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Würthner F, Kaiser TE, Saha-Möller CR. J-Aggregate: von ihrer zufälligen Entdeckung bis zum gezielten supramolekularen Aufbau funktioneller Farbstoffmaterialien. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201002307] [Citation(s) in RCA: 252] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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102
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Würthner F, Kaiser TE, Saha-Möller CR. J-Aggregates: From Serendipitous Discovery to Supramolecular Engineering of Functional Dye Materials. Angew Chem Int Ed Engl 2011; 50:3376-410. [DOI: 10.1002/anie.201002307] [Citation(s) in RCA: 1790] [Impact Index Per Article: 137.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Indexed: 11/08/2022]
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103
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Larson CR, Seng CO, Lauman L, Matthies HJ, Wen J, Blankenship RE, Allen JP. The three-dimensional structure of the FMO protein from Pelodictyon phaeum and the implications for energy transfer. PHOTOSYNTHESIS RESEARCH 2011; 107:139-150. [PMID: 21181557 DOI: 10.1007/s11120-010-9604-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 12/07/2010] [Indexed: 05/30/2023]
Abstract
The Fenna-Matthews-Olson (FMO) antenna protein from the green bacterium Pelodictyon phaeum mediates the transfer of energy from the peripheral chlorosome antenna complex to the membrane-bound reaction center. The three-dimensional structure of this protein has been solved using protein crystallography to a resolution limit of 2.0 Å, with R(work) and R(free) values of 16.6 and 19.9%, respectively. The structure is a trimer of three identical subunits related by a threefold symmetry axis. Each subunit has two beta sheets that surround 8 bacteriochlorophylls. The bacteriochlorophylls are all five-coordinated, with the axial ligand being a histidine, serine, backbone carbonyl, or bound water molecule. The arrangement of the bacteriochlorophylls is generally well conserved in comparison to other FMO structures, but differences are apparent in the interactions with the surrounding protein. In this structure the position and orientation of the eighth bacteriochlorophyll is well defined and shows differences in its location and the coordination of the central Mg compared to previous models. The implications of this structure on the ability of the FMO protein to perform energy transfer are discussed in terms of the experimental optical measurements.
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Affiliation(s)
- Chadwick R Larson
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA
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104
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Tang KH, Urban VS, Wen J, Xin Y, Blankenship RE. SANS investigation of the photosynthetic machinery of Chloroflexus aurantiacus. Biophys J 2011; 99:2398-407. [PMID: 20959079 DOI: 10.1016/j.bpj.2010.07.068] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 07/18/2010] [Accepted: 07/27/2010] [Indexed: 11/30/2022] Open
Abstract
Green photosynthetic bacteria harvest light and perform photosynthesis in low-light environments, and contain specialized antenna complexes to adapt to this condition. We performed small-angle neutron scattering (SANS) studies to obtain structural information about the photosynthetic apparatus, including the peripheral light-harvesting chlorosome complex, the integral membrane light-harvesting B808-866 complex, and the reaction center (RC) in the thermophilic green phototrophic bacterium Chloroflexus aurantiacus. Using contrast variation in SANS measurements, we found that the B808-866 complex is wrapped around the RC in Cfx. aurantiacus, and the overall size and conformation of the B808-866 complex of Cfx. aurantiacus is roughly comparable to the LH1 antenna complex of the purple bacteria. A similar size of the isolated B808-866 complex was suggested by dynamic light scattering measurements, and a smaller size of the RC of Cfx. aurantiacus compared to the RC of the purple bacteria was observed. Further, our SANS measurements indicate that the chlorosome is a lipid body with a rod-like shape, and that the self-assembly of bacteriochlorophylls, the major component of the chlorosome, is lipid-like. Finally, two populations of chlorosome particles are suggested in our SANS measurements.
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Affiliation(s)
- Kuo-Hsiang Tang
- Department of Biology, Washington University in St. Louis, Missouri, USA
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105
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Mass O, Pandithavidana DR, Ptaszek M, Santiago K, Springer JW, Jiao J, Tang Q, Kirmaier C, Bocian DF, Holten D, Lindsey JS. De novo synthesis and properties of analogues of the self-assembling chlorosomal bacteriochlorophylls. NEW J CHEM 2011. [DOI: 10.1039/c1nj20611g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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106
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Abstract
Energy conversion of sunlight by photosynthetic organisms has changed Earth and life on it. Photosynthesis arose early in Earth's history, and the earliest forms of photosynthetic life were almost certainly anoxygenic (non-oxygen evolving). The invention of oxygenic photosynthesis and the subsequent rise of atmospheric oxygen approximately 2.4 billion years ago revolutionized the energetic and enzymatic fundamentals of life. The repercussions of this revolution are manifested in novel biosynthetic pathways of photosynthetic cofactors and the modification of electron carriers, pigments, and existing and alternative modes of photosynthetic carbon fixation. The evolutionary history of photosynthetic organisms is further complicated by lateral gene transfer that involved photosynthetic components as well as by endosymbiotic events. An expanding wealth of genetic information, together with biochemical, biophysical, and physiological data, reveals a mosaic of photosynthetic features. In combination, these data provide an increasingly robust framework to formulate and evaluate hypotheses concerning the origin and evolution of photosynthesis.
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107
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Self-aggregates of natural chlorophylls and their synthetic analogues in aqueous media for making light-harvesting systems. Coord Chem Rev 2010. [DOI: 10.1016/j.ccr.2009.12.027] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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108
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Shibata Y, Tateishi S, Nakabayashi S, Itoh S, Tamiaki H. Intensity Borrowing via Excitonic Couplings among Soret and Qy Transitions of Bacteriochlorophylls in the Pigment Aggregates of Chlorosomes, the Light-Harvesting Antennae of Green Sulfur Bacteria. Biochemistry 2010; 49:7504-15. [DOI: 10.1021/bi100607c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yutaka Shibata
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Shingo Tateishi
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Shosuke Nakabayashi
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Shigeru Itoh
- Division of Material Science (Physics), Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan
| | - Hitoshi Tamiaki
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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109
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Alster J, Polívka T, Arellano J, Chábera P, Vácha F, Pšenčík J. β-Carotene to bacteriochlorophyll c energy transfer in self-assembled aggregates mimicking chlorosomes. Chem Phys 2010. [DOI: 10.1016/j.chemphys.2010.02.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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110
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Oostergetel GT, van Amerongen H, Boekema EJ. The chlorosome: a prototype for efficient light harvesting in photosynthesis. PHOTOSYNTHESIS RESEARCH 2010; 104:245-55. [PMID: 20130996 PMCID: PMC2882566 DOI: 10.1007/s11120-010-9533-0] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Accepted: 01/16/2010] [Indexed: 05/18/2023]
Abstract
Three phyla of bacteria include phototrophs that contain unique antenna systems, chlorosomes, as the principal light-harvesting apparatus. Chlorosomes are the largest known supramolecular antenna systems and contain hundreds of thousands of BChl c/d/e molecules enclosed by a single membrane leaflet and a baseplate. The BChl pigments are organized via self-assembly and do not require proteins to provide a scaffold for efficient light harvesting. Their excitation energy flows via a small protein, CsmA embedded in the baseplate to the photosynthetic reaction centres. Chlorosomes allow for photosynthesis at very low light intensities by ultra-rapid transfer of excitations to reaction centres and enable organisms with chlorosomes to live at extraordinarily low light intensities under which no other phototrophic organisms can grow. This article reviews several aspects of chlorosomes: the supramolecular and molecular organizations and the light-harvesting and spectroscopic properties. In addition, it provides some novel information about the organization of the baseplate.
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Affiliation(s)
- Gert T. Oostergetel
- Biophysical Chemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands
| | - Egbert J. Boekema
- Biophysical Chemistry, Groningen Biomolecular Sciences & Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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111
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Psencík J, Torkkeli M, Zupcanová A, Vácha F, Serimaa RE, Tuma R. The lamellar spacing in self-assembling bacteriochlorophyll aggregates is proportional to the length of the esterifying alcohol. PHOTOSYNTHESIS RESEARCH 2010; 104:211-219. [PMID: 20306134 DOI: 10.1007/s11120-010-9541-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 02/24/2010] [Indexed: 05/29/2023]
Abstract
Chlorosomes from green photosynthetic bacteria are large photosynthetic antennae containing self-assembling aggregates of bacteriochlorophyll c, d, or e. The pigments within chlorosomes are organized in curved lamellar structures. Aggregates with similar optical properties can be prepared in vitro, both in polar as well as non-polar solvents. In order to gain insight into their structure we examined hexane-induced aggregates of purified bacteriochlorophyll c by X-ray scattering. The bacteriochlorophyll c aggregates exhibit scattering features that are virtually identical to those of native chlorosomes demonstrating that the self-assembly of these pigments is fully encoded in their chemical structure. Thus, the hexane-induced aggregates constitute an excellent model to study the effects of chemical structure on assembly. Using bacteriochlorophyllides transesterified with different alcohols we have established a linear relationship between the esterifying alcohol length and the lamellar spacing. The results provide a structural basis for lamellar spacing variability observed for native chlorosomes from different species. A plausible physiological role of this variability is discussed. The X-ray scattering also confirmed the assignments of peaks, which arise from the crystalline baseplate in the native chlorosomes.
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Affiliation(s)
- Jakub Psencík
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic.
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112
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Akutsu H, Egawa A, Fujiwara T. Atomic structure of the bacteriochlorophyll c assembly in intact chlorosomes from Chlorobium limicola determined by solid-state NMR. PHOTOSYNTHESIS RESEARCH 2010; 104:221-231. [PMID: 20063063 DOI: 10.1007/s11120-009-9523-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 12/21/2009] [Indexed: 05/28/2023]
Abstract
Green sulfur photosynthetic bacteria optimize their antennas, chlorosomes, especially for harvesting weak light by organizing bacteriochlorophyll (BChl) assembly without any support of proteins. As it is difficult to crystallize the organelles, a high-resolution structure of the light-harvesting devices in the chlorosomes has not been clarified. We have determined the structure of BChl c assembly in the intact chlorosomes from Chlorobium limicola on the basis of (13)C dipolar spin-diffusion solid-state NMR analysis of uniformly (13)C-labeled chlorosomes. About 90 intermolecular C-C distances were obtained by the simultaneous assignment of distance correlations and the structure optimization preceded by the polarization-transfer matrix analysis. An atomic structure was obtained, using these distance constraints. The determined structure of the chlorosomal BChl c assembly is built with the parallel layers of piggyback-dimers. This supramolecular structure would provide insights into the mechanism of weak-light capturing.
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Affiliation(s)
- Hideo Akutsu
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Japan.
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113
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Pedersen MØ, Linnanto J, Frigaard NU, Nielsen NC, Miller M. A model of the protein-pigment baseplate complex in chlorosomes of photosynthetic green bacteria. PHOTOSYNTHESIS RESEARCH 2010; 104:233-243. [PMID: 20077007 DOI: 10.1007/s11120-009-9519-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2009] [Accepted: 12/16/2009] [Indexed: 05/28/2023]
Abstract
In contrast to photosynthetic reaction centers, which share the same structural architecture, more variety is found in the light-harvesting antenna systems of phototrophic organisms. The largest antenna system described, so far, is the chlorosome found in anoxygenic green bacteria, as well as in a recently discovered aerobic phototroph. Chlorosomes are the only antenna system, in which the major light-harvesting pigments are organized in self-assembled supramolecular aggregates rather than on protein scaffolds. This unique feature is believed to explain why some green bacteria are able to carry out photosynthesis at very low light intensities. Encasing the chlorosome pigments is a protein-lipid monolayer including an additional antenna complex: the baseplate, a two-dimensional paracrystalline structure containing the chlorosome protein CsmA and bacteriochlorophyll a (BChl a). In this article, we review current knowledge of the baseplate antenna complex, which physically and functionally connects the chlorosome pigments to the reaction centers via the Fenna-Matthews-Olson protein, with special emphasis on the well-studied green sulfur bacterium Chlorobaculum tepidum (previously Chlorobium tepidum). A possible role for the baseplate in the biogenesis of chlorosomes is discussed. In the final part, we present a structural model of the baseplate through combination of a recent NMR structure of CsmA and simulation of circular dichroism and optical spectra for the CsmA-BChl a complex.
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Affiliation(s)
- Marie Ø Pedersen
- Center for Insoluble Protein Structures, Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, Arhus C, Aarhus, Denmark
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114
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McConnell I, Li G, Brudvig GW. Energy conversion in natural and artificial photosynthesis. CHEMISTRY & BIOLOGY 2010; 17:434-47. [PMID: 20534342 PMCID: PMC2891097 DOI: 10.1016/j.chembiol.2010.05.005] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 05/02/2010] [Accepted: 05/04/2010] [Indexed: 11/25/2022]
Abstract
Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil-fuel dependence has severe consequences, including energy security issues and greenhouse gas emissions. The consequences of fossil-fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and in artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices, including photoelectrochemical cells, for solar energy conversion.
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Affiliation(s)
- Iain McConnell
- Department of Chemistry, Yale University, New Haven, CT 06520-8107
| | - Gonghu Li
- Department of Chemistry, Yale University, New Haven, CT 06520-8107
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, CT 06520-8107
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115
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Kim Y, Alexander-Katz A. Phase behavior of symmetric disk-coil molecules. J Chem Phys 2010; 132:174901. [DOI: 10.1063/1.3407660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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116
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Spectral properties of single light-harvesting complexes in bacterial photosynthesis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2010. [DOI: 10.1016/j.jphotochemrev.2010.02.002] [Citation(s) in RCA: 156] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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117
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Kunieda M, Yamamoto K, Tamiaki H. Self-aggregation of synthetic multi-hydroxylated zinc chlorophylls. Tetrahedron 2010. [DOI: 10.1016/j.tet.2009.12.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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118
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Balaban TS, Bhise AD, Bringmann G, Bürck J, Chappaz-Gillot C, Eichhöfer A, Fenske D, Götz DCG, Knauer M, Mizoguchi T, Mössinger D, Rösner H, Roussel C, Schraut M, Tamiaki H, Vanthuyne N. Mimics of the self-assembling chlorosomal bacteriochlorophylls: regio- and stereoselective synthesis and stereoanalysis of acyl(1-hydroxyalkyl)porphyrins. J Am Chem Soc 2009; 131:14480-92. [PMID: 19769331 DOI: 10.1021/ja905628h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Diacylation of copper 10,20-bis(3,5-di-tert-butylphenylporphyrin) using Friedel-Crafts conditions at short reaction times, high concentrations of catalyst, and 0-4 degrees C affords only the 3,17-diacyl-substituted porphyrins, out of the 12 possible regioisomers. At longer reaction times and higher temperatures, the 3,13-diacyl compounds are also formed, and the two isomers can be conveniently separated by normal chromatographic techniques. Monoreduction of these diketones affords in good yields the corresponding acyl(1-hydroxyalkyl)porphyrins, which after zinc metalation are mimics of the natural chlorosomal bacteriochlorophyll (BChl) d. Racemate resolution by HPLC on a variety of chiral columns was achieved and further optimized, thus permitting easy access to enantiopure porphyrins. Enantioselective reductions proved to be less effective in this respect, giving moderate yields and only 79% ee in the best case. The absolute configuration of the 3(1)-stereocenter was assigned by independent chemical and spectroscopic methods. Self-assembly of a variety of these zinc BChl d mimics proves that a collinear arrangement of the hydroxyalkyl substituent with the zinc atom and the carbonyl substituent is not a stringent requirement, since both the 3,13 and the 3,17 regioisomers self-assemble readily as the racemates. Interestingly, the separated enantiomers self-assemble less readily, as judged by absorption, fluorescence, and transmission electron microscopy studies. Circular dichroism spectra of the self-assemblies show intense Cotton effects, which are mirror-images for the two 3(1)-enantiomers, proving that the supramolecular chirality is dependent on the configuration at the 3(1)-stereocenter. Upon disruption of these self-assemblies with methanol, which competes with zinc ligation, only very weak monomeric Cotton effects are present. The favored heterochiral self-assembly process may also be encountered for the natural BChls. This touches upon the long-standing problem of why both 3(1)-epimers are encountered in BChls in ratios that vary with the illumination and culturing conditions.
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Affiliation(s)
- Teodor Silviu Balaban
- Institute for Nanotechnology, Karlsruhe Institute of Technology, Postfach 3640, D-76021 Karlsruhe, Germany.
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119
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Hohmann-Marriott MF, Roberson RW. Exploring photosynthesis by electron tomography. PHOTOSYNTHESIS RESEARCH 2009; 102:177-188. [PMID: 19548110 DOI: 10.1007/s11120-009-9452-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 05/28/2009] [Indexed: 05/28/2023]
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120
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Saga Y, Nakai Y, Tamiaki H. Temperature-dependent spectral changes of self-aggregates of zinc chlorophylls esterified by different linear alcohols at the 17-propionate. Supramol Chem 2009. [DOI: 10.1080/10610270902853035] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Yoshitaka Saga
- a Department of Chemistry, Faculty of Science and Engineering , Kinki University , Higashi-Osaka, Osaka, 577-8502, Japan
| | - Yuichi Nakai
- a Department of Chemistry, Faculty of Science and Engineering , Kinki University , Higashi-Osaka, Osaka, 577-8502, Japan
| | - Hitoshi Tamiaki
- b Department of Bioscience and Biotechnology, Faculty of Science and Engineering , Ritsumeikan University , Kusatsu, Shiga, 525-8577, Japan
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121
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Han M, Mei Y, Khant H, Ludtke SJ. Characterization of antibiotic peptide pores using cryo-EM and comparison to neutron scattering. Biophys J 2009; 97:164-72. [PMID: 19580754 DOI: 10.1016/j.bpj.2009.04.039] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 04/24/2009] [Accepted: 04/27/2009] [Indexed: 11/30/2022] Open
Abstract
Magainin, a 23-residue antibiotic peptide, interacts directly with the lipid bilayer leading to cell lysis in a strongly concentration-dependent fashion. Utilizing cryo-electron microscopy, we have directly observed magainin interacting with synthetic DMPC/DMPG membranes. Visual examination shows that visibly unperturbed vesicles are often found adjacent to vesicles that are lysed or porous, demonstrating that magainin disruption is a highly stochastic process. Quantitatively, power spectra of large numbers of porous vesicles can be averaged together to produce the equivalent of an electron scattering curve, which can be related to theory, simulation, and published neutron scattering experiments. We demonstrate that magainin-induced pores in lipid vesicles have a mean diameter of approximately 80 A, compatible with earlier reported results in multilayer stacks. In addition to establishing a connection between experiments in multilayer stacks and vesicles, this also demonstrates that computed power spectra from windowed-out regions of cryo-EM images can be compared to neutron scattering data in a meaningful way, even though the pores of interest cannot yet be individually identified in images. Cryo-EM offers direct imaging of systems in configurations closely related to in vivo conditions, whereas neutron scattering has a greater variety of mechanisms for specific contrast variation via D2O and deuterated lipids. Combined, the two mechanisms support each other, and provide a clearer picture of such 'soft' systems than either could provide alone.
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Affiliation(s)
- Mikyung Han
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
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122
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Envelope proteins of the CsmB/CsmF and CsmC/CsmD motif families influence the size, shape, and composition of chlorosomes in Chlorobaculum tepidum. J Bacteriol 2009; 191:7109-20. [PMID: 19749040 DOI: 10.1128/jb.00707-09] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chlorosome envelope of Chlorobaculum tepidum contains 10 proteins that belong to four structural motif families. A previous mutational study (N.-U. Frigaard, H. Li, K. J. Milks, and D. A. Bryant, J. Bacteriol. 186:646-653, 2004) suggested that some of these proteins might have redundant functions. Six multilocus mutants were constructed to test the effects of eliminating the proteins of the CsmC/CsmD and CsmB/CsmF motif families, and the resulting strains were characterized physiologically and biochemically. Mutants lacking all proteins of either motif family still assembled functional chlorosomes, and as measured by growth rates of the mutant strains, light harvesting was affected only at the lowest light intensities tested (9 and 32 micromol photons m(-2) s(-1)). The size, composition, and biogenesis of the mutant chlorosomes differed from those of wild-type chlorosomes. Mutants lacking proteins of the CsmC/CsmD motif family produced smaller chlorosomes than did the wild type, and the Q(y) absorbance maximum for the bacteriochlorophyll c aggregates in these chlorosomes was strongly blueshifted. Conversely, the chlorosomes of mutants lacking proteins of the CsmB/CsmF motif family were larger than wild-type chlorosomes, and the Q(y) absorption for their bacteriochlorophyll c aggregates was redshifted. When CsmH was eliminated in addition to other proteins of either motif family, chlorosomes had smaller diameters. These data show that the chlorosome envelope proteins of the CsmB/CsmF and CsmC/CsmD families play important roles in determining chlorosome size as well as the assembly and supramolecular organization of the bacteriochlorophyll c aggregates within the chlorosome.
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Structure of chlorosomes from the green filamentous bacterium Chloroflexus aurantiacus. J Bacteriol 2009; 191:6701-8. [PMID: 19717605 DOI: 10.1128/jb.00690-09] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The green filamentous bacterium Chloroflexus aurantiacus employs chlorosomes as photosynthetic antennae. Chlorosomes contain bacteriochlorophyll aggregates and are attached to the inner side of a plasma membrane via a protein baseplate. The structure of chlorosomes from C. aurantiacus was investigated by using a combination of cryo-electron microscopy and X-ray diffraction and compared with that of Chlorobi species. Cryo-electron tomography revealed thin chlorosomes for which a distinct crystalline baseplate lattice was visualized in high-resolution projections. The baseplate is present only on one side of the chlorosome, and the lattice dimensions suggest that a dimer of the CsmA protein is the building block. The bacteriochlorophyll aggregates inside the chlorosome are arranged in lamellae, but the spacing is much greater than that in Chlorobi species. A comparison of chlorosomes from different species suggested that the lamellar spacing is proportional to the chain length of the esterifying alcohols. C. aurantiacus chlorosomes accumulate larger quantities of carotenoids under high-light conditions, presumably to provide photoprotection. The wider lamellae allow accommodation of the additional carotenoids and lead to increased disorder within the lamellae.
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125
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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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Sridharan A, Muthuswamy J, Pizziconi VB. Optoelectronic energy transfer at novel biohybrid interfaces using light harvesting complexes from Chloroflexus aurantiacus. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:6508-6516. [PMID: 19405485 DOI: 10.1021/la900112p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In nature, nanoscale supramolecular light harvesting complexes initiate the photosynthetic energy collection process at high quantum efficiencies. In this study, the distinctive antenna structure from Chloroflexus aurantiacusthe chlorosomeis assessed for potential exploitation in novel biohybrid optoelectronic devices. Electrochemical characterization of bacterial fragments containing intact chlorosomes with the photosynthetic apparatus show an increase in the charge storage density near the working electrode upon light stimulation and suggest that chlorosomes contribute approximately one-third of the overall photocurrent. Further, isolated chlorosomes (without additional photosynthetic components, e.g., reaction centers, biochemical mediators) produce a photocurrent (approximately 8-10 nA) under light saturation conditions. Correlative experiments indicate that the main chlorosome pigment, bacteriochlorophyll-c, contributes to the photocurrent via an oxidative mechanism. The results reported herein are the first to demonstrate that isolated chlorosomes (lipid-enclosed sacs of pigments) directly transduce light energy in an electrochemical manner, laying an alternative, biomimetic approach for designing photosensitized interfaces in biofuel cells and biomedical devices, such as bioenhanced retinal prosthetics.
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Affiliation(s)
- Arati Sridharan
- Harrington Department of Bioengineering, Ira A. Fulton School of Engineering, Arizona State University, Tempe, Arizona 85287, USA
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127
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Zobova AV, Yakovlev AG, Taisova AS, Fetisova ZG. The search for an optimal orientational ordering of Q y transition dipoles of subantenna molecules in the superantenna of photosynthetic green bacteria: Model calculations. Mol Biol 2009. [DOI: 10.1134/s002689330903011x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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128
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Preferential pathways for light-trapping involving beta-ligated chlorophylls. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1254-65. [PMID: 19481055 DOI: 10.1016/j.bbabio.2009.05.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 05/18/2009] [Accepted: 05/20/2009] [Indexed: 11/24/2022]
Abstract
The magnesium atom of chlorophylls (Chls) is always five- or six-coordinated within chlorophyll-protein complexes which are the main light-harvesting systems of plants, algae and most photosynthetic bacteria. Due to the presence of stereocenters and the axial ligation of magnesium the two faces of Chls are diastereotopic. It has been previously recognized that the alpha-configuration having the magnesium ligand on the opposite face of the 17-propionic acid moiety is more frequently encountered and is more stable than the more seldom beta-configuration that has the magnesium ligand on the same face [T.S. Balaban, P. Fromme, A.R. Holzwarth, N. Kraubeta, V.I. Prokhorenko, Relevance of the diastereotopic ligation of magnesium atoms in chlorophylls in Photosystem I, Biochim. Biophys. Acta (Bioenergetics), 1556 (2002) 197-207; T. Oba, H. Tamiaki, Which side of the pi-macrocycle plane of (bacterio)chlorophylls is favored for binding of the fifth ligand? Photosynth. Res. 74 (2002) 1-10]. In photosystem I only 14 Chls out of a total of 96 are in a beta-configuration and these occupy preferential positions around the reaction center. We have now analyzed the alpha/beta dichotomy in the homodimeric photosystem II based on the 2.9 A resolution crystal structure [A. Guskov, J. Kern, A. Gabdulkhakov, M. Broser, A. Zouni, W. Saenger, Cyanobacterial photosystem II at 2.9 A resolution: role of quinones, lipids, channels and chloride, Nature Struct. Mol. Biol. 16 (2009) 334-342] and find that out of 35 Chls in each monomer only 9 are definitively in the beta-configuration, while 4 are uncertain. Ab initio calculations using the approximate coupled-cluster singles-and-doubles model CC2 [O. Christiansen, H. Koch, P. Jørgensen, The second-order approximate coupled cluster singles and doubles model CC2, Chem. Phys. Lett. 243 (1995) 409-418] now correctly predict the absorption spectra of Chls a and b and conclusively show for histidine, which is the most frequent axial ligand of magnesium in chlorophyll-protein complexes, that only slight differences (<4 nm) are encountered between the alpha- and beta-configurations. Significant red shifts (up to 50 nm) can, however, be encountered in excitonically coupled beta-beta-Chl dimers. Surprisingly, in both photosystems I and II very similar "special" beta-beta dimers are encountered at practically the same distances from P700 and P680, respectively. In purple bacteria LH2, the B850 ring is composed exclusively of such tightly coupled beta-bacteriochlorophylls a. A statistical analysis of the close contacts with the protein matrix (<5 A) shows significant differences between the alpha- and beta-configurations and the subunit providing the axial magnesium ligand. The present study allows us to conclude that the excitation energy transfer in light-harvesting systems, from a peripheral antenna towards the reaction center, may follow preferential pathways due to structural reasons involving beta-ligated Chls.
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129
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Alternating syn-anti bacteriochlorophylls form concentric helical nanotubes in chlorosomes. Proc Natl Acad Sci U S A 2009; 106:8525-30. [PMID: 19435848 DOI: 10.1073/pnas.0903534106] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chlorosomes are the largest and most efficient light-harvesting antennae found in nature, and they are constructed from hundreds of thousands of self-assembled bacteriochlorophyll (BChl) c, d, or e pigments. Because they form very large and compositionally heterogeneous organelles, they had been the only photosynthetic antenna system for which no detailed structural information was available. In our approach, the structure of a member of the chlorosome class was determined and compared with the wild type (WT) to resolve how the biological light-harvesting function of the chlorosome is established. By constructing a triple mutant, the heterogeneous BChl c pigment composition of chlorosomes of the green sulfur bacteria Chlorobaculum tepidum was simplified to nearly homogeneous BChl d. Computational integration of two different bioimaging techniques, solid-state NMR and cryoEM, revealed an undescribed syn-anti stacking mode and showed how ligated BChl c and d self-assemble into coaxial cylinders to form tubular-shaped elements. A close packing of BChls via pi-pi stacking and helical H-bonding networks present in both the mutant and in the WT forms the basis for ultrafast, long-distance transmission of excitation energy. The structural framework is robust and can accommodate extensive chemical heterogeneity in the BChl side chains for adaptive optimization of the light-harvesting functionality in low-light environments. In addition, syn-anti BChl stacks form sheets that allow for strong exciton overlap in two dimensions enabling triplet exciton formation for efficient photoprotection.
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130
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Shibata Y, Saga Y, Tamiaki H, Itoh S. Anisotropic distribution of emitting transition dipoles in chlorosome from Chlorobium tepidum: fluorescence polarization anisotropy study of single chlorosomes. PHOTOSYNTHESIS RESEARCH 2009; 100:67-78. [PMID: 19468858 DOI: 10.1007/s11120-009-9429-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2008] [Accepted: 04/23/2009] [Indexed: 05/27/2023]
Abstract
The polarization anisotropy of fluorescence spectra from single chlorosomes isolated from a green sulfur bacterium, Chlorobium (Cb.) tepidum, was observed at 13 K. As the polarizer was rotated, the intensities of the fluorescence bands of both bacteriochlorophyll (BChl)-c self-aggregates and BChl-a in baseplate proteins showed clear oscillations. From the oscillation, the values of the degree of polarization (DP) and the phase shift (PS) between the BChl-c and BChl-a bands were determined for each single chlorosome. The DP versus PS plot for Cb. tepidum chlorosomes showed linear correlations between the PS and the DP values for both BChl-c and BChl-a fluorescence bands. This tendency could be explained from a simulation assuming a random orientation of chlorosomes and a triaxial orientation distribution of emitting transition dipoles within a single chlorosome. The intensity ratios among the X-/Y-/Z-principal transition dipoles were estimated to be 0.3/0.5/1 and 1/0.6/0.1 for the BChl-c and BChl-a fluorescence bands, respectively. Here, the X-, Y-, and Z-axes are perpendicular, parallel to the cytoplasmic membrane, and parallel to the chlorosome long axis, respectively. A theoretical calculation based on the exciton theory was conducted to reproduce the observed triaxial orientation distribution of emitting transition dipoles. The simulation revealed that a deformation introduced to the circular cross section of the rod-shaped BChl-c self-aggregates could qualitatively reproduce results of this study.
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Affiliation(s)
- Yutaka Shibata
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, 464-8602, Japan.
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131
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Wen J, Zhang H, Gross ML, Blankenship RE. Membrane orientation of the FMO antenna protein from Chlorobaculum tepidum as determined by mass spectrometry-based footprinting. Proc Natl Acad Sci U S A 2009; 106:6134-9. [PMID: 19339500 PMCID: PMC2669346 DOI: 10.1073/pnas.0901691106] [Citation(s) in RCA: 170] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Indexed: 11/18/2022] Open
Abstract
The high excitation energy-transfer efficiency demanded in photosynthetic organisms relies on the optimal pigment-protein binding orientation in the individual protein complexes and also on the overall architecture of the photosystem. In green sulfur bacteria, the membrane-attached Fenna-Matthews-Olson (FMO) antenna protein functions as a "wire" to connect the large peripheral chlorosome antenna complex with the reaction center (RC), which is embedded in the cytoplasmic membrane (CM). Energy collected by the chlorosome is funneled through the FMO to the RC. Although there has been considerable effort to understand the relationships between structure and function of the individual isolated complexes, the specific architecture for in vivo interactions of the FMO protein, the CM, and the chlorosome, ensuring highly efficient energy transfer, is still not established experimentally. Here, we describe a mass spectrometry-based method that probes solvent-exposed surfaces of the FMO by labeling solvent-exposed aspartic and glutamic acid residues. The locations and extents of labeling of FMO on the native membrane in comparison with it alone and on a chlorosome-depleted membrane reveal the orientation. The large differences in the modification of certain peptides show that the Bchl a #3 side of the FMO trimer interacts with the CM, which is consistent with recent theoretical predictions. Moreover, the results also provide direct experimental evidence to confirm the overall architecture of the photosystem from Chlorobaculum tepidum (C. tepidum) and give information on the packing of the FMO protein in its native environment.
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Affiliation(s)
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130
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132
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Kakitani Y, Koyama Y, Shimoikeda Y, Nakai T, Utsumi H, Shimizu T, Nagae H. Stacking of Bacteriochlorophyll c Macrocycles in Chlorosome from Chlorobium limicola As Revealed by Intermolecular 13C Magnetic-Dipole Correlation, X-Ray Diffraction, and Quadrupole Coupling in 25Mg NMR. Biochemistry 2008; 48:74-86. [DOI: 10.1021/bi801651w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yoshinori Kakitani
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Analytical Instrument Division, JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan, National Institute for Materials Science, Sakura, Tsukuba, Ibaraki 305-0003, Japan, and Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
| | - Yasushi Koyama
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Analytical Instrument Division, JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan, National Institute for Materials Science, Sakura, Tsukuba, Ibaraki 305-0003, Japan, and Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
| | - Yuichi Shimoikeda
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Analytical Instrument Division, JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan, National Institute for Materials Science, Sakura, Tsukuba, Ibaraki 305-0003, Japan, and Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
| | - Toshihito Nakai
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Analytical Instrument Division, JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan, National Institute for Materials Science, Sakura, Tsukuba, Ibaraki 305-0003, Japan, and Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
| | - Hiroaki Utsumi
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Analytical Instrument Division, JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan, National Institute for Materials Science, Sakura, Tsukuba, Ibaraki 305-0003, Japan, and Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
| | - Tadashi Shimizu
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Analytical Instrument Division, JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan, National Institute for Materials Science, Sakura, Tsukuba, Ibaraki 305-0003, Japan, and Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
| | - Hiroyoshi Nagae
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan, Analytical Instrument Division, JEOL Ltd., Musashino, Akishima, Tokyo 196-8558, Japan, National Institute for Materials Science, Sakura, Tsukuba, Ibaraki 305-0003, Japan, and Kobe City University of Foreign Studies, Gakuen-Higashimachi, Nishi-ku, Kobe 651-2187, Japan
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133
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Mizoguchi T, Kim TY, Sawamura S, Tamiaki H. Pressure-Induced Red Shift and Broadening of the Qy Absorption of Main Light-Harvesting Antennae Chlorosomes from Green Photosynthetic Bacteria and Their Dependency upon Alkyl Substituents of the Composite Bacteriochlorophylls. J Phys Chem B 2008; 112:16759-65. [DOI: 10.1021/jp804990f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tadashi Mizoguchi
- Department of Bioscience and Biotechnology and Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Tae-Yeun Kim
- Department of Bioscience and Biotechnology and Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Seiji Sawamura
- Department of Bioscience and Biotechnology and Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Hitoshi Tamiaki
- Department of Bioscience and Biotechnology and Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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134
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Huber V, Sengupta S, Würthner F. Structure-Property Relationships for Self-Assembled Zinc Chlorin Light-Harvesting Dye Aggregates. Chemistry 2008; 14:7791-807. [DOI: 10.1002/chem.200800764] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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135
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The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c, d, or e mimics. Proc Natl Acad Sci U S A 2008; 105:12736-41. [PMID: 18755898 DOI: 10.1073/pnas.0802719105] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteriochlorophylls (BChls) c, d, and e are the main light-harvesting pigments of green photosynthetic bacteria that self-assemble into nanostructures within the chlorosomes forming the most efficient antennas of photosynthetic organisms. All previous models of the chlorosomal antennae, which are quite controversially discussed because no single crystals could be grown so far from these organelles, involve a strong hydrogen-bonding interaction between the 3(1) hydroxyl group and the 13(1) carbonyl group. We have synthesized different self-assemblies of BChl c mimics having the same functional groups as the natural counterparts, that is, a hydroxyethyl substituent, a carbonyl group and a divalent metal atom ligated by a tetrapyrrole. These artificial BChl mimics have been shown by single crystal x-ray diffraction to form extended stacks that are packed by hydrophobic interactions and in the absence of hydrogen bonding. Time-resolved photoluminescence proves the ordered nature of the self-assembled stacks. FT-IR spectra show that on self-assembly the carbonyl frequency is shifted by approximately 30 cm(-1) to lower wavenumbers. From the FT-IR data we can infer the proximal interactions between the BChls in the chlorosomes consistent with a single crystal x-ray structure that shows a weak electrostatic interaction between carbonyl groups and the central zinc atom.
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136
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Sridharan A, Muthuswamy J, Labelle JT, Pizziconi VB. Immobilization of functional light antenna structures derived from the filamentous green bacterium Chloroflexus aurantiacus. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:8078-8089. [PMID: 18590285 DOI: 10.1021/la703691a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The integration of highly efficient, natural photosynthetic light antenna structures into engineered systems while their biophotonic capabilities are maintained has been an elusive goal in the design of biohybrid photonic devices. In this study, we report a novel technique to covalently immobilize nanoscaled bacterial light antenna structures known as chlorosomes from Chloroflexus aurantiacus on both conductive and nonconductive glass while their energy transducing functionality was maintained. Chlorosomes without their reaction centers (RCs) were covalently immobilized on 3-aminoproyltriethoxysilane (APTES) treated surfaces using a glutaraldehyde linker. AFM techniques verified that the chlorosomes maintained their native ellipsoidal ultrastructure upon immobilization. Results from absorbance and fluorescence spectral analysis (where the Stokes shift to 808/810 nm was observed upon 470 nm blue light excitation) in conjunction with confocal microscopy confirm that the functional integrity of immobilized chlorosomes was also preserved. In addition, experiments with electrochemical impedance spectroscopy (EIS) suggested that the presence of chlorosomes in the electrical double layer of the electrode enhanced the electron transfer capacity of the electrochemical cell. Further, chronoamperometric studies suggested that the reduced form of the Bchl- c pigments found within the chlorosome modulate the conduction properties of the electrochemical cell, where the oxidized form of Bchl- c pigments impeded any current transduction at a bias of 0.4 V within the electrochemical cell. The results therefore demonstrate that the intact chlorosomes can be successfully immobilized while their biophotonic transduction capabilities are preserved through the immobilization process. These findings indicate that it is feasible to design biophotonic devices incorporating fully functional light antenna structures, which may offer significant performance enhancements to current silicon-based photonic devices for diverse technological applications ranging from CCD devices used in retinal implants to terrestrial and space fuel cell applications.
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Affiliation(s)
- Arati Sridharan
- Harrington Department of Bioengineering, Arizona State University, Tempe, Arizona 85287, USA
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137
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Linnanto JM, Korppi-Tommola JEI. Investigation on chlorosomal antenna geometries: tube, lamella and spiral-type self-aggregates. PHOTOSYNTHESIS RESEARCH 2008; 96:227-245. [PMID: 18443917 DOI: 10.1007/s11120-008-9304-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 04/07/2008] [Indexed: 05/26/2023]
Abstract
Molecular mechanics calculations and exciton theory have been used to study pigment organization in chlorosomes of green bacteria. Single and double rod, multiple concentric rod, lamella, and Archimedean spiral macrostructures of bacteriochlorophyll c molecules were created and their spectral properties evaluated. The effects of length, width, diameter, and curvature of the macrostructures as well as orientations of monomeric transition dipole moment vectors on the spectral properties of the aggregates were studied. Calculated absorption, linear dichroism, and polarization dependent fluorescence-excitation spectra of the studied long macrostructures were practically identical, but circular dichroism spectra turned out to be very sensitive to geometry and monomeric transition dipole moment orientations of the aggregates. The simulations for long multiple rod and spiral-type macrostructures, observed in recent high-resolution electron microscopy images (Oostergetel et al., FEBS Lett 581:5435-5439, 2007) gave shapes of circular dichroism spectra observed experimentally for chlorosomes. It was shown that the ratio of total circular dichroism intensity to integrated absorption of the Q(y) transition is a good measure of degree of tubular structures in the chlorosomes. Calculations suggest that the broad Q(y) line width of chlorosomes of sulfur bacteria could be due to (1) different orientations of the transition moment vectors in multi-walled rod structures or (2) a variety of Bchl-aggregate structures in the chlorosomes.
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Affiliation(s)
- Juha M Linnanto
- Department of Chemistry, University of Jyväskylä, Jyväskylä, Finland.
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138
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Balaban MC, Eichhöfer A, Buth G, Hauschild R, Szmytkowski J, Kalt H, Balaban TS. Programmed Metalloporphyrins for Self-Assembly within Light-Harvesting Stacks: (5,15-Dicyano-10,20-bis(3,5-di-tert-butylphenyl)porphyrinato)zinc(II) and Its Push−Pull 15-N,N-Dialkylamino-5-cyano Congeners Obtained by a Facile Direct Amination. J Phys Chem B 2008; 112:5512-21. [DOI: 10.1021/jp801510b] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Mihaela Carmen Balaban
- Karlsruhe Institute of Technology (KIT), Forschungszentrum Karlsruhe (FZK), Institute for Nanotechnology (INT), and Institute for Synchrotron Radiation (ISS), Postfach 3640, D-76021 Karlsruhe, Germany, Faculty for Applied Physics, Universität Karlsruhe (UKA), Karlsruhe, Germany, and Center for Functional Nanostructures (CFN), Universität Karlsruhe, Germany
| | - Andreas Eichhöfer
- Karlsruhe Institute of Technology (KIT), Forschungszentrum Karlsruhe (FZK), Institute for Nanotechnology (INT), and Institute for Synchrotron Radiation (ISS), Postfach 3640, D-76021 Karlsruhe, Germany, Faculty for Applied Physics, Universität Karlsruhe (UKA), Karlsruhe, Germany, and Center for Functional Nanostructures (CFN), Universität Karlsruhe, Germany
| | - Gernot Buth
- Karlsruhe Institute of Technology (KIT), Forschungszentrum Karlsruhe (FZK), Institute for Nanotechnology (INT), and Institute for Synchrotron Radiation (ISS), Postfach 3640, D-76021 Karlsruhe, Germany, Faculty for Applied Physics, Universität Karlsruhe (UKA), Karlsruhe, Germany, and Center for Functional Nanostructures (CFN), Universität Karlsruhe, Germany
| | - Robert Hauschild
- Karlsruhe Institute of Technology (KIT), Forschungszentrum Karlsruhe (FZK), Institute for Nanotechnology (INT), and Institute for Synchrotron Radiation (ISS), Postfach 3640, D-76021 Karlsruhe, Germany, Faculty for Applied Physics, Universität Karlsruhe (UKA), Karlsruhe, Germany, and Center for Functional Nanostructures (CFN), Universität Karlsruhe, Germany
| | - Jȩdrzej Szmytkowski
- Karlsruhe Institute of Technology (KIT), Forschungszentrum Karlsruhe (FZK), Institute for Nanotechnology (INT), and Institute for Synchrotron Radiation (ISS), Postfach 3640, D-76021 Karlsruhe, Germany, Faculty for Applied Physics, Universität Karlsruhe (UKA), Karlsruhe, Germany, and Center for Functional Nanostructures (CFN), Universität Karlsruhe, Germany
| | - Heinz Kalt
- Karlsruhe Institute of Technology (KIT), Forschungszentrum Karlsruhe (FZK), Institute for Nanotechnology (INT), and Institute for Synchrotron Radiation (ISS), Postfach 3640, D-76021 Karlsruhe, Germany, Faculty for Applied Physics, Universität Karlsruhe (UKA), Karlsruhe, Germany, and Center for Functional Nanostructures (CFN), Universität Karlsruhe, Germany
| | - Teodor Silviu Balaban
- Karlsruhe Institute of Technology (KIT), Forschungszentrum Karlsruhe (FZK), Institute for Nanotechnology (INT), and Institute for Synchrotron Radiation (ISS), Postfach 3640, D-76021 Karlsruhe, Germany, Faculty for Applied Physics, Universität Karlsruhe (UKA), Karlsruhe, Germany, and Center for Functional Nanostructures (CFN), Universität Karlsruhe, Germany
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139
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Zupcanova A, Arellano JB, Bina D, Kopecky J, Psencik J, Vacha F. The length of esterifying alcohol affects the aggregation properties of chlorosomal bacteriochlorophylls. Photochem Photobiol 2008; 84:1187-94. [PMID: 18331396 DOI: 10.1111/j.1751-1097.2008.00312.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Chlorosomes, the main light-harvesting complexes of green photosynthetic bacteria, contain bacteriochlorophyll (BChl) molecules in the form of self-assembling aggregates. To study the role of esterifying alcohols in BChl aggregation we have prepared a series of bacteriochlorophyllide c (BChlide c) derivatives differing in the length of the esterifying alcohol (C(1), C(4), C(8) and C(12)). Their aggregation behavior was studied both in polar (aqueous buffer) and nonpolar (hexane) environments and the esterifying alcohols were found to play an essential role. In aqueous buffer, hydrophobic interactions among esterifying alcohols drive BChlide c derivatives with longer chains into the formation of dimers, while this interaction is weak for BChlides with shorter esterifying alcohols and they remain mainly as monomers. All studied BChlide c derivatives form aggregates in hexane, but the process slows down with longer esterifying alcohols due to competing hydrophobic interactions with hexane molecules. In addition, the effect of the length of the solvent molecules (n-alkanes) was explored for BChl c aggregation. With an increasing length of n-alkane molecules, the hydrophobic interaction with the farnesyl chain becomes stronger, leading to a slower aggregation rate. The results show that the hydrophobic interaction is the driving force for the aggregation in an aqueous environment, while in nonpolar solvents it is the hydrophilic interaction.
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Affiliation(s)
- Anita Zupcanova
- Biological Centre, Academy of Sciences of the Czech Republic, Ceske Budejovice, Czech Republic
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140
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Arellano JB, Torkkeli M, Tuma R, Laurinmäki P, Melø TB, Ikonen TP, Butcher SJ, Serimaa RE, Psencík J. Hexanol-induced order-disorder transitions in lamellar self-assembling aggregates of bacteriochlorophyll c in Chlorobium tepidum chlorosomes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:2035-2041. [PMID: 18197717 DOI: 10.1021/la703024e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Chlorosomes are light-harvesting complexes of green photosynthetic bacteria. Chlorosomes contain bacteriochlorophyll (BChl) c, d, or e aggregates that exhibit strong excitonic coupling. The short-range order, which is responsible for the coupling, has been proposed to be augmented by pigment arrangement into undulated lamellar structures with spacing between 2 and 3 nm. Treatment of chlorosomes with hexanol reversibly converts the aggregated chlorosome chlorophylls into a form with spectral properties very similar to that of the monomer. Although this transition has been extensively studied, the structural basis remains unclear due to variability in the obtained morphologies. Here we investigated hexanol-induced structural changes in the lamellar organization of BChl c in chlorosomes from Chlorobium tepidum by a combination of X-ray scattering, electron cryomicroscopy, and optical spectroscopy. At a low hexanol/pigment ratio, the lamellae persisted in the presence of hexanol while the short-range order and exciton interactions between chlorin rings were effectively eliminated, producing a monomer-like absorption. The result suggested that hexanol hydroxyls solvated the chlorin rings while the aliphatic tail partitioned into the hydrophobic part of the lamellar structure. This partitioning extended the chlorosome along its long axis. Further increase of the hexanol/pigment ratio produced round pigment-hexanol droplets, which lost all lamellar order. After hexanol removal the spectral properties were restored. In the samples treated under the high hexanol/pigment ratio, lamellae reassembled in small domains after hexanol removal while the shape and long-range order were irreversibly lost. Thus, all the interactions required for establishing the short-range order by self-assembly are provided by BChl c molecules alone. However, the long-range order and overall shape are imposed by an external structure, e.g., the proteinaceous chlorosome baseplate.
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Affiliation(s)
- Juan B Arellano
- Instituto de Recursos Naturales y Agrobiología (IRNASA-CSIC), Apdo. 257, 37071 Salamanca, Spain
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141
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Huijser A, Suijkerbuijk BMJM, Klein Gebbink RJM, Savenije TJ, Siebbeles. Efficient Exciton Transport in Layers of Self-Assembled Porphyrin Derivatives. J Am Chem Soc 2008; 130:2485-92. [DOI: 10.1021/ja075162a] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Annemarie Huijser
- Opto-Electronic Materials Section, DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Chemical Biology and Organic Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Bart M. J. M. Suijkerbuijk
- Opto-Electronic Materials Section, DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Chemical Biology and Organic Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Robertus J. M. Klein Gebbink
- Opto-Electronic Materials Section, DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Chemical Biology and Organic Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Tom J. Savenije
- Opto-Electronic Materials Section, DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Chemical Biology and Organic Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Siebbeles
- Opto-Electronic Materials Section, DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands, and Chemical Biology and Organic Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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142
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Sørensen PG, Cox RP, Miller M. Chlorosome lipids from Chlorobium tepidum: characterization and quantification of polar lipids and wax esters. PHOTOSYNTHESIS RESEARCH 2008; 95:191-196. [PMID: 17929193 DOI: 10.1007/s11120-007-9242-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Accepted: 09/06/2007] [Indexed: 05/25/2023]
Abstract
We have extracted polar lipids and waxes from isolated chlorosomes from the green sulfur bacterium Chlorobium tepidum and determined the fatty acid composition of each lipid class. Polar lipids amounted to 4.8 mol per 100 mol bacteriochlorophyll in the chlorosomes, while non-polar lipids (waxes) were present at a ratio of 5.9 mol per 100 mol bacteriochlorophyll. Glycolipids constitute 60 % of the polar lipids while phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, and an aminoglycosphingolipid make up respectively 15, 3, 8 and 12 %. A novel glycolipid was identified as a rhamnose derivative of monogalactosyldiacylglycerol, while the other major glycolipid was monogalactosyldiacylglycerol. Tetradecanoic acid was the major fatty acid in the aminoglycosphingolipid, while the other polar lipids contained predominantly hexandecanoic acid. The chlorosome waxes are esters of unbranched fatty acids and fatty alcohols with 14 or 16 carbon atoms, joined to form molecules with between 28 and 32 carbon atoms. The stoichiometry between lipids and bacteriochlorophyll suggests that much of the chlorosome surface is covered by protein.
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Affiliation(s)
- Peder Grove Sørensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
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143
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Alster J, Zupcanova A, Vacha F, Psencik J. Effect of quinones on formation and properties of bacteriochlorophyll c aggregates. PHOTOSYNTHESIS RESEARCH 2008; 95:183-189. [PMID: 17922300 DOI: 10.1007/s11120-007-9259-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 09/10/2007] [Indexed: 05/25/2023]
Abstract
Chlorosomes of green photosynthetic bacterium Chlorobium tepidum contain aggregates of bacteriochlorophyll c (BChl c) with carotenoids and isoprenoid quinones. BChl aggregates with very similar optical properties can be prepared also in vitro either in non-polar solvents or in aqueous buffers with addition of lipids and/or carotenoids. In this work, we show that the aggregation of BChl c in aqueous buffer can be induced also by quinones (vitamin K(1 )and K(2)), provided they are non-polar due to a hydrophobic side-chain. Polar vitamin K(3, )which possess the same functional group as K(1 )and K(2), does not induce the aggregation. The results confirm a principal role of the hydrophobic interactions as a driving force for the aggregation of chlorosomal BChls. The chlorosomal quinones play an important role in a redox-dependent excitation quenching, which may protect the cells against damage under oxygenic conditions. We found that aggregates of BChl c with vitamin K(1 )and K(2) exhibit an excitation quenching as well. The amplitude of the quenching depends on quinone concentration, as determined from fluorescence measurements. No lipid is necessary to induce the quenching, which therefore originates mainly from interactions of BChl c with quinones incorporated in the aggregate structure. In contrast, only a weak quenching was observed for dimers of BChl c in buffer (either with or without vitamin K(3)) and also for BChl c aggregates prepared with a lipid (lecithin). Thus, the weak quenching seems to be a property of BChl c itself.
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Affiliation(s)
- Jan Alster
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic
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144
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Mizoguchi T, Tamiaki H. The Effect of Esterifying Chains at the 17-Propionate of Bacteriochlorophylls-con Their Self-Assembly. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2007. [DOI: 10.1246/bcsj.80.2196] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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145
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Oostergetel GT, Reus M, Gomez Maqueo Chew A, Bryant DA, Boekema EJ, Holzwarth AR. Long-range organization of bacteriochlorophyll in chlorosomes of Chlorobium tepidum investigated by cryo-electron microscopy. FEBS Lett 2007; 581:5435-9. [PMID: 17981156 DOI: 10.1016/j.febslet.2007.10.045] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2007] [Accepted: 10/25/2007] [Indexed: 10/22/2022]
Abstract
Intact chlorosomes of Chlorobium tepidum were embedded in amorphous ice layers and examined by cryo-electron microscopy to study the long-range organization of bacteriochlorophyll (BChl) layers. End-on views reveal that chlorosomes are composed of several multi-layer tubules of variable diameter (20-30 nm) with some locally undulating non-tubular lamellae in between. The multi-layered tubular structures are more regular and larger in a C. tepidum mutant that only synthesizes [8-ethyl, 12-methyl]-BChl d. Our data show that wild-type C. tepidum chlorosomes do not have a highly regular, long-range BChl c layer organization and that they contain several multi-layered tubules rather than single-layer tubules or exclusively undulating lamellae as previously proposed.
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Affiliation(s)
- Gert T Oostergetel
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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146
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Saga Y, Shibata Y, Itoh S, Tamiaki H. Direct Counting of Submicrometer-Sized Photosynthetic Apparatus Dispersed in Medium at Cryogenic Temperature by Confocal Laser Fluorescence Microscopy: Estimation of the Number of Bacteriochlorophyll c in Single Light-Harvesting Antenna Complexes Chlorosomes of Green Photosynthetic Bacteria. J Phys Chem B 2007; 111:12605-9. [DOI: 10.1021/jp071559p] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yoshitaka Saga
- Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan, and Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Yutaka Shibata
- Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan, and Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Shigeru Itoh
- Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan, and Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Hitoshi Tamiaki
- Department of Chemistry, Faculty of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan, and Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
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147
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Tamiaki H, Shibata R, Mizoguchi T. The 17-propionate function of (bacterio)chlorophylls: biological implication of their long esterifying chains in photosynthetic systems. Photochem Photobiol 2007; 83:152-62. [PMID: 16776548 DOI: 10.1562/2006-02-27-ir-819] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Molecular structures of (bacterio)chlorophylls [= (B)Chls] in photosynthetic apparatus are surveyed, and a diversity of the ester groups of the 17-propionate substituent is particularly focused on in this review. In oxygenic photosynthetic species including green plants and algae, the ester of Chl molecules is limited to a phytyl group. Geranylgeranyl and farnesyl groups in addition to phytyl are observed in (B)Chl molecules inside photosynthetic proteins of anoxygenic bacteria. In main light-harvesting antennas of green bacteria (chlorosomes), a greater variety of ester groups including long straight chains are used in the composite BChl molecules. This diversity is ascribable to the fact that chlorosomal BChls self-aggregate to form a core part of chlorosomes without any specific interaction of oligopeptides. Biological significance of the long chains is discussed in photosynthetic apparatus, especially in chlorosomes.
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Affiliation(s)
- Hitoshi Tamiaki
- Department of Bioscience and Biotechnology, Ritsumeikan University, Kusatsu, Japan.
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148
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Kakitani Y, Harada KI, Mizoguchi T, Koyama Y. Isotopic Replacement of Pigments and a Lipid in Chlorosomes fromChlorobium limicola: Characterization of the Resultant Chlorosomes. Biochemistry 2007; 46:6513-24. [PMID: 17497832 DOI: 10.1021/bi602586g] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pigments including bacteriochlorophyll (BChl) c, carotenoids, and a trace of BChl a together with a lipid, monogalactosyl diglyceride (MGDG), were extracted with chloroform/methanol (1:1 v/v) from an aqueous suspension (50 mM Tris-HCl, pH 8.0) of chlorosomes from Chlorobium limicola; other lipids and proteins were left behind in the aqueous layer by funnel separation. The chloroform layer was dried by purging N2 gas, dissolved in methanol, and rapidly injected into the aqueous layer to reassemble chlorosomes. This technique has been developed to replace one-half of the inherent 12C-BChl c by 13C-BChl c to identify the intermolecular 13C...13C magnetic dipole correlation peaks (that are supposed to reduce their intensities to one-fourth by reducing the 13C-BChl c concentration into one-half) and to determine the structure of BChl c aggregates in the rod elements by means of solid-state NMR spectroscopy. The isotopically replaced chlorosomes were characterized (1) by sucrose density gradient centrifugation, zeta potential measurement, electron microscopy, and dynamic light scattering measurement to determine the morphology of chlorosomes, (2) by 13C NMR spectroscopy, electronic absorption and circular dichroism spectroscopies, and low-angle X-ray diffraction to determine the pigment assembly in the rod elements, and (3) by subpicosecond time-resolved absorption spectroscopy to determine the excited-state dynamics in the pigment assembly. The results characterized the reassembled chlorosomes to have (1) similar but longer morphological structures, (2) almost the same pigment assembly in the rod elements, and (3) basically the same excited-state dynamics in the pigment assembly.
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Affiliation(s)
- Yoshinori Kakitani
- Faculty of Science and Technology, Kwansei Gakuin University, Gakuen, Sanda 669-1337, Japan
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149
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Shibata R, Mizoguchi T, Inazu T, Tamiaki H. Self-aggregation of synthetic zinc chlorophyll derivatives possessing multi-perfluoroalkyl chains in perfluorinated solvents. Photochem Photobiol Sci 2007; 6:749-57. [PMID: 17609768 DOI: 10.1039/b702866k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Zinc 3(1)-hydroxy-13(1)-oxo-chlorins possessing two, three, four and six perfluorooctyl chains were synthesized from naturally occurring chlorophyll-a. Only the synthetic zinc chlorin possessing six perfluorooctyl chains was directly dissolved in perfluorinated solvents due to its high fluorine content in molecular weight (over 50%). In this solution, visible absorption spectra gave a red-shifted Q(y) band at 723 nm (compared to 648 nm in THF) and showed the formation of well-ordered self-aggregates. No monomeric form was observed in the solution from any fluorescence emission spectra from visible absorption spectra. In the aggregate solution, no precipitation occurred during either standing for a long period or heating at 70 degrees C. This showed that the supramolecular structure was stabilized by F-F interactions on its surface among the perfluorooctyl chains on the 17-position and perfluorinated solvents. The core part of the supramolecular structure was constructed by a special intramolecular bond of Zn ... O3(2)-H ... O=C13(1), which was confirmed from resonance Raman spectral analysis.
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Affiliation(s)
- Reiko Shibata
- Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, Japan
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150
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Klinger P, Arellano JB, Vácha F, Hála J, PšenčíK J. Effect of Carotenoids and Monogalactosyl Diglyceride on Bacteriochlorophyll c Aggregates in Aqueous Buffer: Implications for the Self-assembly of Chlorosomes¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00131.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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