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Ortega-Martínez P, Nikkanen L, Wey LT, Florencio FJ, Allahverdiyeva Y, Díaz-Troya S. Glycogen synthesis prevents metabolic imbalance and disruption of photosynthetic electron transport from photosystem II during transition to photomixotrophy in Synechocystis sp. PCC 6803. THE NEW PHYTOLOGIST 2024; 243:162-179. [PMID: 38706429 DOI: 10.1111/nph.19793] [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: 02/13/2024] [Accepted: 04/17/2024] [Indexed: 05/07/2024]
Abstract
Some cyanobacteria can grow photoautotrophically or photomixotrophically by using simultaneously CO2 and glucose. The switch between these trophic modes and the role of glycogen, their main carbon storage macromolecule, was investigated. We analysed the effect of glucose addition on the physiology, metabolic and photosynthetic state of Synechocystis sp. PCC 6803 and mutants lacking phosphoglucomutase and ADP-glucose pyrophosphorylase, with limitations in glycogen synthesis. Glycogen acted as a metabolic buffer: glucose addition increased growth and glycogen reserves in the wild-type (WT), but arrested growth in the glycogen synthesis mutants. Already 30 min after glucose addition, metabolites from the Calvin-Benson-Bassham cycle and the oxidative pentose phosphate shunt increased threefold more in the glycogen synthesis mutants than the WT. These alterations substantially affected the photosynthetic performance of the glycogen synthesis mutants, as O2 evolution and CO2 uptake were both impaired. We conclude that glycogen synthesis is essential during transitions to photomixotrophy to avoid metabolic imbalance that induces inhibition of electron transfer from PSII and subsequently accumulation of reactive oxygen species, loss of PSII core proteins, and cell death. Our study lays foundations for optimising photomixotrophy-based biotechnologies through understanding the coordination of the crosstalk between photosynthetic electron transport and metabolism.
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Affiliation(s)
- Pablo Ortega-Martínez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Américo Vespucio 49, Sevilla, 41092, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, Sevilla, 41012, Spain
| | - Lauri Nikkanen
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
| | - Laura T Wey
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
| | - Francisco J Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Américo Vespucio 49, Sevilla, 41092, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, Sevilla, 41012, Spain
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Life Technologies, University of Turku, Turku, FI-20014, Finland
| | - Sandra Díaz-Troya
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas, Américo Vespucio 49, Sevilla, 41092, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, Sevilla, 41012, Spain
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Rohani L, Lamichhane HP, Hastings G. Calculated vibrational properties of pigments in protein binding sites 2: Semiquinones in photosynthetic proteins. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 295:122518. [PMID: 36996613 DOI: 10.1016/j.saa.2023.122518] [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: 10/11/2022] [Revised: 02/03/2023] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
[QA- - QA] Fourier transform infrared difference spectra have previously been obtained using purple bacterial reaction centers from Rhodobacter sphaeroides with unlabeled, 18O and 13C isotope labeled phylloquinone (PhQ, also known as vitamin K1) incorporated into the QA protein binding site (Breton, (1997), Proc. Natl. Acad. Sci. USA94 11318-11323). The nature of the bands in these spectra and the isotope induced band shifts are poorly understood, especially for the phyllosemiquinone anion (PhQ-) state. To aid in the interpretation of the bands in these experimental spectra, ONIOM type QM/MM vibrational frequency calculations were undertaken. Calculations were also undertaken for PhQ- in solution. Surprisingly, both sets of calculated spectra are similar and agree well with the experimental spectra. This similarity suggests pigment-protein interactions do not perturb the electronic structure of the semiquinone in the QA binding site. This is not found to be the case for the neutral PhQ species in the same protein binding site. PhQ also occupies the A1 protein binding site in photosystem I, and the vibrational properties of PhQ- in the QA and A1 binding sites are compared and shown to exhibit considerable differences. These differences probably arise because of changes in the degree of asymmetry of hydrogen bonding of PhQ- in the A1 and QA binding sites.
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Affiliation(s)
- Leyla Rohani
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA
| | - Hari P Lamichhane
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA
| | - Gary Hastings
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA.
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Kim J, Kim C, Kim S, Ihee H, Shin W, Kim EJ, Lee JK. The Photoactive Photosynthetic Reaction Center of a Rhodobacter sphaeroides Mutant Lacking 3-Vinyl (Bacterio)Chlorophyllide a Hydratase Contains 3-Vinyl Bacteriochlorophyll a. Microbiol Spectr 2023; 11:e0387822. [PMID: 36971575 PMCID: PMC10101016 DOI: 10.1128/spectrum.03878-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 02/20/2023] [Indexed: 03/29/2023] Open
Abstract
Rhodobacter sphaeroides mutant BF-lacking 3-vinyl (bacterio)chlorophyllide a hydratase (BchF)-accumulates chlorophyllide a (Chlide a) and 3-vinyl bacteriochlorophyllide a (3V-Bchlide a). BF synthesizes 3-vinyl bacteriochlorophyll a (3V-Bchl a) through prenylation of 3V-Bchlide a and assembles a novel reaction center (V-RC) using 3V-Bchl a and Mg-free 3-vinyl bacteriopheophytin a (3V-Bpheo a) at a molar ratio of 2:1. We aimed to verify whether a bchF-deleted R. sphaeroides mutant produces a photochemically active RC that facilitates photoheterotrophic growth. The mutant grew photoheterotrophically-implying a functional V-RC-as confirmed by the emergence of growth-competent suppressors of bchC-deleted mutant (BC) under irradiation. Suppressor mutations in BC were localized to bchF, which diminished BchF activity and caused 3V-Bchlide a accumulation. bchF expression carrying the suppressor mutations in trans resulted in the coproduction of V-RC and wild-type RC (WT-RC) in BF. The V-RC had a time constant (τ) for electron transfer from the primary electron donor P (a dimer of 3V-Bchl a) to the A-side containing 3V-Bpheo a (HA) similar to that of the WT-RC and a 60% higher τ for electron transfer from HA to quinone A (QA). Thus, the electron transfer from HA to QA in the V-RC should be slower than that in the WT-RC. Furthermore, the midpoint redox potential of P/P+ of the V-RC was 33 mV more positive than that of the WT-RC. R. sphaeroides, thus, synthesizes the V-RC when 3V-Bchlide a accumulates. The V-RC can support photoheterotrophic growth; however, its photochemical activity is inferior to that of the WT-RC. IMPORTANCE 3V-Bchlide a is an intermediate in the bacteriochlorophyll a (Bchl a)-specific biosynthetic branch and prenylated by bacteriochlorophyll synthase. R. sphaeroides synthesizes V-RC that absorbs light at short wavelengths. The V-RC was not previously discovered because 3V-Bchlide a does not accumulate during the growth of WT cells synthesizing Bchl a. The levels of reactive oxygen species increased with the onset of photoheterotrophic growth in BF, resulting in a long lag period. Although the inhibitor of BchF is unknown, the V-RC may act as a substitute for the WT-RC when BchF is completely inhibited. Alternatively, it may act synergistically with WT-RC at low levels of BchF activity. The V-RC may broaden the absorption spectra of R. sphaeroides and supplement its photosynthetic ability at various wavelengths of visible light to a greater extent than that by the WT-RC alone.
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Affiliation(s)
- June Kim
- Department of Life Science, Sogang University, Seoul, Republic of Korea
| | - Changwon Kim
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Siin Kim
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Hyotcherl Ihee
- Department of Chemistry and KI for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- Center for Advanced Reaction Dynamics, Institute for Basic Science, Daejeon, Republic of Korea
| | - Woonsup Shin
- Department of Chemistry, Sogang University, Seoul, Republic of Korea
| | - Eui-Jin Kim
- Microbial Research Department, Nakdonggang National Institute of Biological Resources, Gyeongsangbuk-do, Republic of Korea
| | - Jeong K. Lee
- Department of Life Science, Sogang University, Seoul, Republic of Korea
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Electrostatics of the photosynthetic bacterial reaction center. Protonation of Glu L 212 and Asp L 213 — A new method of calculation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015. [DOI: 10.1016/j.bbabio.2015.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Müh F, Zouni A. The nonheme iron in photosystem II. PHOTOSYNTHESIS RESEARCH 2013; 116:295-314. [PMID: 24077892 DOI: 10.1007/s11120-013-9926-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/17/2013] [Indexed: 06/02/2023]
Abstract
Photosystem II (PSII), the light-driven water:plastoquinone (PQ) oxidoreductase of oxygenic photosynthesis, contains a nonheme iron (NHI) at its electron acceptor side. The NHI is situated between the two PQs QA and QB that serve as one-electron transmitter and substrate of the reductase part of PSII, respectively. Among the ligands of the NHI is a (bi)carbonate originating from CO2, the substrate of the dark reactions of oxygenic photosynthesis. Based on recent advances in the crystallography of PSII, we review the structure of the NHI in PSII and discuss ideas concerning its function and the role of bicarbonate along with a comparison to the reaction center of purple bacteria and other enzymes containing a mononuclear NHI site.
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Chernev P, Zaharieva I, Dau H, Haumann M. Carboxylate shifts steer interquinone electron transfer in photosynthesis. J Biol Chem 2011; 286:5368-74. [PMID: 21169354 PMCID: PMC3037649 DOI: 10.1074/jbc.m110.202879] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 12/10/2010] [Indexed: 11/06/2022] Open
Abstract
Understanding the mechanisms of electron transfer (ET) in photosynthetic reaction centers (RCs) may inspire novel catalysts for sunlight-driven fuel production. The electron exit pathway of type II RCs comprises two quinone molecules working in series and in between a non-heme iron atom with a carboxyl ligand (bicarbonate in photosystem II (PSII), glutamate in bacterial RCs). For decades, the functional role of the iron has remained enigmatic. We tracked the iron site using microsecond-resolution x-ray absorption spectroscopy after laser-flash excitation of PSII. After formation of the reduced primary quinone, Q(A)(-), the x-ray spectral changes revealed a transition (t½ ≈ 150 μs) from a bidentate to a monodentate coordination of the bicarbonate at the Fe(II) (carboxylate shift), which reverted concomitantly with the slower ET to the secondary quinone Q(B). A redox change of the iron during the ET was excluded. Density-functional theory calculations corroborated the carboxylate shift both in PSII and bacterial RCs and disclosed underlying changes in electronic configuration. We propose that the iron-carboxyl complex facilitates the first interquinone ET by optimizing charge distribution and hydrogen bonding within the Q(A)FeQ(B) triad for high yield Q(B) reduction. Formation of a specific priming intermediate by nuclear rearrangements, setting the stage for subsequent ET, may be a common motif in reactions of biological redox cofactors.
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Affiliation(s)
- Petko Chernev
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Ivelina Zaharieva
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Holger Dau
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Michael Haumann
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
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Orzechowska A, Lipińska M, Fiedor J, Chumakov A, Zając M, Ślęzak T, Matlak K, Strzałka K, Korecki J, Fiedor L, Burda K. Coupling of collective motions of the protein matrix to vibrations of the non-heme iron in bacterial photosynthetic reaction centers. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1696-704. [DOI: 10.1016/j.bbabio.2010.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2009] [Revised: 06/23/2010] [Accepted: 06/26/2010] [Indexed: 10/19/2022]
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Semenov A, Cherepanov D, Mamedov M. Electrogenic reactions and dielectric properties of photosystem II. PHOTOSYNTHESIS RESEARCH 2008; 98:121-30. [PMID: 18937043 DOI: 10.1007/s11120-008-9377-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 10/01/2008] [Indexed: 05/12/2023]
Abstract
This review is focused on the mechanism of photovoltage generation involving the photosystem II turnover. This large integral membrane enzyme catalyzes the light-driven oxidation of water and reduction of plastoquinone. The data discussed in this work show that there are four main electrogenic steps in native complexes: (i) light-induced charge separation between special pair chlorophylls P(680) and primary quinone acceptor Q(A); (ii) P(680)(+) reduction by the redox-active tyrosine Y(Z) of polypeptide D1; (iii) oxidation of Mn cluster by Y(Z)(ox) followed by proton release, and (iv) protonation of double reduced secondary quinone acceptor Q(B). The electrogenicity related to (i) proton-coupled electron transfer between Q(A)(-) and preoxidized non-heme iron (Fe(3+)) in native and (ii) electron transfer between protein-water boundary and Y(Z)(ox) in the presence of redox-dye(s) in Mn-depleted samples, respectively, were also considered. Evaluation of the dielectric properties using the electrometric data and the polarity profiles of reaction center from purple bacteria Blastochloris viridis and photosystem II are presented. The knowledge of the profile of dielectric permittivity along the photosynthetic reaction center is important for understanding of the mechanism of electron transfer between redox cofactors.
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Affiliation(s)
- Alexey Semenov
- A.N. Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, Russia.
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Nabedryk E, Breton J. Coupling of electron transfer to proton uptake at the QB site of the bacterial reaction center: A perspective from FTIR difference spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1229-48. [DOI: 10.1016/j.bbabio.2008.06.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/26/2008] [Accepted: 06/27/2008] [Indexed: 01/09/2023]
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