1
|
Russo M, Casazza AP, Cerullo G, Santabarbara S, Maiuri M. Direct Evidence for Excitation Energy Transfer Limitations Imposed by Low-Energy Chlorophylls in Photosystem I-Light Harvesting Complex I of Land Plants. J Phys Chem B 2021; 125:3566-3573. [PMID: 33788560 PMCID: PMC8154617 DOI: 10.1021/acs.jpcb.1c01498] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The overall efficiency
of photosynthetic energy conversion depends
both on photochemical and excitation energy transfer processes from
extended light-harvesting antenna networks. Understanding the trade-offs
between increase in the antenna cross section and bandwidth and photochemical
conversion efficiency is of central importance both from a biological
perspective and for the design of biomimetic artificial photosynthetic
complexes. Here, we employ two-dimensional electronic spectroscopy
to spectrally resolve the excitation energy transfer dynamics and
directly correlate them with the initial site of excitation in photosystem
I–light harvesting complex I (PSI-LHCI) supercomplex of land
plants, which has both a large antenna dimension and a wide optical
bandwidth extending to energies lower than the peak of the reaction
center chlorophylls. Upon preferential excitation of the low-energy
chlorophylls (red forms), the average relaxation time in the bulk
supercomplex increases by a factor of 2–3 with respect to unselective
excitation at higher photon energies. This slowdown is interpreted
in terms of an excitation energy transfer limitation from low-energy
chlorophyll forms in the PSI-LHCI. These results aid in defining the
optimum balance between the extension of the antenna bandwidth to
the near-infrared region, which increases light-harvesting capacity,
and high photoconversion quantum efficiency.
Collapse
Affiliation(s)
- Mattia Russo
- Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Anna Paola Casazza
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale delle Ricerche, Via Bassini 15a, 20133 Milano, Italy
| | - Giulio Cerullo
- Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Stefano Santabarbara
- Photosynthesis Research Unit, Centro Studi sulla Biologia Cellulare e Molecolare delle Piante, Consiglio Nazionale delle Ricerche, Via Celoria 26, 20133 Milano, Italy
| | - Margherita Maiuri
- Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| |
Collapse
|
2
|
Akhtar P, Lambrev PH. On the spectral properties and excitation dynamics of long-wavelength chlorophylls in higher-plant photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2020; 1861:148274. [PMID: 32712151 DOI: 10.1016/j.bbabio.2020.148274] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/13/2020] [Accepted: 07/19/2020] [Indexed: 11/20/2022]
Abstract
In higher-plant Photosystem I (PSI), the majority of "red" chlorophylls (absorbing at longer wavelengths than the reaction centre P700) are located in the peripheral antenna, but contradicting reports are given about red forms in the core complex. Here we attempt to clarify the spectroscopic characteristics and quantify the red forms in the PSI core complex, which have profound implication on understanding the energy transfer and charge separation dynamics. To this end we compare the steady-state absorption and fluorescence spectra and picosecond time-resolved fluorescence kinetics of isolated PSI core complex and PSI-LHCI supercomplex from Pisum sativum recorded at 77 K. Gaussian decomposition of the absorption spectra revealed a broad band at 705 nm in the core complex with an oscillator strength of three chlorophylls. Additional absorption at 703 nm and 711 nm in PSI-LHCI indicated up to five red chlorophylls in the peripheral antenna. Analysis of fluorescence emission spectra resolved states emitting at 705, 715 and 722 nm in the core and additional states around 705-710 nm and 733 nm in PSI-LHCI. The red states compete with P700 in trapping excitations in the bulk antenna, which occurs on a timescale of ~20 ps. The three red forms in the core have distinct decay kinetics, probably in part determined by the rate of quenching by the oxidized P700. These results affirm that the red chlorophylls in the core complex must not be neglected when interpreting kinetic experimental results of PSI.
Collapse
Affiliation(s)
- Parveen Akhtar
- Biological Research Centre, Szeged, Temesvári krt. 62, Szeged 6726, Hungary
| | - Petar H Lambrev
- Biological Research Centre, Szeged, Temesvári krt. 62, Szeged 6726, Hungary.
| |
Collapse
|
3
|
Szewczyk S, Białek R, Giera W, Burdziński G, van Grondelle R, Gibasiewicz K. Excitation dynamics in Photosystem I trapped in TiO 2 mesopores. PHOTOSYNTHESIS RESEARCH 2020; 144:235-245. [PMID: 32114649 PMCID: PMC7203582 DOI: 10.1007/s11120-020-00730-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
Excitation decay in closed Photosystem I (PSI) isolated from cyanobacterium Synechocystis sp. PCC 6803 and dissolved in a buffer solution occurs predominantly with a ~ 24-ps lifetime, as measured both by time-resolved fluorescence and transient absorption. The same PSI particles deposited in mesoporous matrix made of TiO2 nanoparticles exhibit significantly accelerated excitation decay dominated by a ~ 6-ps component. Target analysis indicates that this acceleration is caused by ~ 50% increase of the rate constant of bulk Chls excitation quenching. As an effect of this increase, as much as ~ 70% of bulk Chls excitation is quenched before the establishment of equilibrium with the red Chls. Accelerated quenching may be caused by increased excitation trapping by the reaction center and/or quenching properties of the TiO2 surface directly interacting with PSI Chls. Also properties of the PSI red Chls are affected by the deposition in the TiO2 matrix: they become deeper traps due to an increase of their number and their oscillator strength is significantly reduced. These effects should be taken into account when constructing solar cells' photoelectrodes composed of PSI and artificial matrices.
Collapse
Affiliation(s)
- S Szewczyk
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland
| | - R Białek
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland
| | - W Giera
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland
| | - G Burdziński
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland
| | - R van Grondelle
- Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - K Gibasiewicz
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznan, Poland.
| |
Collapse
|
4
|
Szewczyk S, Białek R, Burdziński G, Gibasiewicz K. Photovoltaic activity of electrodes based on intact photosystem I electrodeposited on bare conducting glass. PHOTOSYNTHESIS RESEARCH 2020; 144:1-12. [PMID: 32078102 PMCID: PMC7113217 DOI: 10.1007/s11120-020-00722-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 02/10/2020] [Indexed: 06/10/2023]
Abstract
We demonstrate photovoltaic activity of electrodes composed of fluorine-doped tin oxide (FTO) conducting glass and a multilayer of trimeric photosystem I (PSI) from cyanobacterium Synechocystis sp. PCC 6803 yielding, at open circuit potential (OCP) of + 100 mV (vs. SHE), internal quantum efficiency of (0.37 ± 0.11)% and photocurrent density of up to (0.5 ± 0.1) µA/cm2. The photocurrent measured for OCP is of cathodic nature meaning that preferentially the electrons are injected from the conducting layer of the FTO glass to the photooxidized PSI primary electron donor, P700+, and further transferred from the photoreduced final electron acceptor of PSI, Fb-, via ascorbate electrolyte to the counter electrode. This observation is consistent with preferential donor-side orientation of PSI on FTO imposed by applied electrodeposition. However, by applying high-positive bias (+ 620 mV) to the PSI-FTO electrode, exceeding redox midpoint potential of P700 (+ 450 mV), the photocurrent reverses its orientation and becomes anodic. This is explained by "switching off" the natural photoactivity of PSI particles (by the electrochemical oxidation of P700 to P700+) and "switching on" the anodic photocurrent from PSI antenna Chls prone to photooxidation at high potentials. The efficient control of the P700 redox state (P700 or P700+) by external bias applied to the PSI-FTO electrodes was evidenced by ultrafast transient absorption spectroscopy. The advantage of the presented system is its structural simplicity together with in situ-proven high intactness of the PSI particles.
Collapse
Affiliation(s)
- Sebastian Szewczyk
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznań, Poland
| | - Rafał Białek
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznań, Poland
| | - Gotard Burdziński
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznań, Poland
| | - Krzysztof Gibasiewicz
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614, Poznań, Poland.
| |
Collapse
|
5
|
Szewczyk S, Abram M, Białek R, Haniewicz P, Karolczak J, Gapiński J, Kargul J, Gibasiewicz K. On the nature of uncoupled chlorophylls in the extremophilic photosystem I-light harvesting I supercomplex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148136. [PMID: 31825811 DOI: 10.1016/j.bbabio.2019.148136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 11/18/2019] [Accepted: 12/05/2019] [Indexed: 01/07/2023]
Abstract
Photosystem I core-light-harvesting antenna supercomplexes (PSI-LHCI) were isolated from the extremophilic red alga Cyanidioschyzon merolae and studied by three fluorescence techniques in order to characterize chlorophylls (Chls) energetically uncoupled from the PSI reaction center (RC). Such Chls are observed in virtually all optical experiments of any PSI core and PSI-LHCI supercomplex preparations across various species and may influence the operation of PSI-based solar cells and other biohybrid systems. However, the nature of the uncoupled Chls (uChls) has never been explored deeply before. In this work, the amount of uChls was controlled by stirring the solution of C. merolae PSI-LHCI supercomplex samples at elevated temperature (~303 K) and was found to increase from <2% in control samples up to 47% in solutions stirred for 3.5 h. The fluorescence spectrum of uChls was found to be blue-shifted by ~20 nm (to ~680 nm) relative to the fluorescence band from Chls that are well coupled to PSI RC. This effect indicates that mechanical stirring leads to disappearance of some red Chls (emitting at above ~700 nm) that are present in the intact LHCI antenna associated with the PSI core. Comparative diffusion studies of control and stirred samples by fluorescence correlation spectroscopy together with biochemical analysis by SDS-PAGE and BN-PAGE indicate that energetically uncoupled Lhcr subunits are likely to be still physically attached to the PSI core, albeit with altered three-dimensional organization due to the mechanical stress.
Collapse
Affiliation(s)
- Sebastian Szewczyk
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Mateusz Abram
- Solar Fuels Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland; Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Rafał Białek
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Patrycja Haniewicz
- Solar Fuels Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland
| | - Jerzy Karolczak
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Jacek Gapiński
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland
| | - Joanna Kargul
- Solar Fuels Lab, Centre of New Technologies, University of Warsaw, Banacha 2C, 02-097 Warsaw, Poland.
| | - Krzysztof Gibasiewicz
- Faculty of Physics, Adam Mickiewicz University in Poznań, ul. Uniwersytetu Poznańskiego 2, 61-614 Poznań, Poland.
| |
Collapse
|
6
|
Furukawa R, Aso M, Fujita T, Akimoto S, Tanaka R, Tanaka A, Yokono M, Takabayashi A. Formation of a PSI-PSII megacomplex containing LHCSR and PsbS in the moss Physcomitrella patens. JOURNAL OF PLANT RESEARCH 2019; 132:867-880. [PMID: 31541373 DOI: 10.1007/s10265-019-01138-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/08/2019] [Indexed: 05/10/2023]
Abstract
Mosses are one of the earliest land plants that diverged from fresh-water green algae. They are considered to have acquired a higher capacity for thermal energy dissipation to cope with dynamically changing solar irradiance by utilizing both the "algal-type" light-harvesting complex stress-related (LHCSR)-dependent and the "plant-type" PsbS-dependent mechanisms. It is hypothesized that the formation of photosystem (PS) I and II megacomplex is another mechanism to protect photosynthetic machinery from strong irradiance. Herein, we describe the analysis of the PSI-PSII megacomplex from the model moss, Physcomitrella patens, which was resolved using large-pore clear-native polyacrylamide gel electrophoresis (lpCN-PAGE). The similarity in the migration distance of the Physcomitrella PSI-PSII megacomplex to the Arabidopsis megacomplex shown during lpCN-PAGE suggested that the Physcomitrella PSI-PSII and Arabidopsis megacomplexes have similar structures. Time-resolved chlorophyll fluorescence measurements show that excitation energy was rapidly and efficiently transferred from PSII to PSI, providing evidence of an ordered association of the two photosystems. We also found that LHCSR and PsbS co-migrated with the Physcomitrella PSI-PSII megacomplex. The megacomplex showed pH-dependent chlorophyll fluorescence quenching, which may have been induced by LHCSR and/or PsbS proteins with the collaboration of zeaxanthin. We discuss the mechanism that regulates the energy distribution balance between two photosystems in Physcomitrella.
Collapse
Affiliation(s)
- Ryo Furukawa
- Institute of Low-Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819, Japan
| | - Michiki Aso
- Institute of Low-Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819, Japan
| | - Tomomichi Fujita
- Faculty of Science, Hokkaido University, N10 W8 Kita-ku, Sapporo, 060-0810, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe, 657-8501, Japan
| | - Ryouichi Tanaka
- Institute of Low-Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819, Japan
| | - Ayumi Tanaka
- Institute of Low-Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819, Japan
| | - Makio Yokono
- Institute of Low-Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819, Japan.
- Innovation Center, Nippon Flour Mills Co., Ltd., Atsugi, 243-0041, Japan.
| | - Atsushi Takabayashi
- Institute of Low-Temperature Science, Hokkaido University, N19 W8 Kita-ku, Sapporo, 060-0819, Japan
| |
Collapse
|
7
|
Chukhutsina VU, Holzwarth AR, Croce R. Time-resolved fluorescence measurements on leaves: principles and recent developments. PHOTOSYNTHESIS RESEARCH 2019; 140:355-369. [PMID: 30478711 PMCID: PMC6509100 DOI: 10.1007/s11120-018-0607-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 11/15/2018] [Indexed: 05/03/2023]
Abstract
Photosynthesis starts when a pigment in the photosynthetic antennae absorbs a photon. The electronic excitation energy is then transferred through the network of light-harvesting pigments to special chlorophyll (Chl) molecules in the reaction centres, where electron transfer is initiated. Energy transfer and primary electron transfer processes take place on timescales ranging from femtoseconds to nanoseconds, and can be monitored in real time via time-resolved fluorescence spectroscopy. This method is widely used for measurements on unicellular photosynthetic organisms, isolated photosynthetic membranes, and individual complexes. Measurements on intact leaves remain a challenge due to their high structural heterogeneity, high scattering, and high optical density, which can lead to optical artefacts. However, detailed information on the dynamics of these early steps, and the underlying structure-function relationships, is highly informative and urgently required in order to get deeper insights into the physiological regulation mechanisms of primary photosynthesis. Here, we describe a current methodology of time-resolved fluorescence measurements on intact leaves in the picosecond to nanosecond time range. Principles of fluorescence measurements on intact leaves, possible sources of alterations of fluorescence kinetics and the ways to overcome them are addressed. We also describe how our understanding of the organisation and function of photosynthetic proteins and energy flow dynamics in intact leaves can be enriched through the application of time-resolved fluorescence spectroscopy on leaves. For that, an example of a measurement on Zea mays leaves is presented.
Collapse
Affiliation(s)
- Volha U Chukhutsina
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Alfred R Holzwarth
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands
| | - Roberta Croce
- Biophysics of Photosynthesis, Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam and LaserLaB Amsterdam, 1081 HV, Amsterdam, The Netherlands.
| |
Collapse
|
8
|
Yokono M, Takabayashi A, Kishimoto J, Fujita T, Iwai M, Murakami A, Akimoto S, Tanaka A. The PSI-PSII Megacomplex in Green Plants. PLANT & CELL PHYSIOLOGY 2019; 60:1098-1108. [PMID: 30753722 DOI: 10.1093/pcp/pcz026] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 02/04/2019] [Indexed: 05/27/2023]
Abstract
Energy dissipation is crucial for land and shallow-water plants exposed to direct sunlight. Almost all green plants dissipate excess excitation energy to protect the photosystem reaction centers, photosystem II (PSII) and photosystem I (PSI), and continue to grow under strong light. In our previous work, we reported that about half of the photosystem reaction centers form a PSI-PSII megacomplex in Arabidopsis thaliana, and that the excess energy was transferred from PSII to PSI fast. However, the physiological function and structure of the megacomplex remained unclear. Here, we suggest that high-light adaptable sun-plants accumulate the PSI-PSII megacomplex more than shade-plants. In addition, PSI of sun-plants has a deep trap to receive excitation energy, which is low-energy chlorophylls showing fluorescence maxima longer than 730 nm. This deep trap may increase the high-light tolerance of PSI by improving excitation energy dissipation. Electron micrographs suggest that one PSII dimer is directly sandwiched between two PSIs with 2-fold rotational symmetry in the basic form of the PSI-PSII megacomplex in green plants. This structure should enable fast energy transfer from PSII to PSI and allow energy in PSII to be dissipated via the deep trap in PSI.
Collapse
Affiliation(s)
- Makio Yokono
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- CREST, JST, Sapporo, Japan
- Nippon Flour Mills Co., Ltd., Innovation Center, Atsugi, Japan
| | - Atsushi Takabayashi
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- CREST, JST, Sapporo, Japan
| | - Junko Kishimoto
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- CREST, JST, Sapporo, Japan
| | - Tomomichi Fujita
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Masakazu Iwai
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Akio Murakami
- Kobe University Research Centre for Inland Seas, Awaji, Japan
- Graduate School of Science, Kobe University, Kobe, Japan
| | - Seiji Akimoto
- Graduate School of Science, Kobe University, Kobe, Japan
| | - Ayumi Tanaka
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- CREST, JST, Sapporo, Japan
| |
Collapse
|
9
|
Akhtar P, Zhang C, Liu Z, Tan HS, Lambrev PH. Excitation transfer and trapping kinetics in plant photosystem I probed by two-dimensional electronic spectroscopy. PHOTOSYNTHESIS RESEARCH 2018; 135:239-250. [PMID: 28808836 DOI: 10.1007/s11120-017-0427-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 08/01/2017] [Indexed: 05/24/2023]
Abstract
Photosystem I is a robust and highly efficient biological solar engine. Its capacity to utilize virtually every absorbed photon's energy in a photochemical reaction generates great interest in the kinetics and mechanisms of excitation energy transfer and charge separation. In this work, we have employed room-temperature coherent two-dimensional electronic spectroscopy and time-resolved fluorescence spectroscopy to follow exciton equilibration and excitation trapping in intact Photosystem I complexes as well as core complexes isolated from Pisum sativum. We performed two-dimensional electronic spectroscopy measurements with low excitation pulse energies to record excited-state kinetics free from singlet-singlet annihilation. Global lifetime analysis resolved energy transfer and trapping lifetimes closely matches the time-correlated single-photon counting data. Exciton energy equilibration in the core antenna occurred on a timescale of 0.5 ps. We further observed spectral equilibration component in the core complex with a 3-4 ps lifetime between the bulk Chl states and a state absorbing at 700 nm. Trapping in the core complex occurred with a 20 ps lifetime, which in the supercomplex split into two lifetimes, 16 ps and 67-75 ps. The experimental data could be modelled with two alternative models resulting in equally good fits-a transfer-to-trap-limited model and a trap-limited model. However, the former model is only possible if the 3-4 ps component is ascribed to equilibration with a "red" core antenna pool absorbing at 700 nm. Conversely, if these low-energy states are identified with the P700 reaction centre, the transfer-to-trap-model is ruled out in favour of a trap-limited model.
Collapse
Affiliation(s)
- Parveen Akhtar
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
- Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, 6726, Hungary
| | - Cheng Zhang
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Zhengtang Liu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Howe-Siang Tan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore.
| | - Petar H Lambrev
- Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, 6726, Hungary.
| |
Collapse
|
10
|
Le Quiniou C, Tian L, Drop B, Wientjes E, van Stokkum IHM, van Oort B, Croce R. PSI-LHCI of Chlamydomonas reinhardtii: Increasing the absorption cross section without losing efficiency. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1847:458-467. [PMID: 25681242 PMCID: PMC4547092 DOI: 10.1016/j.bbabio.2015.02.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/28/2015] [Accepted: 02/02/2015] [Indexed: 11/28/2022]
Abstract
Photosystem I (PSI) is an essential component of photosynthetic membranes. Despite the high sequence and structural homologies, its absorption properties differ substantially in algae, plants and cyanobacteria. In particular it is characterized by the presence of low-energy chlorophylls (red forms), the number and the energy of which vary in different organisms. The PSI-LHCI (PSI-light harvesting complex I) complex of the green alga Chlamydomonas reinhardtii (C.r.) is significantly larger than that of plants, containing five additional light-harvesting complexes (together binding≈65 chlorophylls), and contains red forms with higher energy than plants. To understand how these differences influence excitation energy transfer and trapping in the system, we studied two PSI-LHCI C.r. particles, differing in antenna size and red-form content, using time-resolved fluorescence and compared them to plant PSI-LHCI. The excited state kinetics in C.r. shows the same average lifetime (50 ps) as in plants suggesting that the effect of antenna enlargement is compensated by higher energy red forms. The system equilibrates very fast, indicating that all Lhcas are well-connected, despite their long distance to the core. The differences between C.r. PSI-LHCI with and without Lhca2 and Lhca9 show that these Lhcas bind red forms, although not the red-most. The red-most forms are in (or functionally close to) other Lhcas and slow down the trapping, but hardly affect the quantum efficiency, which remains as high as 97% even in a complex that contains 235 chlorophylls.
Collapse
Affiliation(s)
- Clotilde Le Quiniou
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Lijin Tian
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Bartlomiej Drop
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Emilie Wientjes
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Ivo H M van Stokkum
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Bart van Oort
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
| |
Collapse
|
11
|
Qin X, Wang W, Chang L, Chen J, Wang P, Zhang J, He Y, Kuang T, Shen JR. Isolation and characterization of a PSI-LHCI super-complex and its sub-complexes from a siphonaceous marine green alga, Bryopsis Corticulans. PHOTOSYNTHESIS RESEARCH 2015; 123:61-76. [PMID: 25214185 DOI: 10.1007/s11120-014-0039-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 09/03/2014] [Indexed: 05/24/2023]
Abstract
A novel super-complex of photosystem I (PSI)-light-harvesting complex I (LHCI) was isolated from a siphonaceous marine green alga, Bryopsis corticulans. The super-complex contained 9-10 Lhca antennas as external LHCI bound to the core complex. The super-complex was further disintegrated into PSI core and LHCI sub-complexes, and analysis of the pigment compositions by high-performance liquid chromatography revealed unique characteristics of the B. corticulans PSI in that one PSI core contained around 14 α-carotenes and 1-2 ε-carotenes. This is in sharp contrast to the PSI core from higher plants and most cyanobacteria where only β-carotenes were present, and is the first report for an α-carotene-type PSI core complex among photosynthetic eukaryotes, suggesting a structural flexibility of the PSI core. Lhca antennas from B. corticulans contained seven kinds of carotenoids (siphonaxanthin, all-trans neoxanthin, 9'-cis neoxanthin, violaxanthin, siphonein, ε-carotene, and α-carotene) and showed a high carotenoid:chlorophyll ratio of around 7.5:13. PSI-LHCI super-complex and PSI core showed fluorescence emission peaks at 716 and 718 nm at 77 K, respectively; whereas two Lhca oligomers had fluorescence peaks at 681 and 684 nm, respectively. By comparison with spinach PSI preparations, it was found that B. corticulans PSI had less red chlorophylls, most of them are present in the core complex but not in the outer light-harvesting systems. These characteristics may contribute to the fine tuning of the energy transfer network, and to acclimate to the ever-changing light conditions under which the unique green alga inhabits.
Collapse
Affiliation(s)
- Xiaochun Qin
- Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China,
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Maksimov EG, Schmitt FJ, Tsoraev GV, Ryabova AV, Friedrich T, Paschenko VZ. Fluorescence quenching in the lichen Peltigera aphthosa due to desiccation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2014; 81:67-73. [PMID: 24485218 DOI: 10.1016/j.plaphy.2014.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 01/09/2014] [Indexed: 06/03/2023]
Abstract
Photoprotective mechanisms were studied on the tripartite lichen Peltigera aphthosa that exhibits external cephalodia. Using the methods of steady-state and time-resolved fluorescence microscopy, we studied the dynamics of the rehydration process in different parts of the lichen thalli. It was found that apical, medial and basal parts of the thallus are not only morphologically different, but also show completely different chlorophyll induction curves and other spectral characteristics. In dry state, significant contribution to the fluorescence spectrum of lichen gives a green fluorescence of hyphae forming the upper crust, which is rapidly and almost completely quenched during the rehydration process. Probably this is one of the protective mechanisms that reduce the amount of light reaching the PS II reaction centers in the dry state. In the process of rehydration, we observed an increase in the intensity of the chlorophyll fluorescence of the photobiont at 680 nm, with significant changes of the fluorescence lifetimes and the amplitude ratios of fast and slow components of fluorescence decay kinetics. While in dry state, chlorophyll fluorescence is strongly quenched (opposite to the fluorescence of the hyphae), and the fluorescence time constants recover to the typical decay times of active photosynthetic organisms during rehydration. The quantitative behavior of these changes differs largely between the apical, medial and basal parts of the thallus, probably due to the complex interactions of the fungus, algae and cyanobacteria.
Collapse
Affiliation(s)
- E G Maksimov
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia.
| | - F-J Schmitt
- Institute of Chemistry, Biophysical Chemistry, Berlin Institute of Technology, 10623 Berlin, Germany
| | - G V Tsoraev
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| | - A V Ryabova
- A.M.Prokhorov General Physics Institute RAS, 119991 Moscow, Russia
| | - T Friedrich
- Institute of Chemistry, Biophysical Chemistry, Berlin Institute of Technology, 10623 Berlin, Germany
| | - V Z Paschenko
- Department of Biophysics, Faculty of Biology, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
| |
Collapse
|
13
|
Giera W, Szewczyk S, McConnell MD, Snellenburg J, Redding KE, van Grondelle R, Gibasiewicz K. Excitation dynamics in Photosystem I from Chlamydomonas reinhardtii. Comparative studies of isolated complexes and whole cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:1756-68. [PMID: 24973599 DOI: 10.1016/j.bbabio.2014.06.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 06/15/2014] [Accepted: 06/18/2014] [Indexed: 11/17/2022]
Abstract
Identical time-resolved fluorescence measurements with ~3.5-ps resolution were performed for three types of PSI preparations from the green alga, Chlamydomonas reinhardtii: isolated PSI cores, isolated PSI-LHCI complexes and PSI-LHCI complexes in whole living cells. Fluorescence decay in these types of PSI preparations has been previously investigated but never under the same experimental conditions. As a result we present consistent picture of excitation dynamics in algal PSI. Temporal evolution of fluorescence spectra can be generally described by three decay components with similar lifetimes in all samples (6-8ps, 25-30ps, 166-314ps). In the PSI cores, the fluorescence decay is dominated by the two fastest components (~90%), which can be assigned to excitation energy trapping in the reaction center by reversible primary charge separation. Excitation dynamics in the PSI-LHCI preparations is more complex because of the energy transfer between the LHCI antenna system and the core. The average trapping time of excitations created in the well coupled LHCI antenna system is about 12-15ps longer than excitations formed in the PSI core antenna. Excitation dynamics in PSI-LHCI complexes in whole living cells is very similar to that observed in isolated complexes. Our data support the view that chlorophylls responsible for the long-wavelength emission are located mostly in LHCI. We also compared in detail our results with the literature data obtained for plant PSI.
Collapse
Affiliation(s)
- Wojciech Giera
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland.
| | - Sebastian Szewczyk
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland
| | - Michael D McConnell
- Department of Chemistry and Biochemistry, Arizona State University, 1711 S. Rural Rd, Box 871604, Tempe, AZ 85287-1604, USA
| | - Joris Snellenburg
- Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Kevin E Redding
- Department of Chemistry and Biochemistry, Arizona State University, 1711 S. Rural Rd, Box 871604, Tempe, AZ 85287-1604, USA
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Krzysztof Gibasiewicz
- Department of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Poznań, Poland
| |
Collapse
|
14
|
Ostroumov EE, Khan YR, Scholes GD, Govindjee. Photophysics of Photosynthetic Pigment-Protein Complexes. ADVANCES IN PHOTOSYNTHESIS AND RESPIRATION 2014. [DOI: 10.1007/978-94-017-9032-1_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
15
|
Croce R, van Amerongen H. Light-harvesting in photosystem I. PHOTOSYNTHESIS RESEARCH 2013; 116:153-66. [PMID: 23645376 PMCID: PMC3825136 DOI: 10.1007/s11120-013-9838-x] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/23/2013] [Indexed: 05/18/2023]
Abstract
This review focuses on the light-harvesting properties of photosystem I (PSI) and its LHCI outer antenna. LHCI consists of different chlorophyll a/b binding proteins called Lhca's, surrounding the core of PSI. In total, the PSI-LHCI complex of higher plants contains 173 chlorophyll molecules, most of which are there to harvest sunlight energy and to transfer the created excitation energy to the reaction center (RC) where it is used for charge separation. The efficiency of the complex is based on the capacity to deliver this energy to the RC as fast as possible, to minimize energy losses. The performance of PSI in this respect is remarkable: on average it takes around 50 ps for the excitation to reach the RC in plants, without being quenched in the meantime. This means that the internal quantum efficiency is close to 100% which makes PSI the most efficient energy converter in nature. In this review, we describe the light-harvesting properties of the complex in relation to protein and pigment organization/composition, and we discuss the important parameters that assure its very high quantum efficiency. Excitation energy transfer and trapping in the core and/or Lhcas, as well as in the supercomplexes PSI-LHCI and PSI-LHCI-LHCII are described in detail with the aim of giving an overview of the functional behavior of these complexes.
Collapse
Affiliation(s)
- Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands,
| | | |
Collapse
|
16
|
Snellenburg JJ, Dekker JP, van Grondelle R, van Stokkum IHM. Functional compartmental modeling of the photosystems in the thylakoid membrane at 77 K. J Phys Chem B 2013; 117:11363-71. [PMID: 23848485 DOI: 10.1021/jp4031283] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Time-resolved fluorescence spectroscopy measurements at 77 K on thylakoid membrane preparations and isolated photosynthetic complexes thereof were investigated using target analysis with the aim of building functional compartmental models for the photosystems in the thylakoid membrane. Combining kinetic schemes with different spectral constraints enabled us to resolve the energy transfer pathways and decay characteristics of the different emissive species. We determined the spectral and energetic properties of the red Chl pools in both photosystems and quantified the formation of LHCII-LHCI-PSI supercomplexes in the transition from native to unstacked thylakoid membranes.
Collapse
Affiliation(s)
- Joris J Snellenburg
- Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | | | | | | |
Collapse
|
17
|
Kargul J, Janna Olmos JD, Krupnik T. Structure and function of photosystem I and its application in biomimetic solar-to-fuel systems. JOURNAL OF PLANT PHYSIOLOGY 2012; 169:1639-1653. [PMID: 22784471 DOI: 10.1016/j.jplph.2012.05.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 05/09/2012] [Accepted: 05/11/2012] [Indexed: 06/01/2023]
Abstract
Photosystem I (PSI) is one of the most efficient biological macromolecular complexes that converts solar energy into condensed energy of chemical bonds. Despite high structural complexity, PSI operates with a quantum yield close to 1.0 and to date, no man-made synthetic system approached this remarkable efficiency. This review highlights recent developments in dissecting molecular structure and function of the prokaryotic and eukaryotic PSI. It also overviews progress in the application of this complex as a natural photocathode for production of hydrogen within the biomimetic solar-to-fuel nanodevices.
Collapse
Affiliation(s)
- Joanna Kargul
- Department of Plant Molecular Physiology, University of Warsaw, ul. Miecznikowa 1, 02-096 Warsaw, Poland.
| | | | | |
Collapse
|
18
|
Drop B, Webber-Birungi M, Fusetti F, Kouřil R, Redding KE, Boekema EJ, Croce R. Photosystem I of Chlamydomonas reinhardtii contains nine light-harvesting complexes (Lhca) located on one side of the core. J Biol Chem 2011; 286:44878-87. [PMID: 22049081 PMCID: PMC3247965 DOI: 10.1074/jbc.m111.301101] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 10/28/2011] [Indexed: 11/06/2022] Open
Abstract
In this work we have purified the Photosystem I (PSI) complex of Chlamydomonas reinhardtii to homogeneity. Biochemical, proteomic, spectroscopic, and structural analyses reveal the main properties of this PSI-LHCI supercomplex. The data show that the largest purified complex is composed of one core complex and nine Lhca antennas and that it contains all Lhca gene products. A projection map at 15 Å resolution obtained by electron microscopy reveals that the Lhcas are organized on one side of the core in a double half-ring arrangement, in contrast with previous suggestions. A series of stable disassembled PSI-LHCI intermediates was purified. The analysis of these complexes suggests the sequence of the assembly/disassembly process. It is shown that PSI-LHCI of C. reinhardtii is larger but far less stable than the complex from higher plants. Lhca2 and Lhca9 (the red-most antenna complexes), although present in the largest complex in 1:1 ratio with the core, are only loosely associated with it. This can explain the large variation in antenna composition of PSI-LHCI from C. reinhardtii found in the literature. The analysis of several subcomplexes with reduced antenna size allows determination of the position of Lhca2 and Lhca9 and leads to a proposal for a model of the organization of the Lhcas within the PSI-LHCI supercomplex.
Collapse
Affiliation(s)
- Bartlomiej Drop
- From the Department of Biophysical Chemistry and
- the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | | | - Fabrizia Fusetti
- Department of Biochemistry and the Netherlands Proteomics Centre, Groningen Biological Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Roman Kouřil
- From the Department of Biophysical Chemistry and
| | - Kevin E. Redding
- the Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-1604, and
| | | | - Roberta Croce
- From the Department of Biophysical Chemistry and
- the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| |
Collapse
|
19
|
Busch A, Hippler M. The structure and function of eukaryotic photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1807:864-77. [PMID: 20920463 DOI: 10.1016/j.bbabio.2010.09.009] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 09/20/2010] [Accepted: 09/28/2010] [Indexed: 12/27/2022]
Abstract
Eukaryotic photosystem I consists of two functional moieties: the photosystem I core, harboring the components for the light-driven charge separation and the subsequent electron transfer, and the peripheral light-harvesting complex (LHCI). While the photosystem I-core remained highly conserved throughout the evolution, with the exception of the oxidizing side of photosystem I, the LHCI complex shows a high degree of variability in size, subunits composition and bound pigments, which is due to the large variety of different habitats photosynthetic organisms dwell in. Besides summarizing the most current knowledge on the photosystem I-core structure, we will discuss the composition and structure of the LHCI complex from different eukaryotic organisms, both from the red and the green clade. Furthermore, mechanistic insights into electron transfer between the donor and acceptor side of photosystem I and its soluble electron transfer carrier proteins will be given. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
Collapse
Affiliation(s)
- Andreas Busch
- Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.
| | | |
Collapse
|
20
|
Jung H, Gulis G, Gupta S, Redding K, Gosztola DJ, Wiederrecht GP, Stroscio MA, Dutta M. Optical and Electrical Measurement of Energy Transfer between Nanocrystalline Quantum Dots and Photosystem I. J Phys Chem B 2010; 114:14544-9. [DOI: 10.1021/jp102291e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hyeson Jung
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - Galina Gulis
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - Subhadra Gupta
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - Kevin Redding
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - David J. Gosztola
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - Gary P. Wiederrecht
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - Michael A. Stroscio
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| | - Mitra Dutta
- Department of Electrical Engineering, Department of Bioengineering, and Department of Physics, The University of Illinois at Chicago, Illinois 60607, Department of Metallurgy and Materials Engineering, The University of Alabama, Alabama 35487, Department of Chemistry and Biochemistry, Arizona State University, Arizona 85287, and Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439
| |
Collapse
|
21
|
Komura M, Yamagishi A, Shibata Y, Iwasaki I, Itoh S. Mechanism of strong quenching of photosystem II chlorophyll fluorescence under drought stress in a lichen, Physciella melanchla, studied by subpicosecond fluorescence spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1797:331-8. [PMID: 19962955 DOI: 10.1016/j.bbabio.2009.11.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/16/2009] [Accepted: 11/25/2009] [Indexed: 10/20/2022]
Abstract
The mechanism of the severe quenching of chlorophyll (Chl) fluorescence under drought stress was studied in a lichen Physciella melanchla, which contains a photobiont green alga, Trebouxia sp., using a streak camera and a reflection-mode fluorescence up-conversion system. We detected a large 0.31 ps rise of fluorescence at 715 and 740 nm in the dry lichen suggesting the rapid energy influx to the 715-740 nm bands from the shorter-wavelength Chls with a small contribution from the internal conversion from Soret bands. The fluorescence, then, decayed with time constants of 23 and 112 ps, suggesting the rapid dissipation into heat through the quencher. The result confirms the accelerated 40 ps decay of fluorescence reported in another lichen (Veerman et al., 2007 [36]) and gives a direct evidence for the rapid energy transfer from bulk Chls to the longer-wavelength quencher. We simulated the entire PS II fluorescence kinetics by a global analysis and estimated the 20.2 ns(-1) or 55.0 ns(-1) energy transfer rate to the quencher that is connected either to the LHC II or to the PS II core antenna. The strong quenching with the 3-12 times higher rate compared to the reported NPQ rate, suggests the operation of a new type of quenching, such as the extreme case of Chl-aggregation in LHCII or a new type of quenching in PS II core antenna in dry lichens.
Collapse
Affiliation(s)
- Masayuki Komura
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Furocho, Chikusa, Nagoya 464-8602, Japan
| | | | | | | | | |
Collapse
|
22
|
Stauber EJ, Busch A, Naumann B, Svatoš A, Hippler M. Proteotypic profiling of LHCI from Chlamydomonas reinhardtii provides new insights into structure and function of the complex. Proteomics 2009; 9:398-408. [DOI: 10.1002/pmic.200700620] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
23
|
Abstract
Time-resolved fluorescence measurements were performed on isolated core and intact Photosystem I (PS I) particles and stroma membranes from Arabidopsis thaliana to characterize the type of energy-trapping kinetics in higher plant PS I. Target analysis confirms the previously proposed "charge recombination" model. No bottleneck in the energy flow from the bulk antenna compartments to the reaction center has been found. For both particles a trap-limited kinetics is realized, with an apparent charge separation lifetime of approximately 6 ps. No red chlorophylls (Chls) are found in the PS I-core complex from A. thaliana. Rather, the observed red-shifted fluorescence (700-710 nm range) originates from the reaction center. In contrast, two red Chl compartments, located in the peripheral light-harvesting complexes, are resolved in the intact PS I particles (decay lifetimes 33 and 95 ps, respectively). These two red states have been attributed to the two red states found in Lhca 3 and Lhca 4, respectively. The influence of the red Chls on the slowing of the overall trapping kinetics in the intact PS I complex is estimated to be approximately four times larger than the effect of the bulk antenna enlargement.
Collapse
|
24
|
van der Weij-de Wit CD, Ihalainen JA, van Grondelle R, Dekker JP. Excitation energy transfer in native and unstacked thylakoid membranes studied by low temperature and ultrafast fluorescence spectroscopy. PHOTOSYNTHESIS RESEARCH 2007; 93:173-82. [PMID: 17390231 DOI: 10.1007/s11120-007-9157-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 03/02/2007] [Indexed: 05/14/2023]
Abstract
In this work, the transfer of excitation energy was studied in native and cation-depletion induced, unstacked thylakoid membranes of spinach by steady-state and time-resolved fluorescence spectroscopy. Fluorescence emission spectra at 5 K show an increase in photosystem I (PSI) emission upon unstacking, which suggests an increase of its antenna size. Fluorescence excitation measurements at 77 K indicate that the increase of PSI emission upon unstacking is caused both by a direct spillover from the photosystem II (PSII) core antenna and by a functional association of light-harvesting complex II (LHCII) to PSI, which is most likely caused by the formation of LHCII-LHCI-PSI supercomplexes. Time-resolved fluorescence measurements, both at room temperature and at 77 K, reveal differences in the fluorescence decay kinetics of stacked and unstacked membranes. Energy transfer between LHCII and PSI is observed to take place within 25 ps at room temperature and within 38 ps at 77 K, consistent with the formation of LHCII-LHCI-PSI supercomplexes. At the 150-160 ps timescale, both energy transfer from LHCII to PSI as well as spillover from the core antenna of PSII to PSI is shown to occur at 77 K. At room temperature the spillover and energy transfer to PSI is less clear at the 150 ps timescale, because these processes compete with charge separation in the PSII reaction center, which also takes place at a timescale of about 150 ps.
Collapse
Affiliation(s)
- C D van der Weij-de Wit
- Faculty of Sciences, Department of Physics and Astronomy, Section Biophysics, Vrije Universiteit, De Boelelaan 1081, Amsterdam, 1081 HV, The Netherlands.
| | | | | | | |
Collapse
|
25
|
Jensen PE, Bassi R, Boekema EJ, Dekker JP, Jansson S, Leister D, Robinson C, Scheller HV. Structure, function and regulation of plant photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:335-52. [PMID: 17442259 DOI: 10.1016/j.bbabio.2007.03.004] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2007] [Revised: 03/03/2007] [Accepted: 03/06/2007] [Indexed: 12/20/2022]
Abstract
Photosystem I (PSI) is a multisubunit protein complex located in the thylakoid membranes of green plants and algae, where it initiates one of the first steps of solar energy conversion by light-driven electron transport. In this review, we discuss recent progress on several topics related to the functioning of the PSI complex, like the protein composition of the complex in the plant Arabidopsis thaliana, the function of these subunits and the mechanism by which nuclear-encoded subunits can be inserted into or transported through the thylakoid membrane. Furthermore, the structure of the native PSI complex in several oxygenic photosynthetic organisms and the role of the chlorophylls and carotenoids in the antenna complexes in light harvesting and photoprotection are reviewed. The special role of the 'red' chlorophylls (chlorophyll molecules that absorb at longer wavelength than the primary electron donor P700) is assessed. The physiology and mechanism of the association of the major light-harvesting complex of photosystem II (LHCII) with PSI during short term adaptation to changes in light quality and quantity is discussed in functional and structural terms. The mechanism of excitation energy transfer between the chlorophylls and the mechanism of primary charge separation is outlined and discussed. Finally, a number of regulatory processes like acclimatory responses and retrograde signalling is reviewed with respect to function of the thylakoid membrane. We finish this review by shortly discussing the perspectives for future research on PSI.
Collapse
Affiliation(s)
- Poul Erik Jensen
- Plant Biochemistry Laboratory, Department of Plant Biology, Faculty of Life Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Veerman J, McConnell MD, Vasil'ev S, Mamedov F, Styring S, Bruce D. Functional Heterogeneity of Photosystem II in Domain Specific Regions of the Thylakoid Membrane of Spinach (Spinacia oleracea L.). Biochemistry 2007; 46:3443-53. [PMID: 17302435 DOI: 10.1021/bi061964r] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A mild sonication and phase fractionation method has been used to isolate five regions of the thylakoid membrane in order to characterize the functional lateral heterogeneity of photosynthetic reaction centers and light harvesting complexes. Low-temperature fluorescence and absorbance spectra, absorbance cross-section measurements, and picosecond time-resolved fluorescence decay kinetics were used to determine the relative amounts of photosystem II (PSII) and photosystem I (PSI), to determine the relative PSII antenna size, and to characterize the excited-state dynamics of PSI and PSII in each fraction. Marked progressive increases in the proportion of PSI complexes were observed in the following sequence: grana core (BS), whole grana (B3), margins (MA), stroma lamellae (T3), and purified stromal fraction (Y100). PSII antenna size was drastically reduced in the margins of the grana stack and stroma lamellae fractions as compared to the grana. Picosecond time-resolved fluorescence decay kinetics of PSII were characterized by three exponential decay components in the grana fractions, and were found to have only two decay components with slower lifetimes in the stroma. Results are discussed in the framework of existing models of chloroplast thylakoid membrane lateral heterogeneity and the PSII repair cycle. Kinetic modeling of the PSII fluorescence decay kinetics revealed that PSII populations in the stroma and grana margin fractions possess much slower primary charge separation rates and decreased photosynthetic efficiency when compared to PSII populations in the grana stack.
Collapse
Affiliation(s)
- John Veerman
- Department of Biology, Brock University, St. Catharines, Ontario, L2S 3A1, Canada
| | | | | | | | | | | |
Collapse
|
27
|
Melkozernov AN, Barber J, Blankenship RE. Light Harvesting in Photosystem I Supercomplexes,. Biochemistry 2005; 45:331-45. [PMID: 16401064 DOI: 10.1021/bi051932o] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In photosynthetic membranes of cyanobacteria, algae, and higher plants, photosystem I (PSI) mediates light-driven transmembrane electron transfer from plastocyanin or cytochrome c6 to the ferredoxin-NADP complex. The oxidoreductase function of PSI is sensitized by a reversible photooxidation of primary electron donor P700, which launches a multistep electron transfer via a series of redox cofactors of the reaction center (RC). The excitation energy for the functioning of the primary electron donor in the RC is delivered via the chlorophyll core antenna in the complex with peripheral light-harvesting antennas. Supermolecular complexes of the PSI acquire remarkably different structural forms of the peripheral light-harvesting antenna complexes, including distinct pigment types and organizational principles. The PSI core antenna, being the main functional unit of the supercomplexes, provides an increased functional connectivity in the chlorophyll antenna network due to dense pigment packing resulting in a fast spread of the excitation among the neighbors. Functional connectivity within the network as well as the spectral overlap of antenna pigments allows equilibration of the excitation energy in the depth of the whole membrane within picoseconds and loss-free delivery of the excitation to primary donor P700 within 20-40 ps. Low-light-adapted cyanobacteria under iron-deficiency conditions extend this capacity via assembly of efficiently energy coupled rings of CP43-like complexes around the PSI trimers. In green algae and higher plants, less efficient energy coupling in the eukaryotic PSI-LHCI supercomplexes is probably a result of the structural adaptation of the Chl a/b binding LHCI peripheral antenna that not only extends the absorption cross section of the PSI core but participates in regulation of excitation flows between the two photosystems as well as in photoprotection.
Collapse
Affiliation(s)
- Alexander N Melkozernov
- Department of Chemistry and Biochemistry and Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, USA.
| | | | | |
Collapse
|
28
|
Subramanyam R, Jolley C, Brune DC, Fromme P, Webber AN. Characterization of a novel Photosystem I-LHCI supercomplex isolated fromChlamydomonas reinhardtiiunder anaerobic (State II) conditions. FEBS Lett 2005; 580:233-8. [PMID: 16375899 DOI: 10.1016/j.febslet.2005.12.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Revised: 11/25/2005] [Accepted: 12/01/2005] [Indexed: 10/25/2022]
Abstract
A novel supercomplex of Photosystem I (PSI) with light harvesting complex I (LHCI) was isolated from the green alga Chlamydomonas reinhardtii. This novel supercomplex is unique as it is the first stable supercomplex of PSI together with its external antenna. The supercomplex contains 256 chlorophylls per reaction center. The supercomplex was isolated under anaerobic conditions and may represent the State II form of the photosynthetic unit. In contrast to previously reported supercomplexes isolated in State I, which contain only 4 LHC I proteins, this supercomplex contains 10-11 LHC I proteins tightly bound to the PSI core. In contrast to plants, no LHC II is tightly bound to the PSI-LHCI supercomplex in State II. Investigation of the energy transfer from the antenna system to the reaction center core shows that the LHC supercomplexes are tightly coupled to the PSI core, not only structurally but also energetically. The excitation energy transfer kinetics are completely dominated by the fast phase, with a near-complete lack of long-lived fluorescence. This tight coupling is in contrast to all reports of energy transfer in PSI-LHCI supercomplexes (in State I), which have so far been described as weakly coupled supercomplexes with low efficiency for excitation energy transfer. These results indicate that there are large and dynamic changes of the PSI-LHCI supercomplex during the acclimation from aerobic (State I) to anaerobic (State II) conditions in Chlamydomonas.
Collapse
Affiliation(s)
- Rajagopal Subramanyam
- School of Life Sciences and Center for the Study of Early Events in Photosynthesis, P.O. Box, 874501, Arizona State University, Tempe, AZ 85287-4501, USA
| | | | | | | | | |
Collapse
|
29
|
Melkozernov AN, Kargul J, Lin S, Barber J, Blankenship RE. Spectral and kinetic analysis of the energy coupling in the PS I-LHC I supercomplex from the green alga Chlamydomonas reinhardtii at 77 K. PHOTOSYNTHESIS RESEARCH 2005; 86:203-15. [PMID: 16172939 DOI: 10.1007/s11120-005-4118-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2004] [Accepted: 03/18/2005] [Indexed: 05/04/2023]
Abstract
Energy transfer processes in the chlorophyll antenna of the PS I-LHCI supercomplexes from the green alga Chlamydomonas reinhardtii have been studied at 77 K using transient absorption spectroscopy with multicolor excitation in the 640-670 nm region. Comparison of the kinetic data obtained at low and room temperatures indicates that the slow approximately approximately 100 ps excitation equilibration phase that is characteristic of energy coupling of the LHCI peripheral antenna to the PS I core at physiological temperatures (Melkozernov AN, Kargul J, Lin S, Barber J and Blankenship RE (2004) J Phys Chem B 108: 10547-10555) is not observed in the excitation dynamics of the PS I-LHCI supercomplex at 77 K. This suggests that at low temperatures the peripheral antenna is energetically uncoupled from the PS I core antenna. Under these conditions the observed kinetic phases on the time scales from subpicoseconds to tens of picoseconds represent the superposition of the processes occurring independently in the PS I core antenna and the Chl a/b containing LHCI antenna. In the PS I-LHCI supercomplex with two uncoupled antennas the excitation is channeled to the excitation sinks formed at low temperature by clusters of red pigments. A better spectral resolution of the transient absorption spectra at 77 K results in detection of two DeltaA bands originating from the rise of photobleaching on the picosecond time scale of two clearly distinguished pools of low energy absorbing Chls in the PS I-LHCI supercomplex. The first pool of low energy pigments absorbing at 687 nm is likely to originate from the red pigments in the LHCI where the Lhca1 protein is most abundant. The second pool at 697 nm is suggested to result either from the structural interaction of the LHCI and the PS I core or from other Lhca proteins in the antenna. The kinetic data are discussed based on recent structural models of the PS I-LHCI. It is proposed that the uncoupling of pigment pools may be a control mechanism that regulates energy flow in Photosystem I.
Collapse
Affiliation(s)
- Alexander N Melkozernov
- Department of Chemistry and Biochemistry, Center for the Study of Early Events in Photosynthesis, Tempe, AZ 85287-1604, USA.
| | | | | | | | | |
Collapse
|
30
|
Ihalainen JA, Klimmek F, Ganeteg U, van Stokkum IHM, van Grondelle R, Jansson S, Dekker JP. Excitation energy trapping in photosystem I complexes depleted in Lhca1 and Lhca4. FEBS Lett 2005; 579:4787-91. [PMID: 16098971 DOI: 10.1016/j.febslet.2005.06.091] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Revised: 05/27/2005] [Accepted: 06/10/2005] [Indexed: 01/01/2023]
Abstract
We report a time-resolved fluorescence spectroscopy characterization of photosystem I (PSI) particles prepared from Arabidopsis lines with knock-out mutations against the peripheral antenna proteins of Lhca1 or Lhca4. The first mutant retains Lhca2 and Lhca3 while the second retains one other light-harvesting protein of photosystem I (Lhca) protein, probably Lhca5. The results indicate that Lhca2/3 and Lhca1/4 each provides about equally effective energy transfer routes to the PSI core complex, and that Lhca5 provides a less effective energy transfer route. We suggest that the specific location of each Lhca protein within the PSI-LHCI supercomplex is more important than the presence of so-called red chlorophylls in the Lhca proteins.
Collapse
Affiliation(s)
- Janne A Ihalainen
- Vrije Universiteit Amsterdam, Department of Physics and Astronomy, Biophysics, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
31
|
Santabarbara S, Heathcote P, Evans MCW. Modelling of the electron transfer reactions in Photosystem I by electron tunnelling theory: The phylloquinones bound to the PsaA and the PsaB reaction centre subunits of PS I are almost isoenergetic to the iron–sulfur cluster FX. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1708:283-310. [PMID: 15975545 DOI: 10.1016/j.bbabio.2005.05.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Revised: 04/12/2005] [Accepted: 05/03/2005] [Indexed: 10/25/2022]
Abstract
Photosystem I is a large macromolecular complex located in the thylakoid membranes of chloroplasts and in cyanobacteria that catalyses the light driven reduction of ferredoxin and oxidation of plastocyanin. Due to the very negative redox potential of the primary electron transfer cofactors accepting electrons, direct estimation by redox titration of the energetics of the system is hampered. However, the rates of electron transfer reactions are related to the thermodynamic properties of the system. Hence, several spectroscopic and biochemical techniques have been employed, in combination with the classical Marcus theory for electron transfer tunnelling, in order to access these parameters. Nevertheless, the values which have been presented are very variable. In particular, for the case of the tightly bound phylloquinone molecule A(1), the values of the redox potentials reported in the literature vary over a range of about 350 mV. Previous models of Photosystem I have assumed a unidirectional electron transfer model. In the present study, experimental evidence obtained by means of time resolved absorption, photovoltage, and electron paramagnetic resonance measurements are reviewed and analysed in terms of a bi-directional kinetic model for electron transfer reactions. This model takes into consideration the thermodynamic equilibrium between the iron-sulfur centre F(X) and the phylloquinone bound to either the PsaA (A(1A)) or the PsaB (A(1B)) subunit of the reaction centre and the equilibrium between the iron-sulfur centres F(A) and F(B). The experimentally determined decay lifetimes in the range of sub-picosecond to the microsecond time domains can be satisfactorily simulated, taking into consideration the edge-to-edge distances between redox cofactors and driving forces reported in the literature. The only exception to this general behaviour is the case of phylloquinone (A(1)) reoxidation. In order to describe the reported rates of the biphasic decay, of about 20 and 200 ns, associated with this electron transfer step, the redox potentials of the quinones are estimated to be almost isoenergetic with that of the iron sulfur centre F(X). A driving force in the range of 5 to 15 meV is estimated for these reactions, being slightly exergonic in the case of the A(1B) quinone and slightly endergonic, in the case of the A(1A) quinone. The simulation presented in this analysis not only describes the kinetic data obtained for the wild type samples at room temperature and is consistent with estimates of activation energy by the analysis of temperature dependence, but can also explain the effect of the mutations around the PsaB quinone binding pocket. A model of the overall energetics of the system is derived, which suggests that the only substantially irreversible electron transfer reactions are the reoxidation of A(0) on both electron transfer branches and the reduction of F(A) by F(X).
Collapse
Affiliation(s)
- Stefano Santabarbara
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
| | | | | |
Collapse
|
32
|
Sener MK, Jolley C, Ben-Shem A, Fromme P, Nelson N, Croce R, Schulten K. Comparison of the light-harvesting networks of plant and cyanobacterial photosystem I. Biophys J 2005; 89:1630-42. [PMID: 15994896 PMCID: PMC1366667 DOI: 10.1529/biophysj.105.066464] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
With the availability of structural models for photosystem I (PSI) in cyanobacteria and plants it is possible to compare the excitation transfer networks in this ubiquitous photosystem from two domains of life separated by over one billion years of divergent evolution, thus providing an insight into the physical constraints that shape the networks' evolution. Structure-based modeling methods are used to examine the excitation transfer kinetics of the plant PSI-LHCI supercomplex. For this purpose an effective Hamiltonian is constructed that combines an existing cyanobacterial model for structurally conserved chlorophylls with spectral information for chlorophylls in the Lhca subunits. The plant PSI excitation migration network thus characterized is compared to its cyanobacterial counterpart investigated earlier. In agreement with observations, an average excitation transfer lifetime of approximately 49 ps is computed for the plant PSI-LHCI supercomplex with a corresponding quantum yield of 95%. The sensitivity of the results to chlorophyll site energy assignments is discussed. Lhca subunits are efficiently coupled to the PSI core via gap chlorophylls. In contrast to the chlorophylls in the vicinity of the reaction center, previously shown to optimize the quantum yield of the excitation transfer process, the orientational ordering of peripheral chlorophylls does not show such optimality. The finding suggests that after close packing of chlorophylls was achieved, constraints other than efficiency of the overall excitation transfer process precluded further evolution of pigment ordering.
Collapse
Affiliation(s)
- Melih K Sener
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | | | | | | | | | | | | |
Collapse
|
33
|
Ihalainen JA, van Stokkum IHM, Gibasiewicz K, Germano M, van Grondelle R, Dekker JP. Kinetics of excitation trapping in intact Photosystem I of Chlamydomonas reinhardtii and Arabidopsis thaliana. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2005; 1706:267-75. [PMID: 15694355 DOI: 10.1016/j.bbabio.2004.11.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2004] [Revised: 11/16/2004] [Accepted: 11/19/2004] [Indexed: 11/28/2022]
Abstract
We measured picosecond time-resolved fluorescence of intact Photosystem I complexes from Chlamydomonas reinhardtii and Arabidopsis thaliana. The antenna system of C. reinhardtii contains about 30-60 chlorophylls more than that of A. thaliana, but lacks the so-called red chlorophylls, chlorophylls that absorb at longer wavelength than the primary electron donor. In C. reinhardtii, the main lifetimes of excitation trapping are about 27 and 68 ps. The overall lifetime of C. reinhardtii is considerably shorter than in A. thaliana. We conclude that the amount and energies of the red chlorophylls have a larger effect on excitation trapping time in Photosystem I than the antenna size.
Collapse
Affiliation(s)
- Janne A Ihalainen
- Faculty of Sciences, Department of Physics and Astronomy, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, the Netherlands.
| | | | | | | | | | | |
Collapse
|
34
|
Melkozernov AN, Blankenship RE. Structural and functional organization of the peripheral light-harvesting system in photosystem I. PHOTOSYNTHESIS RESEARCH 2005; 85:33-50. [PMID: 15977058 DOI: 10.1007/s11120-004-6474-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2004] [Accepted: 11/19/2004] [Indexed: 05/03/2023]
Abstract
This review centers on the structural and functional organization of the light-harvesting system in the peripheral antenna of Photosystem I (LHC I) and its energy coupling to the Photosystem I (PS I) core antenna network in view of recently available structural models of the eukaryotic Photosystem I-LHC I complex, eukaryotic LHC II complexes and the cyanobacterial Photosystem I core. A structural model based on the 3D homology of Lhca4 with LHC II is used for analysis of the principles of pigment arrangement in the LHC I peripheral antenna, for prediction of the protein ligands for the pigments that are unique for LHC I and for estimates of the excitonic coupling in strongly interacting pigment dimers. The presence of chlorophyll clusters with strong pigment-pigment interactions is a structural feature of PS I, resulting in the characteristic red-shifted fluorescence. Analysis of the interactions between the PS I core antenna and the peripheral antenna leads to the suggestion that the specific function of the red pigments is likely to be determined by their localization with respect to the reaction center. In the PS I core antenna, the Chl clusters with a different magnitude of low energy shift contribute to better spectral overlap of Chls in the reaction center and the Chls of the antenna network, concentrate the excitation around the reaction center and participate in downhill enhancement of energy transfer from LHC II to the PS I core. Chlorophyll clusters forming terminal emitters in LHC I are likely to be involved in photoprotection against excess energy.
Collapse
Affiliation(s)
- Alexander N Melkozernov
- Department of Chemistry and Biochemistry, Center for the Study of Early Events in Photosynthesis, Tempe, AZ, 85287-1604, USA.
| | | |
Collapse
|