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Utilization of blue-green light by chlorosomes from the photosynthetic bacterium Chloroflexus aurantiacus: Ultrafast excitation energy conversion and transfer. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148396. [PMID: 33581107 DOI: 10.1016/j.bbabio.2021.148396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 02/01/2021] [Accepted: 02/05/2021] [Indexed: 01/14/2023]
Abstract
Chlorosomes of photosynthetic green bacteria are unique molecular assemblies providing efficient light harvesting followed by multi-step transfer of excitation energy to reaction centers. In each chlorosome, 104-105 bacteriochlorophyll (BChl) c/d/e molecules are organized by self-assembly into high-ordered aggregates. We studied the early-time dynamics of the excitation energy flow and energy conversion in chlorosomes isolated from Chloroflexus (Cfx.) aurantiacus bacteria by pump-probe spectroscopy with 30-fs temporal resolution at room temperature. Both the S2 state of carotenoids (Cars) and the Soret states of BChl c were excited at ~490 nm, and absorption changes were probed at 400-900 nm. A global analysis of spectroscopy data revealed that the excitation energy transfer (EET) from Cars to BChl c aggregates occurred within ~100 fs, and the Soret → Q energy conversion in BChl c occurred faster within ~40 fs. This conclusion was confirmed by a detailed comparison of the early exciton dynamics in chlorosomes with different content of Cars. These processes are accompanied by excitonic and vibrational relaxation within 100-270 fs. The well-known EET from BChl c to the baseplate BChl a proceeded on a ps time-scale. We showed that the S1 state of Cars does not participate in EET. We discussed the possible presence (or absence) of an intermediate state that might mediates the Soret → Qy internal conversion in chlorosomal BChl c. We discussed a possible relationship between the observed exciton dynamics and the structural heterogeneity of chlorosomes.
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Yakovlev AG, Taisova AS, Fetisova ZG. Q-band hyperchromism and B-band hypochromism of bacteriochlorophyll c as a tool for investigation of the oligomeric structure of chlorosomes of the green photosynthetic bacterium Chloroflexus aurantiacus. PHOTOSYNTHESIS RESEARCH 2020; 146:95-108. [PMID: 31939070 DOI: 10.1007/s11120-019-00707-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/31/2019] [Indexed: 06/10/2023]
Abstract
Chlorosomes of green photosynthetic bacteria are the most amazing example of long-range ordered natural light-harvesting antennae. Chlorosomes are the largest among all known photosynthetic light-harvesting structures (~ 104-105 pigments in the aggregated state). The chlorosomal bacteriochlorophyll (BChl) c/d/e molecules are organized via self-assembly and do not require proteins to provide a scaffold for efficient light harvesting. Despite numerous investigations, a consensus regarding the spatial structure of chlorosomal antennae has not yet been reached. In the present work, we studied hyperchromism/hypochromism in the chlorosomal BChl c Q/B absorption bands of the green photosynthetic bacterium Chloroflexus (Cfx.) aurantiacus. The chlorosomes were isolated from cells grown under different light intensities and therefore, as we discovered earlier, they had different sizes of both BChl c antennae and their unit building blocks. We have shown experimentally that the Q-/B-band hyperchromism/hypochromism is proportional to the size of the chlorosomal antenna. We explained theoretically these findings in terms of excitonic intensity borrowing between the Q and B bands for the J-/H-aggregates of the BChls. The theory developed by Gülen (Photosynth Res 87:205-214, 2006) showed the dependence of the Q-/B-band hyperchromism/hypochromism on the structure of the aggregates. For the model of exciton-coupled BChl c linear chains within a unit building block, the theory predicted an increase in the hyperchromism/hypochromism with the increase in the number of molecules per chain and a decrease in it with the increase in the number of chains. It was previously shown that this model ensured a good fit with spectroscopy experiments and approximated the BChl c low packing density in vivo. The presented experimental and theoretical studies of the Q-/B-band hyperchromism/hypochromism permitted us to conclude that the unit building block of Cfx. aurantiacus chlorosomes comprises of several short BChl c chains.This conclusion is in accordance with previous linear and nonlinear spectroscopy studies on Cfx. aurantiacus chlorosomes.
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Affiliation(s)
- Andrei G Yakovlev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow, Russian Federation, 119991.
| | - Alexandra S Taisova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow, Russian Federation, 119991
| | - Zoya G Fetisova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow, Russian Federation, 119991.
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Taguchi S, Suga K, Hayashi K, Yoshimoto M, Okamoto Y, Nakamura H, Umakoshi H. Aggregation of chlorophyll a induced in self-assembled membranes composed of DMPC and DHPC. Colloids Surf B Biointerfaces 2019; 175:403-408. [DOI: 10.1016/j.colsurfb.2018.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/26/2018] [Accepted: 12/05/2018] [Indexed: 02/07/2023]
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Saga Y, Yoshida N, Yamada S, Mizoguchi T, Tamiaki H. Biosynthesis of unnatural glycolipids possessing diyne moiety in the acyl chain in the green sulfur photosynthetic bacterium Chlorobaculum tepidum grown by supplementation of 10,12-heptadecadiynic acid. Biochem Biophys Rep 2017; 9:42-46. [PMID: 28955987 PMCID: PMC5614547 DOI: 10.1016/j.bbrep.2016.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/09/2016] [Accepted: 11/12/2016] [Indexed: 12/04/2022] Open
Abstract
Unnatural glycolipids possessing the diyne moiety in their acyl groups were successfully biosynthesized in the green sulfur photosynthetic bacterium Chlorobaculum (Cba.) tepidum by cultivation with supplementation of 10,12-heptadecadiynic acid. Monogalactosyldiacylglycerol (MGDG) and rhamnosylgalactosyldiacylglycerol (RGDG) esterified with one 10,12-heptadecadiynic acid were primarily formed in the cells, and small amounts of glycolipids esterified with the two unnatural fatty acids can also be detected. The relative ratio of these unnatural glycolipids occupied in the total glycolipids was estimated to be 49% based on HPLC analysis using a evaporative light scattering detector. These results indicate that the acyl groups in glycolipids, which play important roles in the formation of extramembranous antenna complexes called chlorosomes, can be modified in vivo by cultivation of green sulfur photosynthetic bacteria with exogenous synthetic fatty acids. Visible absorption and circular dichroism spectra of Cba. tepidum containing the unnatural glycolipids demonstrated the formation of chlorosomes, indicating that the unnatural glycolipids in this study did not interfere with the biogenesis of chlorosomes. Novel glycolipids possessing a diyne moiety in the acyl chain were biosynthesized. Supplemental fatty acids were used in the biosynthesis of glycolipids in the photosynthetic bacterium. The novel glycolipids did not inhibit the formation of photosynthetic antenna complexes.
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Affiliation(s)
- Yoshitaka Saga
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan.,PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Nozomi Yoshida
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Shota Yamada
- Department of Chemistry, Faculty of Science and Engineering, Kindai University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Tadashi Mizoguchi
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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Wan Y, Stradomska A, Knoester J, Huang L. Direct Imaging of Exciton Transport in Tubular Porphyrin Aggregates by Ultrafast Microscopy. J Am Chem Soc 2017; 139:7287-7293. [DOI: 10.1021/jacs.7b01550] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan Wan
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Anna Stradomska
- School
of Chemistry, University of Glasgow, University Avenue, Glasgow, G12 8QQ, United Kingdom
| | - Jasper Knoester
- Zernike
Institute for Advanced Materials, University of Groningen, Nijenborgh
4, 9747AG Groningen, The Netherlands
| | - Libai Huang
- Department
of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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CHATTORAJ SHYAMTANU, BHATTACHARYYA KANKAN. Spatial inhomogeneity in spectra and exciton dynamics in porphyrin micro-rods and micro-brushes: Confocal microscopy. J CHEM SCI 2016. [DOI: 10.1007/s12039-016-1155-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Somoza Márquez A, Chen L, Sun K, Zhao Y. Probing ultrafast excitation energy transfer of the chlorosome with exciton–phonon variational dynamics. Phys Chem Chem Phys 2016; 18:20298-311. [DOI: 10.1039/c5cp06491k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Excitation energy transfer of the chlorosome is investigated using exciton–phonon variational dynamics revealing ultrafast energy relaxation and exciton delocalization on a 100 fs scale.
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Affiliation(s)
| | - Lipeng Chen
- Division of Materials Science
- Nanyang Technological University
- Singapore 639798
- Singapore
| | - Kewei Sun
- School of Science
- Hangzhou Dianzi University
- Hangzhou 310018
- China
| | - Yang Zhao
- Division of Materials Science
- Nanyang Technological University
- Singapore 639798
- Singapore
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Ceymann H, Rosspeintner A, Schreck MH, Mützel C, Stoy A, Vauthey E, Lambert C. Cooperative enhancement versus additivity of two-photon-absorption cross sections in linear and branched squaraine superchromophores. Phys Chem Chem Phys 2016; 18:16404-13. [DOI: 10.1039/c6cp02312f] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Our investigation of the nonlinear optical properties of a series of oligomeric squaraine dyes showed enhanced cross sections for linear oligomers but only additivity for branched systems.
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Affiliation(s)
- Harald Ceymann
- Institut für Organische Chemie
- Universität Würzburg
- Wilhelm Conrad Röntgen Research Center for Complex Material Systems
- Center for Nanosystems Chemistry
- Am Hubland
| | - Arnulf Rosspeintner
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Maximilian H. Schreck
- Institut für Organische Chemie
- Universität Würzburg
- Wilhelm Conrad Röntgen Research Center for Complex Material Systems
- Center for Nanosystems Chemistry
- Am Hubland
| | - Carina Mützel
- Institut für Organische Chemie
- Universität Würzburg
- Wilhelm Conrad Röntgen Research Center for Complex Material Systems
- Center for Nanosystems Chemistry
- Am Hubland
| | - Andreas Stoy
- Institut für Organische Chemie
- Universität Würzburg
- Wilhelm Conrad Röntgen Research Center for Complex Material Systems
- Center for Nanosystems Chemistry
- Am Hubland
| | - Eric Vauthey
- Department of Physical Chemistry
- University of Geneva
- CH-1211 Geneva 4
- Switzerland
| | - Christoph Lambert
- Institut für Organische Chemie
- Universität Würzburg
- Wilhelm Conrad Röntgen Research Center for Complex Material Systems
- Center for Nanosystems Chemistry
- Am Hubland
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9
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Yakovlev A, Novoderezhkin V, Taisova A, Shuvalov V, Fetisova Z. Orientation of B798 BChl a Q y transition dipoles in Chloroflexus aurantiacus chlorosomes: polarized transient absorption spectroscopy studies. PHOTOSYNTHESIS RESEARCH 2015; 125:31-42. [PMID: 25515768 DOI: 10.1007/s11120-014-0060-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/16/2014] [Indexed: 06/04/2023]
Abstract
Isotropic and anisotropic pump-probe spectra of Cfx. aurantiacus chlorosomes were measured on the fs-through ps-time scales for the B798 BChl a Q y band upon direct excitation of the B798 band at T = 293 K and T = 90 K. Upon direct excitation of the B798 band, the anisotropy parameter value r(λ) was constant within the whole BChl a Q y band at any delay time at both temperatures. The value of the anisotropy parameter r decayed from r = 0.4 at both temperatures (at 200 fs delay time after excitation) to the steady-state values r = 0.1 at T = 293 K and to r = 0.09 at T = 90 K (at 30 ÷ 100 ps delay time after excitation). The results were considered within the framework of the model of uniaxial orientation distribution of BChl-a transition dipoles within a single Cfx. aurantiacus chlorosome. This implies that the B798 BChl a Q y transition dipoles, randomly distributed around the normal to the baseplate plane, form the angle θ with the plane. For this model, the theoretical dependence of the steady-state anisotropy parameter r on the angle θ was derived. According to the theoretical dependence r(θ), the angle θ corresponding to the experimental steady-state value r = 0.1 at T = 293 K was found to equal 55°. As the temperature drops to 90 K, the angle θ decreases to 54°.
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Affiliation(s)
- Andrei Yakovlev
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119991, Moscow, Russian Federation
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10
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Lambert C, Scherpf T, Ceymann H, Schmiedel A, Holzapfel M. Coupled Oscillators for Tuning Fluorescence Properties of Squaraine Dyes. J Am Chem Soc 2015; 137:3547-57. [DOI: 10.1021/ja512338w] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Christoph Lambert
- Institut für Organische Chemie, Universität Würzburg, Wilhelm Conrad Röntgen Research
Center for Complex Material Systems, Center for Nanosystems Chemistry,
Am Hubland, 97074 Würzburg, Germany
| | - Thorsten Scherpf
- Institut für Organische Chemie, Universität Würzburg, Wilhelm Conrad Röntgen Research
Center for Complex Material Systems, Center for Nanosystems Chemistry,
Am Hubland, 97074 Würzburg, Germany
| | - Harald Ceymann
- Institut für Organische Chemie, Universität Würzburg, Wilhelm Conrad Röntgen Research
Center for Complex Material Systems, Center for Nanosystems Chemistry,
Am Hubland, 97074 Würzburg, Germany
| | - Alexander Schmiedel
- Institut für Organische Chemie, Universität Würzburg, Wilhelm Conrad Röntgen Research
Center for Complex Material Systems, Center for Nanosystems Chemistry,
Am Hubland, 97074 Würzburg, Germany
| | - Marco Holzapfel
- Institut für Organische Chemie, Universität Würzburg, Wilhelm Conrad Röntgen Research
Center for Complex Material Systems, Center for Nanosystems Chemistry,
Am Hubland, 97074 Würzburg, Germany
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11
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Pšenčík J, Butcher SJ, Tuma R. Chlorosomes: Structure, Function and Assembly. THE STRUCTURAL BASIS OF BIOLOGICAL ENERGY GENERATION 2014. [DOI: 10.1007/978-94-017-8742-0_5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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12
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Saga Y, Saiki T, Takahashi N, Shibata Y, Tamiaki H. Scrambled Self-Assembly of Bacteriochlorophyllscandein Aqueous Triton X-100 Micelles. Photochem Photobiol 2013; 90:552-9. [DOI: 10.1111/php.12219] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Accepted: 11/28/2013] [Indexed: 01/13/2023]
Affiliation(s)
- Yoshitaka Saga
- Department of Chemistry; Faculty of Science and Engineering; Kinki University; Higashi-Osaka Japan
| | - Tatsuya Saiki
- Department of Chemistry; Faculty of Science and Engineering; Kinki University; Higashi-Osaka Japan
| | - Naoya Takahashi
- Department of Chemistry; Faculty of Science and Engineering; Kinki University; Higashi-Osaka Japan
| | - Yutaka Shibata
- Department of Chemistry; Graduate School of Science; Tohoku University; Sendai Japan
| | - Hitoshi Tamiaki
- Graduate School of Life Sciences; Ritsumeikan University; Kusatsu Japan
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13
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Tang JKH, Xu Y, Muhlmann GM, Zare F, Khin Y, Tam SW. Temperature shift effect on the Chlorobaculum tepidum chlorosomes. PHOTOSYNTHESIS RESEARCH 2013; 115:23-41. [PMID: 23435510 DOI: 10.1007/s11120-013-9800-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 01/29/2013] [Indexed: 06/01/2023]
Abstract
Chlorobaculum [Cba.] tepidum is known to grow optimally at 48-52 °C and can also be cultured at ambient temperatures. In this paper, we prepared constant temperature, temperature shift, and temperature shift followed by backshift cultures and investigated the intrinsic properties and spectral features of chlorosomes from those cultures using various approaches, including temperature-dependent measurements on circular dichroism (CD), UV-visible, and dynamic light scattering. Our studies indicate that (1) chlorosomes from constant temperature cultures at 50 and 30 °C exhibited more resistance to heat relative to temperature shift cultures; (2) as temperature increases bacteriochlorophyll c (BChl c) in chlorosomes is prone to demetalation, which forms bacteriopheophytin c, and degradation under aerobic conditions. Some BChl c aggregates inside reduced chlorosomes prepared in low-oxygen environments can reform after heat treatments; (3) temperature shift cultures synthesize and incorporate more BChl c homologs with a smaller substituent at C-8 on the chlorin ring and less BChl c homologs with a larger long-chain alcohol at C-17(3) versus constant-temperature cultures. We hypothesize that the long-chain alcohol at C-17(3) (and perhaps together with the substituent at C-8) may account for thermal stability of chlorosomes and the substituent at C-8 may assist self-assembling BChls; and (4) while almost identical absorption spectra are detected, chlorosomes from different growth conditions exhibited differences in the rotational length of the CD signal, and aerobic and reduced chlorosomes also display different Qy CD intensities. Further, chlorosomes exhibited changes of CD features in response to temperature increases. Additionally, we compare temperature-dependent studies for the Cba. tepidum chlorosomes and previous studies for the Chloroflexus aurantiacus chlorosomes. Together, our work provides useful and novel insights on the properties and organization of chlorosomes.
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Orf GS, Tank M, Vogl K, Niedzwiedzki DM, Bryant DA, Blankenship RE. Spectroscopic insights into the decreased efficiency of chlorosomes containing bacteriochlorophyll f. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1827:493-501. [DOI: 10.1016/j.bbabio.2013.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/08/2013] [Accepted: 01/15/2013] [Indexed: 11/24/2022]
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15
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König C, Neugebauer J. Protein Effects on the Optical Spectrum of the Fenna–Matthews–Olson Complex from Fully Quantum Chemical Calculations. J Chem Theory Comput 2013; 9:1808-20. [DOI: 10.1021/ct301111q] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Carolin König
- Theoretische Organische
Chemie, Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster,
Germany
| | - Johannes Neugebauer
- Theoretische Organische
Chemie, Organisch-Chemisches
Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster,
Germany
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Shoji S, Hashishin T, Tamiaki H. Construction of Chlorosomal Rod Self-Aggregates in the Solid State on Any Substrates from Synthetic Chlorophyll Derivatives Possessing an Oligomethylene Chain at the 17-Propionate Residue. Chemistry 2012; 18:13331-41. [DOI: 10.1002/chem.201201935] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Indexed: 11/09/2022]
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17
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Kataoka Y, Shibata Y, Tamiaki H. Supramolecular energy transfer from photoexcited chlorosomal zinc porphyrin self-aggregates to a chlorin or bacteriochlorin monomer as models of main light-harvesting antenna systems in green photosynthetic bacteria. Bioorg Med Chem Lett 2012; 22:5218-21. [DOI: 10.1016/j.bmcl.2012.06.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 10/28/2022]
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18
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König C, Neugebauer J. Quantum chemical description of absorption properties and excited-state processes in photosynthetic systems. Chemphyschem 2011; 13:386-425. [PMID: 22287108 DOI: 10.1002/cphc.201100408] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Indexed: 11/07/2022]
Abstract
The theoretical description of the initial steps in photosynthesis has gained increasing importance over the past few years. This is caused by more and more structural data becoming available for light-harvesting complexes and reaction centers which form the basis for atomistic calculations and by the progress made in the development of first-principles methods for excited electronic states of large molecules. In this Review, we discuss the advantages and pitfalls of theoretical methods applicable to photosynthetic pigments. Besides methodological aspects of excited-state electronic-structure methods, studies on chlorophyll-type and carotenoid-like molecules are discussed. We also address the concepts of exciton coupling and excitation-energy transfer (EET) and compare the different theoretical methods for the calculation of EET coupling constants. Applications to photosynthetic light-harvesting complexes and reaction centers based on such models are also analyzed.
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Affiliation(s)
- Carolin König
- Institute for Physical and Theoretical Chemistry, Technical University Braunschweig, Braunschweig, Germany
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Tian Y, Camacho R, Thomsson D, Reus M, Holzwarth AR, Scheblykin IG. Organization of bacteriochlorophylls in individual chlorosomes from Chlorobaculum tepidum studied by 2-dimensional polarization fluorescence microscopy. J Am Chem Soc 2011; 133:17192-9. [PMID: 21923120 DOI: 10.1021/ja2019959] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chlorosomes are the largest and most efficient natural light-harvesting systems and contain supramolecular assemblies of bacteriochlorophylls that are organized without proteins. Despite a recent structure determination for chlorosomes from Chlorobaculum tepidum (Ganapathy Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 8525), the issue of a possible large structural disorder is still discussed controversially. We have studied individual chlorosomes prepared under very carefully controlled growth condition by a novel 2-dimensional polarization single molecule imaging technique giving polarization information for both fluorescence excitation and emission simultaneously. Contrary to the existing literature data, the polarization degree or modulation depth (M) for both excitation (absorption) and emission (fluorescence) showed extremely narrow distributions. The fluorescence was always highly polarized with M ≈ 0.77, independent of the excitation wavelength. Moreover, the fluorescence spectra of individual chlorosomes were identical within the error limits. These results lead us to conclude that all chlorosomes possess the same type of internal organization in terms of the arrangement of the bacteriochlorophyll c transition dipole moments and their total excitonic transition dipole possess a cylindrical symmetry in agreement with the previously suggested concentric multitubular chlorophyll aggregate organization (Ganapathy Proc. Natl. Acad. Sci. U.S.A. 2009, 106, 8525).
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Affiliation(s)
- Yuxi Tian
- Chemical Physics, Lund University, Lund, Sweden
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Renger G, Pieper J, Theiss C, Trostmann I, Paulsen H, Renger T, Eichler HJ, Schmitt FJ. Water soluble chlorophyll binding protein of higher plants: a most suitable model system for basic analyses of pigment-pigment and pigment-protein interactions in chlorophyll protein complexes. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1462-1472. [PMID: 21256622 DOI: 10.1016/j.jplph.2010.12.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 12/08/2010] [Accepted: 12/08/2010] [Indexed: 05/30/2023]
Abstract
This short review paper describes spectroscopic studies on pigment-pigment and pigment-protein interactions of chlorophyll (Chl) a and b bound to the recombinant protein of class IIa water soluble chlorophyll protein (WSCP) from cauliflower. Two Chls form a strongly excitonically coupled open sandwich dimer within the tetrameric protein matrix. In marked contrast to the mode of excitonic coupling of Chl and bacterio-Chl molecules in light harvesting complexes and reaction centers of all photosynthetic organisms, the unique structural pigment array in the Chl dimer of WSCP gives rise to an upper excitonic state with a large oscillator strength. This property opens the way for thorough investigations on exciton relaxation processes in Chl-protein complexes. Lifetime measurements of excited singlet states show that the unusual stability towards photodamage of Chls bound to WSCP, which lack any protective carotenoid molecule, originates from a high diffusion barrier to interaction of molecular dioxygen with Chl triplets. Site selective spectroscopic methods provide a wealth of information on the interactions of the Chls with the protein matrix and on the vibronic structure of the pigments. The presented data and discussions illustrate the great potential of WSCP as a model system for systematic experimental and theoretical studies on the functionalizing of Chls by the protein matrix. It opens the way for further detailed analyses and a deeper understanding of the properties of pigment protein complexes.
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Affiliation(s)
- G Renger
- Max Volmer Laboratory for Biophysical Chemistry, Berlin Institute of Technology, Berlin, Germany.
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