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Yakovlev AG, Taisova AS. Downhill excitation energy flow in reaction centers of purple bacteria Rhodospirillum rubrum G9. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149499. [PMID: 39069149 DOI: 10.1016/j.bbabio.2024.149499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/24/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Using femtosecond differential spectroscopy, excitation energy transfer in reaction centers (RCs) of the carotenoidless strain of purple bacteria Rhodospirillum rubrum G9 was studied at room temperature. Excitation and probing of the Qy, Qx and Soret absorption bands of the RCs were carried out by pulses with duration of 25-30 fs. Modeling of ΔA (light - dark) kinetics made it possible to estimate the characteristic time of various stages of excitation energy transformation. It is shown that the dynamics of the downhill energy flow in the RCs is determined both by the internal energy conversion Soret→ Qx → Qy in each cofactor and by the energy transfer H* → B* → P* (H - bacteriopheophytin, B - bacteriochlorophyll a, P - bacteriochlorophyll a dimer) between cofactors. The transfer of energy between the upper excited levels (Soret and Qx) of the cofactors accelerates its arrival to the lower exciton level of the P, from where charge separation begins. It turned out that all conversion and energy transfer processes occur within 40-160 fs: the conversion Soret → Qx occurs in 40-50 fs, the conversion Qx → Qy occurs in 100-140 fs, the transfer H* → B* has a time constant of 80-120 fs, and the transfer B* → P* has a time constant of 130-160 fs. The rate of energy transfer between the upper excited levels is close to the rate of transfer between Qy levels.
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Affiliation(s)
- Andrei G Yakovlev
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 119991 Moscow, Russian Federation.
| | - Alexandra S Taisova
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Leninskie Gory, 119991 Moscow, Russian Federation
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Vitukhnovskaya LA, Zaspa AA, Mamedov MD. Generation of Electric Potential Difference by Chromatophores from Photosynthetic Bacteria in the Presence of Trehalose under Continuous Illumination. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1428-1437. [PMID: 38105015 DOI: 10.1134/s0006297923100024] [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: 06/27/2023] [Revised: 07/20/2023] [Accepted: 08/26/2023] [Indexed: 12/19/2023]
Abstract
Measurement of electrical potential difference (Δψ) in membrane vesicles (chromatophores) from the purple bacterium Rhodobacter sphaeroides associated with the surface of a nitrocellulose membrane filter (MF) impregnated with a phospholipid solution in decane or immersed into it in the presence of exogenous mediators and disaccharide trehalose demonstrated an increase in the amplitude and stabilization of the signal under continuous illumination. The mediators were the ascorbate/N,N,N'N'-tetramethyl-p-phenylenediamine pair and ubiquinone-0 (electron donor and acceptor, respectively). Although stabilization of photoelectric responses upon long-term continuous illumination was observed for both variants of chromatophore immobilization, only the samples immersed into the MF retained the functional activity of reaction centers (RCs) for a month when stored in the dark at room temperature, which might be due to the preservation of integrity of chromatophore proteins inside the MF pores. The stabilizing effect of the bioprotector trehalose could be related to its effect on both the RC proteins and the phospholipid bilayer membrane. The results obtained will expand current ideas on the use of semi-synthetic structures based on various intact photosynthetic systems capable of converting solar energy into its electrochemical form.
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Affiliation(s)
- Liya A Vitukhnovskaya
- Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, 119992, Russia
- Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Andrei A Zaspa
- Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, 119992, Russia
| | - Mahir D Mamedov
- Belozersky Institute of Physical-Chemical Biology, Moscow State University, Moscow, 119992, Russia.
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Vitukhnovskya LA, Zaspa AA, Semenov AY, Mamedov MD. Conversion of light into electricity in a semi-synthetic system based on photosynthetic bacterial chromatophores. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - BIOENERGETICS 2023; 1864:148975. [PMID: 37001791 DOI: 10.1016/j.bbabio.2023.148975] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/02/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023]
Abstract
Chromatophores (Chr) from photosynthetic nonsulfur purple bacterium Rhodobacter sphaeroides immobilized onto a Millipore membrane filter (MF) and sandwiched between two semiconductor indium tin oxide (ITO) electrodes (termed ITO|Chr - MF|ITO) have been used to measure voltage (ΔV) induced by continuous illumination. The maximum ΔV was detected in the presence of ascorbate / N,N,N'N'-tetramethyl-p-phenylenediamine couple, coenzyme UQ0, disaccaride trehalose and antimycin A, an inhibitor of cytochrome bc1 complex. In doing so, the light-induced electron transfer in the reaction centers was the major source of photovoltages. The stability of the voltage signal upon prolonged irradiation (>1 h) may be due to the maintenance of a conformation that is optimal for the functioning of integral protein complexes and stabilization of lipid bilayer membranes in the presence of trehalose. Retaining ∼70 % of the original photovoltage performance on the 30th day of storage at 23 °C in the dark under air was achieved after re-injection of fresh buffer (∼40 μL) containing redox mediators into the ITO|Chr - MF|ITO system. The approach we use is easy and can be extended to other biological intact systems (cells, thylakoid membranes) capable of converting energy of light.
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Noji T, Matsuo M, Takeda N, Sumino A, Kondo M, Nango M, Itoh S, Dewa T. Lipid-Controlled Stabilization of Charge-Separated States (P+QB–) and Photocurrent Generation Activity of a Light-Harvesting–Reaction Center Core Complex (LH1-RC) from Rhodopseudomonas palustris. J Phys Chem B 2018; 122:1066-1080. [DOI: 10.1021/acs.jpcb.7b09973] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Tomoyasu Noji
- The OCU Advanced Research Institute for Natural Science & Technology (OCARINA), Osaka City University, Sugimoto-cho, Sumiyoshi-ku, Osaka 558−8585, Japan
| | - Mikano Matsuo
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Nobutaka Takeda
- Department
of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Ayumi Sumino
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Masaharu Kondo
- Department
of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Mamoru Nango
- The OCU Advanced Research Institute for Natural Science & Technology (OCARINA), Osaka City University, Sugimoto-cho, Sumiyoshi-ku, Osaka 558−8585, Japan
| | - Shigeru Itoh
- Division
of Material Sciences (Physics), Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464−8602, Japan
| | - Takehisa Dewa
- Department
of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
- Department
of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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Larom S, Kallmann D, Saper G, Pinhassi R, Rothschild A, Dotan H, Ankonina G, Schuster G, Adir N. The Photosystem II D1-K238E mutation enhances electrical current production using cyanobacterial thylakoid membranes in a bio-photoelectrochemical cell. PHOTOSYNTHESIS RESEARCH 2015; 126:161-9. [PMID: 25588957 DOI: 10.1007/s11120-015-0075-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 01/02/2015] [Indexed: 05/12/2023]
Abstract
The conversion of solar energy (SEC) to storable chemical energy by photosynthesis has been performed by photosynthetic organisms, including oxygenic cyanobacteria for over 3 billion years. We have previously shown that crude thylakoid membranes from the cyanobacterium Synechocytis sp. PCC 6803 can reduce the electron transfer (ET) protein cytochrome c even in the presence of the PSII inhibitor DCMU. Mutation of lysine 238 of the Photosystem II D1 protein to glutamic acid increased the cytochrome reduction rates, indicating the possible position of this unknown ET pathway. In this contribution, we show that D1-K238E is rather unique, as other mutations to K238, or to other residues in the same vicinity, are not as successful in cytochrome c reduction. This observation indicates the sensitivity of ET reactions to minor changes. As the next step in obtaining useful SEC from biological material, we describe the use of crude Synechocystis membranes in a bio-photovoltaic cell containing an N-acetyl cysteine-modified gold electrode. We show the production of significant current for prolonged time durations, in the presence of DCMU. Surprisingly, the presence of cytochrome c was not found to be necessary for ET to the bio-voltaic cell.
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Affiliation(s)
- Shirley Larom
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Dan Kallmann
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Gadiel Saper
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Roy Pinhassi
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Grand Technion Energy Program, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Avner Rothschild
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Hen Dotan
- Faculty of Material Science and Engineering, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Guy Ankonina
- Photovoltaics Lab, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel
| | - Gadi Schuster
- Faculty of Biology, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel.
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion City, 32000, Haifa, Israel.
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Kamran M, Friebe VM, Delgado JD, Aartsma TJ, Frese RN, Jones MR. Demonstration of asymmetric electron conduction in pseudosymmetrical photosynthetic reaction centre proteins in an electrical circuit. Nat Commun 2015; 6:6530. [PMID: 25751412 PMCID: PMC4366537 DOI: 10.1038/ncomms7530] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 02/04/2015] [Indexed: 12/22/2022] Open
Abstract
Photosynthetic reaction centres show promise for biomolecular electronics as nanoscale solar-powered batteries and molecular diodes that are amenable to atomic-level re-engineering. In this work the mechanism of electron conduction across the highly tractable Rhodobacter sphaeroides reaction centre is characterized by conductive atomic force microscopy. We find, using engineered proteins of known structure, that only one of the two cofactor wires connecting the positive and negative termini of this reaction centre is capable of conducting unidirectional current under a suitably oriented bias, irrespective of the magnitude of the bias or the applied force at the tunnelling junction. This behaviour, strong functional asymmetry in a largely symmetrical protein–cofactor matrix, recapitulates the strong functional asymmetry characteristic of natural photochemical charge separation, but it is surprising given that the stimulus for electron flow is simply an externally applied bias. Reasons for the electrical resistance displayed by the so-called B-wire of cofactors are explored. Photosynthetic reaction centres have been proposed for applications in bioelectronics. Here, the authors examine electron transport through the reaction centre from R. sphaeroides using conductive AFM, observing asymmetric conductance along only one cofactor wire under an applied bias.
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Affiliation(s)
- Muhammad Kamran
- Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Vincent M Friebe
- Department of Physics and Astronomy, LaserLaB Amsterdam, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Juan D Delgado
- Department of Physics and Astronomy, LaserLaB Amsterdam, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Thijs J Aartsma
- Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Raoul N Frese
- Department of Physics and Astronomy, LaserLaB Amsterdam, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Michael R Jones
- School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
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