- Vasco Giovagnetti
- Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
| | - Alexander V Ruban
- Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, UK
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Enhanced Light-Induced Biosynthesis of Fatty Acids Suitable for Biodiesel Production by the Yellow-Green Alga Eustigmatos magnus. ENERGIES 2020. [DOI: 10.3390/en13226098] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Optimization of the fatty acid profile in microalgae is one of the key strategies for obtaining valuable products and sustainable biofuels. Light intensity and light regimes exert an impact on the growth and metabolic process in microalgae. The objective of the present investigations was to assess the effect of light intensity and continuous light vs. photoperiod conditions on the growth and changes in the biomass composition in Eustigmatos magnus, with a focus on bioactive molecules such as lipids and fatty acids. The highest daily productivity of Eustigmatos magnus biomass and lipid yields were detected at continuous illumination and at the highest intensity of light. The results show that the content and composition of fatty acids was influenced by the culture conditions. The biomass of Eustigmatos magnus contained the highest concentrations of polyunsaturated fatty acids in the pphotoperiod conditions with the highest light intensity. This study shows that Eustigmatos magnus has a capacity for the accumulation of palmitoleic acid. A high intensity of continuous light improves the profile of fatty acids in Eustigmatos magnus, which can be suitable for biodiesel applications. At the high intensity of continuous light, Eustigmatos magnus lipids are characterized by high content of oleic acids and low content of saturated and monounsaturated acids.
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Kosugi M, Ozawa SI, Takahashi Y, Kamei Y, Itoh S, Kudoh S, Kashino Y, Koike H. Red-shifted chlorophyll a bands allow uphill energy transfer to photosystem II reaction centers in an aerial green alga, Prasiola crispa, harvested in Antarctica. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148139. [DOI: 10.1016/j.bbabio.2019.148139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 11/14/2019] [Accepted: 12/04/2019] [Indexed: 12/22/2022]
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Wolf BM, Blankenship RE. Far-red light acclimation in diverse oxygenic photosynthetic organisms. PHOTOSYNTHESIS RESEARCH 2019; 142:349-359. [PMID: 31222688 DOI: 10.1007/s11120-019-00653-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/03/2019] [Indexed: 06/09/2023]
Abstract
Oxygenic photosynthesis has historically been considered limited to be driven by the wavelengths of visible light. However, in the last few decades, various adaptations have been discovered that allow algae, cyanobacteria, and even plants to utilize longer wavelength light in the far-red spectral range. These adaptations provide distinct advantages to the species possessing them, allowing the effective utilization of shade light under highly filtered light environments. In prokaryotes, these adaptations include the production of far-red-absorbing chlorophylls d and f and the remodeling of phycobilisome antennas and reaction centers. Eukaryotes express specialized light-harvesting pigment-protein complexes that use interactions between pigments and their protein environment to spectrally tune the absorption of chlorophyll a. If these adaptations could be applied to crop plants, a potentially significant increase in photon utilization in lower shaded leaves could be realized, improving crop yields.
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Affiliation(s)
- Benjamin M Wolf
- Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA.
| | - Robert E Blankenship
- Departments of Biology and Chemistry, Washington University in St. Louis, St. Louis, MO, 63130, USA
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Litvín R, Bína D, Herbstová M, Pazderník M, Kotabová E, Gardian Z, Trtílek M, Prášil O, Vácha F. Red-shifted light-harvesting system of freshwater eukaryotic alga Trachydiscus minutus (Eustigmatophyta, Stramenopila). PHOTOSYNTHESIS RESEARCH 2019; 142:137-151. [PMID: 31375979 DOI: 10.1007/s11120-019-00662-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
Survival of phototrophic organisms depends on their ability to collect and convert enough light energy to support their metabolism. Phototrophs can extend their absorption cross section by using diverse pigments and by tuning the properties of these pigments via pigment-pigment and pigment-protein interaction. It is well known that some cyanobacteria can grow in heavily shaded habitats by utilizing far-red light harvested with far-red-absorbing chlorophylls d and f. We describe a red-shifted light-harvesting system based on chlorophyll a from a freshwater eustigmatophyte alga Trachydiscus minutus (Eustigmatophyceae, Goniochloridales). A comprehensive characterization of the photosynthetic apparatus of T. minutus is presented. We show that thylakoid membranes of T. minutus contain light-harvesting complexes of several sizes differing in the relative amount of far-red chlorophyll a forms absorbing around 700 nm. The pigment arrangement of the major red-shifted light-harvesting complex is similar to that of the red-shifted antenna of a marine alveolate alga Chromera velia. Evolutionary aspects of the algal far-red light-harvesting complexes are discussed. The presence of these antennas in eustigmatophyte algae opens up new ways to modify organisms of this promising group for effective use of far-red light in mass cultures.
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Affiliation(s)
- Radek Litvín
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Biology Centre, The Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - David Bína
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic.
- Biology Centre, The Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic.
| | - Miroslava Herbstová
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Biology Centre, The Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Marek Pazderník
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, 379 81, Třeboň, Czech Republic
| | - Eva Kotabová
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, 379 81, Třeboň, Czech Republic
| | - Zdenko Gardian
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Biology Centre, The Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic
| | - Martin Trtílek
- PSI (Photon Systems Instruments), spol. s r.o. Drásov 470, 664 24, Drásov, Czech Republic
| | - Ondřej Prášil
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Institute of Microbiology, The Czech Academy of Sciences, Opatovický mlýn, 379 81, Třeboň, Czech Republic
| | - František Vácha
- Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05, České Budějovice, Czech Republic
- Biology Centre, The Czech Academy of Sciences, Branišovská 31, 370 05, České Budějovice, Czech Republic
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Büchel C. Light harvesting complexes in chlorophyll c-containing algae. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148027. [PMID: 31153887 DOI: 10.1016/j.bbabio.2019.05.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 12/30/2022]
Abstract
Besides the so-called 'green lineage' of eukaryotic photosynthetic organisms that include vascular plants, a huge variety of different algal groups exist that also harvest light by means of membrane intrinsic light harvesting proteins (Lhc). The main taxa of these algae are the Cryptophytes, Haptophytes, Dinophytes, Chromeridae and the Heterokonts, the latter including diatoms, brown algae, Xanthophyceae and Eustigmatophyceae amongst others. Despite the similarity in Lhc proteins between vascular plants and these algae, pigmentation is significantly different since no Chl b is bound, but often replaced by Chl c, and a large diversity in carotenoids functioning in light harvesting and/or photoprotection is present. Due to the presence of Chl c in most of the taxa the name 'Chl c-containing organisms' has become common, however, Chl b-less is more precise since some harbour Lhc proteins that only bind one type of Chl, Chl a. In recent years huge progress has been made about the occurrence and function of Lhc in diatoms, so-called fucoxanthin chlorophyll proteins (FCP), where also the first molecular structure became available recently. In addition, especially energy transfer amongst the unusual pigments bound was intensively studied in many of these groups. This review summarises the present knowledge about the molecular structure, the arrangement of the different Lhc in complexes, the excitation energy transfer abilities and the involvement in photoprotection of the different Lhc systems in the so-called Chl c-containing organisms. This article is part of a Special Issue entitled Light harvesting, edited by Dr. Roberta Croce.
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Affiliation(s)
- Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt, Germany.
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