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Beraldo C, Traverso E, Boschin M, Cendron L, Morosinotto T, Alboresi A. Physcomitrium patens flavodiiron proteins form heterotetrametric complexes. J Biol Chem 2024; 300:107643. [PMID: 39122005 DOI: 10.1016/j.jbc.2024.107643] [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: 02/06/2024] [Revised: 07/11/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024] Open
Abstract
Flavodiiron proteins (FLVs) catalyze the reduction of oxygen to water by using electrons from Photosystem I (PSI). In several photosynthetic organisms such as cyanobacteria, green algae, mosses and gymnosperms, FLV-dependent electron flow protects PSI from over-reduction and consequent damage especially under fluctuating light conditions. In this work we investigated biochemical and structural properties of FLVA and FLVB from the model moss Physcomitrium patens. The two proteins, expressed and purified from Escherichia coli, bind both iron and flavin cofactors and show NAD(P)H oxidase activity as well as oxygen reductase capacities. Moreover, the co-expression of both FLVA and FLVB, coupled to a tandem affinity purification procedure with two different affinity tags, enabled the isolation of the stable and catalytically active FLVA/B hetero tetrameric protein complex with cooperative nature. The multimeric organization was shown to be stabilized by inter-subunit disulfide bonds. This investigation provides valuable new information on the biochemical properties of FLVs, with new insights into their in vivo activity.
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Affiliation(s)
| | | | - Marco Boschin
- Department of Biology, University of Padova, Padova, Italy
| | - Laura Cendron
- Department of Biology, University of Padova, Padova, Italy
| | | | - Alessandro Alboresi
- Department of Biology, University of Padova, Padova, Italy; National Biodiversity Future Center, Università degli Studi di Palermo, Palermo, Italy.
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Hüner NPA, Ivanov AG, Szyszka-Mroz B, Savitch LV, Smith DR, Kata V. Photostasis and photosynthetic adaptation to polar life. PHOTOSYNTHESIS RESEARCH 2024; 161:51-64. [PMID: 38865029 DOI: 10.1007/s11120-024-01104-7] [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: 04/24/2024] [Accepted: 05/29/2024] [Indexed: 06/13/2024]
Abstract
Photostasis is the light-dependent maintenance of energy balance associated with cellular homeostasis in photoautotrophs. We review evidence that illustrates how photosynthetic adaptation in polar photoautrophs such as aquatic green algae, cyanobacteria, boreal conifers as well as terrestrial angiosperms exhibit an astonishing plasticity in structure and function of the photosynthetic apparatus. This plasticity contributes to the maintenance of photostasis, which is essential for the long-term survival in the seemingly inhospitable Antarctic and Arctic habitats. However, evidence indicates that polar photoautrophic species exhibit different functional solutions for the maintenance of photostasis. We suggest that this reflects, in part, the genetic diversity symbolized by inherent genetic redundancy characteristic of polar photoautotrophs which enhances their survival in a thermodynamically challenging environment.
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Affiliation(s)
- Norman P A Hüner
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada.
| | - Alexander G Ivanov
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 21, Sofia, 1113, Bulgaria
| | - Beth Szyszka-Mroz
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Leonid V Savitch
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre, Ottawa, ON, K1A OC6, Canada
| | - David R Smith
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
| | - Victoria Kata
- Department of Biology, University of Western Ontario, 1151 Richmond St, London, ON, N6A 3K7, Canada
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Grebe S, Porcar-Castell A, Riikonen A, Paakkarinen V, Aro EM. Accounting for photosystem I photoinhibition sheds new light on seasonal acclimation strategies of boreal conifers. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:3973-3992. [PMID: 38572950 PMCID: PMC11233416 DOI: 10.1093/jxb/erae145] [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] [Accepted: 05/30/2024] [Indexed: 04/05/2024]
Abstract
The photosynthetic acclimation of boreal evergreen conifers is controlled by regulatory and photoprotective mechanisms that allow conifers to cope with extreme environmental changes. However, the underlying dynamics of photosystem II (PSII) and photosystem I (PSI) remain unresolved. Here, we investigated the dynamics of PSII and PSI during the spring recovery of photosynthesis in Pinus sylvestris and Picea abies using a combination of chlorophyll a fluorescence, P700 difference absorbance measurements, and quantification of key thylakoid protein abundances. In particular, we derived a new set of PSI quantum yield equations, correcting for the effects of PSI photoinhibition. Using the corrected equations, we found that the seasonal dynamics of PSII and PSI photochemical yields remained largely in balance, despite substantial seasonal changes in the stoichiometry of PSII and PSI core complexes driven by PSI photoinhibition. Similarly, the previously reported seasonal up-regulation of cyclic electron flow was no longer evident, after accounting for PSI photoinhibition. Overall, our results emphasize the importance of considering the dynamics of PSII and PSI to elucidate the seasonal acclimation of photosynthesis in overwintering evergreens. Beyond the scope of conifers, our corrected PSI quantum yields expand the toolkit for future studies aimed at elucidating the dynamic regulation of PSI.
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Affiliation(s)
- Steffen Grebe
- Molecular Plant Biology, Department of Life Technologies, University of Turku, 20014 Turku, Finland
- Optics of Photosynthesis Laboratory, Viikki Plant Science Center, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Albert Porcar-Castell
- Optics of Photosynthesis Laboratory, Viikki Plant Science Center, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Anu Riikonen
- Optics of Photosynthesis Laboratory, Viikki Plant Science Center, Institute for Atmospheric and Earth System Research/Forest Sciences, University of Helsinki, 00014 Helsinki, Finland
| | - Virpi Paakkarinen
- Molecular Plant Biology, Department of Life Technologies, University of Turku, 20014 Turku, Finland
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Life Technologies, University of Turku, 20014 Turku, Finland
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Verhoeven A, Kornkven J. Differences in photoprotective strategy during winter in Eastern white pine and white spruce. TREE PHYSIOLOGY 2024; 44:tpad131. [PMID: 37861656 DOI: 10.1093/treephys/tpad131] [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: 06/30/2023] [Revised: 09/22/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
Conifers growing in temperate forests utilize sustained forms of thermal dissipation during winter to protect the photosynthetic apparatus from damage, which can be monitored via pronounced reductions in photochemical efficiency (Fv/Fm) during winter. Eastern white pine (Pinus strobus L.) and white spruce (Picea glauca (Moench) Voss) are known to recover from winter stress at different rates, with pine recovering more slowly than spruce, suggesting different mechanisms for sustained dissipation in these species. Our objectives were to monitor pine and spruce throughout spring recovery in order to provide insights into key mechanisms for sustained dissipation in both species. We measured chlorophyll fluorescence, pigments, and abundance and phosphorylation status of key photosynthetic proteins. We found that both species rely on two forms of sustained dissipation involving retention of high amounts of antheraxanthin (A) + zeaxanthin (Z), one that is very slowly reversible and temperature independent and one that is more dynamic and occurs only on subzero days. Differences in protein abundance suggest that spruce, but not pine, likely upregulates cyclic or alternative pathways of electron transport involving the cytochrome b6f complex and photosystem I (PSI). Both species show an increased sustained phosphorylation of the D1 protein on subzero days, and spruce additionally shows dramatic increases in the sustained phosphorylation of light-harvesting complex II (LHCII) and other PSII core proteins on subzero days only, suggesting that a mechanism of sustained dissipation that is temperature dependent requires sustained phosphorylation of photosynthetic proteins in spruce, possibly allowing for direct energy transfer from PSII to PSI as a mechanism of photoprotection. The data suggest differences in strategy among conifers in mechanisms of sustained thermal dissipation in response to winter stress. Additionally, the flexible induction of sustained A + Z and phosphorylation of photosynthetic proteins in response to subzero temperatures during spring recovery seem to be important in providing photoprotection during transitional periods with high temperature fluctuation.
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Affiliation(s)
- Amy Verhoeven
- Biology Department (OWS352), University of St Thomas, 2115 Summit Ave, St Paul, MN 55105 USA
| | - Joan Kornkven
- Biology Department (OWS352), University of St Thomas, 2115 Summit Ave, St Paul, MN 55105 USA
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Shevela D, Schröder WP, Messinger J. Measurements of Oxygen Evolution in Photosynthesis. Methods Mol Biol 2024; 2790:133-148. [PMID: 38649570 DOI: 10.1007/978-1-0716-3790-6_8] [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: 04/25/2024]
Abstract
This chapter compares two different techniques for monitoring photosynthetic O2 production; the wide-spread Clark-type O2 electrode and the more sophisticated membrane inlet mass spectrometry (MIMS) technique. We describe how a simple membrane inlet for MIMS can be made out of a commercial Clark-type cell and outline the advantages and drawbacks of the two techniques to guide researchers in deciding which method to use. Protocols and examples are given for measuring O2 evolution rates and for determining the number of chlorophyll molecules per active photosystem II reaction center.
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Affiliation(s)
| | | | - Johannes Messinger
- Department of Chemistry, Umeå University, Umeå, Sweden.
- Department of Chemistry - Ångström, Uppsala University, Uppsala, Sweden.
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