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Amin M. Predicting the oxidation states of Mn ions in the oxygen-evolving complex of photosystem II using supervised and unsupervised machine learning. PHOTOSYNTHESIS RESEARCH 2023; 156:89-100. [PMID: 35896927 PMCID: PMC10070209 DOI: 10.1007/s11120-022-00941-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 07/13/2022] [Indexed: 05/21/2023]
Abstract
Serial Femtosecond Crystallography at the X-ray Free Electron Laser (XFEL) sources enabled the imaging of the catalytic intermediates of the oxygen evolution reaction of Photosystem II (PSII). However, due to the incoherent transition of the S-states, the resolved structures are a convolution from different catalytic states. Here, we train Decision Tree Classifier and K-means clustering models on Mn compounds obtained from the Cambridge Crystallographic Database to predict the S-state of the X-ray, XFEL, and CryoEM structures by predicting the Mn's oxidation states in the oxygen-evolving complex. The model agrees mostly with the XFEL structures in the dark S1 state. However, significant discrepancies are observed for the excited XFEL states (S2, S3, and S0) and the dark states of the X-ray and CryoEM structures. Furthermore, there is a mismatch between the predicted S-states within the two monomers of the same dimer, mainly in the excited states. We validated our model against other metalloenzymes, the valence bond model and the Mn spin densities calculated using density functional theory for two of the mismatched predictions of PSII. The model suggests designing a more optimized sample delivery and illumiation systems are crucial to precisely resolve the geometry of the advanced S-states to overcome the noncoherent S-state transition. In addition, significant radiation damage is observed in X-ray and CryoEM structures, particularly at the dangler Mn center (Mn4). Our model represents a valuable tool for investigating the electronic structure of the catalytic metal cluster of PSII to understand the water splitting mechanism.
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Affiliation(s)
- Muhamed Amin
- Department of Sciences, University College Groningen, University of Groningen, Hoendiepskade 23/24, 9718 BG, Groningen, The Netherlands.
- Rijksuniversiteit Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, Netherlands.
- Center for Free-Electron Laser Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607, Hamburg, Germany.
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Knoppová J, Sobotka R, Yu J, Bečková M, Pilný J, Trinugroho JP, Csefalvay L, Bína D, Nixon PJ, Komenda J. Assembly of D1/D2 complexes of photosystem II: Binding of pigments and a network of auxiliary proteins. PLANT PHYSIOLOGY 2022; 189:790-804. [PMID: 35134246 PMCID: PMC9157124 DOI: 10.1093/plphys/kiac045] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/07/2022] [Indexed: 06/14/2023]
Abstract
Photosystem II (PSII) is the multi-subunit light-driven oxidoreductase that drives photosynthetic electron transport using electrons extracted from water. To investigate the initial steps of PSII assembly, we used strains of the cyanobacterium Synechocystis sp. PCC 6803 arrested at early stages of PSII biogenesis and expressing affinity-tagged PSII subunits to isolate PSII reaction center assembly (RCII) complexes and their precursor D1 and D2 modules (D1mod and D2mod). RCII preparations isolated using either a His-tagged D2 or a FLAG-tagged PsbI subunit contained the previously described RCIIa and RCII* complexes that differ with respect to the presence of the Ycf39 assembly factor and high light-inducible proteins (Hlips) and a larger complex consisting of RCIIa bound to monomeric PSI. All RCII complexes contained the PSII subunits D1, D2, PsbI, PsbE, and PsbF and the assembly factors rubredoxin A and Ycf48, but we also detected PsbN, Slr1470, and the Slr0575 proteins, which all have plant homologs. The RCII preparations also contained prohibitins/stomatins (Phbs) of unknown function and FtsH protease subunits. RCII complexes were active in light-induced primary charge separation and bound chlorophylls (Chls), pheophytins, beta-carotenes, and heme. The isolated D1mod consisted of D1/PsbI/Ycf48 with some Ycf39 and Phb3, while D2mod contained D2/cytochrome b559 with co-purifying PsbY, Phb1, Phb3, FtsH2/FtsH3, CyanoP, and Slr1470. As stably bound, Chl was detected in D1mod but not D2mod, formation of RCII appears to be important for stable binding of most of the Chls and both pheophytins. We suggest that Chl can be delivered to RCII from either monomeric Photosystem I or Ycf39/Hlips complexes.
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Affiliation(s)
- Jana Knoppová
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Photosynthesis, Třeboň 37901, Czech Republic
| | - Roman Sobotka
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Photosynthesis, Třeboň 37901, Czech Republic
| | - Jianfeng Yu
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Martina Bečková
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Photosynthesis, Třeboň 37901, Czech Republic
| | - Jan Pilný
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Photosynthesis, Třeboň 37901, Czech Republic
| | - Joko P Trinugroho
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Ladislav Csefalvay
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Photosynthesis, Třeboň 37901, Czech Republic
| | - David Bína
- Faculty of Science, University of South Bohemia in České Budějovice, České Budějovice 370 05, Czech Republic
- Institute of Plant Molecular Biology, Biology Centre of the Czech Academy of Sciences, České Budějovice 370 05, Czech Republic
| | - Peter J Nixon
- Department of Life Sciences, Sir Ernst Chain Building-Wolfson Laboratories, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Josef Komenda
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Photosynthesis, Třeboň 37901, Czech Republic
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Zhu Y, Zhang Z, Xu X, Cheng J, Chen S, Tian J, Yang W, Crocker M. Simultaneous promotion of photosynthesis and astaxanthin accumulation during two stages of Haematococcus pluvialis with ammonium ferric citrate. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 750:141689. [PMID: 32871372 DOI: 10.1016/j.scitotenv.2020.141689] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
To simultaneously promote biomass yield and astaxanthin content of Haematococcus pluvialis, ammonium ferric citrate (AFC) was employed to stimulate light harvest in photosynthesis during the green stage and oxidation induction in astaxanthin accumulation during the red stage. AFC not only improved chlorophyll synthesis by 22.5% to provide more electrochemical potential energy in the green stage, but also alleviated photosystem II damage to maintain a high level of effective quantum yield by enhancing carotenoid production. The citrate derived from AFC stimulated acetyl-CoA and NADPH production through citric acid cycle and transaminase cycle during the red stage, resulting in an increased lipid content by 1.77-fold. The astaxanthin content in H. pluvialis cells cultivated with 5 μM AFC was 12.5% higher than that without AFC, which was attributed to severe oxidative stress caused by AFC through Haber-Weiss reaction. These results provided a new approach to reduce emission of greenhouse gasses with producing high-value products.
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Affiliation(s)
- Yanxia Zhu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Ze Zhang
- Shanghai Institute of Space Propulsion, Shanghai 201112, China; Shanghai Engineering Research Center of Space Engine, Shanghai 201112, China
| | - Xiaodan Xu
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Jun Cheng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China.
| | - Shutong Chen
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Jianglei Tian
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Weijuan Yang
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
| | - Mark Crocker
- Center of Applied Energy Research, University of Kentucky, Lexington, KY 40511, USA
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A TDDFT investigation of the Photosystem II reaction center: Insights into the precursors to charge separation. Proc Natl Acad Sci U S A 2020; 117:19705-19712. [PMID: 32747579 PMCID: PMC7443915 DOI: 10.1073/pnas.1922158117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Examining the excited states of the Photosystem II reaction center furthers our understanding of available charge separation pathways that lead to successful photosynthesis. Our results comprise the largest complete model of the Photosystem II reaction center to be described using time-dependent density functional theory reported in the literature to date. We reveal the molecular orbitals contributing to the excited states that are precursors to charge separation. We demonstrate that our model can successfully predict the action of specific mutations, a valuable tool for the agricultural industry. These models may also be beneficial in informing the design of artificial photosynthetic complexes as well as enhanced bioengineered photosystems. Photosystem II (PS II) captures solar energy and directs charge separation (CS) across the thylakoid membrane during photosynthesis. The highly oxidizing, charge-separated state generated within its reaction center (RC) drives water oxidation. Spectroscopic studies on PS II RCs are difficult to interpret due to large spectral congestion, necessitating modeling to elucidate key spectral features. Herein, we present results from time-dependent density functional theory (TDDFT) calculations on the largest PS II RC model reported to date. This model explicitly includes six RC chromophores and both the chlorin phytol chains and the amino acid residues <6 Å from the pigments’ porphyrin ring centers. Comparing our wild-type model results with calculations on mutant D1-His-198-Ala and D2-His-197-Ala RCs, our simulated absorption-difference spectra reproduce experimentally observed shifts in known chlorophyll absorption bands, demonstrating the predictive capabilities of this model. We find that inclusion of both nearby residues and phytol chains is necessary to reproduce this behavior. Our calculations provide a unique opportunity to observe the molecular orbitals that contribute to the excited states that are precursors to CS. Strikingly, we observe two high oscillator strength, low-lying states, in which molecular orbitals are delocalized over ChlD1 and PheD1 as well as one weaker oscillator strength state with molecular orbitals delocalized over the P chlorophylls. Both these configurations are a match for previously identified exciton–charge transfer states (ChlD1+PheD1−)* and (PD2+PD1−)*. Our results demonstrate the power of TDDFT as a tool, for studies of natural photosynthesis, or indeed future studies of artificial photosynthetic complexes.
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Zhu Y, Cheng J, Zhang Z, Liu J. Mutation of Arthrospira platensis by gamma irradiation to promote phenol tolerance and CO2 fixation for coal-chemical flue gas reduction. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Abstract
Photosynthesis and nitrogen fixation became evolutionarily immutable as “frozen metabolic accidents” because multiple interactions between the proteins and protein complexes involved led to their co-evolution in modules. This has impeded their adaptation to an oxidizing atmosphere, and reconfiguration now requires modification or replacement of whole modules, using either natural modules from exotic species or non-natural proteins with similar interaction potential. Ultimately, the relevant complexes might be reconstructed (almost) from scratch, starting either from appropriate precursor processes or by designing alternative pathways. These approaches will require advances in synthetic biology, laboratory evolution, and a better understanding of module functions.
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Affiliation(s)
- Dario Leister
- Faculty of Biology, Ludwig-Maximilians-University Munich, Großhaderner Str. 2, 82152, Planegg-Martinsried, Germany.
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Joshi CJ, Peebles CA, Prasad A. Modeling and analysis of flux distribution and bioproduct formation in Synechocystis sp. PCC 6803 using a new genome-scale metabolic reconstruction. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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9
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Kuwahara A, Arisaka S, Takeya M, Iijima H, Hirai MY, Osanai T. Modification of photosynthetic electron transport and amino acid levels by overexpression of a circadian-related histidine kinase hik8 in Synechocystis sp. PCC 6803. Front Microbiol 2015; 6:1150. [PMID: 26539179 PMCID: PMC4611142 DOI: 10.3389/fmicb.2015.01150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/05/2015] [Indexed: 11/13/2022] Open
Abstract
Cyanobacteria perform oxygenic photosynthesis, and the maintenance of photosynthetic electron transport chains is indispensable to their survival in various environmental conditions. Photosynthetic electron transport in cyanobacteria can be studied through genetic analysis because of the natural competence of cyanobacteria. We here show that a strain overexpressing hik8, a histidine kinase gene related to the circadian clock, exhibits an altered photosynthetic electron transport chain in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Respiratory activity was down-regulated under nitrogen-replete conditions. Photosynthetic activity was slightly lower in the hik8-overexpressing strain than in the wild-type after nitrogen depletion, and the values of photosynthetic parameters were altered by hik8 overexpression under nitrogen-replete and nitrogen-depleted conditions. Transcripts of genes encoding Photosystem I and II were increased by hik8 overexpression under nitrogen-replete conditions. Nitrogen starvation triggers increase in amino acids but the magnitude of the increase in several amino acids was diminished by hik8 overexpression. These genetic data indicate that Hik8 regulates the photosynthetic electron transport, which in turn alters primary metabolism during nitrogen starvation in this cyanobacterium.
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Affiliation(s)
- Ayuko Kuwahara
- RIKEN Center for Sustainable Resource ScienceYokohama, Japan
| | - Satomi Arisaka
- Department of Agricultural Chemistry, School of Agriculture, Meiji UniversityKawasaki, Japan
| | - Masahiro Takeya
- Department of Agricultural Chemistry, School of Agriculture, Meiji UniversityKawasaki, Japan
| | - Hiroko Iijima
- Department of Agricultural Chemistry, School of Agriculture, Meiji UniversityKawasaki, Japan
| | | | - Takashi Osanai
- RIKEN Center for Sustainable Resource ScienceYokohama, Japan
- Department of Agricultural Chemistry, School of Agriculture, Meiji UniversityKawasaki, Japan
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