1
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Gray C, Kailas L, Adams PG, Duffy CDP. Unravelling the fluorescence kinetics of light-harvesting proteins with simulated measurements. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149004. [PMID: 37699505 DOI: 10.1016/j.bbabio.2023.149004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/24/2023] [Accepted: 08/31/2023] [Indexed: 09/14/2023]
Abstract
The plant light-harvesting pigment-protein complex LHCII is the major antenna sub-unit of PSII and is generally (though not universally) accepted to play a role in photoprotective energy dissipation under high light conditions, a process known Non-Photochemical Quenching (NPQ). The underlying mechanisms of energy trapping and dissipation within LHCII are still debated. Various models have been proposed for the underlying molecular detail of NPQ, but they are often based on different interpretations of very similar transient absorption measurements of isolated complexes. Here we present a simulated measurement of the fluorescence decay kinetics of quenched LHCII aggregates to determine whether this relatively simple measurement can discriminate between different potential NPQ mechanisms. We simulate not just the underlying physics (excitation, energy migration, quenching and singlet-singlet annihilation) but also the signal detection and typical experimental data analysis. Comparing this to a selection of published fluorescence decay kinetics we find that: (1) Different proposed quenching mechanisms produce noticeably different fluorescence kinetics even at low (annihilation free) excitation density, though the degree of difference is dependent on pulse width. (2) Measured decay kinetics are consistent with most LHCII trimers becoming relatively slow excitation quenchers. A small sub-population of very fast quenchers produces kinetics which do not resemble any observed measurement. (3) It is necessary to consider at least two distinct quenching mechanisms in order to accurately reproduce experimental kinetics, supporting the idea that NPQ is not a simple binary switch.
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Affiliation(s)
- Callum Gray
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, United Kingdom
| | - Lekshmi Kailas
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Peter G Adams
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Christopher D P Duffy
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End, London E1 4NS, United Kingdom.
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2
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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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3
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Chlorophyll fluorescence parameters to assess utilization of excitation energy in photosystem II independently of changes in leaf absorption. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2019; 197:111535. [PMID: 31319267 DOI: 10.1016/j.jphotobiol.2019.111535] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/06/2019] [Accepted: 06/14/2019] [Indexed: 01/03/2023]
Abstract
Measurement of Pulse-Amplitude-Modulated (PAM) chlorophyll a fluorescence is widely used method for obtaining information on the functional state of photosystem II (PSII). Recently, it has been shown that some of long-established fluorescence parameters must be interpreted with caution, when the light-induced chloroplast movements occur. In our work we have analyzed the effect of chloroplast movements on these parameters. We have derived new parameters that are independent of the change in PSII absorption occurring during measurement. To verify whether there is a need for new parameters or the difference between the parameters commonly used and the newly derived ones is insignificant, we conducted an experiment with Arabidopsis thaliana wild type plants and its phot1 phot2 mutant defective in chloroplast movement. Plants were exposed to light of different qualities (450, 470, 550 or 660 nm) and quantities (100, 400 or 1200 μmol m-2 s-1) for up to 40 min. Since the blue light-induced chloroplast avoidance reaction is a photoprotective mechanism, we expected that phot1 phot2 mutant will compensate the lack of this mechanism by increasing non-photochemical quenching. However, using the light at both 450 and 470 nm, the calculation of commonly used parameter, ΦNPQ (quantum yield of regulated light-induced thermal energy dissipation in PSII) based on Hendrickson et al. [L. Hendrickson, R.T. Furbank, W.S. Chow, Photosynth. Res. 82 (2004) 73-81] showed the opposite. On the other hand, the results obtained using our newly proposed formulae to determine quantum yield of PSII thermal energy dissipation were in line with our assumption. Thus, the experimental data showed that some formulae of fluorescence parameters are dependent on the change in PSII absorption and need to be interpreted carefully. On the contrary, the formulae introduced by us can remove the effect of changes in PSII absorption that occur during measurement, without additional measurements, and give the real estimate of light-induced non-photochemical quenching.
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4
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Iwai M, Roth MS, Niyogi KK. Subdiffraction-resolution live-cell imaging for visualizing thylakoid membranes. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:233-243. [PMID: 29982996 PMCID: PMC6150804 DOI: 10.1111/tpj.14021] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 06/18/2018] [Accepted: 06/25/2018] [Indexed: 05/19/2023]
Abstract
The chloroplast is the chlorophyll-containing organelle that produces energy through photosynthesis. Within the chloroplast is an intricate network of thylakoid membranes containing photosynthetic membrane proteins that mediate electron transport and generate chemical energy. Historically, electron microscopy (EM) has been a powerful tool for visualizing the macromolecular structure and organization of thylakoid membranes. However, an understanding of thylakoid membrane dynamics remains elusive because EM requires fixation and sectioning. To improve our knowledge of thylakoid membrane dynamics we need to consider at least two issues: (i) the live-cell imaging conditions needed to visualize active processes in vivo; and (ii) the spatial resolution required to differentiate the characteristics of thylakoid membranes. Here, we utilize three-dimensional structured illumination microscopy (3D-SIM) to explore the optimal imaging conditions for investigating the dynamics of thylakoid membranes in living plant and algal cells. We show that 3D-SIM is capable of examining broad characteristics of thylakoid structures in chloroplasts of the vascular plant Arabidopsis thaliana and distinguishing the structural differences between wild-type and mutant strains. Using 3D-SIM, we also visualize thylakoid organization in whole cells of the green alga Chlamydomonas reinhardtii. These data reveal that high light intensity changes thylakoid membrane structure in C. reinhardtii. Moreover, we observed the green alga Chromochloris zofingiensis and the moss Physcomitrella patens to show the applicability of 3D-SIM. This study demonstrates that 3D-SIM is a promising approach for studying the dynamics of thylakoid membranes in photoautotrophic organisms during photoacclimation processes.
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Affiliation(s)
- Masakazu Iwai
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3102, USA
- Contact Author: Masakazu Iwai
| | - Melissa S. Roth
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3102, USA
| | - Krishna K. Niyogi
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Plant and Microbial Biology, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720-3102, USA
- For correspondence ( or )
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5
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Langlois A, Camus JM, Karsenti PL, Guilard R, Harvey PD. Metal Dependence on the Bidirectionality and Reversibility of the Singlet Energy Transfer in Artificial Special Pair-Containing Dyads. Inorg Chem 2017; 56:2506-2517. [DOI: 10.1021/acs.inorgchem.6b02684] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adam Langlois
- Département
de Chimie, Université de Sherbrooke, Sherbrooke J1K 2R1, PQ, Canada
| | - Jean-Michel Camus
- Institut
de Chimie Moléculaire de l’Université de Bourgogne,
UMR CNRS 6302,Univ. Bourgogne Franche-Comté, 9 Avenue Alain Savary, BP 47870-21078 Dijon, France
| | | | - Roger Guilard
- Institut
de Chimie Moléculaire de l’Université de Bourgogne,
UMR CNRS 6302,Univ. Bourgogne Franche-Comté, 9 Avenue Alain Savary, BP 47870-21078 Dijon, France
| | - Pierre D. Harvey
- Département
de Chimie, Université de Sherbrooke, Sherbrooke J1K 2R1, PQ, Canada
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6
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Quan WD, Pitto-Barry A, Baker LA, Stulz E, Napier R, O'Reilly RK, Stavros VG. Retaining individualities: the photodynamics of self-ordering porphyrin assemblies. Chem Commun (Camb) 2016; 52:1938-41. [PMID: 26680651 PMCID: PMC4720934 DOI: 10.1039/c5cc09095d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Retained photochemical properties – a simple porphyrin–polyDMA conjugate with the ability to self assemble into large (∼1 μm) vesicles in water. The photodynamics are remarkably preserved despite the extensive aggregation.
The retention of photochemical properties of individual chromophores is a key feature of biological light harvesting complexes. This is achieved despite extensive aggregation of the chromophores, which in synthetic chromophore assemblies often yields a change in spectral characteristics. As an alternative approach towards mimicking biological light harvesting complexes, we report the synthesis of porphyrin assemblies which retained the photochemical properties of the individual chromophore units despite their substantial aggregation. These new materials highlight a new bottom-up approach towards the design and understanding of more complex biomimetic and naturally occurring biological systems.
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Affiliation(s)
- Wen-Dong Quan
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, UK. and Molecular Organisation and Assembly of Cells Doctoral Training Center (MOAC DTC), University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Anaïs Pitto-Barry
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, UK.
| | - Lewis A Baker
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, UK. and Molecular Organisation and Assembly of Cells Doctoral Training Center (MOAC DTC), University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Eugen Stulz
- School of Chemistry & Institute for Life Sciences, University of Southampton, Highfield, Southampton, UK
| | - Richard Napier
- School of Life Science, University of Warwick, Gibbet Hill Road, Coventry, UK
| | - Rachel K O'Reilly
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, UK.
| | - Vasilios G Stavros
- Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, UK.
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7
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Wahadoszamen M, Belgio E, Rahman MA, Ara AM, Ruban AV, van Grondelle R. Identification and characterization of multiple emissive species in aggregated minor antenna complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1917-1924. [PMID: 27666345 DOI: 10.1016/j.bbabio.2016.09.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/10/2016] [Accepted: 09/21/2016] [Indexed: 11/16/2022]
Abstract
Aggregation induced conformational change of light harvesting antenna complexes is believed to constitute one of the pathways through which photosynthetic organisms can safely dissipate the surplus of energy while exposed to saturating light. In this study, Stark fluorescence (SF) spectroscopy is applied to minor antenna complexes (CP24, CP26 and CP29) both in their light-harvesting and energy-dissipating states to trace and characterize different species generated upon energy dissipation through aggregation (in-vitro) induced conformational change. SF spectroscopy could identify three spectral species in the dissipative state of CP24, two in CP26 and only one in CP29. The comprehensive analysis of the SF spectra yielded different sets of molecular parameters for the multiple spectral species identified in CP24 or CP26, indicating the involvement of different pigments in their formation. Interestingly, a species giving emission around the 730nm spectral region is found to form in both CP24 and CP26 following transition to the energy dissipative state, but not in CP29. The SF analyses revealed that the far red species has exceptionally large charge transfer (CT) character in the excited state. Moreover, the far red species was found to be formed invariably in both Zeaxanthin (Z)- and Violaxathin (V)-enriched CP24 and CP26 antennas with identical CT character but with larger emission yield in Z-enriched ones. This suggests that the carotenoid Z is not directly involved but only confers an allosteric effect on the formation of the far red species. Similar far red species with remarkably large CT character were also observed in the dissipative state of the major light harvesting antenna (LHCII) of plants [Wahadoszamen et al. PCCP, 2012], the fucoxanthin-chlorophyll protein (FCP) of brown algae [Wahadoszamen et al. BBA, 2014] and cyanobacterial IsiA [Wahadoszamen et al. BBA, 2015], thus pointing to identical sites and pigments active in the formation of the far red quenching species in different organisms.
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Affiliation(s)
- Md Wahadoszamen
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands; Department of Physics, University of Dhaka, Dhaka 1000, Bangladesh.
| | - Erica Belgio
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Opatovický mlýn, 379 81 Třeboň, Czech Republic; School of Biological and Chemical Sciences, Department of Cell and Molecular Biology, Queen Mary University of London
| | - Md Ashiqur Rahman
- Department of Physics, Khulna University of Engineering and Technology (KUET), Khulna 9203, Bangladesh
| | - Anjue Mane Ara
- Department of Physics, Jagannath University, Dhaka 1100, Bangladesh
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Department of Cell and Molecular Biology, Queen Mary University of London
| | - Rienk van Grondelle
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, The Netherlands.
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8
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Chmeliov J, Gelzinis A, Songaila E, Augulis R, Duffy CDP, Ruban AV, Valkunas L. The nature of self-regulation in photosynthetic light-harvesting antenna. NATURE PLANTS 2016; 2:16045. [PMID: 27243647 DOI: 10.1038/nplants.2016.45] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/09/2016] [Indexed: 05/08/2023]
Abstract
The photosynthetic apparatus of green plants is well known for its extremely high efficiency that allows them to operate under dim light conditions. On the other hand, intense sunlight may result in overexcitation of the light-harvesting antenna and the formation of reactive compounds capable of 'burning out' the whole photosynthetic unit. Non-photochemical quenching is a self-regulatory mechanism utilized by green plants on a molecular level that allows them to safely dissipate the detrimental excess excitation energy as heat. Although it is believed to take place in the plant's major light-harvesting complexes (LHC) II, there is still no consensus regarding its molecular nature. To get more insight into its physical origin, we performed high-resolution time-resolved fluorescence measurements of LHCII trimers and their aggregates across a wide temperature range. Based on simulations of the excitation energy transfer in the LHCII aggregate, we associate the red-emitting state, having fluorescence maximum at ∼700 nm, with the partial mixing of excitonic and chlorophyll-chlorophyll charge transfer states. On the other hand, the quenched state has a totally different nature and is related to the incoherent excitation transfer to the short-lived carotenoid excited states. Our results also show that the required level of photoprotection in vivo can be achieved by a very subtle change in the number of LHCIIs switched to the quenched state.
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Affiliation(s)
- Jevgenij Chmeliov
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Andrius Gelzinis
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Egidijus Songaila
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Ramūnas Augulis
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
| | - Christopher D P Duffy
- The School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Alexander V Ruban
- The School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
| | - Leonas Valkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
- Department of Molecular Compound Physics, Centre for Physical Sciences and Technology, Saulėtekio Avenue 3, LT-10222 Vilnius, Lithuania
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9
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Zhang HD, Yan Y. Kinetic Rate Kernels via Hierarchical Liouville–Space Projection Operator Approach. J Phys Chem A 2016; 120:3241-5. [DOI: 10.1021/acs.jpca.5b11731] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hou-Dao Zhang
- Department
of Chemistry, Hong Kong University of Science and Technology, Hong Kong, China
| | - YiJing Yan
- Department
of Chemistry, Hong Kong University of Science and Technology, Hong Kong, China
- Hefei
National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for
Energy Materials), University of Science and Technology of China, Hefei 230026, China
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10
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Chmeliov J, Trinkunas G, van Amerongen H, Valkunas L. Excitation migration in fluctuating light-harvesting antenna systems. PHOTOSYNTHESIS RESEARCH 2016; 127:49-60. [PMID: 25605669 DOI: 10.1007/s11120-015-0083-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/07/2015] [Indexed: 06/04/2023]
Abstract
Complex multi-exponential fluorescence decay kinetics observed in various photosynthetic systems like photosystem II (PSII) have often been explained by the reversible quenching mechanism of the charge separation taking place in the reaction center (RC) of PSII. However, this description does not account for the intrinsic dynamic disorder of the light-harvesting proteins as well as their fluctuating dislocations within the antenna, which also facilitate the repair of RCs, state transitions, and the process of non-photochemical quenching. Since dynamic fluctuations result in varying connectivity between pigment-protein complexes, they can also lead to non-exponential excitation decay kinetics. Based on this presumption, we have recently proposed a simple conceptual model describing excitation diffusion in a continuous medium and accounting for possible variations of the excitation transfer pathways. In the current work, this model is further developed and then applied to describe fluorescence kinetics originating from very diverse antenna systems, ranging from PSII of various sizes to LHCII aggregates and even the entire thylakoid membrane. In all cases, complex multi-exponential fluorescence kinetics are perfectly reproduced on the entire relevant time scale without assuming any radical pair equilibration at the side of the excitation quencher, but using just a few parameters reflecting the mean excitation energy transfer rate as well as the overall average organization of the photosynthetic antenna.
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Affiliation(s)
- Jevgenij Chmeliov
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, 10222, Vilnius, Lithuania
- Institute of Physics, Center for Physical Sciences and Technology, Gostauto 11, 01108, Vilnius, Lithuania
| | - Gediminas Trinkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, 10222, Vilnius, Lithuania
- Institute of Physics, Center for Physical Sciences and Technology, Gostauto 11, 01108, Vilnius, Lithuania
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700, Wageningen, The Netherlands
| | - Leonas Valkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Saulėtekio Ave. 9, 10222, Vilnius, Lithuania.
- Institute of Physics, Center for Physical Sciences and Technology, Gostauto 11, 01108, Vilnius, Lithuania.
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11
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Fox KF, Bricker WP, Lo C, Duffy CDP. Distortions of the Xanthophylls Caused by Interactions with Neighboring Pigments and the LHCII Protein Are Crucial for Studying Energy Transfer Pathways within the Complex. J Phys Chem B 2015; 119:15550-60. [DOI: 10.1021/acs.jpcb.5b08941] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. F. Fox
- The
School of Biological and Chemical Sciences, Queen Mary’s University of London, Mile End Road, London E1 4NS, England
| | - William P. Bricker
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, 1 Brookings Drive, Saint Louis, Missouri 63130-4899, United States
| | - Cynthia Lo
- Department
of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, 1 Brookings Drive, Saint Louis, Missouri 63130-4899, United States
| | - C. D. P. Duffy
- The
School of Biological and Chemical Sciences, Queen Mary’s University of London, Mile End Road, London E1 4NS, England
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12
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Ware MA, Belgio E, Ruban AV. Photoprotective capacity of non-photochemical quenching in plants acclimated to different light intensities. PHOTOSYNTHESIS RESEARCH 2015; 126:261-74. [PMID: 25702085 DOI: 10.1007/s11120-015-0102-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 02/15/2015] [Indexed: 05/20/2023]
Abstract
Arabidopsis plants grown at low light were exposed to a gradually increasing actinic light routine. This method allows for the discerning of the photoprotective component of NPQ, pNPQ and photoinhibition. They exhibited lower values of Photosystem II (PSII) yield in comparison to high-light grown plants, and higher calculated dark fluorescence level (F'o calc.) than the measured one (F'o act.). As a result, in low-light grown plants, the values of qP measured in the dark appeared higher than 1. Normally, F'o act. and F'o calc. match well at moderate light intensities but F'o act. becomes higher at increasing intensities due to reaction centre (RCII) damage; this indicates the onset of photoinhibition. To explain the unusual increase of qP in the dark in low-light grown plants, we have undertaken an analysis of PSII antenna size using biochemical and spectroscopic approaches. Sucrose gradient separation of thylakoid membrane complexes and fast fluorescence induction experiments illustrated that the relative PSII cross section does not increase appreciably with the rise in PSII antenna size in the low-light grown plants. This suggests that part of the increased LHCII antenna is less efficiently coupled to the RCII. A model based upon the existence of an uncoupled population LHCII is proposed to explain the discrepancies in calculated and measured values of F'o.
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Affiliation(s)
- Maxwell A Ware
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Erica Belgio
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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13
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Chen L, Shenai P, Zheng F, Somoza A, Zhao Y. Optimal Energy Transfer in Light-Harvesting Systems. Molecules 2015; 20:15224-72. [PMID: 26307957 PMCID: PMC6332264 DOI: 10.3390/molecules200815224] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 08/03/2015] [Accepted: 08/14/2015] [Indexed: 01/25/2023] Open
Abstract
Photosynthesis is one of the most essential biological processes in which specialized pigment-protein complexes absorb solar photons, and with a remarkably high efficiency, guide the photo-induced excitation energy toward the reaction center to subsequently trigger its conversion to chemical energy. In this work, we review the principles of optimal energy transfer in various natural and artificial light harvesting systems. We begin by presenting the guiding principles for optimizing the energy transfer efficiency in systems connected to dissipative environments, with particular attention paid to the potential role of quantum coherence in light harvesting systems. We will comment briefly on photo-protective mechanisms in natural systems that ensure optimal functionality under varying ambient conditions. For completeness, we will also present an overview of the charge separation and electron transfer pathways in reaction centers. Finally, recent theoretical and experimental progress on excitation energy transfer, charge separation, and charge transport in artificial light harvesting systems is delineated, with organic solar cells taken as prime examples.
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Affiliation(s)
- Lipeng Chen
- Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue,Singapore 639798, Singapore.
| | - Prathamesh Shenai
- Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue,Singapore 639798, Singapore.
| | - Fulu Zheng
- Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue,Singapore 639798, Singapore.
| | - Alejandro Somoza
- Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue,Singapore 639798, Singapore.
| | - Yang Zhao
- Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue,Singapore 639798, Singapore.
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14
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Harriman A. Artificial light-harvesting arrays for solar energy conversion. Chem Commun (Camb) 2015; 51:11745-56. [DOI: 10.1039/c5cc03577e] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Following natures' blueprint, the concept of artificial light-harvesting antennae is discussed in terms of sophisticated molecular arrays displaying a tailored cascade of electronic energy transfer steps.
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Affiliation(s)
- Anthony Harriman
- Molecular Photonics Laboratory
- School of Chemistry
- Bedson Building
- Newcastle University
- Newcastle upon Tyne
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15
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Ruban AV. Evolution under the sun: optimizing light harvesting in photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:7-23. [PMID: 25336689 DOI: 10.1093/jxb/eru400] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The emergence and evolution of life on our planet was possible because the sun provides energy to our biosphere. Indeed, all life forms need energy for existence and proliferation in space and time. Light-energy conversion takes place in photosynthetic organisms that evolve in various environments featuring an impressive range of light intensities that span several orders of magnitude. This property is achieved by the evolution of mechanisms of efficient energy capture that involved development of antenna pigments and pigment-protein complexes as well as the emergence of various strategies on the organismal, cellular, and molecular levels to counteract the detrimental effects of high light intensity on the delicate photosynthetic apparatus. Darwin was one of the first to describe the behaviour of plants towards light. He noticed that some plants try to avoid full daylight and called this reaction paraheliotropism. However, it was only in the second half of the 20th century, when scientists began to discover the structure and molecular mechanisms of the photosynthetic machinery, that the reasons for paraheliotropisms became clear. This review explains the need for the evolution of light adaptations using the example of higher plants. The review focuses on short-term adaptation mechanisms that occur on the minute scale, showing that these processes are fast enough to track rapid fluctuations in light intensity and that they evolved to be effective, allowing for the expansion of plant habitats and promoting diversification and survival. Also introduced are the most recent developments in methods that enable quantification of the light intensities that can be tolerated by plants.
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Affiliation(s)
- Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK
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Zhang L, Silva DA, Zhang H, Yue A, Yan Y, Huang X. Dynamic protein conformations preferentially drive energy transfer along the active chain of the photosystem II reaction centre. Nat Commun 2014; 5:4170. [PMID: 24954746 PMCID: PMC4083425 DOI: 10.1038/ncomms5170] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 05/20/2014] [Indexed: 11/11/2022] Open
Abstract
One longstanding puzzle concerning photosystem II, a core component of photosynthesis, is that only one of the two symmetric branches in its reaction centre is active in electron transfer. To investigate the effect of the photosystem II environment on the preferential selection of the energy transfer pathway (a prerequisite for electron transfer), we have constructed an exciton model via extensive molecular dynamics simulations and quantum mechanics/molecular mechanics calculations based on a recent X-ray structure. Our results suggest that it is essential to take into account an ensemble of protein conformations to accurately compute the site energies. We identify the cofactor CLA606 of active chain as the most probable site for the energy excitation. We further pinpoint a number of charged protein residues that collectively lower the CLA606 site energy. Our work provides insights into the understanding of molecular mechanisms of the core machinery of the green-plant photosynthesis. Cofactor-mediated energy and electron transfer in photosystem II occurs preferentially through one branch of the reaction centre, despite there being a symmetric path available. Here, the authors use computational methods to determine the influence of protein conformation on this selectivity.
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Affiliation(s)
- Lu Zhang
- Department of Chemistry, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Daniel-Adriano Silva
- 1] Department of Chemistry, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong [2]
| | - Houdao Zhang
- Department of Chemistry, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Alexander Yue
- Division of Biomedical Engineering, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - YiJing Yan
- 1] Department of Chemistry, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong [2] Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, China
| | - Xuhui Huang
- 1] Department of Chemistry, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong [2] Division of Biomedical Engineering, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong [3] Centre of Systems Biology and Human Health, Institute for Advance Study and School of Science, Hong Kong University of Science and Technology, Kowloon, Hong Kong
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Chmeliov J, Trinkunas G, van Amerongen H, Valkunas L. Light harvesting in a fluctuating antenna. J Am Chem Soc 2014; 136:8963-72. [PMID: 24870124 DOI: 10.1021/ja5027858] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of the major players in oxygenic photosynthesis, photosystem II (PSII), exhibits complex multiexponential fluorescence decay kinetics that for decades has been ascribed to reversible charge separation taking place in the reaction center (RC). However, in this description the protein dynamics is not taken into consideration. The intrinsic dynamic disorder of the light-harvesting proteins along with their fluctuating dislocations within the antenna inevitably result in varying connectivity between pigment-protein complexes and therefore can also lead to nonexponential excitation decay kinetics. On the basis of this presumption, we propose a simple conceptual model describing excitation diffusion in a continuous medium and accounting for possible variations of the excitation transfer rates. Recently observed fluorescence kinetics of PSII of different sizes are perfectly reproduced with only two adjustable parameters instead of the many decay times and amplitudes required in standard analysis procedures; no charge recombination in the RC is required. The model is also able to provide valuable information about the structural and functional organization of the photosynthetic antenna and in a straightforward way solves various contradictions currently existing in the literature.
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Affiliation(s)
- Jevgenij Chmeliov
- Department of Theoretical Physics, Faculty of Physics, Vilnius University , Sauletekio Avenue 9, LT-10222 Vilnius, Lithuania
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Huh J, Saikin SK, Brookes JC, Valleau S, Fujita T, Aspuru-Guzik A. Atomistic study of energy funneling in the light-harvesting complex of green sulfur bacteria. J Am Chem Soc 2014; 136:2048-57. [PMID: 24405318 DOI: 10.1021/ja412035q] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phototrophic organisms such as plants, photosynthetic bacteria, and algae use microscopic complexes of pigment molecules to absorb sunlight. Within the light-harvesting complexes, which frequently have several functional and structural subunits, the energy is transferred in the form of molecular excitations with very high efficiency. Green sulfur bacteria are considered to be among the most efficient light-harvesting organisms. Despite multiple experimental and theoretical studies of these bacteria, the physical origin of the efficient and robust energy transfer in their light-harvesting complexes is not well understood. To study excitation dynamics at the systems level, we introduce an atomistic model that mimics a complete light-harvesting apparatus of green sulfur bacteria. The model contains approximately 4000 pigment molecules and comprises a double wall roll for the chlorosome, a baseplate, and six Fenna-Matthews-Olson trimer complexes. We show that the fast relaxation within functional subunits combined with the transfer between collective excited states of pigments can result in robust energy funneling to the initial excitation conditions and temperature changes. Moreover, the same mechanism describes the coexistence of multiple time scales of excitation dynamics frequently observed in ultrafast optical experiments. While our findings support the hypothesis of supertransfer, the model reveals energy transport through multiple channels on different length scales.
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Affiliation(s)
- Joonsuk Huh
- Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States
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Matsuoka T, Tanaka S, Ebina K. Hierarchical coarse-graining model for photosystem II including electron and excitation-energy transfer processes. Biosystems 2014; 117:15-29. [PMID: 24418347 DOI: 10.1016/j.biosystems.2013.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/27/2013] [Accepted: 12/31/2013] [Indexed: 11/24/2022]
Abstract
We propose a hierarchical reduction scheme to cope with coupled rate equations that describe the dynamics of multi-time-scale photosynthetic reactions. To numerically solve nonlinear dynamical equations containing a wide temporal range of rate constants, we first study a prototypical three-variable model. Using a separation of the time scale of rate constants combined with identified slow variables as (quasi-)conserved quantities in the fast process, we achieve a coarse-graining of the dynamical equations reduced to those at a slower time scale. By iteratively employing this reduction method, the coarse-graining of broadly multi-scale dynamical equations can be performed in a hierarchical manner. We then apply this scheme to the reaction dynamics analysis of a simplified model for an illuminated photosystem II, which involves many processes of electron and excitation-energy transfers with a wide range of rate constants. We thus confirm a good agreement between the coarse-grained and fully (finely) integrated results for the population dynamics.
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Affiliation(s)
- Takeshi Matsuoka
- Graduate School of System Informatics, Department of Computational Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
| | - Shigenori Tanaka
- Graduate School of System Informatics, Department of Computational Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe 657-8501, Japan.
| | - Kuniyoshi Ebina
- Graduate School of Human Development and Environment, Kobe University, 3-11 Tsurukabuto, Nada-ku, Kobe 657-8501, Japan.
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Camus JM, Langlois A, Aly S, Guilard R, Harvey PD. Evidence for reverse pathways and equilibrium in singlet energy transfers between an artificial special pair and an antenna. J PORPHYR PHTHALOCYA 2013. [DOI: 10.1142/s108842461350017x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A dyad, 1, built on an artificial special pair (bis(meso-nonyl)zinc(II)porphyrin), [Zn2], a spacer (biphenylene), a bridge (1,4-benzene), and an antenna (di-meso-(3,5-di(t-butyl)phenyl)porphyrin free base), FB, is prepared by Suzuki coupling and is analyzed by absorption and steady state, and time-resolved emission spectroscopy at 298 and 77 K. Using bases from the Förster theory, evidence for two pathways for S 1 energy transfer, FB* → [Zn2], and [Zn2]* → FB, along with their respective rates, k ET ( S 1)1 and k ET ( S 1)-1, are extracted from the comparison of the fluorescence decays monitored at the emission maximum. At 77 K, the unquenched (1.79 ([Zn2]) and 10.6 ns (FB)) and quenched components (<100 ps; i.e. k ET ( S 1) > 10 (ns)-1), are observed, hence, demonstrating the bidirectional paths with no back energy transfer. A 298 K, only two components are detected (0.44 ([Zn2]) and 2.64 ns (FB)) and the resulting reduced τFs indicates back energy transfer, therefore cycling and equilibrium. Their global rates are 0.31 and 1.8 (ns)-1 for k ET ( S 1)1 and k ET ( S 1)-1 at 298 K. This large temperature dependence on k ET ( S 1) is fully consistent with the participation of thermal activation. Finally, DFT calculations (B3LYP) were used to illustrate a clear correlation between the relative k ET ( S 1) s and the amplitude of the MO couplings between the artificial special pair and the antenna.
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Affiliation(s)
- Jean-Michel Camus
- Institut de Chimie Moléculaire de l'Université de Bourgogne ICMUB (UMR 6302), Université de Bourgogne, 9 avenue Alain Savary, 21000 Dijon, France
| | - Adam Langlois
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada
| | - Shawkat Aly
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada
- On leave from the Chemistry Department, Assiut University, Assiut, Egypt
| | - Roger Guilard
- Institut de Chimie Moléculaire de l'Université de Bourgogne ICMUB (UMR 6302), Université de Bourgogne, 9 avenue Alain Savary, 21000 Dijon, France
| | - Pierre D. Harvey
- Institut de Chimie Moléculaire de l'Université de Bourgogne ICMUB (UMR 6302), Université de Bourgogne, 9 avenue Alain Savary, 21000 Dijon, France
- Département de Chimie, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Québec J1K 2R1, Canada
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Camus JM, Langlois A, Aly SM, Guilard R, Harvey PD. Is the special pair structure a good strategy for the kinetics during the last step of the energy transfer with the nearest antenna? A chemical model approach. Chem Commun (Camb) 2013; 49:2228-30. [PMID: 23396549 DOI: 10.1039/c3cc38740b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A cofacial bis(Mg(II)porphyrin)-C(6)H(4)-free base ([Mg(2)]-bridge-FB) dyad shows S(1) energy transfer in both directions and much slower rates than similar monoporphyrin systems are observed.
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Affiliation(s)
- Jean-Michel Camus
- Institut de Chimie Moléculaire de l'Université de Bourgogne (ICMUB,UMR 6302), Université de Bourgogne, Dijon, France
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Bennett DIG, Amarnath K, Fleming GR. A structure-based model of energy transfer reveals the principles of light harvesting in photosystem II supercomplexes. J Am Chem Soc 2013; 135:9164-73. [PMID: 23679235 DOI: 10.1021/ja403685a] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) initiates photosynthesis in plants through the absorption of light and subsequent conversion of excitation energy to chemical energy via charge separation. The pigment binding proteins associated with PSII assemble in the grana membrane into PSII supercomplexes and surrounding light harvesting complex II trimers. To understand the high efficiency of light harvesting in PSII requires quantitative insight into energy transfer and charge separation in PSII supercomplexes. We have constructed the first structure-based model of energy transfer in PSII supercomplexes. This model shows that the kinetics of light harvesting cannot be simplified to a single rate limiting step. Instead, substantial contributions arise from both excitation diffusion through the antenna pigments and transfer from the antenna to the reaction center (RC), where charge separation occurs. Because of the lack of a rate-limiting step, fitting kinetic models to fluorescence lifetime data cannot be used to derive mechanistic insight on light harvesting in PSII. This model will clarify the interpretation of chlorophyll fluorescence data from PSII supercomplexes, grana membranes, and leaves.
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Affiliation(s)
- Doran I G Bennett
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Duffy CDP, Valkunas L, Ruban AV. Light-harvesting processes in the dynamic photosynthetic antenna. Phys Chem Chem Phys 2013; 15:18752-70. [DOI: 10.1039/c3cp51878g] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Fluorescence lifetime snapshots reveal two rapidly reversible mechanisms of photoprotection in live cells of Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A 2012; 109:8405-10. [PMID: 22586081 DOI: 10.1073/pnas.1205303109] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Photosynthetic organisms avoid photodamage to photosystem II (PSII) in variable light conditions via a suite of photoprotective mechanisms called nonphotochemical quenching (NPQ), in which excess absorbed light is dissipated harmlessly. To quantify the contributions of different quenching mechanisms to NPQ, we have devised a technique to measure the changes in chlorophyll fluorescence lifetime as photosynthetic organisms adapt to varying light conditions. We applied this technique to measure the fluorescence lifetimes responsible for the predominant, rapidly reversible component of NPQ, qE, in living cells of Chlamydomonas reinhardtii. Application of high light to dark-adapted cells of C. reinhardtii led to an increase in the amplitudes of 65 ps and 305 ps chlorophyll fluorescence lifetime components that was reversed after the high light was turned off. Removal of the pH gradient across the thylakoid membrane linked the changes in the amplitudes of the two components to qE quenching. The rise times of the amplitudes of the two components were significantly different, suggesting that the changes are due to two different qE mechanisms. We tentatively suggest that the changes in the 65 ps component are due to charge-transfer quenching in the minor light-harvesting complexes and that the changes in the 305 ps component are due to aggregated light-harvesting complex II trimers that have detached from PSII. We anticipate that this technique will be useful for resolving the various mechanisms of NPQ and for quantifying the timescales associated with these mechanisms.
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