Linearly polarized light absorption spectra of chlorosomes, light-harvesting antennas of photosynthetic green sulfur bacteria

Tamiaki, Hitoshi; Tateishi, Shingo; Nakabayashi, Shosuke; Shibata, Yutaka; Itoh, Shigeru

doi:10.1016/j.cplett.2009.12.018

Cited by 18 publications

(26 citation statements)

References 28 publications

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“…B). This spectral pattern in the Soret region of the BChl e aggregates is characteristic of chlorosomes containing BChl e . The FWHM of the Q y band of the BChl e aggregates was estimated to be 850 cm −1 .…”

Section: Resultsmentioning

confidence: 79%

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Scrambled Self‐Assembly of Bacteriochlorophylls c and e in Aqueous Triton X‐100 Micelles

Saga

Saiki

Shibata

et al. 2013

Photochem & Photobiology

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Bacteriochlorophyll (BChl) e was coassembled with BChl c in Triton X-100 micelles in aqueous solutions. The Qy absorption bands of the coaggregates were positioned between those of aggregates consisting solely of BChl c or e. The electronic absorption spectra of the coaggregates could not be reproduced by linear combinations of the spectra of the aggregates consisting solely of each pigment, but they were in line with the simulated spectra for the self-aggregates in which both BChls were randomly distributed. These suggest that BChls c and e are not spatially separated; they are homogenously distributed over the self-aggregates to give electronic spectra that are different from those of the aggregate consisting solely of each pigment. Deaggregation of the scrambled self-aggregates by excess Triton X-100 did not produce any spectral components assigned to an aggregate consisting solely of either BChl c or e. Acid-induced decomposition of the scrambled aggregates showed different kinetics from those of the aggregates consisting solely of each pigment. These also support the homogeneous distribution of BChls c and e in the scrambled self-aggregates. These results will be useful to investigate the major light-harvesting antenna systems of green photosynthetic bacteria that contain two kinds of chlorosomal BChls.

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Section: Resultsmentioning

confidence: 79%

“…BChl c possesses a methyl group at the 7‐position, but BChl e has a formyl group at this position. This substitution is responsible for the spectral properties of the self‐assemblies in chlorosomes as well as the monomeric forms .…”

Section: Introductionmentioning

confidence: 99%

Scrambled Self‐Assembly of Bacteriochlorophylls c and e in Aqueous Triton X‐100 Micelles

Saga

Saiki

Shibata

et al. 2013

Photochem & Photobiology

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“…This means that the phases of absorption and fluorescence are always the same, even though the modulation depths are different. According to the reported assignments of the exciton bands 30 (Figure 8a), the 458, 633, and 750 nm excitations are expected to excite the EB y , EQ x , and EQ y exciton transitions, respectively. For 750-nmexcitation, the absorption and fluorescence originate from the same set of exciton transitions (EQ y band).…”

Section: Excitonic Transitions and Internal Organization Of Bchlsmentioning

confidence: 97%

Organization of Bacteriochlorophylls in Individual Chlorosomes from Chlorobaculum tepidum Studied by 2-Dimensional Polarization Fluorescence Microscopy

et al. 2011

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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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“…However, this basic interaction model still allows a number of different supermolecule arrangements, which can be validated by their ability to explain experimental data (see, e.g., refs. [451,[453][454][455]). For example, in ref.…”

Section: Chlorosomesmentioning

confidence: 97%

Quantum Chemical Description of Absorption Properties and Excited‐State Processes in Photosynthetic Systems

2011

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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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Linearly polarized light absorption spectra of chlorosomes, light-harvesting antennas of photosynthetic green sulfur bacteria

Cited by 18 publications

References 28 publications

Scrambled Self‐Assembly of Bacteriochlorophylls c and e in Aqueous Triton X‐100 Micelles

Scrambled Self‐Assembly of Bacteriochlorophylls c and e in Aqueous Triton X‐100 Micelles

Organization of Bacteriochlorophylls in Individual Chlorosomes from Chlorobaculum tepidum Studied by 2-Dimensional Polarization Fluorescence Microscopy

Quantum Chemical Description of Absorption Properties and Excited‐State Processes in Photosynthetic Systems

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