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Magyar M, Sipka G, Han W, Li X, Han G, Shen JR, Lambrev PH, Garab G. Characterization of the Rate-Limiting Steps in the Dark-To-Light Transitions of Closed Photosystem II: Temperature Dependence and Invariance of Waiting Times during Multiple Light Reactions. Int J Mol Sci 2022; 24:ijms24010094. [PMID: 36613535 PMCID: PMC9820552 DOI: 10.3390/ijms24010094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/09/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022] Open
Abstract
Rate-limiting steps in the dark-to-light transition of Photosystem II (PSII) were discovered by measuring the variable chlorophyll-a fluorescence transients elicited by single-turnover saturating flashes (STSFs). It was shown that in diuron-treated samples: (i) the first STSF, despite fully reducing the QA quinone acceptor molecule, generated only an F1(<Fm) fluorescence level; (ii) to produce the maximum (Fm) level, additional excitations were required, which, however, (iii) were effective only with sufficiently long Δτ waiting times between consecutive STSFs. Detailed studies revealed the gradual formation of the light-adapted charge-separated state, PSIIL. The data presented here substantiate this assignment: (i) the Δτ1/2 half-increment rise (or half-waiting) times of the diuron-treated isolated PSII core complexes (CCs) of Thermostichus vulcanus and spinach thylakoid membranes displayed similar temperature dependences between 5 and −80 °C, with substantially increased values at low temperatures; (ii) the Δτ1/2 values in PSII CC were essentially invariant on the Fk−to-Fk+1 (k = 1−4) increments both at 5 and at −80 °C, indicating the involvement of the same physical mechanism during the light-adaptation process of PSIIL. These data are in harmony with the earlier proposed role of dielectric relaxation processes in the formation of the light-adapted charge-separated state and in the variable chlorophyll-a fluorescence of PSII.
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Affiliation(s)
- Melinda Magyar
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
| | - Gábor Sipka
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
| | - Wenhui Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xingyue Li
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- Research Institute for Interdisciplinary Science, and Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Petar H. Lambrev
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
| | - Győző Garab
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
- Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
- Correspondence:
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Zabelin AA, Khristin AM, Shkuropatova VA, Khatypov RA, Shkuropatov AY. Primary electron transfer in Rhodobacter sphaeroides R-26 reaction centers under dehydration conditions. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148238. [PMID: 32533935 DOI: 10.1016/j.bbabio.2020.148238] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/28/2020] [Accepted: 06/03/2020] [Indexed: 11/26/2022]
Abstract
The photoinduced charge separation in QB-depleted reaction centers (RCs) from Rhodobacter sphaeroides R-26 in solid air-dried and vacuum-dried (~10-2 Torr) films, obtained in the presence of detergent n-dodecyl-β-D-maltoside (DM), is characterized using ultrafast transient absorption spectroscopy. It is shown that drying of RC-DM complexes is accompanied by reversible blue shifts of the ground-state absorption bands of the pigment ensemble, which suggest that no dehydration-induced structural destruction of RCs occurs in both types of films. In air-dried films, electron transfer from the excited primary electron donor P⁎ to the photoactive bacteriopheophytin HA proceeds in 4.7 ps to form the P+HA- state with essentially 100% yield. P+HA- decays in 260 ps both by electron transfer to the primary quinone QA to give the state P+QA- (87% yield) and by charge recombination to the ground state (13% yield). In vacuum-dried films, P⁎ decay is characterized by two kinetic components with time constants of 4.1 and 46 ps in a proportion of ~55%/45%, and P+HA- decays about 2-fold slower (462 ps) than in air-dried films. Deactivation of both P⁎ and P+HA- to the ground state effectively competes with the corresponding forward electron-transfer reactions in vacuum-dried RCs, reducing the yield of P+QA- to 68%. The results are compared with the data obtained for fully hydrated RCs in solution and are discussed in terms of the presence in the RC complexes of different water molecules, the removal/displacement of which affects spectral properties of pigment cofactors and rates and yields of the electron-transfer reactions.
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Affiliation(s)
- Alexey A Zabelin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Anton M Khristin
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Valentina A Shkuropatova
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Ravil A Khatypov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation
| | - Anatoly Ya Shkuropatov
- Institute of Basic Biological Problems of the Russian Academy of Sciences, Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", 142290 Pushchino, Moscow Region, Russian Federation.
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3
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Quinone transport in the closed light-harvesting 1 reaction center complex from the thermophilic purple bacterium Thermochromatium tepidum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148307. [PMID: 32926863 DOI: 10.1016/j.bbabio.2020.148307] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 09/03/2020] [Accepted: 09/09/2020] [Indexed: 11/22/2022]
Abstract
Redox-active quinones play essential roles in efficient light energy conversion in type-II reaction centers of purple phototrophic bacteria. In the light-harvesting 1 reaction center (LH1-RC) complex of purple bacteria, QB is converted to QBH2 upon light-induced reduction and QBH2 is transported to the quinone pool in the membrane through the LH1 ring. In the purple bacterium Rhodobacter sphaeroides, the C-shaped LH1 ring contains a gap for quinone transport. In contrast, the thermophilic purple bacterium Thermochromatium (Tch.) tepidum has a closed O-shaped LH1 ring that lacks a gap, and hence the mechanism of photosynthetic quinone transport is unclear. Here we detected light-induced Fourier transform infrared (FTIR) signals responsible for changes of QB and its binding site that accompany photosynthetic quinone reduction in Tch. tepidum and characterized QB and QBH2 marker bands based on their 15N- and 13C-isotopic shifts. Quinone exchanges were monitored using reconstituted photosynthetic membranes comprised of solubilized photosynthetic proteins, membrane lipids, and exogenous ubiquinone (UQ) molecules. In combination with 13C-labeling of the LH1-RC and replacement of native UQ8 by ubiquinones of different tail lengths, we demonstrated that quinone exchanges occur efficiently within the hydrophobic environment of the lipid membrane and depend on the side chain length of UQ. These results strongly indicate that unlike the process in Rba. sphaeroides, quinone transport in Tch. tepidum occurs through the size-restricted hydrophobic channels in the closed LH1 ring and are consistent with structural studies that have revealed narrow hydrophobic channels in the Tch. tepidum LH1 transmembrane region.
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4
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Knox PP, Lukashev EP, Gorokhov VV, Seifullina NK, Paschenko VZ. Relaxation processes accompanying electron stabilization in the quinone acceptor part of Rb. sphaeroides reaction centers. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2018; 189:145-151. [PMID: 30347352 DOI: 10.1016/j.jphotobiol.2018.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/03/2018] [Accepted: 10/04/2018] [Indexed: 06/08/2023]
Abstract
The temperature dependence of the dark recombination rate in photooxidized bacteriochlorophyll (P) and photoreduced quinone acceptors (ubiquinones) QA and QB of photosynthetic reaction centers of purple bacteria Rhodobacter sphaeroides (Rb. sphaeroides) was studied. Photoinduced changes in the absorption were detected in the Qx absorption band of photooxidized bacteriochlorophyll at 600 nm and in the bands corresponding to the redox changes of ubiquinones at 335 and 420-450 nm. Kinetic analysis was used to evaluate the activation energy and the characteristic time of the transient process of relaxation accompanying electron stabilization at the final quinone acceptor. A comparative study of the kinetics of oxidation-reduction reactions of photoactive bacteriochlorophyll RC purple bacteria and quinone acceptors in their individual absorption bands is an informative approach to studying the mechanisms of this stabilization. The analysis of the revealed kinetic differences makes it possible to estimate the activation energy and the characteristic times of the transition relaxation processes associated with the stabilization of the electron in the quinone acceptor part of RC. Purple bacterial reaction centers have fundamental similarities with PSII reaction centers. Such a similarity represents evolutional closeness between the two types of RC. So it is possible that the photoinduced charge separation in PSII RC, as well as in purple bacteria RC, is also accompanied by definite conformational changes. The possible role of hydrogen bonds of surrounding protein in the relaxation processes accompanying the electron transfer to quinone acceptors is discussed.
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Affiliation(s)
- P P Knox
- Department of Biophysics, Biological Faculty of the M.V., Lomonosov Moscow State University, 119991 Moscow, Russia
| | - E P Lukashev
- Department of Biophysics, Biological Faculty of the M.V., Lomonosov Moscow State University, 119991 Moscow, Russia
| | - V V Gorokhov
- Department of Biophysics, Biological Faculty of the M.V., Lomonosov Moscow State University, 119991 Moscow, Russia
| | - N Kh Seifullina
- Department of Biophysics, Biological Faculty of the M.V., Lomonosov Moscow State University, 119991 Moscow, Russia
| | - V Z Paschenko
- Department of Biophysics, Biological Faculty of the M.V., Lomonosov Moscow State University, 119991 Moscow, Russia.
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Banerjee G, Ghosh I, Kim CJ, Debus RJ, Brudvig GW. Substitution of the D1-Asn 87 site in photosystem II of cyanobacteria mimics the chloride-binding characteristics of spinach photosystem II. J Biol Chem 2017; 293:2487-2497. [PMID: 29263091 DOI: 10.1074/jbc.m117.813170] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 12/19/2017] [Indexed: 11/06/2022] Open
Abstract
Photoinduced water oxidation at the O2-evolving complex (OEC) of photosystem II (PSII) is a complex process involving a tetramanganese-calcium cluster that is surrounded by a hydrogen-bonded network of water molecules, chloride ions, and amino acid residues. Although the structure of the OEC has remained conserved over eons of evolution, significant differences in the chloride-binding characteristics exist between cyanobacteria and higher plants. An analysis of amino acid residues in and around the OEC has identified residue 87 in the D1 subunit as the only significant difference between PSII in cyanobacteria and higher plants. We substituted the D1-Asn87 residue in the cyanobacterium Synechocystis sp. PCC 6803 (wildtype) with alanine, present in higher plants, or with aspartic acid. We studied PSII core complexes purified from D1-N87A and D1-N87D variant strains to probe the function of the D1-Asn87 residue in the water-oxidation mechanism. EPR spectra of the S2 state and flash-induced FTIR spectra of both D1-N87A and D1-N87D PSII core complexes exhibited characteristics similar to those of wildtype Synechocystis PSII core complexes. However, flash-induced O2-evolution studies revealed a decreased cycling efficiency of the D1-N87D variant, whereas the cycling efficiency of the D1-N87A PSII variant was similar to that of wildtype PSII. Steady-state O2-evolution activity assays revealed that substitution of the D1 residue at position 87 with alanine perturbs the chloride-binding site in the proton-exit channel. These findings provide new insight into the role of the D1-Asn87 site in the water-oxidation mechanism and explain the difference in the chloride-binding properties of cyanobacterial and higher-plant PSII.
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Affiliation(s)
- Gourab Banerjee
- From the Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107 and
| | - Ipsita Ghosh
- From the Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107 and
| | - Christopher J Kim
- the Department of Biochemistry, University of California, Riverside, California 92521
| | - Richard J Debus
- the Department of Biochemistry, University of California, Riverside, California 92521
| | - Gary W Brudvig
- From the Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107 and
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6
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Kim CJ, Debus RJ. Evidence from FTIR Difference Spectroscopy That a Substrate H2O Molecule for O2 Formation in Photosystem II Is Provided by the Ca Ion of the Catalytic Mn4CaO5 Cluster. Biochemistry 2017; 56:2558-2570. [DOI: 10.1021/acs.biochem.6b01278] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Christopher J. Kim
- Department of Biochemistry, University of California, Riverside, California 92521, United States
| | - Richard J. Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
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7
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Mezzetti A, Leibl W. Time-resolved infrared spectroscopy in the study of photosynthetic systems. PHOTOSYNTHESIS RESEARCH 2017; 131:121-144. [PMID: 27678250 DOI: 10.1007/s11120-016-0305-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 09/05/2016] [Indexed: 06/06/2023]
Abstract
Time-resolved (TR) infrared (IR) spectroscopy in the nanosecond to second timescale has been extensively used, in the last 30 years, in the study of photosynthetic systems. Interesting results have also been obtained at lower time resolution (minutes or even hours). In this review, we first describe the used techniques-dispersive IR, laser diode IR, rapid-scan Fourier transform (FT)IR, step-scan FTIR-underlying the advantages and disadvantages of each of them. Then, the main TR-IR results obtained so far in the investigation of photosynthetic reactions (in reaction centers, in light-harvesting systems, but also in entire membranes or even in living organisms) are presented. Finally, after the general conclusions, the perspectives in the field of TR-IR applied to photosynthesis are described.
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Affiliation(s)
- Alberto Mezzetti
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 7197, Laboratoire de Réactivité de Surfaces, 4 Pl. Jussieu, 75005, Paris, France.
- Institut de Biologie Intégrative de la Cellule (I2BC), IBITECS, CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette, France.
| | - Winfried Leibl
- Institut de Biologie Intégrative de la Cellule (I2BC), IBITECS, CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette, France
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8
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Bhaduri S, Stadnytskyi V, Zakharov SD, Hasan SS, Bujnowicz Ł, Sarewicz M, Savikhin S, Osyczka A, Cramer WA. Pathways of Transmembrane Electron Transfer in Cytochrome bc Complexes: Dielectric Heterogeneity and Interheme Coulombic Interactions. J Phys Chem B 2017; 121:975-983. [DOI: 10.1021/acs.jpcb.6b11709] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
| | | | | | | | - Ł. Bujnowicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and
Biotechnology, Jagiellonian University, Kraków 31-007, Poland
| | - M. Sarewicz
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and
Biotechnology, Jagiellonian University, Kraków 31-007, Poland
| | | | - A. Osyczka
- Department
of Molecular Biophysics, Faculty of Biochemistry, Biophysics, and
Biotechnology, Jagiellonian University, Kraków 31-007, Poland
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9
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Malferrari M, Turina P, Francia F, Mezzetti A, Leibl W, Venturoli G. Dehydration affects the electronic structure of the primary electron donor in bacterial photosynthetic reaction centers: evidence from visible-NIR and light-induced difference FTIR spectroscopy. Photochem Photobiol Sci 2015; 14:238-51. [PMID: 25188921 DOI: 10.1039/c4pp00245h] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The photosynthetic reaction center (RC) is a membrane pigment-protein complex that catalyzes the initial charge separation reactions of photosynthesis. Following photoexcitation, the RC undergoes conformational relaxations which stabilize the charge-separated state. Dehydration of the complex inhibits its conformational dynamics, providing a useful tool to gain insights into the relaxational processes. We analyzed the effects of dehydration on the electronic structure of the primary electron donor P, as probed by visible-NIR and light-induced FTIR difference spectroscopy, in RC films equilibrated at different relative humidities r. Previous FTIR and ENDOR spectroscopic studies revealed that P, an excitonically coupled dimer of bacteriochlorophylls, can be switched between two conformations, P866 and P850, which differ in the extent of delocalization of the unpaired electron between the two bacteriochlorophyll moieties (PL and PM) of the photo-oxidized radical P(+). We found that dehydration (at r = 11%) shifts the optical Qy band of P from 866 to 850-845 nm, a large part of the effect occurring already at r = 76%. Such a dehydration weakens light-induced difference FTIR marker bands, which probe the delocalization of charge distribution within the P(+) dimer (the electronic band of P(+) at 2700 cm(-1), and the associated phase-phonon vibrational modes at around 1300, 1480, and 1550 cm(-1)). From the analysis of the P(+) keto C[double bond, length as m-dash]O bands at 1703 and 1713-15 cm(-1), we inferred that dehydration induces a stronger localization of the unpaired electron on PL(+). The observed charge redistribution is discussed in relation to the dielectric relaxation of the photoexcited RC on a long (10(2) s) time scale.
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Affiliation(s)
- Marco Malferrari
- Dipartimento di Farmacia e Biotecnologie, FaBiT, Università di Bologna, Bologna, Italy.
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10
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Lórenz-Fonfría VA, Muders V, Schlesinger R, Heberle J. Changes in the hydrogen-bonding strength of internal water molecules and cysteine residues in the conductive state of channelrhodopsin-1. J Chem Phys 2015; 141:22D507. [PMID: 25494778 DOI: 10.1063/1.4895796] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Water plays an essential role in the structure and function of proteins, particularly in the less understood class of membrane proteins. As the first of its kind, channelrhodopsin is a light-gated cation channel and paved the way for the new and vibrant field of optogenetics, where nerve cells are activated by light. Still, the molecular mechanism of channelrhodopsin is not understood. Here, we applied time-resolved FT-IR difference spectroscopy to channelrhodopsin-1 from Chlamydomonas augustae. It is shown that the (conductive) P2(380) intermediate decays with τ ≈ 40 ms and 200 ms after pulsed excitation. The vibrational changes between the closed and the conductive states were analyzed in the X-H stretching region (X = O, S, N), comprising vibrational changes of water molecules, sulfhydryl groups of cysteine side chains and changes of the amide A of the protein backbone. The O-H stretching vibrations of "dangling" water molecules were detected in two different states of the protein using H2 (18)O exchange. Uncoupling experiments with a 1:1 mixture of H2O:D2O provided the natural uncoupled frequencies of the four O-H (and O-D) stretches of these water molecules, each with a very weakly hydrogen-bonded O-H group (3639 and 3628 cm(-1)) and with the other O-H group medium (3440 cm(-1)) to moderately strongly (3300 cm(-1)) hydrogen-bonded. Changes in amide A and thiol vibrations report on global and local changes, respectively, associated with the formation of the conductive state. Future studies will aim at assigning the respective cysteine group(s) and at localizing the "dangling" water molecules within the protein, providing a better understanding of their functional relevance in CaChR1.
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Affiliation(s)
| | - Vera Muders
- Genetic Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | | | - Joachim Heberle
- Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
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11
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Malferrari M, Francia F, Venturoli G. Retardation of Protein Dynamics by Trehalose in Dehydrated Systems of Photosynthetic Reaction Centers. Insights from Electron Transfer and Thermal Denaturation Kinetics. J Phys Chem B 2015; 119:13600-18. [DOI: 10.1021/acs.jpcb.5b02986] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marco Malferrari
- Laboratorio di Biochimica e Biofisica Molecolare, Dipartimento di
Farmacia e Biotecnologie, FaBiT, Università di Bologna, 40126 Bologna, Italy
| | - Francesco Francia
- Laboratorio di Biochimica e Biofisica Molecolare, Dipartimento di
Farmacia e Biotecnologie, FaBiT, Università di Bologna, 40126 Bologna, Italy
| | - Giovanni Venturoli
- Laboratorio di Biochimica e Biofisica Molecolare, Dipartimento di
Farmacia e Biotecnologie, FaBiT, Università di Bologna, 40126 Bologna, Italy
- Consorzio Nazionale
Interuniversitario per le Scienze Fisiche della Materia (CNISM), c/o
Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy
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12
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Nakamura S, Nagao R, Takahashi R, Noguchi T. Fourier transform infrared detection of a polarizable proton trapped between photooxidized tyrosine YZ and a coupled histidine in photosystem II: relevance to the proton transfer mechanism of water oxidation. Biochemistry 2014; 53:3131-44. [PMID: 24786306 DOI: 10.1021/bi500237y] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The redox-active tyrosine YZ (D1-Tyr161) in photosystem II (PSII) functions as an immediate electron acceptor of the Mn4Ca cluster, which is the catalytic center of photosynthetic water oxidation. YZ is also located in the hydrogen bond network that connects the Mn4Ca cluster to the lumen and hence is possibly related to the proton transfer process during water oxidation. To understand the role of YZ in the water oxidation mechanism, we have studied the hydrogen bonding interactions of YZ and its photooxidized neutral radical YZ(•) together with the interaction of the coupled His residue, D1-His190, using light-induced Fourier transform infrared (FTIR) difference spectroscopy. The YZ(•)-minus-YZ FTIR difference spectrum of Mn-depleted PSII core complexes exhibited a broad positive feature around 2800 cm(-1), which was absent in the corresponding spectrum of another redox-active tyrosine YD (D2-Tyr160). Analyses by (15)N and H/D substitutions, examination of the pH dependence, and density functional theory and quantum mechanics/molecular mechanics (QM/MM) calculations showed that this band arises from the N-H stretching vibration of the protonated cation of D1-His190 forming a charge-assisted strong hydrogen bond with YZ(•). This result provides strong evidence that the proton released from YZ upon its oxidation is trapped in D1-His190 and a positive charge remains on this His. The broad feature of the ~2800 cm(-1) band reflects a large proton polarizability in the hydrogen bond between YZ(•) and HisH(+). QM/MM calculations further showed that upon YZ oxidation the hydrogen bond network is rearranged and one water molecule moves toward D1-His190. From these data, a novel proton transfer mechanism via YZ(•)-HisH(+) is proposed, in which hopping of the polarizable proton of HisH(+) to this water triggers the transfer of the proton from substrate water to the luminal side. This proton transfer mechanism could be functional in the S2 → S3 transition, which requires proton release before electron transfer because of an excess positive charge on the Mn4Ca cluster.
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Affiliation(s)
- Shin Nakamura
- Division of Material Science, Graduate School of Science, Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
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Debus RJ. Evidence from FTIR Difference Spectroscopy That D1-Asp61 Influences the Water Reactions of the Oxygen-Evolving Mn4CaO5 Cluster of Photosystem II. Biochemistry 2014; 53:2941-55. [DOI: 10.1021/bi500309f] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Richard J. Debus
- Department of Biochemistry, University of California, Riverside, California 92521, United States
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14
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Möbius K, Lubitz W, Savitsky A. High-field EPR on membrane proteins - crossing the gap to NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2013; 75:1-49. [PMID: 24160760 DOI: 10.1016/j.pnmrs.2013.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/15/2013] [Accepted: 07/15/2013] [Indexed: 06/02/2023]
Abstract
In this review on advanced EPR spectroscopy, which addresses both the EPR and NMR communities, considerable emphasis is put on delineating the complementarity of NMR and EPR concerning the measurement of molecular interactions in large biomolecules. From these interactions, detailed information can be revealed on structure and dynamics of macromolecules embedded in solution- or solid-state environments. New developments in pulsed microwave and sweepable cryomagnet technology as well as ultrafast electronics for signal data handling and processing have pushed to new horizons the limits of EPR spectroscopy and its multifrequency extensions concerning the sensitivity of detection, the selectivity with respect to interactions, and the resolution in frequency and time domains. One of the most important advances has been the extension of EPR to high magnetic fields and microwave frequencies, very much in analogy to what happens in NMR. This is exemplified by referring to ongoing efforts for signal enhancement in both NMR and EPR double-resonance techniques by exploiting dynamic nuclear or electron spin polarization via unpaired electron spins and their electron-nuclear or electron-electron interactions. Signal and resolution enhancements are particularly spectacular for double-resonance techniques such as ENDOR and PELDOR at high magnetic fields. They provide greatly improved orientational selection for disordered samples that approaches single-crystal resolution at canonical g-tensor orientations - even for molecules with small g-anisotropies. Exchange of experience between the EPR and NMR communities allows for handling polarization and resolution improvement strategies in an optimal manner. Consequently, a dramatic improvement of EPR detection sensitivity could be achieved, even for short-lived paramagnetic reaction intermediates. Unique structural and dynamic information is thus revealed that can hardly be obtained by any other analytical techniques. Micromolar quantities of sample molecules have become sufficient to characterize stable and transient reaction intermediates of complex molecular systems - offering highly interesting applications for chemists, biochemists and molecular biologists. In three case studies, representative examples of advanced EPR spectroscopy are reviewed: (I) High-field PELDOR and ENDOR structure determination of cation-anion radical pairs in reaction centers from photosynthetic purple bacteria and cyanobacteria (Photosystem I); (II) High-field ENDOR and ELDOR-detected NMR spectroscopy on the oxygen-evolving complex of Photosystem II; and (III) High-field electron dipolar spectroscopy on nitroxide spin-labelled bacteriorhodopsin for structure-function studies. An extended conclusion with an outlook to further developments and applications is also presented.
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Affiliation(s)
- Klaus Möbius
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany; Department of Physics, Free University Berlin, Arnimallee 14, D-14195 Berlin, Germany.
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15
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Chernev P, Zaharieva I, Dau H, Haumann M. Coordination Changes of Carboxyl Ligands at the QAFeQB Triad in Photosynthetic Reaction Centers Studied by Density-Functional Theory. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/978-3-642-32034-7_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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16
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Effects of dehydration on light-induced conformational changes in bacterial photosynthetic reaction centers probed by optical and differential FTIR spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:328-39. [PMID: 23103449 DOI: 10.1016/j.bbabio.2012.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 10/16/2012] [Accepted: 10/19/2012] [Indexed: 11/22/2022]
Abstract
Following light-induced electron transfer between the primary donor (P) and quinone acceptor (Q(A)) the bacterial photosynthetic reaction center (RC) undergoes conformational relaxations which stabilize the primary charge separated state P(+)Q(A)(-). Dehydration of RCs from Rhodobacter sphaeroides hinders these conformational dynamics, leading to acceleration of P(+)Q(A)(-) recombination kinetics [Malferrari et al., J. Phys. Chem. B 115 (2011) 14732-14750]. To clarify the structural basis of the conformational relaxations and the involvement of bound water molecules, we analyzed light-induced P(+)Q(A)(-)/PQ(A) difference FTIR spectra of RC films at two hydration levels (relative humidity r=76% and r=11%). Dehydration reduced the amplitude of bands in the 3700-3550cm(-1) region, attributed to water molecules hydrogen bonded to the RC, previously proposed to stabilize the charge separation by dielectric screening [Iwata et al., Biochemistry 48 (2009) 1220-1229]. Other features of the FTIR difference spectrum were affected by partial depletion of the hydration shell (r=11%), including contributions from modes of P (9-keto groups), and from NH or OH stretching modes of amino acidic residues, absorbing in the 3550-3150cm(-1) range, a region so far not examined in detail for bacterial RCs. To probe in parallel the effects of dehydration on the RC conformational relaxations, we analyzed by optical absorption spectroscopy the kinetics of P(+)Q(A)(-) recombination following the same photoexcitation used in FTIR measurements (20s continuous illumination). The results suggest a correlation between the observed FTIR spectral changes and the conformational rearrangements which, in the hydrated system, strongly stabilize the P(+)Q(A)(-) charge separated state over the second time scale.
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Abstract
In this paper, we describe a new method to obtain D2O/H2O exchange in photosynthetic reaction centres fromRhodobacter sphaeroides. The method is characterized by: (i) a very high efficiency of the isotopic replacement; (ii) an extremely low amount of D2O needed; (iii) the short time required for dehydration and D2O rehydration; (iv) the possibility of controlling concomitantly the hydration state of the sample. The proposed method can be applied to other proteins.
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Malferrari M, Francia F, Venturoli G. Coupling between Electron Transfer and Protein–Solvent Dynamics: FTIR and Laser-Flash Spectroscopy Studies in Photosynthetic Reaction Center Films at Different Hydration Levels. J Phys Chem B 2011; 115:14732-50. [DOI: 10.1021/jp2057767] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Marco Malferrari
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy
| | - Francesco Francia
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy
| | - Giovanni Venturoli
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy
- Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, c/o Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy
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Hou LH, Wu CM, Huang HH, Chu HA. Effects of ammonia on the structure of the oxygen-evolving complex in photosystem II as revealed by light-induced FTIR difference spectroscopy. Biochemistry 2011; 50:9248-54. [PMID: 21942297 DOI: 10.1021/bi200943q] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
NH(3) is a structural analogue of substrate H(2)O and an inhibitor to the water oxidation reaction in photosystem II. To test whether or not NH(3) is able to replace substrate water molecules on the oxygen-evolving complex in photosystem II, we studied the effects of NH(3) on the high-frequency region (3750-3550 cm(-1)) of the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectra (pH 7.5 at 250 K), where OH stretch modes of weak hydrogen-bonded active water molecules occur. Our results showed that NH(3) did not replace the active water molecule on the oxygen-evolving complex that gave rise to the S(1) mode at ~3586 cm(-1) and the S(2) mode at ~3613 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) FTIR difference spectrum of PSII. In addition, our mid-frequency FTIR results showed a clear difference between pH 6.5 and 7.5 on the concentration dependence of the NH(4)Cl-induced upshift of the S(2) state carboxylate mode at 1365 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) spectra of NH(4)Cl-treated PSII samples. Our results provided strong evidence that NH(3) induced this upshift in the spectra of NH(4)Cl-treated PSII samples at 250 K. Moreover, our low-frequency FTIR results showed that the Mn-O-Mn cluster vibrational mode at 606 cm(-1) in the S(2)Q(A)(-)/S(1)Q(A) spectrum of the NaCl control PSII sample was diminished in those samples treated with NH(4)Cl. Our results suggest that NH(3) induced a significant alteration on the core structure of the Mn(4)CaO(5) cluster in PSII. The implication of our findings on the structure of the NH(3)-binding site on the OEC in PSII will be discussed.
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Affiliation(s)
- Li-Hsiu Hou
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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Lutz S, Tubert-Brohman I, Yang Y, Meuwly M. Water-assisted proton transfer in ferredoxin I. J Biol Chem 2011; 286:23679-87. [PMID: 21531725 DOI: 10.1074/jbc.m111.230003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The role of water molecules in assisting proton transfer (PT) is investigated for the proton-pumping protein ferredoxin I (FdI) from Azotobacter vinelandii. It was shown previously that individual water molecules can stabilize between Asp(15) and the buried [3Fe-4S](0) cluster and thus can potentially act as a proton relay in transferring H(+) from the protein to the μ(2) sulfur atom. Here, we generalize molecular mechanics with proton transfer to studying proton transfer reactions in the condensed phase. Both umbrella sampling simulations and electronic structure calculations suggest that the PT Asp(15)-COOH + H(2)O + [3Fe-4S](0) → Asp(15)-COO(-) + H(2)O + [3Fe-4S](0) H(+) is concerted, and no stable intermediate hydronium ion (H(3)O(+)) is expected. The free energy difference of 11.7 kcal/mol for the forward reaction is in good agreement with the experimental value (13.3 kcal/mol). For the reverse reaction (Asp(15)-COO(-) + H(2)O + [3Fe-4S](0)H(+) → Asp(15)-COOH + H(2)O + [3Fe-4S](0)), a larger barrier than for the forward reaction is correctly predicted, but it is quantitatively overestimated (23.1 kcal/mol from simulations versus 14.1 from experiment). Possible reasons for this discrepancy are discussed. Compared with the water-assisted process (ΔE ≈ 10 kcal/mol), water-unassisted proton transfer yields a considerably higher barrier of ΔE ≈ 35 kcal/mol.
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Affiliation(s)
- Stephan Lutz
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
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Chernev P, Zaharieva I, Dau H, Haumann M. Carboxylate shifts steer interquinone electron transfer in photosynthesis. J Biol Chem 2011; 286:5368-74. [PMID: 21169354 PMCID: PMC3037649 DOI: 10.1074/jbc.m110.202879] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 12/10/2010] [Indexed: 11/06/2022] Open
Abstract
Understanding the mechanisms of electron transfer (ET) in photosynthetic reaction centers (RCs) may inspire novel catalysts for sunlight-driven fuel production. The electron exit pathway of type II RCs comprises two quinone molecules working in series and in between a non-heme iron atom with a carboxyl ligand (bicarbonate in photosystem II (PSII), glutamate in bacterial RCs). For decades, the functional role of the iron has remained enigmatic. We tracked the iron site using microsecond-resolution x-ray absorption spectroscopy after laser-flash excitation of PSII. After formation of the reduced primary quinone, Q(A)(-), the x-ray spectral changes revealed a transition (t½ ≈ 150 μs) from a bidentate to a monodentate coordination of the bicarbonate at the Fe(II) (carboxylate shift), which reverted concomitantly with the slower ET to the secondary quinone Q(B). A redox change of the iron during the ET was excluded. Density-functional theory calculations corroborated the carboxylate shift both in PSII and bacterial RCs and disclosed underlying changes in electronic configuration. We propose that the iron-carboxyl complex facilitates the first interquinone ET by optimizing charge distribution and hydrogen bonding within the Q(A)FeQ(B) triad for high yield Q(B) reduction. Formation of a specific priming intermediate by nuclear rearrangements, setting the stage for subsequent ET, may be a common motif in reactions of biological redox cofactors.
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Affiliation(s)
- Petko Chernev
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Ivelina Zaharieva
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Holger Dau
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
| | - Michael Haumann
- From the Freie Universität Berlin, Institut für Experimentalphysik, 14195 Berlin, Germany
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22
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Flores M, Savitsky A, Paddock ML, Abresch EC, Dubinskii AA, Okamura MY, Lubitz W, Möbius K. Electron−Nuclear and Electron−Electron Double Resonance Spectroscopies Show that the Primary Quinone Acceptor QA in Reaction Centers from Photosynthetic Bacteria Rhodobacter sphaeroides Remains in the Same Orientation Upon Light-Induced Reduction. J Phys Chem B 2010; 114:16894-901. [DOI: 10.1021/jp107051r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marco Flores
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Anton Savitsky
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Mark L. Paddock
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Edward C. Abresch
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Alexander A. Dubinskii
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Melvin Y. Okamura
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Wolfgang Lubitz
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
| | - Klaus Möbius
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Department of Physics, University of California at San Diego, La Jolla, California 92093, United States, Semenov Institute of Chemical Physics, 117977 Moscow, Russia, and Department of Physics, Free University Berlin, 14195 Berlin, Germany
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23
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Mezzetti A, Blanchet L, de Juan A, Leibl W, Ruckebusch C. Ubiquinol formation in isolated photosynthetic reaction centres monitored by time-resolved differential FTIR in combination with 2D correlation spectroscopy and multivariate curve resolution. Anal Bioanal Chem 2010; 399:1999-2014. [DOI: 10.1007/s00216-010-4325-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 10/07/2010] [Accepted: 10/10/2010] [Indexed: 11/24/2022]
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Savitsky A, Malferrari M, Francia F, Venturoli G, Möbius K. Bacterial Photosynthetic Reaction Centers in Trehalose Glasses: Coupling between Protein Conformational Dynamics and Electron-Transfer Kinetics as Studied by Laser-Flash and High-Field EPR Spectroscopies. J Phys Chem B 2010; 114:12729-43. [DOI: 10.1021/jp105801q] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anton Savitsky
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, c/o Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy, and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Marco Malferrari
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, c/o Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy, and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Francesco Francia
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, c/o Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy, and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Giovanni Venturoli
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, c/o Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy, and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Klaus Möbius
- Max-Planck-Institut für Bioanorganische Chemie, 45470 Mülheim an der Ruhr, Germany, Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, c/o Dipartimento di Fisica, Università di Bologna, 40127 Bologna, Italy, and Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
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25
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Takahashi R, Hasegawa K, Takano A, Noguchi T. Structures and Binding Sites of Phenolic Herbicides in the QB Pocket of Photosystem II. Biochemistry 2010; 49:5445-54. [DOI: 10.1021/bi100639q] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Ryouta Takahashi
- Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Koji Hasegawa
- AdvanceSoft Corporation, Akasaka, Tokyo 107-0052, Japan
| | - Akira Takano
- Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
| | - Takumi Noguchi
- Division of Material Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nogoya 464-8602, Japan
- Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573, Japan
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Cheap H, Bernad S, Derrien V, Gerencsér L, Tandori J, de Oliveira P, Hanson DK, Maróti P, Sebban P. M234Glu is a component of the proton sponge in the reaction center from photosynthetic bacteria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1505-15. [PMID: 19632193 DOI: 10.1016/j.bbabio.2009.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 07/13/2009] [Accepted: 07/15/2009] [Indexed: 10/20/2022]
Abstract
Bacterial reaction centers use light energy to couple the uptake of protons to the successive semi-reduction of two quinones, namely Q(A) and Q(B). These molecules are situated symmetrically in regard to a non-heme iron atom. Four histidines and one glutamic acid, M234Glu, constitute the five ligands of this atom. By flash-induced absorption spectroscopy and delayed fluorescence we have studied in the M234EH and M234EL variants the role played by this acidic residue on the energetic balance between the two quinones as well as in proton uptake. Delayed fluorescence from the P(+)Q(A)(-) state (P is the primary electron donor) and temperature dependence of the rate of P(+)Q(A)(-) charge recombination that are in good agreement show that in the two RC variants, both Q(A)(-) and Q(B)(-) are destabilized by about the same free energy amount: respectively approximately 100 +/- 5 meV and 90 +/- 5 meV for the M234EH and M234EL variants, as compared to the WT. Importantly, in the M234EH and M234EL variants we observe a collapse of the high pH band (present in the wild-type reaction center) of the proton uptake amplitudes associated with formation of Q(A)(-) and Q(B)(-). This band has recently been shown to be a signature of a collective behaviour of an extended, multi-entry, proton uptake network. M234Glu seems to play a central role in the proton sponge-like system formed by the RC protein.
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Affiliation(s)
- Hélène Cheap
- Laboratoire de Chimie Physique, UMR 8000, University of Paris-Sud 11/CNRS, 91405 cedex, France
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Francia F, Malferrari M, Sacquin-Mora S, Venturoli G. Charge Recombination Kinetics and Protein Dynamics in Wild Type and Carotenoid-less Bacterial Reaction Centers: Studies in Trehalose Glasses. J Phys Chem B 2009; 113:10389-98. [DOI: 10.1021/jp902287y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Francesco Francia
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Laboratoire de Biochimie Théorique, CNRS UPR 9080, Institut de Biologie Physico-Chimique, 75005 Paris, France, and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Bologna, Italy
| | - Marco Malferrari
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Laboratoire de Biochimie Théorique, CNRS UPR 9080, Institut de Biologie Physico-Chimique, 75005 Paris, France, and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Bologna, Italy
| | - Sophie Sacquin-Mora
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Laboratoire de Biochimie Théorique, CNRS UPR 9080, Institut de Biologie Physico-Chimique, 75005 Paris, France, and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Bologna, Italy
| | - Giovanni Venturoli
- Laboratorio di Biochimica e Biofisica, Dipartimento di Biologia, Università di Bologna, 40126 Bologna, Italy, Laboratoire de Biochimie Théorique, CNRS UPR 9080, Institut de Biologie Physico-Chimique, 75005 Paris, France, and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Bologna, Italy
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