Multidimensional CP-MAS 13C NMR of uniformly enriched chlorophyll

Rossum, Barth van; Boender, Gert Jan; Mulder, Fokko M.; Raap, J.; Balaban, Teodor Silviu; Holzwarth, Alfred R.; Schaffner, Kurt; Prytulla, S.; Oschkinat, Hartmut; Groot, Huub J. M. de

doi:10.1016/s1386-1425(98)00067-5

Cited by 48 publications

(50 citation statements)

References 33 publications

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“…Very recently, Lindsey and coworkers, after designing synthetic methods for one-carbon-atom-based recognition groups for porphyrins, have also shown the absence of putative hydrogen bonds with formation of staircase architectures (28). Formation of extended stacks in BChls is in accord with previous solid-state 13 C-NMR data (29)(30)(31) and this is depicted in diagrams in Fig. 5.…”

Section: Thesupporting

confidence: 73%

The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c , d , or e mimics

Jochum

Reddy

Eichhöfer

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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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 Ϸ30 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. chlorosome model ͉ crystal structure ͉ FT-IR ͉ light-harvesting ͉ time-resolved fluorescence

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Section: Thesupporting

confidence: 73%

The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c , d , or e mimics

Jochum

Reddy

Eichhöfer

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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“…[2][3][4]46 The application to the bilayer synthetic aggregates of carbocyanine dyes is discussed elsewhere. 10 In terms of our stack of rings representation, the chlorosomal cylinders, consisting of tens of thousands of bacteriochlorophyll c mol- 48 -50 using the expression from Ref.…”

Section: Numerical Results For the Spectramentioning

confidence: 99%

Optical spectra and localization of excitons in inhomogeneous helical cylindrical aggregates

Didraga

Knoester

2004

The Journal of Chemical Physics

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We study the linear optical properties of helical cylindrical molecular aggregates accounting for the effects of static diagonal disorder. Absorption, linear dichroism, and circular dichroism spectra are presented, calculated using brute force numerical simulations and a modified version of the coherent potential approximation that accounts for finite size effects by using the appropriate open boundary conditions. Excellent agreement between both approaches is found. It is also shown that the inclusion of disorder results in a better agreement between calculated and measured spectra for the chlorosomes of green bacteria as compared to our previous report, where we restricted ourselves to homogeneous cylinders ͓Didraga, Klugkist, and Knoester, J. Phys. Chem. B 106, 11474 ͑2002͔͒. For the excitons that govern the optical response, we also investigate the disorder-induced localization properties. By analyzing an autocorrelation function of the exciton wave function, we find a strongly anisotropic localization behavior, closely following the properties of chiral wave functions which previously have been found for homogenoeus helical cylinders ͓Didraga and Knoester, J. Chem. Phys. 121, 946 ͑2004͔͒. It is shown that the circular dichroism spectrum may still show a strong dependence on the cylinder length, even when the exciton wave function is localized in a region small compared to the cylinder's size.

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“…A variety of structural models have been proposed based on the results of visible absorption and NMR spectroscopy of artificial aggregates and chlorosomes (12,16,17). Recent models were constructed based mainly on a few distance constraints and chemical shifts such as ring current shifts in solid-state NMR spectra (27,28). It is difficult to assign the chemical shifts to structural factors in the stacking BChl c complex.…”

Section: Discussionmentioning

confidence: 99%

Structure of the light-harvesting bacteriochlorophyll c assembly in chlorosomes from Chlorobium limicola determined by solid-state NMR

Egawa

Fujiwara

Mizoguchi

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

101

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We have determined the atomic structure of the bacteriochlorophyll c (BChl c) assembly in a huge light-harvesting organelle, the chlorosome of green photosynthetic bacteria, by solid-state NMR. Previous electron microscopic and spectroscopic studies indicated that chlorosomes have a cylindrical architecture with a diameter of Ϸ10 nm consisting of layered BChl molecules. Assembly structures in huge noncrystalline chlorosomes have been proposed based mainly on structure-dependent chemical shifts and a few distances acquired by solid-state NMR, but those studies did not provide a definite structure. Our approach is based on 13 C dipolar spindiffusion solid-state NMR of uniformly 13 C-labeled chlorosomes under magic-angle spinning. Approximately 90 intermolecular COC distances were obtained by simultaneous assignment of distance correlations and structure optimization preceded by polarization-transfer matrix analysis. It was determined from the Ϸ90 intermolecular distances that BChl c molecules form piggybackdimer-based parallel layers. This finding rules out the well known monomer-based structures. A molecular model of the cylinder in the chlorosome was built by using this structure. It provided insights into the mechanisms of efficient light harvesting and excitation transfer to the reaction centers. This work constitutes an important advance in the structure determination of huge intact systems that cannot be crystallized.spin diffusion ͉ distance analysis ͉ photosynthesis ͉ antenna complex ͉ excitation transfer P hotosynthesis is the primary energy source for all living organisms. Chlorophyll-protein complexes capture light energy in most photosynthetic systems. Their structures are well known (1, 2). However, there are other light-harvesting devices called chlorosomes, which contain bacteriochlorophyll (BChl) assemblies. No protein is present in the BChl assemblies in sharp contrast to the light-harvesting chlorophyll-protein complexes mentioned above. Chlorosomes are found only in green sulfur bacteria and green filamentous bacteria. They catch weak light in an environment (3). A green sulfur bacterium species found in a deep-sea hydrothermal vent (4), for example, uses the dim light of geothermal radiation for photosynthesis. The atomic structure of chlorosomes has not been determined, which has impeded structure-based study of their functions. Because the design of chlorosomes is completely different from that of other light-harvesting devices, elucidation of their structure provides insight into the light-harvesting mechanism involved.Freeze-fracture electron microscopy revealed that chlorosomes were oblong bodies filled with several rod-shaped elements and were attached to the cytoplasmic side of cell membranes (5, 6). The rod elements of Chlorobium limicola, the target of this work, are composed of BChl c. Light energy captured by BChl c in the rod elements is transferred to the reaction centers in the cytoplasmic membrane through BChl a in baseplate proteins (7). The BChl c molecule has two stereoisomers...

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Multidimensional CP-MAS 13C NMR of uniformly enriched chlorophyll

Cited by 48 publications

References 33 publications

The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c , d , or e mimics

The supramolecular organization of self-assembling chlorosomal bacteriochlorophyll c , d , or e mimics

Optical spectra and localization of excitons in inhomogeneous helical cylindrical aggregates

Structure of the light-harvesting bacteriochlorophyll c assembly in chlorosomes from Chlorobium limicola determined by solid-state NMR

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