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EPR of Type I photosynthetic reaction centers. Methods Enzymol 2022; 666:413-450. [DOI: 10.1016/bs.mie.2022.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Cherepanov DA, Shelaev IV, Gostev FE, Nadtochenko VA, Xu W, Golbeck JH, Semenov AY. Symmetry breaking in photosystem I: ultrafast optical studies of variants near the accessory chlorophylls in the A- and B-branches of electron transfer cofactors. Photochem Photobiol Sci 2021; 20:1209-1227. [PMID: 34478050 DOI: 10.1007/s43630-021-00094-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/18/2021] [Indexed: 11/25/2022]
Abstract
Femtosecond absorption spectroscopy of Photosystem I (PS I) complexes from the cyanobacterium Synechocystis sp. PCC 6803 was carried out on three pairs of complementary amino acid substitutions located near the second pair of chlorophyll molecules Chl2A and Chl2B (also termed A-1A and A-1B). The absorption dynamics at delays of 0.1-500 ps were analyzed by decomposition into discrete decay-associated spectra and continuously distributed exponential components. The multi-exponential deconvolution of the absorption changes revealed that the electron transfer reactions in the PsaA-N600M, PsaA-N600H, and PsaA-N600L variants near the B-branch of cofactors are similar to those of the wild type, while the PsaB-N582M, PsaB-N582H, and PsaB-N582L variants near the A-branch of cofactors cause significant alterations of the photochemical processes, making them heterogeneous and poorly described by a discrete exponential kinetic model. A redistribution of the unpaired electron between the second and the third monomers Chl2A/Chl2B and Chl3A/Chl3B was identified in the time range of 9-20 ps, and the subsequent reduction of A1 was identified in the time range of 24-70 ps. In the PsaA-N600L and PsaB-N582H/L variants, the reduction of A1 occurred with a decreased quantum yield of charge separation. The decreased quantum yield correlates with a slowing of the phylloquinone A0 → A1 reduction, but not with the initial transient spectra measured at the shortest time delay. The results support a branch competition model, where the electron is sheared between Chl2A-Chl3A and Chl2B-Chl3B cofactors before its transfer to phylloquinone in either A1A or A1B sites.
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Affiliation(s)
- Dmitry A Cherepanov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina St. 4, Moscow, 117977, Russian Federation.
| | - Ivan V Shelaev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina St. 4, Moscow, 117977, Russian Federation
| | - Fedor E Gostev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina St. 4, Moscow, 117977, Russian Federation
| | - Victor A Nadtochenko
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina St. 4, Moscow, 117977, Russian Federation.,Department of Chemistry, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, 119991, Russian Federation
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA, 70504, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16801, USA.,Department of Chemistry, The Pennsylvania State University, University Park, PA, 16801, USA
| | - Alexey Yu Semenov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Kosygina St. 4, Moscow, 117977, Russian Federation.,A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 1, Moscow, 119992, Russian Federation
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Cherepanov DA, Shelaev IV, Gostev FE, Petrova A, Aybush AV, Nadtochenko VA, Xu W, Golbeck JH, Semenov AY. Primary charge separation within the structurally symmetric tetrameric Chl 2AP AP BChl 2B chlorophyll exciplex in photosystem I. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2021; 217:112154. [PMID: 33636482 DOI: 10.1016/j.jphotobiol.2021.112154] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/05/2021] [Accepted: 02/12/2021] [Indexed: 12/01/2022]
Abstract
In Photosystem I (PS I), the role of the accessory chlorophyll (Chl) molecules, Chl2A and Chl2B (also termed A-1A and A-1B), which are directly adjacent to the special pair P700 and fork into the A- and B-branches of electron carriers, is incompletely understood. In this work, the Chl2A and Chl2B transient absorption ΔA0(λ) at a time delay of 100 fs was identified by ultrafast pump-probe spectroscopy in three pairs of PS I complexes from Synechocystis sp. PCC 6803 with residues PsaA-N600 or PsaB-N582 (which ligate Chl2B or Chl2A through a H2O molecule) substituted by Met, His, and Leu. The ΔA0(λ) spectra were quantified using principal component analysis, the main component of which was interpreted as a mutation-induced shift of the equilibrium between the excited state of primary donor P700⁎ and the primary charge-separated state P700+Chl2-. This equilibrium is shifted to the charge-separated state in wild-type PS I and to the excited P700 in the PS I complexes with the substituted ligands to the Chl2A and Chl2B monomers. The results can be rationalized within the framework of an adiabatic model in which the P700 is electronically coupled with the symmetrically arranged monomers Chl2A and Chl2B; such a structure can be considered a symmetric tetrameric exciplex Chl2APAPBChl2B, in which the excited state (Chl2APAPBChl2B)* is mixed with two charge-transfer states P700+Chl2A- and P700+Chl2B-. The electron redistribution between the two branches in favor of the A-branch apparently takes place in the picosecond time scale after reduction of the Chl2A and Chl2B monomers.
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Affiliation(s)
- Dmitry A Cherepanov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Kosygina st., 4, Russia.
| | - Ivan V Shelaev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Kosygina st., 4, Russia
| | - Fedor E Gostev
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Kosygina st., 4, Russia
| | - Anastasia Petrova
- A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Leninskie gory, 1, Building 40, Russia
| | - Arseniy V Aybush
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Kosygina st., 4, Russia
| | - Victor A Nadtochenko
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Kosygina st., 4, Russia; Department of Chemistry, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow 119991, Russian Federation
| | - Wu Xu
- Department of Chemistry, University of Louisiana at Lafayette, Lafayette, LA 70504, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16801, USA; Department of Chemistry, The Pennsylvania State University, University Park, PA 16801, USA
| | - Alexey Yu Semenov
- N.N. Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Kosygina st., 4, Russia; A.N. Belozersky Institute of Physical-Chemical Biology, Lomonosov Moscow State University, 119992 Moscow, Leninskie gory, 1, Building 40, Russia
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He Z, Ferlez B, Kurashov V, Tank M, Golbeck JH, Bryant DA. Reaction centers of the thermophilic microaerophile, Chloracidobacterium thermophilum (Acidobacteria) I: biochemical and biophysical characterization. PHOTOSYNTHESIS RESEARCH 2019; 142:87-103. [PMID: 31161318 DOI: 10.1007/s11120-019-00650-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 05/27/2019] [Indexed: 06/09/2023]
Abstract
Chloracidobacterium thermophilum is a microaerophilic, anoxygenic member of the green chlorophototrophic bacteria. This bacterium is the first characterized oxygen-requiring chlorophototroph with chlorosomes, the FMO protein, and homodimeric type-1 reaction centers (RCs). The RCs of C. thermophilum are also unique because they contain three types of chlorophylls, bacteriochlorophyll aP esterified with phytol, Chl aPD esterified with Δ2,6-phytadienol, and Zn-BChl aP' esterified with phytol, in the approximate molar ratio 32:24:4. The light-induced difference spectrum of these RCs had a bleaching maximum at 839 nm and also revealed an electrochromic bandshift that is probably derived from a BChl a molecule near P840+. The FX [4Fe-4S] cluster had a midpoint potential of ca. - 581 mV, and the spectroscopic properties of the P+ F X - spin-polarized radical pair were very similar to those of reaction centers of heliobacteria and green sulfur bacteria. The data further indicate that electron transfer occurs directly from A0- to FX, as occurs in other homodimeric type-1 RCs. Washing experiments with isolated membranes suggested that the PscB subunit of these reaction centers is more tightly bound than PshB in heliobacteria. Thus, the reaction centers of C. thermophilum have some properties that resemble other homodimeric reaction centers but also have specific properties that are more similar to those of Photosystem I. These differences probably contribute to protection of the electron transfer chain from oxygen, contributing to the oxygen tolerance of this microaerophile.
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Affiliation(s)
- Zhihui He
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, 612 Wilson Road, East Lansing, MI, 48824, USA
| | - Vasily Kurashov
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
| | - Marcus Tank
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo, 192-0397, Japan
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, S-002 Frear Building, University Park, PA, 16802, USA.
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA.
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Chauvet A, Dashdorj N, Golbeck JH, Johnson TW, Savikhin S. Spectral resolution of the primary electron acceptor A0 in Photosystem I. J Phys Chem B 2012; 116:3380-6. [PMID: 22332796 DOI: 10.1021/jp211246a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reduced state of the primary electron acceptor of Photosystem I, A(0), was resolved spectroscopically in its lowest energy Q(y) region for the first time without the addition of chemical reducing agents and without extensive data manipulation. To carry this out, we used the menB mutant of Synechocystis sp. PCC 6803 in which phylloquinone is replaced by plastoquinone-9 in the A(1) sites of Photosystem I. The presence of plastoquinone-9 slows electron transfer from A(0) to A(1), leading to a long-lived A(0)(-) state. This allows its spectral signature to be readily detected in a time-resolved optical pump-probe experiment. The maximum bleaching (A(0)(-) - A(0)) was found to occur at 684 nm with a corresponding extinction coefficient of 43 mM(-1) cm(-1). The data show evidence for an electrochromic shift of an accessory chlorophyll pigment, suggesting that the latter Q(y) absorption band is centered around 682 nm.
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Affiliation(s)
- Adrien Chauvet
- Department of Physics, Purdue University, 525 Northwestern Ave, West Lafayette, Indiana 47907, USA
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Santabarbara S, Galuppini L, Casazza AP. Bidirectional electron transfer in the reaction centre of photosystem I. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2010; 52:735-749. [PMID: 20666929 DOI: 10.1111/j.1744-7909.2010.00977.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In the past decade light-induced electron transfer reactions in photosystem I have been the subject of intensive investigations that have led to the elucidation of some unique characteristics, the most striking of which is the existence of two parallel, functional, redox active cofactors chains. This process is generally referred to as bidirectional electron transfer. Here we present a review of the principal evidences that have led to the uncovering of bidirectionality in the reaction centre of photosystem I. A special focus is dedicated to the results obtained combining time-resolved spectroscopic techniques, either difference absorption or electron paramagnetic resonance, with molecular genetics, which allows, through modification of the binding of redox active cofactors with the reaction centre subunits, an effect on their physical-chemical properties.
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Femtosecond primary charge separation in Synechocystis sp. PCC 6803 photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1410-20. [PMID: 20219440 DOI: 10.1016/j.bbabio.2010.02.026] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2009] [Revised: 01/25/2010] [Accepted: 02/23/2010] [Indexed: 11/21/2022]
Abstract
The ultrafast (<100 fs) conversion of delocalized exciton into charge-separated state between the primary donor P700 (bleaching at 705 nm) and the primary acceptor A0 (bleaching at 690 nm) in photosystem I (PS I) complexes from Synechocystis sp. PCC 6803 was observed. The data were obtained by application of pump-probe technique with 20-fs low-energy pump pulses centered at 720 nm. The earliest absorbance changes (close to zero delay) with a bleaching at 690 nm are similar to the product of the absorption spectrum of PS I complex and the laser pulse spectrum, which represents the efficiency spectrum of the light absorption by PS I upon femtosecond excitation centered at 720 nm. During the first approximately 60 fs the energy transfer from the chlorophyll (Chl) species bleaching at 690 nm to the Chl bleaching at 705 nm occurs, resulting in almost equal bleaching of the two forms with the formation of delocalized exciton between 690-nm and 705-nm Chls. Within the next approximately 40 fs the formation of a new broad band centered at approximately 660 nm (attributed to the appearance of Chl anion radical) is observed. This band decays with time constant simultaneously with an electron transfer to A1 (phylloquinone). The subtraction of kinetic difference absorption spectra of the closed (state P700+A0A1) PS I reaction center (RC) from that of the open (state P700A0A1) RC reveals the pure spectrum of the P700+A0- ion-radical pair. The experimental data were analyzed using a simple kinetic scheme: An*-->k1[(PA0)*A1--><100 fs P+A0-A1]-->k2P+A0A1-, and a global fitting procedure based on the singular value decomposition analysis. The calculated kinetics of transitions between intermediate states and their spectra were similar to the kinetics recorded at 694 and 705 nm and the experimental spectra obtained by subtraction of the spectra of closed RCs from the spectra of open RCs. As a result, we found that the main events in RCs of PS I under our experimental conditions include very fast (<100 fs) charge separation with the formation of the P700+A0-A1 state in approximately one half of the RCs, the approximately 5-ps energy transfer from antenna Chl* to P700A0A1 in the remaining RCs, and approximately 25-ps formation of the secondary radical pair P700+A0A1-.
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Agalarov R, Byrdin M, Rappaport F, Shen G, Bryant DA, van der Est A, Golbeck JH. Removal of the PsaF Polypeptide Biases Electron Transfer in Favor of the PsaB Branch of Cofactors in Triton X-100 Photosystem I Complexes fromSynechococcussp. PCC 7002†. Photochem Photobiol 2008; 84:1371-80. [DOI: 10.1111/j.1751-1097.2008.00457.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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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).
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Affiliation(s)
- Stefano Santabarbara
- School of Biological Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
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Gibasiewicz K, Ramesh VM, Lin S, Redding K, Woodbury NW, Webber AN. Excitonic interactions in wild-type and mutant PSI reaction centers. Biophys J 2004; 85:2547-59. [PMID: 14507717 PMCID: PMC1303478 DOI: 10.1016/s0006-3495(03)74677-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Femtosecond excitation of the red edge of the chlorophyll a Q(Y) transition band in photosystem I (PSI), with light of wavelength > or = 700 nm, leads to wide transient (subpicosecond) absorbance changes: positive DeltaA between 635 and 665 nm, and four negative DeltaA bands at 667, 675, 683, and 695 nm. Here we compare the transient absorbance changes after excitation at 700, 705, and 710 nm at 20 K in several PSI preparations of Chlamydomonas reinhardtii where amino acid ligands of the primary donor, primary acceptor, or connecting chlorophylls have been mutated. Most of these mutations influence the spectrum of the absorbance changes. This supports the view that the chlorophylls of the electron transfer chain as well as the connecting chlorophylls are engaged in the observed absorbance changes. The wide absorption spectrum of the electron transfer chain revealed by the transient measurements may contribute to the high efficiency of energy trapping in photosystem 1. Exciton calculations, based on the recent PSI structure, allow an assignment of the DeltaA bands to particular chlorophylls: the bands at 675 and 695 nm to the dimers of primary acceptor and accessory chlorophyll and the band at 683 nm to the connecting chlorophylls. The subpicosecond transient absorption bands decay may reflect rapid charge separation in the PSI reaction center.
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Affiliation(s)
- Krzysztof Gibasiewicz
- Department of Plant Biology and Center for the Study of Early Events in Photosynthesis, Arizona State University, Tempe, Arizona 85287-1601 USA
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Setif P, Bottin H. Identification of electron-transfer reactions involving the acceptor A1 of photosystem I at room temperature. Biochemistry 2002. [DOI: 10.1021/bi00432a049] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Iwaki M, Itoh S. Electron transfer in spinach photosystem I reaction center containing benzo-, naphtho- and anthraquinones in place of phylloquinone. FEBS Lett 2002. [DOI: 10.1016/0014-5793(89)81708-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Itoh S, Iwaki M, Ikegami I. Modification of photosystem I reaction center by the extraction and exchange of chlorophylls and quinones. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1507:115-38. [PMID: 11687211 DOI: 10.1016/s0005-2728(01)00199-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The photosystem (PS) I photosynthetic reaction center was modified thorough the selective extraction and exchange of chlorophylls and quinones. Extraction of lyophilized photosystem I complex with diethyl ether depleted more than 90% chlorophyll (Chl) molecules bound to the complex, preserving the photochemical electron transfer activity from the primary electron donor P700 to the acceptor chlorophyll A(0). The treatment extracted all the carotenoids and the secondary acceptor phylloquinone (A(1)), and produced a PS I reaction center that contains nine molecules of Chls including P700 and A(0), and three Fe-S clusters (F(X), F(A) and F(B)). The ether-extracted PS I complex showed fast electron transfer from P700 to A(0) as it is, and to FeS clusters if phylloquinone or an appropriate artificial quinone was reconstituted as A(1). The ether-extracted PS I enabled accurate detection of the primary photoreactions with little disturbance from the absorbance changes of the bulk pigments. The quinone reconstitution created the new reactions between the artificial cofactors and the intrinsic components with altered energy gaps. We review the studies done in the ether-extracted PS I complex including chlorophyll forms of the core moiety of PS I, fluorescence of P700, reaction rate between A(0) and reconstituted A(1), and the fast electron transfer from P700 to A(0). Natural exchange of chlorophyll a to 710-740 nm absorbing chlorophyll d in PS I of the newly found cyanobacteria-like organism Acaryochloris marina was also reviewed. Based on the results of exchange studies in different systems, designs of photosynthetic reaction centers are discussed.
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Affiliation(s)
- S Itoh
- Laboratory of Photobioenergetics, Graduate School of Science, Nagoya University, Japan.
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Kumazaki S, Ikegami I, Furusawa H, Yasuda S, Yoshihara K. Observation of the Excited State of the Primary Electron Donor Chlorophyll (P700) and the Ultrafast Charge Separation in the Spinach Photosystem I Reaction Center. J Phys Chem B 2001. [DOI: 10.1021/jp003122m] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shigeichi Kumazaki
- School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa 923-1292, Japan, and Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, 199-0195, Japan
| | - Isamu Ikegami
- School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa 923-1292, Japan, and Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, 199-0195, Japan
| | - Hiroko Furusawa
- School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa 923-1292, Japan, and Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, 199-0195, Japan
| | - Shuichiro Yasuda
- School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa 923-1292, Japan, and Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, 199-0195, Japan
| | - Keitaro Yoshihara
- School of Materials Science, Japan Advanced Institute of Science and Technology, Tatsunokuchi, Ishikawa 923-1292, Japan, and Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, 199-0195, Japan
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Ikegami I, Itoh S, Iwaki M. Selective extraction of antenna chlorophylls, carotenoids and quinones from photosystem I reaction center. PLANT & CELL PHYSIOLOGY 2000; 41:1085-1095. [PMID: 11148266 DOI: 10.1093/pcp/pcd033] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
By the ether treatment of lyophilized PSI pigment-protein complexes, all the carotenoids and the secondary acceptor phylloquinone (A1), and more than 90% of the Chl were removed to yield the PSI complex with 9-11 molecules of Chl per reaction-center unit. The complexes retained the primary electron donor and acceptor (P700 and A0), in addition to three FeS clusters (F(X), F(A) and F(B)), and showed an activity of highly efficient electron transfer when phylloquinone was reconstituted. The methods for the preparation and the characterization of the ether-extracted PSI complexes are reviewed in this article. We also review the studies done with this PSI preparation on (1) the identification of the absorption and fluorescence spectra of P700, (2) the nano- and picosecond reaction of A0 and A1, (3) the energy-gap dependency of the reaction rate between A0 and the artificial quinones reconstituted at the A1 site, (4) the direct excitation of P700 followed by the ultra-fast electron transfer from P700 to A0, and (5) the de- and re-stabilization of the PSI structure by the removal and reconstitution, respectively, of antenna Chl in the presence of certain lipids.
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Affiliation(s)
- I Ikegami
- Faculty of Pharmaceutical Sciences, Teikyo University, Kanagawa, Japan.
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Byrdin M, Rimke I, Schlodder E, Stehlik D, Roelofs TA. Decay kinetics and quantum yields of fluorescence in photosystem I from Synechococcus elongatus with P700 in the reduced and oxidized state: are the kinetics of excited state decay trap-limited or transfer-limited? Biophys J 2000; 79:992-1007. [PMID: 10920029 PMCID: PMC1300995 DOI: 10.1016/s0006-3495(00)76353-3] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Transfer and trapping of excitation energy in photosystem I (PS I) trimers isolated from Synechococcus elongatus have been studied by an approach combining fluorescence induction experiments with picosecond time-resolved fluorescence measurements, both at room temperature (RT) and at low temperature (5 K). Special attention was paid to the influence of the oxidation state of the primary electron donor P700. A fluorescence induction effect has been observed, showing a approximately 12% increase in fluorescence quantum yield upon P700 oxidation at RT, whereas at temperatures below 160 K oxidation of P700 leads to a decrease in fluorescence quantum yield ( approximately 50% at 5 K). The fluorescence quantum yield for open PS I (with P700 reduced) at 5 K is increased by approximately 20-fold and that for closed PS I (with P700 oxidized) is increased by approximately 10-fold, as compared to RT. Picosecond fluorescence decay kinetics at RT reveal a difference in lifetime of the main decay component: 34 +/- 1 ps for open PS I and 37 +/- 1 ps for closed PS I. At 5 K the fluorescence yield is mainly associated with long-lived components (lifetimes of 401 ps and 1.5 ns in closed PS I and of 377 ps, 1.3 ns, and 4.1 ns in samples containing approximately 50% open and 50% closed PS I). The spectra associated with energy transfer and the steady-state emission spectra suggest that the excitation energy is not completely thermally equilibrated over the core-antenna-RC complex before being trapped. Structure-based modeling indicates that the so-called red antenna pigments (A708 and A720, i.e., those with absorption maxima at 708 nm and 720 nm, respectively) play a decisive role in the observed fluorescence kinetics. The A720 are preferentially located at the periphery of the PS I core-antenna-RC complex; the A708 must essentially connect the A720 to the reaction center. The excited-state decay kinetics turn out to be neither purely trap limited nor purely transfer (to the trap) limited, but seem to be rather balanced.
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Affiliation(s)
- M Byrdin
- Institute of Experimental Physics, Freie Universität Berlin, D-14195 Berlin, Germany
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Yoshihara K, Kumazaki S. Primary processes in plant photosynthesis: photosystem I reaction center. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2000. [DOI: 10.1016/s1389-5567(00)00003-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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18
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Brettel K, Vos MH. Spectroscopic resolution of the picosecond reduction kinetics of the secondary electron acceptor A1 in photosystem I. FEBS Lett 1999; 447:315-7. [PMID: 10214969 DOI: 10.1016/s0014-5793(99)00317-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Forward electron transfer in photosystem I from Synechocystis sp. PCC 6803 has been studied in the picosecond time range with transient absorption spectroscopy in the blue and near-UV spectral regions. From the direct measurement, at 380-390 nm, of the reduction kinetics of the phylloquinone secondary acceptor A1 and from the absence of spectral evolution between 100 ps and 2 ns, we conclude that electron transfer, from the chlorophyll a primary acceptor A0, to A1 occurs directly and completely with a time constant of about 30 ps.
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Affiliation(s)
- K Brettel
- Section de Bioénergétique and CNRS URA 2096, DBCM, CEA Saclay, Gif-sur-Yvette, France.
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20
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The P700 triplet state in an intact environment detected by ODMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(97)00068-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Electron transfer and arrangement of the redox cofactors in photosystem I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1997. [DOI: 10.1016/s0005-2728(96)00112-0] [Citation(s) in RCA: 380] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Jung YS, Vassiliev IR, Qiao F, Yang F, Bryant DA, Golbeck JH. Modified ligands to FA and FB in photosystem I. Proposed chemical rescue of a [4Fe-4S] cluster with an external thiolate in alanine, glycine, and serine mutants of PsaC. J Biol Chem 1996; 271:31135-44. [PMID: 8940111 DOI: 10.1074/jbc.271.49.31135] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The FB and FA electron acceptors in Photosystem I (PS I) are [4Fe-4S] clusters ligated by cysteines provided by PsaC. In a previous study (Mehari, T., Qiao, F., Scott, M. P., Nellis, D., Zhao, J., Bryant, D., and Golbeck, J. H. (1995) J. Biol. Chem. 270, 28108-28117), we showed that when cysteines 14 and 51 were replaced with serine or alanine, the free proteins contained a S = 1/2, [4Fe-4S] cluster at the unmodified site and a mixed population of S = 1/2, [3Fe-4S] and S = 3/2, [4Fe-4S] clusters at the modified site. We show here that these mutant PsaC proteins can be rebound to P700-FX cores, resulting in fully functional PS I complexes. The low temperature EPR spectra of the C14XPsaC.PS I complexes (where X = S, A, or G) show the photoreduction of a wild-type FA cluster and a modified FB' cluster, the latter with g values of 2.115, 1.899, and 1.852 and linewidths of 110, 70, and 85 MHz. Since neither alanine nor glycine contains a suitable side group, an external thiolate provided by beta-mercaptoethanol has likely been recruited to supply the requisite ligand to the [4Fe-4S] cluster. The EPR spectrum of the C51SPsaC.PS I complex differs from that of the C51APsaC.PS I or C51GPsaC.PS I complexes by the presence of an additional set of resonances, which may be derived from the serine oxygen-ligated cluster. In all other mutant PS I complexes, a wild-type spin-coupled interaction spectrum appears when FA and FB are simultaneously reduced. Single turnover flash studies indicate approximately 50% efficient electron transfer to FA/FB in the C14SPsaC.PS I, C51SPsaC.PS I, C14GPsaC.PS I, and C51GPsaC.PS I mutants and less than 40% in the C14APsaC.PS I and C51APsaC.PS I mutants, compared with approximately 76% in the PS I core reconstructed with wild-type PsaC. These data are consistent with the measurements of the rates of cytochrome c6-NADP+ reductase activity, indicating lower rates in the alanine mutants. It is proposed that the chemical rescue of a [4Fe-4S] cluster with a recruited external thiolate at the modified site allows the mutant PsaC proteins to rebind to PS I and to function in forward electron transfer.
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Affiliation(s)
- Y S Jung
- Department of Biochemistry, and Center for Biological Chemistry, George W. Beadle Center, University of Nebraska, Lincoln, Nebraska 68588-0664, USA.
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23
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White NTH, Beddard GS, Thorne JRG, Feehan TM, Keyes TE, Heathcote P. Primary Charge Separation and Energy Transfer in the Photosystem I Reaction Center of Higher Plants. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9604709] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nigel T. H. White
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Godfrey S. Beddard
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Jonathan R. G. Thorne
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Tim M. Feehan
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Tia E. Keyes
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
| | - Peter Heathcote
- Department of Chemistry, University of Manchester, Manchester M13 9PL, U.K., and School of Biological Sciences, Queen Mary and Westfield College, Mile End Road, London E1 4NS, U.K
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Vrieze J, Gast P, Hoff AJ. Structure of the Reaction Center of Photosystem I of Plants. An Investigation with Linear-Dichroic Absorbance-Detected Magnetic Resonance. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9524789] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. Vrieze
- Department of Biophysics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - P. Gast
- Department of Biophysics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - A. J. Hoff
- Department of Biophysics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
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25
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Krawczyk S, Ikegami I. Stark signals associated with the reduced and oxidized states of P700 in P700-enriched particles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90199-p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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26
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Sieckmann I, Brettel K, Bock C, van der Est A, Stehlik D. Transient electron paramagnetic resonance of the triplet state of P700 in photosystem I: evidence for triplet delocalization at room temperature. Biochemistry 1993; 32:4842-7. [PMID: 8387818 DOI: 10.1021/bi00069a020] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Spin-polarized EPR spectra of the triplet state of P700, the primary electron donor in photosystem I (PS I), have been measured for the first time at room temperature. The measurements were performed on intact PS I from Synechococcus sp. after prereduction of all iron-sulfur centers and on vitamin K1 depleted PS I from Synechocystis 6803. The two preparations give similar spectra with a polarization pattern which indicates that the triplet state is formed via recombination of a radical pair. The axial and nonaxial zero-field splitting (zfs) parameters are found to be magnitude of D = (284 +/- 15) x 10(-4) cm-1 and magnitude of E = (22 +/- 3) x 10(-4) cm-1, respectively. The E-value is 42% smaller than in monomeric chlorophyll a, while the D-value is nearly the same. Measurements of the Synechocystis 6803 sample at 4.5 K yielded zfs parameters which are identical with those of the chlorophyll monomer, in agreement with previous results. In order to explain this behavior, it is proposed that the triplet excitation is delocalized over the two halves of a chlorophyll dimer at room temperature but appears localized on one half at low temperature. The observed zfs parameters are obtained if (1) the magnetic z-axes of the two chlorophylls are collinear, (2) the magnetic y-axes (and x-axes) of the two chlorophylls make an angle of approximately 55 degrees with each other, and (3) the admixture of charge-transfer states to 3P700 is negligible.(ABSTRACT TRUNCATED AT 250 WORDS)
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27
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Kleinherenbrink F, Ikegami I, Hiraishi A, Otte S, Amesz J. Electron transfer in menaquinone-depleted membranes of Heliobacterium chlorum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1993. [DOI: 10.1016/0005-2728(93)90085-t] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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28
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Warren PV, Golbeck JH, Warden JT. Charge recombination between P700+ and A1- occurs directly to the ground state of P700 in a photosystem I core devoid of FX, FB, and FA. Biochemistry 1993; 32:849-57. [PMID: 8422389 DOI: 10.1021/bi00054a016] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The charge recombination between P700+ and electron acceptor A1- was studied by flash kinetic spectroscopy in a photosystem I core devoid of iron-sulfur centers FX, FB, and FA. We showed previously that the majority of the flash-induced absorption change at 820 nm decayed with a 10-microseconds half-time, which we assigned to the disappearance of the P700 triplet formed from the backreaction of P700+ with A1- [Warren, P.V., Parrett, K.G., Warden, J.T., & Golbeck, J.H. (1990) Biochemistry 29, 6545-6550]. We have reinvestigated this assignment in the near-UV, blue, and near-IR wavelength regions. The difference spectrum from 380 to 480 nm and from 720 to 910 nm shows that the P700+ A1- charge recombination is dominated by the P700 cation rather than the P700 triplet. Accordingly, the 10-microseconds kinetic transient represents the direct backreaction of P700+ with A1-, which repopulates the ground state of P700. This is unlike a P700-FA/FB complex where, in the presence of reduced FX-, FB-, and FA-, the P700+ A1- charge recombination populates the P700 triplet state [Sétif, P., & Bottin, H. (1989) Biochemistry 28, 2689-2697]. The A1 acceptor is highly susceptible to disruption by detergents in the absence of iron-sulfur center FX. The addition of 0.1% Triton X-100 to the P700-A1 core leads to a approximately 2.5-fold increase in the magnitude of the flash-induced absorption change at 780 nm; thereafter, 85% of the absorption change decays with a 25-ns half-time and 15% decays with a 3-microseconds half-time.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- P V Warren
- Department of Biochemistry, University of Nebraska, Lincoln 68583-0718
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29
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Ikegami I, Katoh S. Antenna chlorophyll a has a structural role in stabilizing the functional conformation of P-700-chlorophyll-protein complexes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80212-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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30
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Breton J, Ikegami I. Orientation of Photosystem-I pigments: low temperature linear dichroism spectroscopy of a highly-enriched P700 particle isolated from spinach. PHOTOSYNTHESIS RESEARCH 1989; 21:27-36. [PMID: 24424490 DOI: 10.1007/bf00047172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/1988] [Accepted: 09/12/1988] [Indexed: 06/03/2023]
Abstract
The linear dichroism of Photosystem I particles containing 10 chlorophylls per P700 has been investigated at 10 K. The particles were oriented by uniaxial squeezing of polyacrylamide gels. The oxidation state of P700 was altered either by incubation of the gels with redox mediators or by low temperature illumination. The QY transitions of the primary electron donor P700, of the remaining unoxidized chlorophyll in P700(+) and of a chlorophyll molecule absorbing at 686 nm, which presumably corresponds to the primary electron acceptor A0, are all preferentially oriented perpendicular to the gel squeezing direction. The QY transition of the chlorophyll forms absorbing at 670 and 675 nm appear tilted at 40 ± 5° from this orientation axis. This orientation of the various chlorophylls is compared to that previously reported for more native Photosystem I particles.
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Affiliation(s)
- J Breton
- Service de Biophysique, Département de Biologie, CEN Saclay, 91191, Gif-sur-Yvette Cedex, France
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