1
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Eder M, Renger T. A Simple Expression for the Screening of Excitonic Couplings between Chlorophylls as Inferred for Photosystem I Trimers. Int J Mol Sci 2024; 25:9006. [PMID: 39201694 PMCID: PMC11355009 DOI: 10.3390/ijms25169006] [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: 07/19/2024] [Revised: 08/14/2024] [Accepted: 08/16/2024] [Indexed: 09/03/2024] Open
Abstract
The Coulomb coupling between transition densities of the pigments in photosynthetic pigment-protein complexes, termed excitonic coupling, is a key factor for the description of optical spectra and energy transfer. A challenging question is the quantification of the screening of the excitonic coupling by the optical polarizability of the environment. We use the equivalence between the sophisticated quantum chemical polarizable continuum (PCM) model and the simple electrostatic Poisson-TrEsp approach to analyze the distance and orientation dependence of the dielectric screening between chlorophylls in photosystem I trimers. On the basis of these calculations we find that the vacuum couplings Vmn(0) and the couplings in the dielectric medium Vmn=fmnVmn(0) are related by the empirical screening factor fmn=0.60+39.6θ(|κmn|-1.17)exp(-0.56Rmn/Å), where κmn is the usual orientational factor of the dipole-dipole coupling between the pigments, Rmn is the center-to-center distance, and the Heaviside-function θ(|κmn|-1.17) ensures that the exponential distance dependence only contributes for in-line type dipole geometries. We are confident that the present expression can be applied also to other pigment-protein complexes with chlorophyll or related pigments of similar shape. The variance between the Poisson-TrEsp and the approximate coupling values is found to decrease by a factor of 8 and 3-4 using the present expression, instead of an exponential distance dependent or constant screening factor, respectively, assumed previously in the literature.
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Affiliation(s)
| | - Thomas Renger
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria;
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2
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Akhtar P, Feng Y, Jana S, Wang W, Shen JR, Tan HS, Lambrev PH. Ultrafast Energy Transfer in a Diatom Photosystem II Supercomplex. J Phys Chem Lett 2024; 15:5838-5847. [PMID: 38788163 DOI: 10.1021/acs.jpclett.4c01029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
The light-harvesting complexes (LHCs) of diatoms, specifically fucoxanthin-Chl a/c binding proteins (FCPs), exhibit structural and functional diversity, as highlighted by recent structural studies of photosystem II-FCP (PSII-FCPII) supercomplexes from different diatom species. The excitation dynamics of PSII-FCPII supercomplexes isolated from the diatom Thalassiosira pseudonana was explored using time-resolved fluorescence spectroscopy and two-dimensional electronic spectroscopy at room temperature and 77 K. Energy transfer between FCPII and PSII occurred remarkably fast (<5 ps), emphasizing the efficiency of FCPII as a light-harvesting antenna. The presence of long-wavelength chlorophylls may further help concentrate excitations in the core complex and increase the efficiency of light harvesting. Structure-based calculations reveal remarkably strong excitonic couplings between chlorophylls in the FCP antenna and between FCP and the PSII core antenna that are the basis for the rapid energy transfer.
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Affiliation(s)
- Parveen Akhtar
- HUN-REN Biological Research Centre, Szeged, Temesvári körút 62, Szeged 6726, Hungary
| | - Yue Feng
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
| | - Sanjib Jana
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Wenda Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, People's Republic of China
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Howe-Siang Tan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Petar H Lambrev
- HUN-REN Biological Research Centre, Szeged, Temesvári körút 62, Szeged 6726, Hungary
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3
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Zheng M, Pang X, Chen M, Tian L. Ultrafast energy quenching mechanism of LHCSR3-dependent photoprotection in Chlamydomonas. Nat Commun 2024; 15:4437. [PMID: 38789432 PMCID: PMC11126702 DOI: 10.1038/s41467-024-48789-x] [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: 11/07/2023] [Accepted: 05/08/2024] [Indexed: 05/26/2024] Open
Abstract
Photosynthetic organisms have evolved an essential energy-dependent quenching (qE) mechanism to avoid any lethal damages caused by high light. While the triggering mechanism of qE has been well addressed, candidates for quenchers are often debated. This lack of understanding is because of the tremendous difficulty in measuring intact cells using transient absorption techniques. Here, we have conducted femtosecond pump-probe measurements to characterize this photophysical reaction using micro-sized cell fractions of the green alga Chlamydomonas reinhardtii that retain physiological qE function. Combined with kinetic modeling, we have demonstrated the presence of an ultrafast excitation energy transfer (EET) pathway from Chlorophyll a (Chl a) Qy to a carotenoid (car) S1 state, therefore proposing that this carotenoid, likely lutein1, is the quencher. This work has provided an easy-to-prepare qE active thylakoid membrane system for advanced spectroscopic studies and demonstrated that the energy dissipation pathway of qE is evolutionarily conserved from green algae to land plants.
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Affiliation(s)
- Mengyuan Zheng
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaojie Pang
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Chen
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
- China National Botanical Garden, Beijing, 100093, China
| | - Lijin Tian
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- China National Botanical Garden, Beijing, 100093, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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4
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Citty B, Lynd JK, Gera T, Varvelo L, Raccah DIGB. MesoHOPS: Size-invariant scaling calculations of multi-excitation open quantum systems. J Chem Phys 2024; 160:144118. [PMID: 38619062 DOI: 10.1063/5.0197825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/11/2024] [Indexed: 04/16/2024] Open
Abstract
The photoexcitation dynamics of molecular materials on the 10-100 nm length scale depend on complex interactions between electronic and vibrational degrees of freedom, rendering exact calculations difficult or intractable. The adaptive Hierarchy of Pure States (adHOPS) is a formally exact method that leverages the locality imposed by interactions between thermal environments and electronic excitations to achieve size-invariant scaling calculations for single-excitation processes in systems described by a Frenkel-Holstein Hamiltonian. Here, we extend adHOPS to account for arbitrary couplings between thermal environments and vertical excitation energies, enabling formally exact, size-invariant calculations that involve multiple excitations or states with shared thermal environments. In addition, we introduce a low-temperature correction and an effective integration of the noise to reduce the computational expense of including ultrafast vibrational relaxation in Hierarchy of Pure States (HOPS) simulations. We present these advances in the latest version of the open-source MesoHOPS library and use MesoHOPS to characterize charge separation at a one-dimensional organic heterojunction when both the electron and hole are mobile.
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Affiliation(s)
- Brian Citty
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
| | - Jacob K Lynd
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
| | - Tarun Gera
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
| | - Leonel Varvelo
- Department of Chemistry, Southern Methodist University, PO Box 750314 Dallas, Texas 75205, USA
| | - Doran I G B Raccah
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, USA
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5
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Pirnia A, Maqdisi R, Mittal S, Sener M, Singharoy A. Perspective on Integrative Simulations of Bioenergetic Domains. J Phys Chem B 2024; 128:3302-3319. [PMID: 38562105 DOI: 10.1021/acs.jpcb.3c07335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Bioenergetic processes in cells, such as photosynthesis or respiration, integrate many time and length scales, which makes the simulation of energy conversion with a mere single level of theory impossible. Just like the myriad of experimental techniques required to examine each level of organization, an array of overlapping computational techniques is necessary to model energy conversion. Here, a perspective is presented on recent efforts for modeling bioenergetic phenomena with a focus on molecular dynamics simulations and its variants as a primary method. An overview of the various classical, quantum mechanical, enhanced sampling, coarse-grained, Brownian dynamics, and Monte Carlo methods is presented. Example applications discussed include multiscale simulations of membrane-wide electron transport, rate kinetics of ATP turnover from electrochemical gradients, and finally, integrative modeling of the chromatophore, a photosynthetic pseudo-organelle.
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Affiliation(s)
- Adam Pirnia
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Ranel Maqdisi
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Sumit Mittal
- VIT Bhopal University, Sehore 466114, Madhya Pradesh, India
| | - Melih Sener
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Abhishek Singharoy
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
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6
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Nguyen HL, Do TN, Zhong K, Akhtar P, Jansen TLC, Knoester J, Caffarri S, Lambrev P, Tan HS. Inter-subunit energy transfer processes in a minimal plant photosystem II supercomplex. SCIENCE ADVANCES 2024; 10:eadh0911. [PMID: 38394196 PMCID: PMC10889429 DOI: 10.1126/sciadv.adh0911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 01/22/2024] [Indexed: 02/25/2024]
Abstract
Photosystem II (PSII) is an integral part of the photosynthesis machinery, in which several light-harvesting complexes rely on inter-complex excitonic energy transfer (EET) processes to channel energy to the reaction center. In this paper, we report on a direct observation of the inter-complex EET in a minimal PSII supercomplex from plants, containing the trimeric light-harvesting complex II (LHCII), the monomeric light-harvesting complex CP26, and the monomeric PSII core complex. Using two-dimensional (2D) electronic spectroscopy, we measure an inter-complex EET timescale of 50 picoseconds for excitations from the LHCII-CP26 peripheral antenna to the PSII core. The 2D electronic spectra also reveal that the transfer timescale is nearly constant over the pump spectrum of 600 to 700 nanometers. Structure-based calculations reveal the contribution of each antenna complex to the measured inter-complex EET time. These results provide a step in elucidating the full inter-complex energy transfer network of the PSII machinery.
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Affiliation(s)
- Hoang Long Nguyen
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Thanh Nhut Do
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
| | - Kai Zhong
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Parveen Akhtar
- ELI-ALPS, ELI-HU Nonprofit Limited, Wolfgang Sandner utca 3, Szeged 6728, Hungary
- HUN-REN Biological Research Centre, Szeged, Temesvári körút 62, Szeged 6726, Hungary
| | - Thomas L. C. Jansen
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Jasper Knoester
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
- Faculty of Science, Leiden University, Einsteinweg 55, NL-2300 RA Leiden, Netherlands
| | - Stefano Caffarri
- Aix Marseille Université, CEA, CNRS, BIAM, LGBP, 13009 Marseille, France
| | - Petar Lambrev
- HUN-REN Biological Research Centre, Szeged, Temesvári körút 62, Szeged 6726, Hungary
| | - Howe-Siang Tan
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
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7
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Cook RL, Ko L, Whaley KB. A quantum trajectory picture of single photon absorption and energy transport in photosystem II. J Chem Phys 2023; 159:134108. [PMID: 37795784 DOI: 10.1063/5.0168631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 09/12/2023] [Indexed: 10/06/2023] Open
Abstract
We use quantum trajectory theory to study the dynamics of the first step in photosynthesis for a single photon interacting with photosystem II (PSII). By considering individual trajectories we are able to look beyond the ensemble average dynamics to compute the PSII system evolution conditioned upon individual photon counting measurements. Measurements of the transmitted photon beam strongly affects the system state, since detection of an outgoing photon confirms that the PSII must be in the electronic ground state, while a null measurement implies it is in an excited electronic state. We show that under ideal conditions, observing the null result transforms a state with a low excited state population to a state with nearly all population contained in the excited states. We study the PSII dynamics conditioned on such photon counting for both a pure excitonic model of PSII and a more realistic model with exciton-phonon coupling to a dissipative phononic environment. In the absence of such coupling, we show that the measured fluorescence rates show oscillations constituting a photon-counting witness of excitonic coherence. Excitonic coupling to the phonon environment has a strong effect on the observed rates of fluorescence, damping the oscillations. Addition of non-radiative decay and incoherent transitions to radical pair states in the reaction center to the phononic model allows extraction of a quantum efficiency of 92.5% from the long-time evolution, consistent with bulk experimental measurements.
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Affiliation(s)
- Robert L Cook
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Liwen Ko
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - K Birgitta Whaley
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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8
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Hassani SB, Latifi M, Aliniaeifard S, Sohrabi Bonab S, Nasiri Almanghadim N, Jafari S, Mohebbifar E, Ahangir A, Seifikalhor M, Rezadoost H, Bosacchi M, Rastogi A, Bernard F. Response to Cadmium Toxicity: Orchestration of Polyamines and microRNAs in Maize Plant. PLANTS (BASEL, SWITZERLAND) 2023; 12:1991. [PMID: 37653908 PMCID: PMC10223431 DOI: 10.3390/plants12101991] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 04/13/2023] [Accepted: 05/10/2023] [Indexed: 09/02/2023]
Abstract
Cadmium (Cd) is a heavy metal that is widely contaminating the environment due to its uses in industries as corrosive reagents, paints, batteries, etc. Cd can easily be absorbed through plant roots and may have serious negative impacts on plant growth. To investigate the mechanisms utilized by plants to cope with Cd toxicity, an experiment was conducted on maize seedlings. We observed that the plant growth and photosynthetic mechanism were negatively influenced during 20 days of Cd stress. The expression levels of ornithine decarboxylase (ORDC) increased in the six seedlings under Cd exposure compared to the control. However, Cd toxicity led to an increase in putrescine (Put) content only on day 15 when compared to the control plants. In fact, with the exception of day 15, the increases in the ORDC transcript levels did not show a direct correlation with the observed increases in Put content. Spermidine and Spermine levels were reduced on day 6 by Cd application, which was parallel with suppressed Spermidine synthase gene. However, an increase in Spermidine and Spermine levels was observed on day 12 along with a significant elevation in Spermidine synthase expression. On day 6, Cd was observed to start accumulating in the root with an increase in the expression of microRNA 528; while on day 15, Cd started to be observed in the shoot part with an increase in microRNA 390 and microRNA 168. These results imply that different miRNAs may regulate polyamines (PAs) in maize under Cd toxicity, suggesting a plant-derived strategy to commit a PAs/miRNA-regulated mechanism/s in different developmental stages (time points) in response to Cd exposure.
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Affiliation(s)
- Seyedeh Batool Hassani
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
| | - Mojgan Latifi
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
| | - Sasan Aliniaeifard
- Photosynthesis Laboratory, Department of Horticulture, College of Agricultural Technology (Aburaihan), University of Tehran, Tehran 33916-53755, Iran
| | - Shabnam Sohrabi Bonab
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
| | - Neda Nasiri Almanghadim
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
| | - Sara Jafari
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
| | - Elham Mohebbifar
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
| | - Anahita Ahangir
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
| | | | - Hassan Rezadoost
- Department of Phytochemistry, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Tehran 19839-69411, Iran
| | - Massimo Bosacchi
- Park at the Danforth Plant Science Center, KWS Gateway Research Center, LLC, BRDG, Saint Louis, MO 95618, USA
| | - Anshu Rastogi
- Laboratory of Bioclimatology, Department of Ecology and Environmental Protection, Faculty of Environmental Engineering and Mechanical Engineering, Poznan University of Life Sciences, Piątkowska 94, 60-649 Poznań, Poland
| | - Françoise Bernard
- Department of Plant Sciences and Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran 19839-69411, Iran; (S.B.H.)
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9
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Beauzamy L, Longatte G, Guille-Collignon M, Lemaître F. Investigation of quinone reduction by microalgae using fluorescence - do "lake" and "puddle" mechanisms matter? Bioelectrochemistry 2023; 152:108454. [PMID: 37172391 DOI: 10.1016/j.bioelechem.2023.108454] [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: 02/14/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023]
Abstract
Photosynthesis is a fundamental process used by Nature to convert solar energy into chemical energy. For the last twenty years, many solutions have been explored to provide electrical power from the photosynthetic chain. In this context, the coupling between microalgae and exogenous quinones is an encouraging strategy because of the capability of quinones to be reduced by the photosynthetic chain. The ability of a quinone to be a good or bad electron acceptor can be evaluated by fluorescence measurements. Fluorescence analyses are thus a convenient tool helping to define a diverting parameter for some quinones. However, this parameter is implicitly designed on the basis of a particular light capture mechanism by algae. In this paper, we propose to revisit previous fluorescence experimental data by considering the two possible mechanisms (lake vs. puddle) and discussing their implication on the conclusions of the analysis. In particular, we show that the maximum extraction efficiency depends on the mechanism (in the case of 2,6-dichlorobenzoquinone - 2,6-DCBQ, (0.45 ± 0.02) vs (0.61 ± 0.03) for lake and puddle mechanisms respectively) but that the trends for different quinones remain correlated to the redox potentials independently of the mechanism.
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Affiliation(s)
- Léna Beauzamy
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France; Laboratory of Membrane and Molecular Physiology at IBPC, UMR 7141, CNRS/Sorbonne Université, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Guillaume Longatte
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France; University of Bordeaux, Bordeaux INP, ISM, UMR CNRS 5255, Pessac 33607, France(2)
| | - Manon Guille-Collignon
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Frédéric Lemaître
- PASTEUR, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
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10
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Gu L, Grodzinski B, Han J, Marie T, Zhang YJ, Song YC, Sun Y. An exploratory steady-state redox model of photosynthetic linear electron transport for use in complete modelling of photosynthesis for broad applications. PLANT, CELL & ENVIRONMENT 2023; 46:1540-1561. [PMID: 36760139 DOI: 10.1111/pce.14563] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/24/2023] [Accepted: 02/05/2023] [Indexed: 06/18/2023]
Abstract
A photochemical model of photosynthetic electron transport (PET) is needed to integrate photophysics, photochemistry, and biochemistry to determine redox conditions of electron carriers and enzymes for plant stress assessment and mechanistically link sun-induced chlorophyll fluorescence to carbon assimilation for remotely sensing photosynthesis. Towards this goal, we derived photochemical equations governing the states and redox reactions of complexes and electron carriers along the PET chain. These equations allow the redox conditions of the mobile plastoquinone pool and the cytochrome b6 f complex (Cyt) to be inferred with typical fluorometry. The equations agreed well with fluorometry measurements from diverse C3 /C4 species across environments in the relationship between the PET rate and fraction of open photosystem II reaction centres. We found the oxidation of plastoquinol by Cyt is the bottleneck of PET, and genetically improving the oxidation of plastoquinol by Cyt may enhance the efficiency of PET and photosynthesis across species. Redox reactions and photochemical and biochemical interactions are highly redundant in their complex controls of PET. Although individual reaction rate constants cannot be resolved, they appear in parameter groups which can be collectively inferred with fluorometry measurements for broad applications. The new photochemical model developed enables advances in different fronts of photosynthesis research.
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Affiliation(s)
- Lianhong Gu
- Oak Ridge National Laboratory, Environmental Sciences Division and Climate Change Science Institute, Oak Ridge, Tennessee, USA
| | - Bernard Grodzinski
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| | - Jimei Han
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
| | - Telesphore Marie
- Department of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, Maine, USA
| | - Yang C Song
- Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, Arizona, USA
| | - Ying Sun
- School of Integrative Plant Science, Cornell University, Ithaca, New York, USA
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11
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Maity S, Kleinekathöfer U. Recent progress in atomistic modeling of light-harvesting complexes: a mini review. PHOTOSYNTHESIS RESEARCH 2023; 156:147-162. [PMID: 36207489 PMCID: PMC10070314 DOI: 10.1007/s11120-022-00969-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
In this mini review, we focus on recent advances in the atomistic modeling of biological light-harvesting (LH) complexes. Because of their size and sophisticated electronic structures, multiscale methods are required to investigate the dynamical and spectroscopic properties of such complexes. The excitation energies, in this context also known as site energies, excitonic couplings, and spectral densities are key quantities which usually need to be extracted to be able to determine the exciton dynamics and spectroscopic properties. The recently developed multiscale approach based on the numerically efficient density functional tight-binding framework followed by excited state calculations has been shown to be superior to the scheme based on pure classical molecular dynamics simulations. The enhanced approach, which improves the description of the internal vibrational dynamics of the pigment molecules, yields spectral densities in good agreement with the experimental counterparts for various bacterial and plant LH systems. Here, we provide a brief overview of those results and described the theoretical foundation of the multiscale protocol.
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Affiliation(s)
- Sayan Maity
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen, Campus Ring 1, 28759, Bremen, Germany.
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12
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Varvelo L, Lynd JK, Citty B, Kühn O, Raccah DIGB. Formally Exact Simulations of Mesoscale Exciton Diffusion in a Light-Harvesting 2 Antenna Nanoarray. J Phys Chem Lett 2023; 14:3077-3083. [PMID: 36947483 PMCID: PMC10069740 DOI: 10.1021/acs.jpclett.3c00086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
The photosynthetic apparatus of plants and bacteria combine atomically precise pigment-protein complexes with dynamic membrane architectures to control energy transfer on the 10-100 nm length scales. Recently, synthetic materials have integrated photosynthetic antenna proteins to enhance exciton transport, though the influence of artificial packing on the excited-state dynamics in these biohybrid materials is not fully understood. Here, we use the adaptive hierarchy of pure states (adHOPS) to perform a formally exact simulation of excitation energy transfer within artificial aggregates of light-harvesting complex 2 (LH2) with a range of packing densities. We find that LH2 aggregates support a remarkable exciton diffusion length ranging from 100 nm at a biological packing density to 300 nm at the densest packing previously suggested in an artificial aggregate. The unprecedented scale of these formally exact calculations also underscores the efficiency with which adHOPS simulates excited-state processes in molecular materials.
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Affiliation(s)
- Leonel Varvelo
- Department
of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, Texas 75275, United States
| | - Jacob K. Lynd
- Department
of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, Texas 75275, United States
| | - Brian Citty
- Department
of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, Texas 75275, United States
| | - Oliver Kühn
- Institute
of Physics, University of Rostock, Albert-Einstein-Strasse 23-24, 18059 Rostock, Germany
| | - Doran I. G. B. Raccah
- Department
of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, Texas 75275, United States
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13
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Kalra A, Benny A, Travis SM, Zizzi EA, Morales-Sanchez A, Oblinsky DG, Craddock TJA, Hameroff SR, MacIver MB, Tuszyński JA, Petry S, Penrose R, Scholes GD. Electronic Energy Migration in Microtubules. ACS CENTRAL SCIENCE 2023; 9:352-361. [PMID: 36968538 PMCID: PMC10037452 DOI: 10.1021/acscentsci.2c01114] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Indexed: 05/29/2023]
Abstract
The repeating arrangement of tubulin dimers confers great mechanical strength to microtubules, which are used as scaffolds for intracellular macromolecular transport in cells and exploited in biohybrid devices. The crystalline order in a microtubule, with lattice constants short enough to allow energy transfer between amino acid chromophores, is similar to synthetic structures designed for light harvesting. After photoexcitation, can these amino acid chromophores transfer excitation energy along the microtubule like a natural or artificial light-harvesting system? Here, we use tryptophan autofluorescence lifetimes to probe energy hopping between aromatic residues in tubulin and microtubules. By studying how the quencher concentration alters tryptophan autofluorescence lifetimes, we demonstrate that electronic energy can diffuse over 6.6 nm in microtubules. We discover that while diffusion lengths are influenced by tubulin polymerization state (free tubulin versus tubulin in the microtubule lattice), they are not significantly altered by the average number of protofilaments (13 versus 14). We also demonstrate that the presence of the anesthetics etomidate and isoflurane reduce exciton diffusion. Energy transport as explained by conventional Förster theory (accommodating for interactions between tryptophan and tyrosine residues) does not sufficiently explain our observations. Our studies indicate that microtubules are, unexpectedly, effective light harvesters.
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Affiliation(s)
- Aarat
P. Kalra
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Alfy Benny
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Sophie M. Travis
- Department
of Molecular Biology, Schultz Laboratory, Princeton University, Princeton, New Jersey08544, United States
| | - Eric A. Zizzi
- Department
of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Torino10129, Italy
| | - Austin Morales-Sanchez
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Daniel G. Oblinsky
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
| | - Travis J. A. Craddock
- Departments
of Psychology & Neuroscience, Computer Science, and Clinical Immunology, Nova Southeastern University, Ft. Lauderdale, Florida33314, United States
| | - Stuart R. Hameroff
- Department
of Anesthesiology, Center for Consciousness Studies, University of Arizona, Tucson, Arizona85721, United States
| | - M. Bruce MacIver
- Department
of Anesthesiology, Stanford University School
of Medicine, Stanford, California94305, United States
| | - Jack A. Tuszyński
- Department
of Mechanical and Aerospace Engineering (DIMEAS), Politecnico di Torino, Torino10129, Italy
- Department
of Physics, University of Alberta, Edmonton, AlbertaT6G 2E1, Canada
- Department
of Oncology, University of Alberta, Edmonton, AlbertaT6G 1Z2, Canada
| | - Sabine Petry
- Department
of Molecular Biology, Schultz Laboratory, Princeton University, Princeton, New Jersey08544, United States
| | - Roger Penrose
- Mathematical
Institute, Andrew Wiles Building, University
of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, United
Kingdom
| | - Gregory D. Scholes
- Department
of Chemistry, New Frick Chemistry Building, Princeton University, Princeton, New Jersey08544, United States
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14
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Feighan O, Manby FR, Bourne-Worster S. An efficient protocol for excited states of large biochromophores. J Chem Phys 2023; 158:024107. [PMID: 36641400 DOI: 10.1063/5.0132417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Efficient energy transport in photosynthetic antenna is a long-standing source of inspiration for artificial light harvesting materials. However, characterizing the excited states of the constituent chromophores poses a considerable challenge to mainstream quantum chemical and semiempirical excited state methods due to their size and complexity and the accuracy required to describe small but functionally important changes in their properties. In this paper, we explore an alternative approach to calculating the excited states of large biochromophores, exemplified by a specific method for calculating the Qy transition of bacteriochlorophyll a, which we name Chl-xTB. Using a diagonally dominant approximation to the Casida equation and a bespoke parameterization scheme, Chl-xTB can match time-dependent density functional theory's accuracy and semiempirical speed for calculating the potential energy surfaces and absorption spectra of chlorophylls. We demonstrate that Chl-xTB (and other prospective realizations of our protocol) can be integrated into multiscale models, including concurrent excitonic and point-charge embedding frameworks, enabling the analysis of biochromophore networks in a native environment. We exploit this capability to probe the low-frequency spectral densities of excitonic energies and interchromophore interactions in the light harvesting antenna protein LH2 (light harvesting complex 2). The impact of low-frequency protein motion on interchromophore coupling and exciton transport has routinely been ignored due to the prohibitive costs of including it in simulations. Our results provide a more rigorous basis for continued use of this approximation by demonstrating that exciton transition energies are unaffected by low-frequency vibrational coupling to exciton interaction energies.
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Affiliation(s)
- Oliver Feighan
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Frederick R Manby
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
| | - Susannah Bourne-Worster
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
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15
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Nawrocki WJ, Liu X, Raber B, Hu C, de Vitry C, Bennett DIG, Croce R. Molecular origins of induction and loss of photoinhibition-related energy dissipation q I. SCIENCE ADVANCES 2021; 7:eabj0055. [PMID: 34936440 PMCID: PMC8694598 DOI: 10.1126/sciadv.abj0055] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 11/08/2021] [Indexed: 05/02/2023]
Abstract
Photosynthesis fuels life on Earth using sunlight as energy source. However, light has a simultaneous detrimental effect on the enzyme triggering photosynthesis and producing oxygen, photosystem II (PSII). Photoinhibition, the light-dependent decrease of PSII activity, results in a major limitation to aquatic and land photosynthesis and occurs upon all environmental stress conditions. In this work, we investigated the molecular origins of photoinhibition focusing on the paradoxical energy dissipation process of unknown nature coinciding with PSII damage. Integrating spectroscopic, biochemical, and computational approaches, we demonstrate that the site of this quenching process is the PSII reaction center. We propose that the formation of quenching and the closure of PSII stem from the same event. We lastly reveal the heterogeneity of PSII upon photoinhibition using structure-function modeling of excitation energy transfer. This work unravels the functional details of the damage-induced energy dissipation at the heart of photosynthesis.
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Affiliation(s)
- Wojciech J. Nawrocki
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
| | - Xin Liu
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
| | - Bailey Raber
- Department of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, TX, USA
| | - Chen Hu
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
| | - Catherine de Vitry
- Institut de Biologie Physico-Chimique, UMR 7141, CNRS-Sorbonne Université, 75005 Paris, France
| | - Doran I. G. Bennett
- Department of Chemistry, Southern Methodist University, P.O. Box 750314, Dallas, TX, USA
| | - Roberta Croce
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
- LaserLaB Amsterdam, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, Netherlands
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16
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Ptushenko VV, Bondarenko GN, Vinogradova EN, Glagoleva ES, Karpova OV, Ptushenko OS, Solovchenko AE, Trubitsin BV, Chivkunova OB, Shibzukhova KA, Shcherbakov PN. The Effect of Chilling on the Photosynthetic Apparatus of Microalga Lobosphaera incisa IPPAS C-2047. BIOCHEMISTRY. BIOKHIMIIA 2021; 86:1590-1598. [PMID: 34937538 DOI: 10.1134/s0006297921120087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Photosynthetic organisms have developed a set of mechanisms aimed at preventing photo-oxidative reactions in the photosynthetic apparatus (PSA) initiated by excessively absorbed light energy. Along with high irradiance, other stressors, e.g., chilling temperatures, can lead to the absorption of the excess of light energy and hence to photo-oxidative stress. Here, we studied induction of photoprotective mechanisms in response to chilling (0°C) at a low irradiance (50 µmol PAR photons m-2·s-1) in the cells of microalga Lobosphaera incisa IPPAS C-2047. After 4 days of incubation at a low temperature, L. incisa IPPAS C-2047 cells showed a notable decrease in the photochemical activity of photosystem II (PSII) and in the efficiency of photosynthetic electron transport, as well as a significant increase in the thermal dissipation of the absorbed light energy in the light-harvesting antenna. In contrast, most conventional markers of PSA acclimation to excess light energy [total chlorophyll and carotenoid content; violaxanthin cycle pigment content and de-epoxidation state; photosynthetic antenna, PSII, and photosystem I (PSI) ratio] remained virtually unchanged. The content of major unsaturated fatty acids also remained almost unaffected, except for arachidonic acid (increased by 40%) recently assumed to activate violaxanthin de-epoxidase by adjusting its lipid microenvironment. Significant changes (4-7-fold increase) were observed in the expression of the gene encoding protective protein LhcSR. Pre-conditioning at 5°C prior to the acclimation to 0°C augmented the PSA photochemical activity. Our data show that the mid-term (4-d) acclimation of L. incisa IPPAS C-2047 to a chilling temperature at a low irradiance triggers the PSA response resembling, in part, the response to high light but relying mostly on the LhcSR protein-dependent quenching of excitation in the photosynthetic antenna.
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Affiliation(s)
- Vasily V Ptushenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia. .,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, 119334, Russia
| | | | - Elizaveta N Vinogradova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.,National Research Center "Kurchatov Institute", 123182 Moscow Russia
| | - Elena S Glagoleva
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Olga V Karpova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Oxana S Ptushenko
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | | | - Boris V Trubitsin
- Faculty of Physics, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Olga B Chivkunova
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | | | - Pavel N Shcherbakov
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
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17
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The development of luminescent solar concentrator-based photomicroreactors: a cheap reactor enabling efficient solar-powered photochemistry. Photochem Photobiol Sci 2021; 21:705-717. [PMID: 34767247 DOI: 10.1007/s43630-021-00130-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/27/2021] [Indexed: 12/16/2022]
Abstract
Sunlight strikes our planet every day with more energy than we consume in an entire year. Therefore, many researchers have explored ways to efficiently harvest and use sunlight energy for the activation of organic molecules. However, implementation of this energy source in the large-scale production of fine chemicals has been mostly neglected. The use of solar energy for chemical transformations suffers from potential drawbacks including scattering, reflections, cloud shading and poor matches between the solar emission and absorption characteristics of the photochemical reaction. In this account, we provide an overview of our efforts to overcome these issues through the development of Luminescent Solar Concentrator-based PhotoMicroreactors (LSC-PM). Such reactors can efficiently convert solar energy with a broad spectral distribution to concentrated and wavelength-shifted irradiation which matches the absorption maximum of the photocatalyst. Hence, the use of these conceptually new photomicroreactors provides an increased solar light harvesting capacity, enabling efficient solar-powered photochemistry.
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18
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Son M, Moya R, Pinnola A, Bassi R, Schlau-Cohen GS. Protein-Protein Interactions Induce pH-Dependent and Zeaxanthin-Independent Photoprotection in the Plant Light-Harvesting Complex, LHCII. J Am Chem Soc 2021; 143:17577-17586. [PMID: 34648708 DOI: 10.1021/jacs.1c07385] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Plants use energy from the sun yet also require protection against the generation of deleterious photoproducts from excess energy. Photoprotection in green plants, known as nonphotochemical quenching (NPQ), involves thermal dissipation of energy and is activated by a series of interrelated factors: a pH drop in the lumen, accumulation of the carotenoid zeaxanthin (Zea), and formation of arrays of pigment-containing antenna complexes. However, understanding their individual contributions and their interactions has been challenging, particularly for the antenna arrays, which are difficult to manipulate in vitro. Here, we achieved systematic and discrete control over the array size for the principal antenna complex, light-harvesting complex II, using near-native in vitro membranes called nanodiscs. Each of the factors had a distinct influence on the level of dissipation, which was characterized by measurements of fluorescence quenching and ultrafast chlorophyll-to-carotenoid energy transfer. First, an increase in array size led to a corresponding increase in dissipation; the dramatic changes in the chlorophyll dynamics suggested that this is due to an allosteric conformational change of the protein. Second, a pH drop increased dissipation but exclusively in the presence of protein-protein interactions. Third, no Zea dependence was identified which suggested that Zea regulates a distinct aspect of NPQ. Collectively, these results indicate that each factor provides a separate type of control knob for photoprotection, which likely enables a flexible and tunable response to solar fluctuations.
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Affiliation(s)
- Minjung Son
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Raymundo Moya
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alberta Pinnola
- Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy
| | - Roberto Bassi
- Department of Biotechnology, University of Verona, 37134 Verona, Italy.,Accademia Nazionale di Lincei, 00165 Rome, Italy
| | - Gabriela S Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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19
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Zhang Z, Han Q, Liu S, Wang Z, Hu M, Domnic SMW, Lau R, Xing B. Recomposition and storage of sunlight with intelligent phosphors for enhanced photosynthesis. Dalton Trans 2021; 50:11025-11029. [PMID: 34370806 DOI: 10.1039/d1dt02207e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This work presents a smart solar energy regulation strategy using photon tunable long persistent phosphors as solar energy harvesting antennas to enhance overall sunlight utilization by photosynthetic organisms in multiple modes.
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Affiliation(s)
- Zhijun Zhang
- Key Laboratory of Surface & Interface of Polymer Materials of Zhejiang Province, Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China
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20
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Varvelo L, Lynd JK, Bennett DIG. Formally exact simulations of mesoscale exciton dynamics in molecular materials. Chem Sci 2021; 12:9704-9711. [PMID: 34349941 PMCID: PMC8293828 DOI: 10.1039/d1sc01448j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/31/2021] [Indexed: 02/04/2023] Open
Abstract
Excited state carriers, such as excitons, can diffuse on the 100 nm to micron length scale in molecular materials but only delocalize over short length scales due to coupling between electronic and vibrational degrees-of-freedom. Here, we leverage the locality of excitons to adaptively solve the hierarchy of pure states equations (HOPS). We demonstrate that our adaptive HOPS (adHOPS) methodology provides a formally exact and size-invariant (i.e., ) scaling algorithm for simulating mesoscale quantum dynamics. Finally, we provide proof-of-principle calculations for exciton diffusion on linear chains containing up to 1000 molecules. The adaptive hierarchy of pure states (adHOPS) algorithm leverages the locality of excitons in molecular materials to perform formally-exact simulations with size-invariant (i.e., ) scaling, enabling efficient simulations of mesoscale exciton dynamics.![]()
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Affiliation(s)
- Leonel Varvelo
- Department of Chemistry, Southern Methodist University PO Box 750314 Dallas TX USA
| | - Jacob K Lynd
- Department of Chemistry, Southern Methodist University PO Box 750314 Dallas TX USA
| | - Doran I G Bennett
- Department of Chemistry, Southern Methodist University PO Box 750314 Dallas TX USA
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21
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Bassi R, Dall'Osto L. Dissipation of Light Energy Absorbed in Excess: The Molecular Mechanisms. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:47-76. [PMID: 34143647 DOI: 10.1146/annurev-arplant-071720-015522] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Light is essential for photosynthesis. Nevertheless, its intensity widely changes depending on time of day, weather, season, and localization of individual leaves within canopies. This variability means that light collected by the light-harvesting system is often in excess with respect to photon fluence or spectral quality in the context of the capacity of photosynthetic metabolism to use ATP and reductants produced from the light reactions. Absorption of excess light can lead to increased production of excited, highly reactive intermediates, which expose photosynthetic organisms to serious risks of oxidative damage. Prevention and management of such stress are performed by photoprotective mechanisms, which operate by cutting down light absorption, limiting the generation of redox-active molecules, or scavenging reactive oxygen species that are released despite the operation of preventive mechanisms. Here, we describe the major physiological and molecular mechanisms of photoprotection involved in the harmless removal of the excess light energy absorbed by green algae and land plants. In vivo analyses of mutants targeting photosynthetic components and the enhanced resolution of spectroscopic techniques have highlighted specific mechanisms protecting the photosynthetic apparatus from overexcitation. Recent findings unveil a network of multiple interacting elements, the reaction times of which vary from a millisecond to weeks, that continuously maintain photosynthetic organisms within the narrow safety range between efficient light harvesting and photoprotection.
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Affiliation(s)
- Roberto Bassi
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
| | - Luca Dall'Osto
- Department of Biotechnology, University of Verona, 37134 Verona, Italy;
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22
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Johnson JE, Berry JA. The role of Cytochrome b 6f in the control of steady-state photosynthesis: a conceptual and quantitative model. PHOTOSYNTHESIS RESEARCH 2021; 148:101-136. [PMID: 33999328 PMCID: PMC8292351 DOI: 10.1007/s11120-021-00840-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 04/26/2021] [Indexed: 05/06/2023]
Abstract
Here, we present a conceptual and quantitative model to describe the role of the Cytochrome [Formula: see text] complex in controlling steady-state electron transport in [Formula: see text] leaves. The model is based on new experimental methods to diagnose the maximum activity of Cyt [Formula: see text] in vivo, and to identify conditions under which photosynthetic control of Cyt [Formula: see text] is active or relaxed. With these approaches, we demonstrate that Cyt [Formula: see text] controls the trade-off between the speed and efficiency of electron transport under limiting light, and functions as a metabolic switch that transfers control to carbon metabolism under saturating light. We also present evidence that the onset of photosynthetic control of Cyt [Formula: see text] occurs within milliseconds of exposure to saturating light, much more quickly than the induction of non-photochemical quenching. We propose that photosynthetic control is the primary means of photoprotection and functions to manage excitation pressure, whereas non-photochemical quenching functions to manage excitation balance. We use these findings to extend the Farquhar et al. (Planta 149:78-90, 1980) model of [Formula: see text] photosynthesis to include a mechanistic description of the electron transport system. This framework relates the light captured by PS I and PS II to the energy and mass fluxes linking the photoacts with Cyt [Formula: see text], the ATP synthase, and Rubisco. It enables quantitative interpretation of pulse-amplitude modulated fluorometry and gas-exchange measurements, providing a new basis for analyzing how the electron transport system coordinates the supply of Fd, NADPH, and ATP with the dynamic demands of carbon metabolism, how efficient use of light is achieved under limiting light, and how photoprotection is achieved under saturating light. The model is designed to support forward as well as inverse applications. It can either be used in a stand-alone mode at the leaf-level or coupled to other models that resolve finer-scale or coarser-scale phenomena.
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Affiliation(s)
- J E Johnson
- Dept. Global Ecology, Carnegie Institution, Stanford, CA, 94305, USA.
| | - J A Berry
- Dept. Global Ecology, Carnegie Institution, Stanford, CA, 94305, USA
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23
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d'Auriac JCA, Iglói F. Statistics of percolating clusters in a model of photosynthetic bacteria. Phys Rev E 2021; 103:052103. [PMID: 34134283 DOI: 10.1103/physreve.103.052103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
In photosynthetic organisms the energy of the illuminating light is absorbed by the antenna complexes and transmitted by the excitons to the reaction centers (RCs). The energy of light is either absorbed by the RCs, leading to their "closing" or is emitted through fluorescence. The dynamics of the light absorption is described by a simple model developed for exciton migration that involves the exciton hopping probability and the exciton lifetime. During continuous illumination the fraction of closed RCs x continuously increases, and at a critical threshold x_{c}, a percolation transition takes place. Performing extensive Monte Carlo simulations, we study the properties of the transition in this correlated percolation model. We measure the spanning probability in the vicinity of x_{c}, as well as the fractal properties of the critical percolating cluster, both in the bulk and at the surface.
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Affiliation(s)
| | - Ferenc Iglói
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, P.O. Box 49, H-1525 Budapest, Hungary
- Institute of Theoretical Physics, Szeged University, H-6720 Szeged, Hungary
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24
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Wu J, Hu J, Wang L, Zhao L, Ma F. Responses of Phragmites australis to copper stress: A combined analysis of plant morphology, physiology and proteomics. PLANT BIOLOGY (STUTTGART, GERMANY) 2021; 23:351-362. [PMID: 32810882 DOI: 10.1111/plb.13175] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 08/03/2020] [Indexed: 05/11/2023]
Abstract
Few relevant research attempts have been made to determine heavy metal resistance mechanisms of rhizomatous perennial plants. Thus, it is pertinent to investigate the physiological and biochemical changes in Phragmites australis under metal-stressed conditions to facilitate the development of strategies to enhance copper (Cu) tolerance. We measured parameters related to plant growth and development, metal translocation and physiological responses of P. australis subjected to Cu stress. In addition, the differentially expressed proteins (DEP) were evaluated using the isobaric tag for relative and absolute quantification (iTRAQ) system. A large amount of copper accumulates in the roots of P.australis, but the growth parameters were not sensitive to Cu. However, the high concentration of Cu reduced the content of chlorophyll a and chlorophyll b, and the expression of important photosynthesis proteins PsbD, PsbO and PsaA were all down-regulated, so photosynthesis was inhibited. In contrast, the content of ascorbic acid and proline both increased with the increase of copper stress. P.australis fixed a large amount of Cu in its roots, limiting the migration of Cu to other parts of the plant. Moreover, Cu stress can affect photosynthesis by inhibiting the activity of PSI, PSII and LHCII. In addition, P.australis synthesizes ascorbic acid through the D-mannose/L-galactose pathway, and synthesizes proline through the ornithine pathway. Ascorbic acid and proline can increase Cu tolerance and protect photosynthesis. These results provide a theoretical basis for understanding the tolerance and repair mechanisms of plants in response to heavy metal pollution.
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Affiliation(s)
- J Wu
- School of Environmental Science, Liaoning University, Shenyang, China
| | - J Hu
- School of Environmental Science, Liaoning University, Shenyang, China
| | - L Wang
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - L Zhao
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
| | - F Ma
- State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China
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25
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Oja V, Laisk A. Time- and reduction-dependent rise of photosystem II fluorescence during microseconds-long inductions in leaves. PHOTOSYNTHESIS RESEARCH 2020; 145:209-225. [PMID: 32918663 DOI: 10.1007/s11120-020-00783-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 09/02/2020] [Indexed: 05/16/2023]
Abstract
Lettuce (Lactuca sativa) and benth (Nicotiana benthamiana) leaves were illuminated with 720 nm background light to mix S-states and oxidize electron carriers. Green-filtered xenon flashes of different photon dose were applied and O2 evolution induced by a flash was measured. After light intensity gradient across the leaf was mathematically considered, the flash-induced PSII electron transport (= 4·O2 evolution) exponentially increased with the flash photon dose in any differential layer of the leaf optical density. This proved the absence of excitonic connectivity between PSII units. Time courses of flash light intensity and 680 nm chlorophyll fluorescence emission were recorded. While with connected PSII the sigmoidal fluorescence rise has been explained by quenching of excitation in closed PSII by its open neighbors, in the absence of connectivity the sigmoidicity indicates gradual rise of the fluorescence yield of an individual closed PSII during the induction. Two phases were discerned: the specific fluorescence yield immediately increased from Fo to 1.8Fo in a PSII, whose reaction center became closed; fluorescence yield of the closed PSII was keeping time-dependent rise from 1.8Fo to about 3Fo, approaching the flash fluorescence yield Ff = 0.6Fm during 40 μs. The time-dependent fluorescence rise was resolved from the quenching by 3Car triplets and related to protein conformational change. We suggest that QA reduction induces a conformational change, which by energetic or structural means closes the gate for excitation entrance into the central radical pair trap-efficiently when QB cannot accept the electron, but less efficiently when it can.
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Affiliation(s)
- Vello Oja
- Institute of Technology, University of Tartu, Nooruse st. 1, 50411, Tartu, Estonia
| | - Agu Laisk
- Institute of Technology, University of Tartu, Nooruse st. 1, 50411, Tartu, Estonia.
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26
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Maróti P, Kovács IA, Kis M, Smart JL, Iglói F. Correlated clusters of closed reaction centers during induction of intact cells of photosynthetic bacteria. Sci Rep 2020; 10:14012. [PMID: 32814810 PMCID: PMC7438532 DOI: 10.1038/s41598-020-70966-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 07/29/2020] [Indexed: 01/18/2023] Open
Abstract
Antenna systems serve to absorb light and to transmit excitation energy to the reaction center (RC) in photosynthetic organisms. As the emitted (bacterio)chlorophyll fluorescence competes with the photochemical utilization of the excitation, the measured fluorescence yield is informed by the migration of the excitation in the antenna. In this work, the fluorescence yield concomitant with the oxidized dimer (P+) of the RC were measured during light excitation (induction) and relaxation (in the dark) for whole cells of photosynthetic bacterium Rhodobacter sphaeroides lacking cytochrome c2 as natural electron donor to P+ (mutant cycA). The relationship between the fluorescence yield and P+ (fraction of closed RC) showed deviations from the standard Joliot-Lavergne-Trissl model: (1) the hyperbola is not symmetric and (2) exhibits hysteresis. These phenomena originate from the difference between the delays of fluorescence relative to P+ kinetics during induction and relaxation, and in structural terms from the non-random distribution of the closed RCs during induction. The experimental findings are supported by Monte Carlo simulations and by results from statistical physics based on random walk approximations of the excitation in the antenna. The applied mathematical treatment demonstrates the generalization of the standard theory and sets the stage for a more adequate description of the long-debated kinetics of fluorescence and of the delicate control and balance between efficient light harvest and photoprotection in photosynthetic organisms.
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Affiliation(s)
- Péter Maróti
- Department of Medical Physics and Informatics, Szeged University, Rerrich Béla tér 1., 6720, Szeged, Hungary.
| | - István A Kovács
- Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208-3112, USA
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, P.O. Box 49, 1525, Budapest, Hungary
- Department of Network and Data Science, Central European University, Budapest, 1051, Hungary
| | - Mariann Kis
- Department of Medical Physics and Informatics, Szeged University, Rerrich Béla tér 1., 6720, Szeged, Hungary
| | - James L Smart
- Department of Biological Sciences, University of Tennessee at Martin, Martin, TN, 38238, USA
| | - Ferenc Iglói
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, P.O. Box 49, 1525, Budapest, Hungary
- Institute of Theoretical Physics, Szeged University, 6720, Szeged, Hungary
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27
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Huang X, Vasilev C, Hunter CN. Excitation energy transfer between monomolecular layers of light harvesting LH2 and LH1-reaction centre complexes printed on a glass substrate. LAB ON A CHIP 2020; 20:2529-2538. [PMID: 32662473 DOI: 10.1039/d0lc00156b] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Light-harvesting 2 (LH2) and light-harvesting 1 - reaction centre (RCLH1) complexes purified from the photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were cross-patterned on glass surfaces for energy transfer studies. Atomic force microscopy (AFM) images of the RCLH1 and LH2 patterns show the deposition of monomolecular layers of complexes on the glass substrate. Spectral imaging and fluorescence life-time imaging microscopy (FLIM) revealed that RCLH1 and LH2 complexes, sealed under physiological conditions, retained their native light-harvesting and energy transfer functions. Measurements of the amplitude and lifetime decay of fluorescence emission from LH2 complexes, the energy transfer donors, and gain of fluorescence emission from acceptor RCLH1 complexes, provide evidence for excitation energy transfer from LH2 to RCLH1. Directional energy transfer on the glass substrate was unequivocally established by using LH2-carotenoid complexes and RCLH1 complexes with genetically removed carotenoids. Specific excitation of carotenoids in donor LH2 complexes elicited fluorescence emission from RCLH1 acceptors. To explore the longevity of this novel nanoprinted photosynthetic unit, RCLH1 and LH2 complexes were cross-patterned on a glass surface and sealed under a protective argon atmosphere. The results show that both complexes retained their individual and collective functions and are capable of directional excitation energy transfer for at least 60 days.
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Affiliation(s)
- Xia Huang
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK.
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28
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Ghassemi-Golezani K, Hosseinzadeh-Mahootchi A, Farhangi-Abriz S. Chlorophyll a fluorescence of safflower affected by salt stress and hormonal treatments. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-3133-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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29
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Lattice Models for Protein Organization throughout Thylakoid Membrane Stacks. Biophys J 2020; 118:2680-2693. [PMID: 32413311 DOI: 10.1016/j.bpj.2020.03.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 03/14/2020] [Accepted: 03/24/2020] [Indexed: 11/21/2022] Open
Abstract
Proteins in photosynthetic membranes can organize into patterned arrays that span the membrane's lateral size. Attractions between proteins in different layers of a membrane stack can play a key role in this ordering, as was suggested by microscopy and fluorescence spectroscopy and demonstrated by computer simulations of a coarse-grained model. The architecture of thylakoid membranes, however, also provides opportunities for interlayer interactions that instead disfavor the high protein densities of ordered arrangements. Here, we explore the interplay between these opposing driving forces and, in particular, the phase transitions that emerge in the periodic geometry of stacked thylakoid membrane disks. We propose a lattice model that roughly accounts for proteins' attraction within a layer and across the stromal gap, steric repulsion across the lumenal gap, and regulation of protein density by exchange with the stroma lamellae. Mean-field analysis and computer simulation reveal rich phase behavior for this simple model, featuring a broken-symmetry striped phase that is disrupted at both high and low extremes of chemical potential. The resulting sensitivity of microscopic protein arrangement to the thylakoid's mesoscale vertical structure raises intriguing possibilities for regulation of photosynthetic function.
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30
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Li C, Ji J, Wang G, Li Z, Wang Y, Fan Y. Over-Expression of LcPDS, LcZDS, and LcCRTISO, Genes From Wolfberry for Carotenoid Biosynthesis, Enhanced Carotenoid Accumulation, and Salt Tolerance in Tobacco. FRONTIERS IN PLANT SCIENCE 2020; 11:119. [PMID: 32174932 PMCID: PMC7054348 DOI: 10.3389/fpls.2020.00119] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/27/2020] [Indexed: 05/15/2023]
Abstract
It is of great importance to combine stress tolerance and plant quality for breeding research. In this study, the role of phytoene desaturase (PDS), ζ-carotene desaturase (ZDS) and carotene isomerase (CRTISO) in the carotenoid biosynthesis are correlated and compared. The three genes were derived from Lycium chinenses and involved in the desaturation of tetraterpene. Their over-expression significantly increased carotenoid accumulation and enhanced photosynthesis and salt tolerance in transgenic tobacco. Up-regulation of almost all the genes involved in the carotenoid biosynthesis pathway and only significant down-regulation of lycopene ε-cyclase (ε-LCY) gene were detected in those transgenic plants. Under salt stress, proline content, and activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) were significantly increased, whereas malonaldehyde (MDA) and hydrogen peroxide (H2O2) accumulated less in the transgenic plants. The genes encoding ascorbate peroxidase (APX), CAT, POD, SOD, and pyrroline-5-carboxylate reductase (P5CR) were shown to responsive up-regulated significantly under the salt stress in the transgenic plants. This study indicated that LcPDS, LcZDS, and LcCRTISO have the potential to improve carotenoid content and salt tolerance in higher plant breeding.
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Affiliation(s)
- Chen Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Jing Ji
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Gang Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Zhaodi Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
| | - Yurong Wang
- Division of Biological Sciences, University of California, San Diego, San Diego, CA, United States
| | - Yajun Fan
- School of Environmental Science and Engineering, Tianjin University, Tianjin, China
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31
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Macroorganisation and flexibility of thylakoid membranes. Biochem J 2019; 476:2981-3018. [DOI: 10.1042/bcj20190080] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/19/2019] [Accepted: 10/03/2019] [Indexed: 02/07/2023]
Abstract
Abstract
The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.
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32
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Pinnola A. The rise and fall of Light-Harvesting Complex Stress-Related proteins as photoprotection agents during evolution. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5527-5535. [PMID: 31424076 DOI: 10.1093/jxb/erz317] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/22/2019] [Indexed: 05/18/2023]
Abstract
Photosynthesis depends on light. However, excess light can be harmful for the photosynthetic apparatus because it produces reactive oxygen species (ROS) that cause photoinhibition. Oxygenic organisms evolved photoprotection mechanisms to counteract light-dependent ROS production, including preventive dissipation of excited states of chlorophyll (1Chl*) into heat in the process termed non-photochemical quenching (NPQ). This consists in the activation of 1Chl* quenching reactions when the thylakoid luminal pH drops below 5.2. In turn, acidification occurs when the rate of the CO2 reducing cycle is saturated and cannot regenerate ADP+Pi, thus inhibiting ATPase activity and the return of protons (H+) to the stromal compartment. The major and fastest component of NPQ is energy quenching, qE, which in algae depends on the Light-Harvesting Complex Stress-Related (LHCSR) proteins. In mosses, LHCSR proteins have remained the major catalysts of energy dissipation, but a minor contribution also occurs via a homologous protein, Photosystem II Subunit S (PSBS). In vascular plants, however, LHCSR has disappeared and PSBS is the only pH-sensitive trigger of qE. Why did PSBS replace LHCSR in the later stages of land colonization? Both PSBS and LHCSR belong to the Light Harvesting Complex superfamily (LHC) and share properties such as harboring protonatable residues that are exposed to the chloroplast lumen, which is essential for pH sensing. However, there are also conspicuous differences: LHCSR binds chlorophylls and xanthophylls while PSBS does not, implying that the former may well catalyse quenching reactions while the latter needs pigment-binding partners for its quenching function. Here, the evolution of quenching mechanisms for excess light is reviewed with a focus on the role of LHCSR versus PSBS, and the reasons for the redundancy of LHCSR in vascular plants as PSBS became established.
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Affiliation(s)
- Alberta Pinnola
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Pavia, Italy
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33
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Park S, Steen CJ, Fischer AL, Fleming GR. Snapshot transient absorption spectroscopy: toward in vivo investigations of nonphotochemical quenching mechanisms. PHOTOSYNTHESIS RESEARCH 2019; 141:367-376. [PMID: 31020482 DOI: 10.1007/s11120-019-00640-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 04/15/2019] [Indexed: 06/09/2023]
Abstract
Although the importance of nonphotochemical quenching (NPQ) on photosynthetic biomass production and crop yields is well established, the in vivo operation of the individual mechanisms contributing to overall NPQ is still a matter of controversy. In order to investigate the timescale and activation dynamics of specific quenching mechanisms, we have developed a technique called snapshot transient absorption (TA) spectroscopy, which can monitor molecular species involved in the quenching response with a time resolution of 30 s. Using intact thylakoid membrane samples, we show how conventional TA kinetic and spectral analyses enable the determination of the appropriate wavelength and time delay for snapshot TA experiments. As an example, we show how the chlorophyll-carotenoid charge transfer and excitation energy transfer mechanisms can be monitored based on signals corresponding to the carotenoid (Car) radical cation and Car S1 excited state absorption, respectively. The use of snapshot TA spectroscopy together with the previously reported fluorescence lifetime snapshot technique (Sylak-Glassman et al. in Photosynth Res 127:69-76, 2016) provides valuable information such as the concurrent appearance of specific quenching species and overall quenching of excited Chl. Furthermore, we show that the snapshot TA technique can be successfully applied to completely intact photosynthetic organisms such as live cells of Nannochloropsis. This demonstrates that the snapshot TA technique is a valuable method for tracking the dynamics of intact samples that evolve over time, such as the photosynthetic system in response to high-light exposure.
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Affiliation(s)
- Soomin Park
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy Nanoscience Institute, Berkeley, CA, 94720, USA
| | - Collin J Steen
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy Nanoscience Institute, Berkeley, CA, 94720, USA
| | - Alexandra L Fischer
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Kavli Energy Nanoscience Institute, Berkeley, CA, 94720, USA
- Intel Corporation, NE Century Blvd 2501, Hillsboro, OR, 97214, USA
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA.
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
- Kavli Energy Nanoscience Institute, Berkeley, CA, 94720, USA.
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34
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Kirchhoff H. Chloroplast ultrastructure in plants. THE NEW PHYTOLOGIST 2019; 223:565-574. [PMID: 30721547 DOI: 10.1111/nph.15730] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 01/25/2019] [Indexed: 05/23/2023]
Abstract
The chloroplast organelle in mesophyll cells of higher plants represents a sunlight-driven metabolic factory that eventually fuels life on our planet. Knowledge of the ultrastructure and the dynamics of this unique organelle is essential to understanding its function in an ever-changing and challenging environment. Recent technological developments promise unprecedented insights into chloroplast architecture and its functionality. The review highlights these new methodical approaches and provides structural models based on recent findings about the plasticity of the thylakoid membrane system in response to different light regimes. Furthermore, the potential role of the lipid droplets plastoglobuli is discussed. It is emphasized that detailed structural insights are necessary on different levels ranging from molecules to entire membrane systems for a holistic understanding of chloroplast function.
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Affiliation(s)
- Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA, 99164-6340, USA
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35
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Bennett DIG, Amarnath K, Park S, Steen CJ, Morris JM, Fleming GR. Models and mechanisms of the rapidly reversible regulation of photosynthetic light harvesting. Open Biol 2019; 9:190043. [PMID: 30966997 PMCID: PMC6501642 DOI: 10.1098/rsob.190043] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 03/07/2019] [Indexed: 02/02/2023] Open
Abstract
The rapid response of photosynthetic organisms to fluctuations in ambient light intensity is incompletely understood at both the molecular and membrane levels. In this review, we describe research from our group over a 10-year period aimed at identifying the photophysical mechanisms used by plants, algae and mosses to control the efficiency of light harvesting by photosystem II on the seconds-to-minutes time scale. To complement the spectroscopic data, we describe three models capable of describing the measured response at a quantitative level. The review attempts to provide an integrated view that has emerged from our work, and briefly looks forward to future experimental and modelling efforts that will refine and expand our understanding of a process that significantly influences crop yields.
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Affiliation(s)
- Doran I. G. Bennett
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Kapil Amarnath
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Soomin Park
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
| | - Collin J. Steen
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
| | - Jonathan M. Morris
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
| | - Graham R. Fleming
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
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36
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Koochak H, Puthiyaveetil S, Mullendore DL, Li M, Kirchhoff H. The structural and functional domains of plant thylakoid membranes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 97:412-429. [PMID: 30312499 DOI: 10.1111/tpj.14127] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/24/2018] [Accepted: 10/01/2018] [Indexed: 05/07/2023]
Abstract
In plants, the stacking of part of the photosynthetic thylakoid membrane generates two main subcompartments: the stacked grana core and unstacked stroma lamellae. However, a third distinct domain, the grana margin, has been postulated but its structural and functional identity remains elusive. Here, an optimized thylakoid fragmentation procedure combined with detailed ultrastructural, biochemical, and functional analyses reveals the distinct composition of grana margins. It is enriched with lipids, cytochrome b6 f complex, and ATPase while depleted in photosystems and light-harvesting complexes. A quantitative method is introduced that is based on Blue Native Polyacrylamide Gel Electrophoresis (BN-PAGE) and dot immunoblotting for quantifying various photosystem II (PSII) assembly forms in different thylakoid subcompartments. The results indicate that the grana margin functions as a degradation and disassembly zone for photodamaged PSII. In contrast, the stacked grana core region contains fully assembled and functional PSII holocomplexes. The stroma lamellae, finally, contain monomeric PSII as well as a significant fraction of dimeric holocomplexes that identify this membrane area as the PSII repair zone. This structural organization and the heterogeneous PSII distribution support the idea that the stacking of thylakoid membranes leads to a division of labor that establishes distinct membrane areas with specific functions.
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Affiliation(s)
- Haniyeh Koochak
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA, 99164-6340, USA
| | - Sujith Puthiyaveetil
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA, 99164-6340, USA
| | - Daniel L Mullendore
- Franceschi Microscopy and Imaging Center, Washington State University, Pullman, WA, 99164, USA
| | - Meng Li
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA, 99164-6340, USA
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, WA, 99164-6340, USA
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37
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Zhai X, Li Z, Zhang J, Shi J, Zou X, Huang X, Zhang D, Sun Y, Yang Z, Holmes M, Gong Y, Povey M. Natural Biomaterial-Based Edible and pH-Sensitive Films Combined with Electrochemical Writing for Intelligent Food Packaging. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:9159-9161. [PMID: 30450908 DOI: 10.1021/acs.jafc.8b01788] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
An edible and pH-sensitive film combined with electrochemical writing was developed by using gelatin, gellan gum, and red radish anthocyanins extract for intelligent food packaging. The composite film showed an orange red-to-yellow color change in the pH range of 2-12. The tensile strength, ductility, and barrier abilities to ultraviolet (UV) light and oxygen of the films were improved as the concentration of red radish anthocyanins increased. Multicolor patterns were successfully drawn on the films by using the electrochemical writing method. The composite films, which acted as gas sensors, presented visible color changes in the presence of milk and fish spoilage, while the written patterns were well-preserved. Accordingly, this composite film with written patterns could be an easy-to-use indicator with great potential for monitoring food spoilage as a part of an intelligent packaging system.
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Affiliation(s)
- Xiaodong Zhai
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Zhihua Li
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Junjun Zhang
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Jiyong Shi
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Xiaobo Zou
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Xiaowei Huang
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Di Zhang
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Yue Sun
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Zhikun Yang
- Agricultural Product Processing and Storage Lab, School of Food and Biological Engineering , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Melvin Holmes
- School of Food Science and Nutrition , University of Leeds , Leeds LS2 9JT , United Kingdom
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Yunyun Gong
- School of Food Science and Nutrition , University of Leeds , Leeds LS2 9JT , United Kingdom
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
| | - Megan Povey
- School of Food Science and Nutrition , University of Leeds , Leeds LS2 9JT , United Kingdom
- China-U.K. Joint Laboratory for Nondestructive Detection of Agro-products , Jiangsu University , Zhenjiang , Jiangsu 212013 , China
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38
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Energy transfer and distribution in photosystem super/megacomplexes of plants. Curr Opin Biotechnol 2018; 54:50-56. [DOI: 10.1016/j.copbio.2018.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 12/25/2017] [Accepted: 01/04/2018] [Indexed: 11/18/2022]
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Energy-dependent quenching adjusts the excitation diffusion length to regulate photosynthetic light harvesting. Proc Natl Acad Sci U S A 2018; 115:E9523-E9531. [PMID: 30237283 PMCID: PMC6187178 DOI: 10.1073/pnas.1806597115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Plants’ photosynthetic mechanism adjusts to fluctuations in light intensity. Intermittent bright sunlight can damage light-harvesting proteins; to preempt this, plants dissipate excess absorbed excitation energy as heat. Energy-dependent quenching (qE) of excitations occurs on the seconds to minutes timescale through conformational changes in antenna proteins. Using a multiscale model of photosystem II, we show that changes in light harvesting due to qE can be explained using a single parameter, the excitation diffusion length, which decreases as qE activates. These findings have implications for the interpretation of pulse amplitude-modulated fluorescence, a common noninvasive measurement of photosynthetic activity in leaves. An important determinant of crop yields is the regulation of photosystem II (PSII) light harvesting by energy-dependent quenching (qE). However, the molecular details of excitation quenching have not been quantitatively connected to the fraction of excitations converted to chemical energy by PSII reaction centers (PSII yield), which determines flux to downstream metabolism. Here, we incorporate excitation dissipation by qE into a pigment-scale model of excitation transfer and trapping for a 200 × 200-nm patch of the grana membrane. We show that excitation transport can be rigorously coarse grained to a 2D random walk with an excitation diffusion length determined by the extent of quenching. We present an alternative method for analyzing pulse amplitude-modulated chlorophyll fluorescence measurements that incorporates the effects of a variable excitation diffusion length during qE activation.
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40
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Kodaimati MS, Lian S, Schatz GC, Weiss EA. Energy transfer-enhanced photocatalytic reduction of protons within quantum dot light-harvesting-catalyst assemblies. Proc Natl Acad Sci U S A 2018; 115:8290-8295. [PMID: 30068607 PMCID: PMC6099859 DOI: 10.1073/pnas.1805625115] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Excitonic energy transfer (EnT) is the mechanism by which natural photosynthetic systems funnel energy from hundreds of antenna pigments to a single reaction center, which allows multielectron redox reactions to proceed with high efficiencies in low-flux natural light. This paper describes the use of electrostatically assembled CdSe quantum dot (QD) aggregates as artificial light harvesting-reaction center units for the photocatalytic reduction of H+ to H2, where excitons are funneled through EnT from sensitizer QDs (sQDs) to catalyst QDs (cQDs). Upon increasing the sensitizer-to-catalyst ratio in the aggregates from 1:2 to 20:1, the number of excitons delivered to each cQD (via EnT) per excitation of the system increases by a factor of nine. At the optimized sensitizer-to-catalyst ratio of 4:1, the internal quantum efficiency (IQE) of the reaction system is 4.0 ± 0.3%, a factor of 13 greater than the IQE of a sample that is identical except that EnT is suppressed due to the relative core sizes of the sQDs and cQDs. A kinetic model supports the proposed exciton funneling mechanism for enhancement of the catalytic activity.
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Affiliation(s)
| | - Shichen Lian
- Department of Chemistry, Northwestern University, Evanston, IL 60208-3113
| | - George C Schatz
- Department of Chemistry, Northwestern University, Evanston, IL 60208-3113
- Center for Bio-Inspired Energy Science, Northwestern University, Chicago, IL 60611-3015
| | - Emily A Weiss
- Department of Chemistry, Northwestern University, Evanston, IL 60208-3113;
- Center for Bio-Inspired Energy Science, Northwestern University, Chicago, IL 60611-3015
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41
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Blau SM, Bennett DIG, Kreisbeck C, Scholes GD, Aspuru-Guzik A. Local protein solvation drives direct down-conversion in phycobiliprotein PC645 via incoherent vibronic transport. Proc Natl Acad Sci U S A 2018; 115:E3342-E3350. [PMID: 29588417 PMCID: PMC5899487 DOI: 10.1073/pnas.1800370115] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mechanisms controlling excitation energy transport (EET) in light-harvesting complexes remain controversial. Following the observation of long-lived beats in 2D electronic spectroscopy of PC645, vibronic coherence, the delocalization of excited states between pigments supported by a resonant vibration, has been proposed to enable direct excitation transport from the highest-energy to the lowest-energy pigments, bypassing a collection of intermediate states. Here, we instead show that for phycobiliprotein PC645 an incoherent vibronic transport mechanism is at play. We quantify the solvation dynamics of individual pigments using ab initio quantum mechanics/molecular mechanics (QM/MM) nuclear dynamics. Our atomistic spectral densities reproduce experimental observations ranging from absorption and fluorescence spectra to the timescales and selectivity of down-conversion observed in transient absorption measurements. We construct a general model for vibronic dimers and establish the parameter regimes of coherent and incoherent vibronic transport. We demonstrate that direct down-conversion in PC645 proceeds incoherently, enhanced by large reorganization energies and a broad collection of high-frequency vibrations. We suggest that a similar incoherent mechanism is appropriate across phycobiliproteins and represents a potential design principle for nanoscale control of EET.
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Affiliation(s)
- Samuel M Blau
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Doran I G Bennett
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
- Bio-Inspired Solar Energy Program, Canadian Institute for Advanced Research, Toronto, ON M5G 1Z8, Canada
| | - Christoph Kreisbeck
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Gregory D Scholes
- Bio-Inspired Solar Energy Program, Canadian Institute for Advanced Research, Toronto, ON M5G 1Z8, Canada
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138;
- Bio-Inspired Solar Energy Program, Canadian Institute for Advanced Research, Toronto, ON M5G 1Z8, Canada
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42
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Fleming GR. The contributions of 49ers to the measurements and models of ultrafast photosynthetic energy transfer. PHOTOSYNTHESIS RESEARCH 2018; 135:3-8. [PMID: 28247235 DOI: 10.1007/s11120-017-0360-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 02/21/2017] [Indexed: 06/06/2023]
Abstract
Progress in measuring and understanding the mechanism of the elementary energy transfer steps in photosynthetic light harvesting from roughly 1949 to the present is sketched with a focus on the group of scientists born in 1949 ± 1. Improvements in structural knowledge, laser spectroscopic methods, and quantum dynamical theories have led to the ability to record and calculate with reasonable accuracy the timescales of elementary energy transfer steps. The significance of delocalized excited states and of near-field Coulombic coupling is noted. The microscopic understanding enables consistent coarse graining and should enable a much-improved understanding of the regulation of photosynthetic light harvesting.
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Affiliation(s)
- Graham R Fleming
- Department of Chemistry and Kavli Energy NanoScience Institute, University of California Berkeley, Berkeley, CA, 94720, USA.
- Molecular Biophysics and Integrated Bioengineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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43
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Häse F, Kreisbeck C, Aspuru-Guzik A. Machine learning for quantum dynamics: deep learning of excitation energy transfer properties. Chem Sci 2017; 8:8419-8426. [PMID: 29619189 PMCID: PMC5863613 DOI: 10.1039/c7sc03542j] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 10/23/2017] [Indexed: 12/20/2022] Open
Abstract
Understanding the relationship between the structure of light-harvesting systems and their excitation energy transfer properties is of fundamental importance in many applications including the development of next generation photovoltaics. Natural light harvesting in photosynthesis shows remarkable excitation energy transfer properties, which suggests that pigment-protein complexes could serve as blueprints for the design of nature inspired devices. Mechanistic insights into energy transport dynamics can be gained by leveraging numerically involved propagation schemes such as the hierarchical equations of motion (HEOM). Solving these equations, however, is computationally costly due to the adverse scaling with the number of pigments. Therefore virtual high-throughput screening, which has become a powerful tool in material discovery, is less readily applicable for the search of novel excitonic devices. We propose the use of artificial neural networks to bypass the computational limitations of established techniques for exploring the structure-dynamics relation in excitonic systems. Once trained, our neural networks reduce computational costs by several orders of magnitudes. Our predicted transfer times and transfer efficiencies exhibit similar or even higher accuracies than frequently used approximate methods such as secular Redfield theory.
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Affiliation(s)
- Florian Häse
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; ; Tel: +1-617-384-8188
| | - Christoph Kreisbeck
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; ; Tel: +1-617-384-8188
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology , Harvard University , Cambridge , 02138 , USA . ; ; Tel: +1-617-384-8188
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44
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The Douglas-Fir Genome Sequence Reveals Specialization of the Photosynthetic Apparatus in Pinaceae. G3-GENES GENOMES GENETICS 2017; 7:3157-3167. [PMID: 28751502 PMCID: PMC5592940 DOI: 10.1534/g3.117.300078] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A reference genome sequence for Pseudotsuga menziesii var. menziesii (Mirb.) Franco (Coastal Douglas-fir) is reported, thus providing a reference sequence for a third genus of the family Pinaceae. The contiguity and quality of the genome assembly far exceeds that of other conifer reference genome sequences (contig N50 = 44,136 bp and scaffold N50 = 340,704 bp). Incremental improvements in sequencing and assembly technologies are in part responsible for the higher quality reference genome, but it may also be due to a slightly lower exact repeat content in Douglas-fir vs. pine and spruce. Comparative genome annotation with angiosperm species reveals gene-family expansion and contraction in Douglas-fir and other conifers which may account for some of the major morphological and physiological differences between the two major plant groups. Notable differences in the size of the NDH-complex gene family and genes underlying the functional basis of shade tolerance/intolerance were observed. This reference genome sequence not only provides an important resource for Douglas-fir breeders and geneticists but also sheds additional light on the evolutionary processes that have led to the divergence of modern angiosperms from the more ancient gymnosperms.
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45
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Leuenberger M, Morris JM, Chan AM, Leonelli L, Niyogi KK, Fleming GR. Dissecting and modeling zeaxanthin- and lutein-dependent nonphotochemical quenching in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2017; 114:E7009-E7017. [PMID: 28652334 PMCID: PMC5565437 DOI: 10.1073/pnas.1704502114] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Photosynthetic organisms use various photoprotective mechanisms to dissipate excess photoexcitation as heat in a process called nonphotochemical quenching (NPQ). Regulation of NPQ allows for a rapid response to changes in light intensity and in vascular plants, is primarily triggered by a pH gradient across the thylakoid membrane (∆pH). The response is mediated by the PsbS protein and various xanthophylls. Time-correlated single-photon counting (TCSPC) measurements were performed on Arabidopsis thaliana to quantify the dependence of the response of NPQ to changes in light intensity on the presence and accumulation of zeaxanthin and lutein. Measurements were performed on WT and mutant plants deficient in one or both of the xanthophylls as well as a transgenic line that accumulates lutein via an engineered lutein epoxide cycle. Changes in the response of NPQ to light acclimation in WT and mutant plants were observed between two successive light acclimation cycles, suggesting that the character of the rapid and reversible response of NPQ in fully dark-acclimated plants is substantially different from in conditions plants are likely to experience caused by changes in light intensity during daylight. Mathematical models of the response of zeaxanthin- and lutein-dependent reversible NPQ were constructed that accurately describe the observed differences between the light acclimation periods. Finally, the WT response of NPQ was reconstructed from isolated components present in mutant plants with a single common scaling factor, which enabled deconvolution of the relative contributions of zeaxanthin- and lutein-dependent NPQ.
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Affiliation(s)
- Michelle Leuenberger
- Department of Chemistry, University of California, Berkeley, CA 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Kavli Energy Nanoscience Institute, Berkeley, CA 94720
| | - Jonathan M Morris
- Department of Chemistry, University of California, Berkeley, CA 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Kavli Energy Nanoscience Institute, Berkeley, CA 94720
- Graduate Group in Applied Science & Technology, University of California, Berkeley, CA 94720
| | - Arnold M Chan
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Lauriebeth Leonelli
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Krishna K Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Howard Hughes Medical Institute, Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Graham R Fleming
- Department of Chemistry, University of California, Berkeley, CA 94720;
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Kavli Energy Nanoscience Institute, Berkeley, CA 94720
- Graduate Group in Applied Science & Technology, University of California, Berkeley, CA 94720
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46
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de Sousa CAF, de Paiva DS, Casari RADCN, de Oliveira NG, Molinari HBC, Kobayashi AK, Magalhães PC, Gomide RL, Souza MT. A procedure for maize genotypes discrimination to drought by chlorophyll fluorescence imaging rapid light curves. PLANT METHODS 2017; 13:61. [PMID: 28769996 PMCID: PMC5530575 DOI: 10.1186/s13007-017-0209-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 07/17/2017] [Indexed: 05/30/2023]
Abstract
BACKGROUND Photosynthesis can be roughly separated into biochemical and photochemical processes. Both are affected by drought and can be assessed by non-invasive standard methods. Gas exchange, which mainly assesses the first process, has well-defined protocols. It is considered a standard method for evaluation of plant responses to drought. Under such stress, assessment of photochemical apparatus by chlorophyll fluorescence needs improvement to become faster and reproducible, especially in growing plants under field conditions. For this, we developed a protocol based on chlorophyll fluorescence imaging, using a rapid light curve approach. RESULTS Almost all parameters obtained by rapid light curves have shown statistical differences between control and drought stressed maize plants. However, most of them were affected by induction processes, relaxation rate, and/or differences in chlorophyll content; while they all were influenced by actinic light intensity on each light step of light curve. Only the normalized parameters related to photochemical and non-photochemical quenching were strongly correlated with data obtained by gas exchange, but only from the light step in which the linear electron flow reached saturation. CONCLUSIONS The procedure developed in this study for discrimination of plant responses to water deficit stress proved to be as fast, efficient and reliable as the standard technique of gas exchange in order to discriminate the responses of maize genotypes to drought. However, unlike that, there is no need to perform daily and time consuming calibration routines. Moreover, plant acclimation to the dark is not required. The protocol can be applied to plants growing in both controlled conditions and full sunlight in the field. In addition, it generates parameters in a fast and accurate measurement process, which enables evaluating several plants in a short period of time.
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Affiliation(s)
| | - Dayane Silva de Paiva
- Embrapa Agroenergia, Parque Estação Biológica (PqEB), Avenida W3 Norte (Final), Brasília, DF 70770-901 Brazil
| | | | - Nelson Geraldo de Oliveira
- Embrapa Agroenergia, Parque Estação Biológica (PqEB), Avenida W3 Norte (Final), Brasília, DF 70770-901 Brazil
| | - Hugo Bruno Correa Molinari
- Embrapa Agroenergia, Parque Estação Biológica (PqEB), Avenida W3 Norte (Final), Brasília, DF 70770-901 Brazil
| | - Adilson Kenji Kobayashi
- Embrapa Agroenergia, Parque Estação Biológica (PqEB), Avenida W3 Norte (Final), Brasília, DF 70770-901 Brazil
| | - Paulo Cesar Magalhães
- Embrapa Milho e Sorgo, Rod. MG 424 km 45, Zona Rural, Sete Lagoas, MG 35701-970 Brazil
| | - Reinaldo Lúcio Gomide
- Embrapa Milho e Sorgo, Rod. MG 424 km 45, Zona Rural, Sete Lagoas, MG 35701-970 Brazil
| | - Manoel Teixeira Souza
- Embrapa Agroenergia, Parque Estação Biológica (PqEB), Avenida W3 Norte (Final), Brasília, DF 70770-901 Brazil
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47
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Kodaimati MS, Wang C, Chapman C, Schatz GC, Weiss EA. Distance-Dependence of Interparticle Energy Transfer in the Near-Infrared within Electrostatic Assemblies of PbS Quantum Dots. ACS NANO 2017; 11:5041-5050. [PMID: 28398717 DOI: 10.1021/acsnano.7b01778] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
This paper describes control of the rate constant for near-infrared excitonic energy transfer (EnT) within soluble aqueous assemblies of PbS quantum dots, cross-linked by Zn2+, by changing the length of the mercapto-alkanoic acid (MAA) that serves as the cross-linking ligand. Sequestration of Zn2+ by a chelating agent or zinc hydroxide species results in deaggregation of the assemblies with EnT turned "off". Upon decreasing the number of methylene groups in MAAs from 16 to 3, the interparticle separation decreases from 5.8 nm to 3.7 nm and the average observed EnT rate increases from ∼(150 ns)-1 to ∼(2 ns)-1. A master equation translates intrinsic (single-donor-single-acceptor) EnT rate constants predicted for each ligand length using Förster theory to observed average rate constants. For interparticle distances greater than ∼4 nm, the point dipole approximation (PDA) implementation of Förster theory agrees with experimentally measured rates. At shorter interparticle distances, the PDA drastically underestimates the observed EnT rate. The prediction of the rates of these short-distance EnT processes is improved by ∼20% by replacing the PDA with a transition density cube calculation of the interparticle Coulombic coupling.
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Affiliation(s)
- Mohamad S Kodaimati
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Chen Wang
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Craig Chapman
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - George C Schatz
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
| | - Emily A Weiss
- Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States
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48
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Puthiyaveetil S, van Oort B, Kirchhoff H. Surface charge dynamics in photosynthetic membranes and the structural consequences. NATURE PLANTS 2017; 3:17020. [PMID: 28263304 DOI: 10.1038/nplants.2017.20] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 02/03/2017] [Indexed: 05/22/2023]
Abstract
The strict stacking of plant photosynthetic membranes into granal structures plays a vital role in energy conversion. The molecular forces that lead to grana stacking, however, are poorly understood. Here we evaluate the interplay between repulsive electrostatic (Fel) and attractive van der Waals (FvdWaals) forces in grana stacking. In contrast to previous reports, we find that the physicochemical balance between attractive and repulsive forces fully explains grana stacking. Extending the force balance analysis to lateral interactions within the oxygen-evolving photosystem II (PSII)-light harvesting complex II (LHCII) supercomplex reveals that supercomplex stability is very sensitive to Fel changes. Fel is highly dynamic, increasing up to 1.7-fold on addition of negative charges by phosphorylation of grana-hosted proteins. We show that this leads to specific destabilization of the supercomplex, and that changes in Fel have contrasting effects on vertical stacking and lateral intramembrane organization. This enables discrete biological control of these central structural features.
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Affiliation(s)
- Sujith Puthiyaveetil
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, Washington 99164-6340, USA
| | - Bart van Oort
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Helmut Kirchhoff
- Institute of Biological Chemistry, Washington State University, PO Box 646340, Pullman, Washington 99164-6340, USA
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49
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Roden JJJ, Bennett DIG, Whaley KB. Long-range energy transport in photosystem II. J Chem Phys 2017; 144:245101. [PMID: 27369543 DOI: 10.1063/1.4953243] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We simulate the long-range inter-complex electronic energy transfer in photosystem II-from the antenna complex, via a core complex, to the reaction center-using a non-Markovian (ZOFE) quantum master equation description that allows the electronic coherence involved in the energy transfer to be explicitly included at all length scales. This allows us to identify all locations where coherence is manifested and to further identify the pathways of the energy transfer in the full network of coupled chromophores using a description based on excitation probability currents. We investigate how the energy transfer depends on the initial excitation-localized, coherent initial excitation versus delocalized, incoherent initial excitation-and find that the overall energy transfer is remarkably robust with respect to such strong variations of the initial condition. To explore the importance of vibrationally enhanced transfer and to address the question of optimization in the system parameters, we systematically vary the strength of the coupling between the electronic and the vibrational degrees of freedom. We find that the natural parameters lie in a (broad) region that enables optimal transfer efficiency and that the overall long-range energy transfer on a ns time scale appears to be very robust with respect to variations in the vibronic coupling of up to an order of magnitude. Nevertheless, vibrationally enhanced transfer appears to be crucial to obtain a high transfer efficiency, with the latter falling sharply for couplings outside the optimal range. Comparison of our full quantum simulations to results obtained with a "classical" rate equation based on a modified-Redfield/generalized-Förster description previously used to simulate energy transfer dynamics in the entire photosystem II complex shows good agreement for the overall time scales of excitation energy transport.
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Affiliation(s)
- Jan J J Roden
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Doran I G Bennett
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - K Birgitta Whaley
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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50
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Gunner MR, Koder R. The design features cells use to build their transmembrane proton gradient. Phys Biol 2017; 14:013001. [DOI: 10.1088/1478-3975/14/1/013001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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