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Osadchuk I, Luts HE, Zahharova A, Tamm T, Borovkov V. Controlling Chirogenic Effects in Porphyrin Based Supramolecular Systems: Theoretical Analysis Versus Experimental Observations. Chemphyschem 2024; 25:e202400104. [PMID: 38693766 DOI: 10.1002/cphc.202400104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/18/2024] [Indexed: 05/03/2024]
Abstract
Electronic circular dichroism (ECD) spectroscopy is a widely employed method for studying chiral analysis, requiring the presence of a chromophore close to a chiral centre. Porphyrinoids are found to be one of the best chromophoric systems serving for this purpose and enabling the application of ECD spectroscopy for chirality determination across diverse classes of organic compounds. Consequently, it is crucial to understand the induction mechanisms of ECD in the porphyrin-based complexes. The present study explores systematically the influence of secondary chromophores, bonded to an achiral zinc porphyrin or to chiral guest molecules, on the B-region of ECD spectra using the time-dependent density functional theory (TD-DFT) calculations. The study analyses the impact of change in both the conformation of achiral porphyrin (host) and change in position and conformation of chiral organic molecule (guest) on the B-band of ECD spectra (energy, intensity, sign of Cotton effect). Finally, conclusions made on model complexes are applied to published experimental data, contributing to a deeper understanding of various factors influencing ECD spectra in chiral systems. In addition, a computer program aimed to help rationalise ECD spectra by visualizing corresponding orbital energies, rotatory strengths, electric and magnetic transition moments, and angles between them, is presented.
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Affiliation(s)
- Irina Osadchuk
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Hanna-Eliisa Luts
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Aleksandra Zahharova
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Toomas Tamm
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
| | - Victor Borovkov
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Akadeemia tee 15, 12618, Tallinn, Estonia
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Zabelin AA, Shkuropatov AY. Pigment-modified reaction centers of Chloroflexus aurantiacus: chemical exchange of bacteriopheophytins with plant-type pheophytins. PHOTOSYNTHESIS RESEARCH 2021; 149:313-328. [PMID: 34138452 DOI: 10.1007/s11120-021-00855-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/06/2021] [Indexed: 06/12/2023]
Abstract
The pigment composition of isolated reaction centers (RCs) of the green filamentous bacterium Chloroflexus (Cfl.) aurantiacus was changed by chemical exchange of native bacteriopheophytin a (BPheo) molecules with externally added pheophytin a (Pheo) or [3-acetyl]-Pheo upon incubation of RC/pheophytin mixtures at room temperature and 45 °C. The modified RCs were characterized by Vis/NIR absorption spectroscopy, and the effect of pigment exchange on RC photochemical activity was assessed by measuring the photoaccumulation of the reduced pigment at the binding site HA. It is shown that both pheophytins can be exchanged into the HA site instead of BPheo by incubation at room temperature. While the newly introduced Pheo molecule is not active in electron transfer, the [3-acetyl]-Pheo molecule is able to replace functionally the photoreducible HA BPheo molecule with the formation of the [3-acetyl]-Pheo- radical anion instead of the BPheo-. After incubation at 45 °C, the majority (~ 90%) of HA BPheo molecules is replaced by both Pheo and [3-acetyl]-Pheo. Only a partial replacement of inactive BPheo molecules with pheophytins is observed even when the incubation temperature is raised to 50 °C. The results are discussed in terms of (i) differences in the accessibility of BPheo binding sites for extraneous pigments depending on structural constraints and incubation temperature and (ii) the effect of the reduction potential of pigments introduced into the HA site on the energetics of the charge separation process. The possible implication of Pheo-exchanged preparations for studying early electron-transfer events in Cfl. aurantiacus RCs is considered.
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Affiliation(s)
- Alexey A Zabelin
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Basic Biological Problems of the Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russian Federation
| | - Anatoly Ya Shkuropatov
- Federal Research Center "Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences", Institute of Basic Biological Problems of the Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russian Federation.
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Kirmaier C, Holten D. Subpicosecond Spectroscopy of Charge Separation inRhodobacter capsulatusReaction Centers. Isr J Chem 2013. [DOI: 10.1002/ijch.198800016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Yakovlev AG, Khmelnitsky AY, Shuvalov VA. Femtosecond charge separation in dry films of reaction centers of Rhodobacter sphaeroides and Chloroflexus aurantiacus. BIOCHEMISTRY (MOSCOW) 2012; 77:444-55. [DOI: 10.1134/s0006297912050045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zabelin AA, Shkuropatova VA, Shuvalov VA, Shkuropatov AY. FTIR spectroscopy of the reaction center of Chloroflexus aurantiacus: Photooxidation of the primary electron donor. BIOCHEMISTRY (MOSCOW) 2012; 77:157-64. [DOI: 10.1134/s000629791202006x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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YAKOVLEV ANDREIG, SHKUROPATOVA TATIANAA, VASILIEVA LYUDMILAG, YA. SHKUROPATOV ANATOLI, SHUVALOV VLADIMIRA. WAVE PACKET MOTIONS COUPLED TO ELECTRON TRANSFER IN REACTION CENTERS OF CHLOROFLEXUS AURANTIACUS. J Bioinform Comput Biol 2012; 6:643-66. [DOI: 10.1142/s0219720008003680] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 12/03/2007] [Accepted: 01/04/2008] [Indexed: 11/18/2022]
Abstract
Transient absorption difference spectroscopy with ~20 femtosecond (fs) resolution was applied to study the time and spectral evolution of low-temperature (90 K) absorbance changes in isolated reaction centers (RCs) of Chloroflexus (C.) aurantiacus. In RCs, the composition of the B-branch chromophores is different with respect to that of purple bacterial RCs by occupying the BB binding site of accessory bacteriochlorophyll by bacteriopheophytin molecule (ΦB). It was found that the nuclear wave packet motion induced on the potential energy surface of the excited state of the primary electron donor P* by ~20 fs excitation leads to a coherent formation of the states [Formula: see text] and [Formula: see text] (BA is a bacteriochlorophyll monomer in the A-branch of cofactors). The processes were studied by measuring coherent oscillations in kinetics of the absorbance changes at 900 nm and 940 nm (P* stimulated emission), at 750 nm and 785 nm (ΦB absorption bands), and at 1,020–1028 nm ([Formula: see text] absorption band). In RCs, the immediate bleaching of the P band at 880 nm and the appearance of the stimulated wave packet emission at 900 nm were accompanied (with a small delay of 10–20 fs) by electron transfer from P* to the B-branch with bleaching of the ΦB absorption band at 785 nm due to [Formula: see text] formation. These data are consistent with recent measurements for the mutant HM182L Rb. sphaeroides RCs (Yakovlev et al., Biochim Biophys Acta1757:369–379, 2006). Only at a delay of 120 fs was the electron transfer from P* to the A-branch observed with a development of the [Formula: see text] absorption band at 1028 nm. This development was in phase with the appearance of the P* stimulated emission at 940 nm. The data on the A-branch electron transfer in C. aurantiacus RCs are consistent with those observed in native RCs of Rb. sphaeroides. The mechanism of charge separation in RCs with the modified B-branch pigment composition is discussed in terms of coupling between the nuclear wave packet motion and electron transfer from P* to ΦB and BA primary acceptors in the B-branch and A-branch, respectively.
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Affiliation(s)
- ANDREI G. YAKOVLEV
- Department of Photobiophysics, Belozersky Institute of Chemical and Physical Biology, Moscow State University, Moscow 119991, Russian Federation
| | - TATIANA A. SHKUROPATOVA
- Department of Biophysics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - LYUDMILA G. VASILIEVA
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation
| | - ANATOLI YA. SHKUROPATOV
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation
| | - VLADIMIR A. SHUVALOV
- Department of Photobiophysics, Belozersky Institute of Chemical and Physical Biology, Moscow State University, Moscow 119991, Russian Federation
- Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russian Federation
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Zabelin AA, Shkuropatova VA, Shuvalov VA, Shkuropatov AY. FTIR spectroscopy of the reaction center of Chloroflexus aurantiacus: Photoreduction of the bacteriopheophytin electron acceptor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1013-21. [DOI: 10.1016/j.bbabio.2011.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 05/18/2011] [Accepted: 05/19/2011] [Indexed: 11/25/2022]
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Yakovlev AG, Shkuropatova TA, Vasilieva LG, Shkuropatov AY, Shuvalov VA. Femtosecond phase of charge separation in reaction centers of Chloroflexus aurantiacus. BIOCHEMISTRY. BIOKHIMIIA 2009; 74:846-854. [PMID: 19817684 DOI: 10.1134/s0006297909080057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Difference absorption spectroscopy with temporal resolution of approximately 20 fsec was used to study the primary phase of charge separation in isolated reaction centers (RCs) of Chloroflexus aurantiacus at 90 K. An ensemble of difference (light-minus-dark) absorption spectra in the 730-795 nm region measured at -0.1 to 4 psec delays relative to the excitation pulse was analyzed. Comparison with analogous data for RCs of HM182L mutant of Rhodobacter sphaeroides having the same pigment composition identified the 785 nm absorption band as the band of bacteriopheophytin Phi(B) in the B-branch. By study the bleaching of this absorption band due to formation of Phi(B)(-), it was found that a coherent electron transfer from P* to the B-branch occurs with a very small delay of 10-20 fsec after excitation of dimer bacteriochlorophyll P. Only at 120 fsec delay electron transfer from P* to the A-branch occurs with the formation of bacteriochlorophyll anion B(A)(-) absorption band at 1028 nm and the appearance of P* stimulated emission at 940 nm, as also occurs in native RCs of Rb. sphaeroides. It is concluded that a nuclear wave packet motion on the potential energy surface of P* after a 20-fsec light pulse excitation leads to the coherent formation of the P(+)Phi(B)(-) and P(+)B(A)(-) states.
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Affiliation(s)
- A G Yakovlev
- Department of Photobiophysics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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Xin Y, Lin S, Blankenship RE. Femtosecond Spectroscopy of the Primary Charge Separation in Reaction Centers of Chloroflexus aurantiacus with Selective Excitation in the QY and Soret Bands. J Phys Chem A 2007; 111:9367-73. [PMID: 17715904 DOI: 10.1021/jp073900b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The primary charge separation and electron-transfer processes of photosynthesis occur in the reaction center (RC). Isolated RCs of the green filamentous anoxygenic phototrophic bacterium Chloroflexus aurantiacus were studied at room temperature by using femtosecond transient absorption spectroscopy with selective excitation. Upon excitation in the Q(Y) absorbance band of the bacteriochlorophyll (BChl) dimer (P) at 865 nm, a 7.0 +/- 0.5 ps kinetic component was observed in the 538 nm region (Q(X) band of the bacteriopheophytin (BPheo)), 750 nm region (Q(Y) band of the BPheo), and 920 nm region (stimulated emission of the excited-state of P), indicating that this lifetime represents electron transfer from P to BPheo. The same time constant was also observed upon 740 nm or 800 nm excitation. A longer lifetime (300 +/- 30 ps), which was assigned to the time of reduction of the primary quinone, Q(A), was also observed. The transient absorption spectra and kinetics all indicate that only one electron-transfer branch is involved in primary charge separation under these excitation conditions. However, the transient absorption changes upon excitation in the Soret band at 390 nm reveal a more complex set of energy and electron-transfer processes. By comparison to studies on the RCs of the purple bacterium Rhodobacter sphaeroides, we discuss the possible mechanism of electron-transfer pathway dependence on excitation energy and propose a model of the Cf. aurantiacus RC that better explains the observed results.
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Affiliation(s)
- Yueyong Xin
- Department of Biology, Washington University, St. Louis, Missouri 63130, USA
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Yamada M, Zhang H, Hanada S, Nagashima KVP, Shimada K, Matsuura K. Structural and spectroscopic properties of a reaction center complex from the chlorosome-lacking filamentous anoxygenic phototrophic bacterium Roseiflexus castenholzii. J Bacteriol 2005; 187:1702-9. [PMID: 15716441 PMCID: PMC1063993 DOI: 10.1128/jb.187.5.1702-1709.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The photochemical reaction center (RC) complex of Roseiflexus castenholzii, which belongs to the filamentous anoxygenic phototrophic bacteria (green filamentous bacteria) but lacks chlorosomes, was isolated and characterized. The genes coding for the subunits of the RC and the light-harvesting proteins were also cloned and sequenced. The RC complex was composed of L, M, and cytochrome subunits. The cytochrome subunit showed a molecular mass of approximately 35 kDa, contained hemes c, and functioned as the electron donor to the photo-oxidized special pair of bacteriochlorophylls in the RC. The RC complex appeared to contain three molecules of bacteriochlorophyll and three molecules of bacteriopheophytin, as in the RC preparation from Chloroflexus aurantiacus. Phylogenetic trees based on the deduced amino acid sequences of the RC subunits suggested that R. castenholzii had diverged from C. aurantiacus very early after the divergence of filamentous anoxygenic phototrophic bacteria from purple bacteria. Although R. castenholzii is phylogenetically related to C. aurantiacus, the arrangement of its puf genes, which code for the light-harvesting proteins and the RC subunits, was different from that in C. aurantiacus and similar to that in purple bacteria. The genes are found in the order pufB, -A, -L, -M, and -C, with the pufL and pufM genes forming one continuous open reading frame. Since the photosynthetic apparatus and genes of R. castenholzii have intermediate characteristics between those of purple bacteria and C. aurantiacus, it is likely that they retain many features of the common ancestor of purple bacteria and filamentous anoxygenic phototrophic bacteria.
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Affiliation(s)
- Mitsunori Yamada
- Department of Biology, Tokyo Metropolitan University, Minamiohsawa, Hachioji, Tokyo, Japan.
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11
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A structural model for the assembly of the reaction centre and the B808-866 complex in the membranes of Chloroflexus aurantiacus based on the calculation of the triplet minus singlet spectrum of the primary donor. Chem Phys 2003. [DOI: 10.1016/s0301-0104(03)00280-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Vácha F, Durchan M, Siffel P. Excitonic interactions in the reaction centre of photosystem II studied by using circular dichroism. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1554:147-52. [PMID: 12160987 DOI: 10.1016/s0005-2728(02)00238-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Changes in excitonic interactions of photosystem II (PSII) reaction centre (RC) pigments upon light-induced oxidation of primary donor (P680) or reduction of primary acceptor (pheophytin (Pheo)) were analysed using circular dichroism (CD). The CD spectrum of PSII RC shows positive bands at 417, 435 and 681 and negative bands at 447 and 664 nm. Oxidation of the primary donor by illuminating the sample in the presence of silicomolybdate resulted in nearly symmetric decrease of CD amplitudes at 664 and 684 nm. In the Soret region, the maximum bleaching of CD signal was detected at 449 and 440 nm. Accumulation of reduced Pheo in the presence of dithionite brought about much lower changes in CD amplitudes than P680 oxidation. In this case, only a small asymmetric bleaching at 680 and 668 nm in the red region and a bleaching at 445, 435 and 416 nm in the Soret region has been detected. Therefore, we suppose that the contribution of the Pheo of the primary acceptor to the total CD signal of RC is negligible. In contrast to the oxidation of primary donor, the light-induced change in the CD spectrum upon primary acceptor reduction was strongly temperature-dependent. The reversible CD bleaching was completely inhibited below 200 K, although the reduced Pheo was accumulated even at a temperature of 77 K. Since the temperature does not influence the excitonic interaction, the temperature dependence of the CD changes upon Pheo reduction does not support the model of Pheo excitonically interacting with the other chlorophylls (Chl) of the RC. We propose that Pheo should not be considered as a part of a multimer model.
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Affiliation(s)
- Frantisek Vácha
- Photosynthesis Research Centre of Faculty of Biological Sciences, University of South Bohemia and Institute of Plant Molecular Biology, Academy of Sciences of the Czech Republic, Branisovská 31, 370 05, Ceské Budejovice, Czech Republic.
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Kirmaier C, Holten D. Subpicosecond characterization of the optical properties of the primary electron donor and the mechanism of the initial electron transfer in Rhodobacter capsulatus
reaction centers. FEBS Lett 2001. [DOI: 10.1016/0014-5793(88)80919-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Volk M, Aumeier G, Langenbacher T, Feick R, Ogrodnik A, Michel-Beyerle ME. Energetics and Mechanism of Primary Charge Separation in Bacterial Photosynthesis. A Comparative Study on Reaction Centers of Rhodobacter sphaeroides and Chloroflexus aurantiacus. J Phys Chem B 1998. [DOI: 10.1021/jp972743l] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Martin Volk
- Institut für Physikalische und Theoretische Chemie, Technische Universität München, 85748 Garching, Germany, and Max-Planck-Institut für Biochemie, 82152 Martinsried, Germany
| | - Gudrun Aumeier
- Institut für Physikalische und Theoretische Chemie, Technische Universität München, 85748 Garching, Germany, and Max-Planck-Institut für Biochemie, 82152 Martinsried, Germany
| | - Thomas Langenbacher
- Institut für Physikalische und Theoretische Chemie, Technische Universität München, 85748 Garching, Germany, and Max-Planck-Institut für Biochemie, 82152 Martinsried, Germany
| | - Reiner Feick
- Institut für Physikalische und Theoretische Chemie, Technische Universität München, 85748 Garching, Germany, and Max-Planck-Institut für Biochemie, 82152 Martinsried, Germany
| | - Alexander Ogrodnik
- Institut für Physikalische und Theoretische Chemie, Technische Universität München, 85748 Garching, Germany, and Max-Planck-Institut für Biochemie, 82152 Martinsried, Germany
| | - Maria-Elisabeth Michel-Beyerle
- Institut für Physikalische und Theoretische Chemie, Technische Universität München, 85748 Garching, Germany, and Max-Planck-Institut für Biochemie, 82152 Martinsried, Germany
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Hartwich G, Scheer H, Aust V, Angerhofer A. Absorption and ADMR studies on bacterial photosynthetic reaction centres with modified pigments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1995. [DOI: 10.1016/0005-2728(95)00038-k] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mimuro M, Nozawa T, Tamai N, Nishimura Y, Yamazaki I. Presence and significance of minor antenna components in the energy transfer sequence of the green photosynthetic bacterium Chloroflexus aurantiacus. FEBS Lett 1994; 340:167-72. [PMID: 8131839 DOI: 10.1016/0014-5793(94)80130-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Antenna components in the energy transfer processes of a green photosynthetic bacterium Chloroflexus aurantiacus were spectrally investigated by time-resolved fluorescence spectroscopy at -196 degrees C on intact cells. Besides major antenna components so far reported, three minor components were resolved; those were Bchl c located at 785 nm, the baseplate Bchl a at 819 nm and Bchl a in the B808-866 complex at 910 nm. The last component was assigned to a longer wavelength antenna closely associated with a reaction center. An additional Bchl c fluorescence component was kinetically suggested to be present, which can be an energy donor to a major Bchl c. Presence of these minor components was signified in terms of (1) increase in the spectral overlap integral and (2) adjustment of the direction of dipole moments in the energy transfer sequence of intact cells.
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Affiliation(s)
- M Mimuro
- National Institute for Basic Biology, Aichi, Japan
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van Vliet P, Zannoni D, Nitschke W, Rutherford AW. Membrane-bound cytochromes in Chloroflexus aurantiacus studied by EPR. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 199:317-23. [PMID: 1649048 DOI: 10.1111/j.1432-1033.1991.tb16127.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The heme components of chlorosome-depleted membranes of the green-gliding bacterium Chloroflexus aurantiacus were studied by EPR spectroscopy. The four major species, which are present in approximately equimolar quantities, are characterized by the following gz values, redox midpoint potentials and orientations of heme planes with respect to the plane of the membrane: gz = 3.40, Em = +280 mV, 30 degrees; gz = 3.33, Em = 0 mV, 45 degrees; gz = 3.03, Em = +95 mV, 40-50 degrees and gz = 2.95, Em = +150 mV, 90 degrees. These four hemes were attributed to cytochrome c554, the membrane-bound immediate electron donor to the photosynthetic reaction centre in Chloroflexus. All hemes except that with the highest potential were able to undergo photooxidation at 4 K. The photooxidation of the lowest potential heme was stable, whereas that of the +95 mV and the +150 mV hemes reversed on increasing the temperature to 100 K in darkness, due to charge recombination. The ability to photooxidize these hemes at 4 K was lost upon aging of samples. The results demonstrate that a reaction-centre-associated tetraheme cytochrome subunit, analogous to that of purple bacteria, is also present in C. aurantiacus.
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Affiliation(s)
- P van Vliet
- Départment de Biologie Cellulaire et Moléculaire, CE Saclay, Gif sur Yvette, France
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Volk M, Scheidel G, Ogrodnik A, Feick R, Michel-Beyerle M. High quantum yield of charge separation in reaction centers of Chloroflexus aurantiacus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80240-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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19
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Temperature dependence of the initial electron-transfer kinetics in photosynthetic reaction centers of Chloroflexus aurantiacus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1991. [DOI: 10.1016/s0005-2728(05)80141-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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20
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Budil DE, Thurnauer MC. The chlorophyll triplet state as a probe of structure and function in photosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA 1991; 1057:1-41. [PMID: 1849002 DOI: 10.1016/s0005-2728(05)80081-7] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- D E Budil
- Baker Laboratory of Chemistry, Cornell University, Ithaca, NY 14850
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21
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Time-resolved spectroscopy at 10 K of the Photosystem II reaction center; deconvolution of the red absorption band. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1990. [DOI: 10.1016/0005-2728(90)90045-6] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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22
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Biexponential Charge Seapration and Monoexponential Decay of P+H− in Reaction Centers of Chloroflexus aurantiacus. REACTION CENTERS OF PHOTOSYNTHETIC BACTERIA 1990. [DOI: 10.1007/978-3-642-61297-8_18] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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23
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Ovchinnikov YuA, Abdulaev NG, Shmuckler BE, Zargarov AA, Kutuzov MA, Telezhinskaya IN, Levina NB, Zolotarev AS. Photosynthetic reaction centre of Chloroflexus aurantiacus. Primary structure of M-subunit. FEBS Lett 1988; 232:364-8. [PMID: 3288502 DOI: 10.1016/0014-5793(88)80770-1] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The M-subunit primary structure of the reaction centre (RC) from Chloroflexus aurantiacus composed of 306 amino acid residues has been determined by parallel analysis of the protein and corresponding DNA. The blocked N-terminus as well as replacement of the essential histidine liganding Mg of an accessory bacteriochlorophyll in purple bacteria by leucine distinguishes the M-subunit of Chloroflexus RC from that of purple bacteria.
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Affiliation(s)
- Ovchinnikov YuA
- Shemyakin Institute of Bioorganic Chemistry, USSR Academy of Sciences, Moscow
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van Dorssen R, Hunter C, van Grondelle R, Korenhof A, Amesz J. Spectroscopic properties of antenna complexes of Rhodobacter sphaeroides in vivo. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1988. [DOI: 10.1016/0005-2728(88)90154-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Nozawa T, Trost JT, Fukada T, Hatano M, McManus JD, Blankenship RE. Properties of the reaction center of the thermophilic purple photosynthetic bacterium Chromatium tepidum. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 894:468-76. [PMID: 3318928 DOI: 10.1016/0005-2728(87)90126-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Reaction centers were purified from the thermophilic purple sulfur photosynthetic bacterium Chromatium tepidum. The reaction center consists of four polypeptides L, M, H and C, whose apparent molecular masses were determined to be 25, 30, 34 and 44 kDa, respectively, by polyacrylamide gel electrophoresis. The heaviest peptide corresponds to tightly bound cytochrome. The tightly bound cytochrome c contains two types of heme, high-potential c-556 and low-potential c-553. The low-potential heme is able to be photooxidized at 77 K. The reaction center exhibits laser-flash-induced absorption changes and circular dichroism spectra similar to those observed in other purple photosynthetic bacteria. Whole cells contain both ubiquinone and menaquinone. Reaction centers contain only a single active quinone; chemical analysis showed this to be menaquinone. Reaction center complexes without the tightly bound cytochrome were also prepared. The near-infrared pigment absorption bands are red-shifted in reaction centers with cytochrome compared to those without cytochrome.
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Affiliation(s)
- T Nozawa
- Chemical Research Institute of Non-aqueous Solutions, Tohoku University, Sendai, Japan
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Kirmaier C, Holten D. Primary photochemistry of reaction centers from the photosynthetic purple bacteria. PHOTOSYNTHESIS RESEARCH 1987; 13:225-260. [PMID: 24435821 DOI: 10.1007/bf00029401] [Citation(s) in RCA: 264] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/1987] [Accepted: 04/20/1987] [Indexed: 06/03/2023]
Abstract
Photosynthetic organisms transform the energy of sunlight into chemical potential in a specialized membrane-bound pigment-protein complex called the reaction center. Following light activation, the reaction center produces a charge-separated state consisting of an oxidized electron donor molecule and a reduced electron acceptor molecule. This primary photochemical process, which occurs via a series of rapid electron transfer steps, is complete within a nanosecond of photon absorption. Recent structural data on reaction centers of photosynthetic bacteria, combined with results from a large variety of photochemical measurements have expanded our understanding of how efficient charge separation occurs in the reaction center, and have changed many of the outstanding questions.
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Affiliation(s)
- C Kirmaier
- Department of Chemistry, Washington University, 63130, St. Louis, MO, USA
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Application of exciton theory to optical spectra of sodium borohydride treated reaction centres from rhodobacter sphaeroides R26. Chem Phys Lett 1987. [DOI: 10.1016/0009-2614(87)80299-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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29
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Scherer P, Fischer SF. On the localization and charge transfer character of the “special pair” triplet states for bacterial reaction centers. Chem Phys Lett 1987. [DOI: 10.1016/0009-2614(87)80281-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Model studies to low-temperature optical transitions of photosynthetic reaction centers. II. Rhodobacter sphaeroides and Chloroflexus aurantiacus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1987. [DOI: 10.1016/0005-2728(87)90008-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Chapter 13 Structure and exciton effects in photosynthesis. ACTA ACUST UNITED AC 1987. [DOI: 10.1016/s0167-7306(08)60144-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2023]
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