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Mirkovic T, Ostroumov EE, Anna JM, van Grondelle R, Govindjee, Scholes GD. Light Absorption and Energy Transfer in the Antenna Complexes of Photosynthetic Organisms. Chem Rev 2016; 117:249-293. [PMID: 27428615 DOI: 10.1021/acs.chemrev.6b00002] [Citation(s) in RCA: 587] [Impact Index Per Article: 73.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The process of photosynthesis is initiated by the capture of sunlight by a network of light-absorbing molecules (chromophores), which are also responsible for the subsequent funneling of the excitation energy to the reaction centers. Through evolution, genetic drift, and speciation, photosynthetic organisms have discovered many solutions for light harvesting. In this review, we describe the underlying photophysical principles by which this energy is absorbed, as well as the mechanisms of electronic excitation energy transfer (EET). First, optical properties of the individual pigment chromophores present in light-harvesting antenna complexes are introduced, and then we examine the collective behavior of pigment-pigment and pigment-protein interactions. The description of energy transfer, in particular multichromophoric antenna structures, is shown to vary depending on the spatial and energetic landscape, which dictates the relative coupling strength between constituent pigment molecules. In the latter half of the article, we focus on the light-harvesting complexes of purple bacteria as a model to illustrate the present understanding of the synergetic effects leading to EET optimization of light-harvesting antenna systems while exploring the structure and function of the integral chromophores. We end this review with a brief overview of the energy-transfer dynamics and pathways in the light-harvesting antennas of various photosynthetic organisms.
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Affiliation(s)
- Tihana Mirkovic
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Evgeny E Ostroumov
- Department of Chemistry, Princeton University , Washington Road, Princeton, New Jersey 08544, United States
| | - Jessica M Anna
- Department of Chemistry, University of Pennsylvania , 231 S. 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Govindjee
- Department of Biochemistry, Center of Biophysics & Quantitative Biology, and Department of Plant Biology, University of Illinois at Urbana-Champaign , 265 Morrill Hall, 505 South Goodwin Avenue, Urbana, Illinois 61801, United States
| | - Gregory D Scholes
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.,Department of Chemistry, Princeton University , Washington Road, Princeton, New Jersey 08544, United States
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Niedzwiedzki DM, Orf GS, Tank M, Vogl K, Bryant DA, Blankenship RE. Photophysical properties of the excited states of bacteriochlorophyll f in solvents and in chlorosomes. J Phys Chem B 2014; 118:2295-305. [PMID: 24410285 DOI: 10.1021/jp409495m] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Bacteriochlorophyll f (BChl f) is a photosynthetic pigment predicted nearly 40 years ago as a fourth potential member of the Chlorobium chlorophyll family (BChl c, d, and e). However, this pigment still has not been found in a naturally occurring organism. BChl c, d, and e are utilized by anoxygenic green photosynthetic bacteria for assembly of chlorosomes--large light-harvesting complexes that allow those organisms to survive in habitats with extremely low light intensities. Recently, using genetic methods on two different strains of Chlorobaculum limnaeum that naturally produce BChl e, two research groups produced mutants that synthesize BChl f and assemble it into chlorosomes. In this study, we present detailed investigations on spectral and dynamic characteristics of singlet excited and triplet states of BChl f with the application of ultrafast time-resolved absorption and fluorescence spectroscopies. The studies were performed on isolated BChl f in various solvents, at different temperatures, and on BChl f-containing chlorosomes in order to uncover any unusual or unfavorable properties that stand behind the lack of appearance of this pigment in natural environments.
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Affiliation(s)
- Dariusz M Niedzwiedzki
- Photosynthetic Antenna Research Center, ‡Departments of Biology and Chemistry, Washington University in St. Louis , St. Louis, Missouri 63130, United States
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Vengris M, Larsen DS, Valkunas L, Kodis G, Herrero C, Gust D, Moore T, Moore A, van Grondelle R. Separating annihilation and excitation energy transfer dynamics in light harvesting systems. J Phys Chem B 2013; 117:11372-82. [PMID: 23662680 DOI: 10.1021/jp403301c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The dependence of excitation energy transfer kinetics on the electronic state of the acceptor (ground vs excited) has been resolved with a novel multipulse prePump-Pump-Probe spectroscopy. The primary energy transfer and annihilation dynamics in two model light-harvesting systems were explored: an artificially synthesized carotenoid-zinc-phthalocyanine dyad and a naturally occurring light-harvesting peridinin-chlorophyll protein complex from Amphidinium carterae. Both systems use carotenoid as the primary excitation energy donor with porphyrin chromophores as the acceptor molecules. The prePump-Pump-Probe transient signals were analyzed with Monte Carlo modeling to explicitly address the underlying step-by-step kinetics involved in both excitation migration and annihilation processes. Both energy transfer and annihilation dynamics were demonstrated to occur with approximately the same rate in both systems, regardless of the excitation status of the acceptor pigments. The possible reasons for these observations are discussed in the framework of the Förster energy transfer model.
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Affiliation(s)
- Mikas Vengris
- Quantum Electronics Department, Faculty of Physics, Vilnius University , Saulėtekio 9-III, 10222 Vilnius, Lithuania
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Borisov AY. On the structure and function of “chlorosomes” of green bacteria. Biophysics (Nagoya-shi) 2012. [DOI: 10.1134/s0006350912040021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Martiskainen J, Linnanto J, Aumanen V, Myllyperkiö P, Korppi-Tommola J. Excitation Energy Transfer in Isolated Chlorosomes from Chlorobaculum tepidum and Prosthecochloris aestuarii. Photochem Photobiol 2012; 88:675-83. [DOI: 10.1111/j.1751-1097.2012.01098.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Martiskainen J, Linnanto J, Kananavičius R, Lehtovuori V, Korppi-Tommola J. Excitation energy transfer in isolated chlorosomes from Chloroflexus aurantiacus. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.06.080] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Borisov AY. Can giant chlorosomes be part of the light-harvesting antennae of green bacteria? Biophysics (Nagoya-shi) 2009. [DOI: 10.1134/s0006350909030063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Walree CA, Sakuragi Y, Steensgaard DB, Bösinger CS, Frigaard NU, Cox RP, Holzwarth AR, Miller M. Effect of Alkaline Treatment on Bacteriochlorophyll a, Quinones and Energy Transfer in Chlorosomes from Chlorobium tepidum and Chlorobium phaeobacteroides. Photochem Photobiol 2008. [DOI: 10.1111/j.1751-1097.1999.tb03293.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Kakitani Y, Rondonuwu FS, Mizoguchi T, Watanabe Y, Koyama Y. Energy Dissipations in Chlorosomes: Emission from the Qy State Following Singlet−Singlet and Triplet−Triplet Annihilation Reactions in the Cylindrical Aggregate and Its Reversible Dissociation into the Piggy-Back Dimers. J Phys Chem B 2003. [DOI: 10.1021/jp0300288] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yoshinori Kakitani
- Department of Chemistry and Department of Physics, Faculty of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan, and Department of Bioscience and Biotechnology, Ritsumeikan University, Nojihigashi, Kusatsu 525-8577, Japan
| | - Ferdy S. Rondonuwu
- Department of Chemistry and Department of Physics, Faculty of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan, and Department of Bioscience and Biotechnology, Ritsumeikan University, Nojihigashi, Kusatsu 525-8577, Japan
| | - Tadashi Mizoguchi
- Department of Chemistry and Department of Physics, Faculty of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan, and Department of Bioscience and Biotechnology, Ritsumeikan University, Nojihigashi, Kusatsu 525-8577, Japan
| | - Yasutaka Watanabe
- Department of Chemistry and Department of Physics, Faculty of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan, and Department of Bioscience and Biotechnology, Ritsumeikan University, Nojihigashi, Kusatsu 525-8577, Japan
| | - Yasushi Koyama
- Department of Chemistry and Department of Physics, Faculty of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda 669-1337, Japan, and Department of Bioscience and Biotechnology, Ritsumeikan University, Nojihigashi, Kusatsu 525-8577, Japan
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Psencík J, Ma YZ, Arellano JB, Hála J, Gillbro T. Excitation energy transfer dynamics and excited-state structure in chlorosomes of Chlorobium phaeobacteroides. Biophys J 2003; 84:1161-79. [PMID: 12547796 PMCID: PMC1302692 DOI: 10.1016/s0006-3495(03)74931-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The excited-state relaxation within bacteriochlorophyll (BChl) e and a in chlorosomes of Chlorobium phaeobacteroides has been studied by femtosecond transient absorption spectroscopy at room temperature. Singlet-singlet annihilation was observed to strongly influence both the isotropic and anisotropic decays. Pump intensities in the order of 10(11) photons x pulse(-1) x cm(-2) were required to obtain annihilation-free conditions. The most important consequence of applied very low excitation doses is an observation of a subpicosecond process within the BChl e manifold (approximately 200-500 fs), manifesting itself as a rise in the red part of the Q(y) absorption band of the BChl e aggregates. The subsequent decay of the kinetics measured in the BChl e region and the corresponding rise in the baseplate BChl a is not single-exponential, and at least two components are necessary to fit the data, corresponding to several BChl e-->BChl a transfer steps. Under annihilation-free conditions, the anisotropic kinetics show a generally slow decay within the BChl e band (10-20 ps) whereas it decays more rapidly in the BChl a region ( approximately 1 ps). Analysis of the experimental data gives a detailed picture of the overall time evolution of the energy relaxation and energy transfer processes within the chlorosome. The results are interpreted within an exciton model based on the proposed structure.
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Affiliation(s)
- Jakub Psencík
- Department of Chemistry, Biophysical Chemistry, Umeå University, S-901 87 Umeå, Sweden.
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Steensgaard DB, Cox RP, Miller M. Manipulation of the bacteriochlorophyll c homolog distribution in the green sulfur bacterium Chlorobium tepidum. PHOTOSYNTHESIS RESEARCH 1996; 48:385-393. [PMID: 24271479 DOI: 10.1007/bf00029471] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/1996] [Accepted: 03/22/1996] [Indexed: 06/02/2023]
Abstract
We have shown that the green sulfur bacterium Chlorobium tepidum can be grown in batch culture supplemented with potentially toxic fatty alcohols without a major effect on the growth rate if the concentration of the alcohols is kept low either by programmed addition or by adding the alcohol as an inclusion complex with β-cyclodextrin. HPLC and GC analysis of pigment extracts from the supplemented cells showed that the fatty alcohols were incorporated into bacteriochlorophyll c as the esterifying alcohol. It was possible to change up to 43% of the naturally occurring farnesyl ester of bacteriochlorophyll c with the added alcohol. This change in the homolog composition had no effect on the spectral properties of the cells when farnesol was partially replaced by stearol, phytol or geranylgeraniol. However, with dodecanol we obtained a blue-shift of 6 nm of the Qy band of the bacteriochlorophyll c and a concomitant change in the fluorescence emission was observed. The possible significance of these findings is discussed in the light of current ideas about bacteriochlorophyll organization in the chlorosomes.
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Affiliation(s)
- D B Steensgaard
- Institute of Biochemistry, Odense University, Campusvej 55, DK-5230, Odense M, Denmark
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Cherepy NJ, Du M, Holzwarth AR, Mathies RA. Near-Infrared Resonance Raman Spectra of Chlorosomes: Probing Nuclear Coupling in Electronic Energy Transfer. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp952992e] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nerine J. Cherepy
- Department of Chemistry, University of California, Berkeley, California 94720, and The Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Mei Du
- Department of Chemistry, University of California, Berkeley, California 94720, and The Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Alfred R. Holzwarth
- Department of Chemistry, University of California, Berkeley, California 94720, and The Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45470 Mülheim a.d. Ruhr, Germany
| | - Richard A. Mathies
- Department of Chemistry, University of California, Berkeley, California 94720, and The Max-Planck-Institut für Strahlenchemie, Stiftstrasse 34-36, D-45470 Mülheim a.d. Ruhr, Germany
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14
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Zhu Y, Lin S, Ramakrishna BL, van Noort PI, Blankenship RE. Self quenching of chlorosome chlorophylls in water and hexanol-saturated water. PHOTOSYNTHESIS RESEARCH 1996; 47:207-218. [PMID: 24301988 DOI: 10.1007/bf02184282] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/1995] [Accepted: 12/06/1995] [Indexed: 06/02/2023]
Abstract
The optical properties of a methyl ester homolog of bacteriochlorophylld (BChld M ) and bacteriochlorophyllc (BChlc) in H2O, hexanol-saturated H2O and methanol were studied by absorption, fluorescence emission, and circular dichroism (CD). In H2O, BChld M spontaneously forms an aggregate similar to that formed in hexane, with absorption maximum at 730 nm and fluorescence emission at 748 nm. For the pigment sample in hexanol-saturated H2O, while the absorption peaks at 661 nm, only slightly red-shifted compared to the monomer, the fluorescence emission is highly quenched. When diluted 2-3 fold with H2O, the absorption returns to around 720 nm, characteristic of an aggregate. The CD spectrum of the H2O aggregate exhibits a derivative-shaped feature with positive and negative peaks, while the amplitude is lower than that of chlorosomes. The Fourier transform infrared spectra of BChld M aggregates in H2O and hexane were measured. A 1644 cm(-1) band, indicative of a bonded 13(1)-keto group, is detected for both samples. A marker band for 5-coordinated Mg was observed at 1611 cm(-1) for the two samples as well. To study the kinetic behavior of the samples, both single-photon counting (SPC) fluorescence and transient absorption difference spectroscopic measurements were performed. For BChld M in hexanol-saturated H2O, a fast decay component with a lifetime of 10 to 14 ps was detected using the two different techniques. The fast decay could be explained by the concentration quenching phenomenon due to a high local pigment concentration. For the pigment sample in H2O, SPC gave a 16 ps component, whereas global analysis of transient absorption data generated two fast components: 3.5 and 26 ps. The difference may arise from the different excitation intensities. With a much higher excitation in the latter measurements, other quenching processes, e.g. annihilation, might be introduced, giving the 3.5 ps component. Finally, atomic force microscopy was used to examine the ultrastructure of BChld M in H2O and hexanol-saturated H2O. Pigment clusters with diameters ranging from 15 to 45 nm were observed in both samples.
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Affiliation(s)
- Y Zhu
- Department of Chemistry and Biochemistry, Arizona State University, 85287-1604, Tempe, AZ, USA
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Ma YZ, Cox RP, Gillbro T, Miller M. Bacteriochlorophyll organization and energy transfer kinetics in chlorosomes from Chloroflexus aurantiacus depend on the light regime during growth. PHOTOSYNTHESIS RESEARCH 1996; 47:157-165. [PMID: 24301823 DOI: 10.1007/bf00016178] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/1995] [Accepted: 12/06/1995] [Indexed: 06/02/2023]
Abstract
We have used measurements of fluorescence and circular dichroism (CD) to compare chlorosome-membrane preparations derived from the green filamentous bacterium Chloroflexus aurantiacus grown in continuous culture at two different light-intensities. The cells grown under low light (6 μmol m(-2) s(-1)) had a higher ratio of bacteriochlorophyll (BChl) c to BChl a than cells grown at a tenfold higher light intensity; the high-light-grown cells had much more carotenoid per bacteriochlorophyll.The anisotropy of the QY band of BChl c was calculated from steady-state fluorescence excitation and emission spectra with polarized light. The results showed that the BChl c in the chlorosomes derived from cells grown under high light has a higher structural order than BChl c in chlorosomes from low-light-grown cells. In the central part of the BChl c fluorescence emission band, the average angles between the transition dipole moments for BChl c molecules and the symmetry axis of the chlorosome rod element were estimated as 25° and 17° in chlorosomes obtained from the low- and high-light-grown cells, respectively.This difference in BChl organization was confirmed by the decay associated spectra of the two samples obtained using picosecond single-photon-counting experiments and global analysis of the fluorescence decays. The shortest decay component obtained, which probably represents energy-transfer from the chlorosome bacteriochlorophylls to the BChl a in the baseplate, was 15 ps in the chlorosomes from high-light-grown cell but only 7 ps in the preparation from low-light grown cells. The CD spectra of the two preparations were very different: chlorosomes from low-light-grown cells had a type II spectrum, while those from high-light-grown cells was of type I (Griebenow et al. (1991) Biochim Biophys Acta 1058: 194-202). The different shapes of the CD spectra confirm the existence of a qualitatively different organization of the BChl c in the two types of chlorosome.
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Affiliation(s)
- Y Z Ma
- Department of Physical Chemistry, Umeå University, S-901 87, Umeå, Sweden
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Zhu Y, Ramakrishna B, van Noort PI, Blankenship RE. Microscopic and spectroscopic studies of untreated and hexanol-treated chlorosomes from Chloroflexus aurantiacus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1995. [DOI: 10.1016/0005-2728(95)00118-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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17
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Incorporation of exogenous long-chain alcohols into bacteriochlorophyll c homologs by Chloroflexus aurantiacus. Arch Microbiol 1995. [DOI: 10.1007/bf00381785] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mimuro M, Hirota M, Nishimura Y, Moriyama T, Yamazaki I, Shimada K, Matsuura K. Molecular organization of bacteriochlorophyll in chlorosomes of the green photosynthetic bacteriumChloroflexus aurantiacus: Studies of fluorescence depolarization accompanied by energy transfer processes. PHOTOSYNTHESIS RESEARCH 1994; 41:181-191. [PMID: 24310025 DOI: 10.1007/bf02184159] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/1993] [Accepted: 03/14/1994] [Indexed: 06/02/2023]
Abstract
Examination was made of changes in fluorescence polarization plane by energy transfer in the chlorosomes of the green photosynthetic bacterium,Chloroflexus aurantiacus. Fluorescence anisotropy in the picosecond (ps) time region was analyzed using chlorosomes suspended in solution as well as those oriented in a polyacrylamide gel. When the main component of BChlc was preferentially excited, the decay of fluorescence anisotropy was found to depend on wavelength. In the chlorosome suspension, the anisotropy ratio of BChlc changed from 0.31 to 0.24 within 100 ps following excitation. In the baseplate BChla region, this ratio decreased to a negative value (-0.09) from the initial 0.14. In oriented samples, the degree of polarization remained at 0.68 for BChlc, and changed from 0.25 to -0.40 for the baseplate BChla by excitation light whose electric vector was parallel to the longest axis of chlorosomes. In the latter case, there was a shift from 0.30 to -0.55 by excitation perpendicular to the longest axis. Time-resolved fluorescence polarization spectra clearly indicated extensive changes in polarization plane accompanied by energy transfer. The directions of polarization plane of emission from oriented samples were mostly dependent on chlorosome orientation in the gel but not on that of the polarization plane of excitation light. Orientations of the dipole moment of fluorescence components was consistent with that of absorption components as determined by the linear dichroism (Matsuura et al. (1993) Photochem. Photobiol. 57: 92-97). A model for molecular organization of BChlc anda in chlorosomes is proposed based on anisotropic optical properties.
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Affiliation(s)
- M Mimuro
- National Institute for Basic Biology, 444, Myodaiji, Okazaki, Japan
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Larsen KL, Cox RP, Miller M. Effects of illumination intensity on bacteriochlorophyllc homolog distribution inChloroflexus aurantiacus grown under controlled conditions. PHOTOSYNTHESIS RESEARCH 1994; 41:151-156. [PMID: 24310021 DOI: 10.1007/bf02184155] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/1994] [Accepted: 03/01/1994] [Indexed: 06/02/2023]
Abstract
Green photosynthetic bacteria contain a mixture of stereoisomers and homologs of their major light harvesting pigment, bacteriochlorophyll (BChl)c. We have determined the distribution of photosynthetic pigments in the green filamentous bacteriumChloroflexus aurantiacus grown in turbidostat culture under light-limited conditions at 5 different illumination intensities. Pigments were extracted from isolated cells, analyzed by HPLC, and the homologs of BChlc identified by their mass spectra. The ratio between BChlc, BChla and carotenoid remained constant at low illumination intensities; at higher intensities BChla and carotenoid increased in parallel compared to BChlc. The BChlc homolog distribution changed even under conditions where the ratio of the total amount to the other pigments was unchanged, but there were no evidence for a constant stoichiometric ratio between any pair of homologs.
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Affiliation(s)
- K L Larsen
- Institute of Biochemistry, Odense University, Campusvej 55, DK-5230, Odense M, Denmark
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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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Trissl HW. Long-wavelength absorbing antenna pigments and heterogeneous absorption bands concentrate excitons and increase absorption cross section. PHOTOSYNTHESIS RESEARCH 1993; 35:247-263. [PMID: 24318755 DOI: 10.1007/bf00016556] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/1992] [Accepted: 10/05/1992] [Indexed: 06/02/2023]
Abstract
The light-harvesting apparatus of photosynthetic organisms is highly optimized with respect to efficient collection of excitation energy from photons of different wavelengths and with respect to a high quantum yield of the primary photochemistry. In many cases the primary donor is not an energetic trap as it absorbs hypsochromically compared to the most red-shifted antenna pigment present (long-wavelength antenna). The possible reasons for this as well as for the spectral heterogeneity which is generally found in antenna systems is examined on a theoretical basis using the approach of thermal equilibration of the excitation energy. The calculations show that long-wavelength antenna pigments and heterogeneous absorption bands lead to a concentration of excitons and an increased effective absorption cross section. The theoretically predicted trapping times agree remarkably well with experimental data from several organisms. It is shown that the kinetics of the energy transfer from a long-wavelength antenna pigment to a hypsochromically absorbing primary donor does not represent a major kinetic limitation. The development of long-wavelength antenna and spectrally heterogeneous absorption bands means an evolutionary advantage based on the chromatic adaptation of photosynthetic organelles to spectrally filtered light caused by self-absorption.
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Affiliation(s)
- H W Trissl
- Abt. Biophysik, Fachbereich Biologie/Chemie, Universität Osnabrück, Barbarastr. 11, D-4500, Osnabrück, Germany
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Miller M, Simpson D, Redlinger TE. The effect of detergent on the structure and composition of chlorosomes isolated from Chloroflexus aurantiacus. PHOTOSYNTHESIS RESEARCH 1993; 35:275-283. [PMID: 24318757 DOI: 10.1007/bf00016558] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/1992] [Accepted: 10/12/1992] [Indexed: 06/02/2023]
Abstract
Isolated chlorosomes, treated with the detergent lithium dodecyl sulfate (LDS), can be separated into two green fractions by agarose gel electrophoresis. One fraction contains chlorosomes with a full complement of proteins and antenna BChl c absorbing at 740 nm, but with a more spherical form than the normal ellipsoid shape observed in control chlorosomes. The second fraction was completely devoid of proteins but had a similar absorption spectrum. Electron micrographs of the protein-free fraction indicated the presence of stain-excluding spheres with overall dimensions resembling those of intact chlorosomes (40-100 nm). These spheres are probably micelles of BChl c liberated from the chlorosomes during the detergent treatment, since similar structures could be produced when purified BChl c, dissolved in 1-hexanol, was dispersed in buffer, producing an aggregate absorbing at 742 nm. These results suggest that the chlorosome proteins are not required to produce an arrangement of BChl c chromophores which gives rise to a 740 nm absorption peak resembling that of intact chlorosomes. It seems probable, however, that proteins have a role in determining the overall shape of the chlorosome. Treatment with cross-linking reagents did not prevent the detergent-induced changes in chlorosome morphology.
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Affiliation(s)
- M Miller
- Institute of Biochemistry, Odense University, Campusvej 55, DK-5230, Odense M, Denmark
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Miller M, Gillbro T, Olson JM. AQUEOUS AGGREGATES OF BACTERIOCHLOROPHYLL c AS A MODEL FOR PIGMENT ORGANIZATION IN CHLOROSOMES. Photochem Photobiol 1993. [DOI: 10.1111/j.1751-1097.1993.tb02262.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Niedermeier G, Scheer H, Feick RG. The functional role of protein in the organization of bacteriochlorophyll c in chlorosomes of Chloroflexus aurantiacus. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 204:685-92. [PMID: 1541281 DOI: 10.1111/j.1432-1033.1992.tb16682.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The preparation of five different fractions containing bacteriochlorophyll (Bchl) c and their absorption and circular dichroic properties have been described. The fractions investigated were purified chlorosomes, proteolytically modified chlorosomes, chlorosomes treated with lithium dodecyl sulfate (LDS) which were subsequently subjected to size-exclusion chromatography, in vitro Bchl c aggregates and, additionally, the so-called GEF chlorosomes [prepared according to Griebenow and Holzwarth (1989) Biochim. Biophys. Acta 973, 235-240]. Proteolysis of chlorosomes caused a 35-40% decrease in absorption intensity, a 6-8 nm blue shift of the 740-nm peak and, in particular, a drastic increase of rotational strength as revealed by CD spectroscopy. Although oligomeric Bchl c aggregates and LDS-treated chlorosomes had absorption characteristics similar to Bchl c in vivo, the data clearly indicated that protein, perhaps the chlorosome-specific Mr-3700 polypeptide, was involved in the organization of Bchl c in chlorosomes from C. aurantiacus. Furthermore, the results showed that the LDS-treated chlorosome fraction was most likely comprised of a micellar complex of Bchl c with LDS which represented an entity entirely different from chlorosomes.
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Affiliation(s)
- G Niedermeier
- Max-Planck-Institut für Biochemie, Martinsried, Federal Republic of Germany
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Andrews DL, Juzeliūnas G. The range dependence of fluorescence anisotropy in molecular energy transfer. J Chem Phys 1991. [DOI: 10.1063/1.461624] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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