The chromophore topography and binding environment of peridinin·chlorophyll a·protein complexes from marine dinoflagellate algae

Koka, Prasad S; Song, Pill‐Soon

doi:10.1016/0005-2795(77)90379-8

Cited by 91 publications

(69 citation statements)

References 6 publications

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“…An additional non-decaying component, which represents excitations being trapped in the lowest excited state of Chl-a (lifetime $4.5 ns, Koka and Song 1977), is needed to reproduce the final state of the system. The first EADS depicted by the black line is created directly upon excitation.…”

Section: Resultsmentioning

confidence: 99%

Tuning Energy Transfer in the Peridinin–chlorophyll Complex by Reconstitution with Different Chlorophylls

et al. 2005

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In vitro studies of the carotenoid peridinin, which is the primary pigment from the peridinin chlorophyll-a protein (PCP) light harvesting complex, showed a strong dependence on the lifetime of the peridinin lowest singlet excited state on solvent polarity. This dependence was attributed to the presence of an intramolecular charge transfer (ICT) state in the peridinin excited state manifold. The ICT state was also suggested to be a crucial factor in efficient peridinin to Chl-a energy transfer in the PCP complex. Here we extend our studies of peridinin dynamics to reconstituted PCP complexes, in which Chl-a was replaced by different chlorophyll species (Chl-b, acetyl Chl-a, Chl-d and BChl-a). Reconstitution of PCP with different Chl species maintains the energy transfer pathways within the complex, but the efficiency depends on the chlorophyll species. In the native PCP complex, the peridinin S1/ICT state has a lifetime of 2.7 ps, whereas in reconstituted PCP complexes it is 5.9 ps (Chl-b) 2.9 ps (Chl-a), 2.2 ps (acetyl Chl-a), 1.9 ps (Chl-d), and 0.45 ps (BChl-a). Calculation of energy transfer rates using the Förster equation explains the differences in energy transfer efficiency in terms of changing spectral overlap between the peridinin emission and the absorption spectrum of the acceptor. It is proposed that the lowest excited state of peridinin is a strongly coupled S1/ICT state, which is the energy donor for the major energy transfer channel. The significant ICT character of the S1/ICT state in PCP enhances the transition dipole moment of the S1/ICT state, facilitating energy transfer to chlorophyll via the Förster mechanism. In addition to energy transfer via the S1/ICT, there is also energy transfer via the S2 and hot S1/ICT states to chlorophyll in all reconstituted PCP complexes.

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Section: Resultsmentioning

confidence: 99%

Tuning Energy Transfer in the Peridinin–chlorophyll Complex by Reconstitution with Different Chlorophylls

et al. 2005

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“…are predominantly hydrophilic, surrounding the chromophore which lies in a hydrophobic crevice (2). In addition, they contain a larger number of polar amino acids (4,20) than reported for known membrane-bound Chl a-protein complexes (8,12). In fact, in Glenodinium and other PCP-containing dinoflagellates, PCP is water soluble and is readily removed experimentally from the cells without addition of detergent (10,21 (2).…”

Section: T)mentioning

confidence: 90%

Photosynthetic characteristics and organization of chlorophyll in marine dinoflagellates

Prézelin

Alberte

1978

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

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The photosystem I reaction center complex, the P -700-chlorophyll a -protein, has been isolated from the photosynthetic membranes of two marine dinoflagellates, Gonyaulax polyedra and Glenodinium sp., by detergent solubilization with Triton X-100. The complexes isolated from the two species were indistinguishable, exhibiting identical absorption properties (400-700 nm) at both room (300 K) and low (77 K) temperature. The room temperature, red wavelength maximum was at 675 nm. The absorption properties, kinetics of photobleaching, sodium dodecyl sulfate electrophoretic mobilities, and chlorophyll a/P -700 ratio (50 ± 10) of the P -700-chlorophyll a -protein complexes from the two species also were essentially the same and similar to those properties characterizing P -700-chlorophyll a -protein complexes of higher plants and green algae. Photosynthetic unit sizes were determined for cells grown at 1000 μW/cm 2 . Both dinoflagellates had unit sizes (total chlorophyll/ P -700 ratios) of about 600, even though the distribution of chlorophyll a , chlorophyll c , and peridinin in the light-harvesting components differed in Gonyaulax and Glenodinium . The number of photosynthetic units per cell in the two species correlates directly with their photosynthetic activities. A model is presented for the distribution of chlorophyll in the photosynthetic apparatus of these dinoflagellates which accounts for the known role of the isolated pigment-protein complexes and for the known photoadaptive physiology in pigmentation and photosynthesis for these species.

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“…One fixed time constant was a long-lived component seen in all traces. This component has a time constant of Ϸ3.7 Ϯ 1 ns, which is clearly the Chl-a lifetime (20). The other fixed component, with a time constant of Ͻ100 fs, is due to an ultrafast S 2 decay manifested as the S 2 3S N ESA in the near-infrared region (21), which was also observed for peridinin in solution (17).…”

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confidence: 81%

Carotenoid to chlorophyll energy transfer in the peridinin–chlorophyll- a –protein complex involves an intramolecular charge transfer state

Zigmantas

Hiller

Sundström

et al. 2002

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

194

282

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Carotenoids are, along with chlorophylls, crucial pigments involved in light-harvesting processes in photosynthetic organisms. Details of carotenoid to chlorophyll energy transfer mechanisms and their dependence on structural variability of carotenoids are as yet poorly understood. Here, we employ femtosecond transient absorption spectroscopy to reveal energy transfer pathways in the peridinin-chlorophyll-a-protein (PCP) complex containing the highly substituted carotenoid peridinin, which includes an intramolecular charge transfer (ICT) state in its excited state manifold. Extending the transient absorption spectra toward nearinfrared region (600 -1800 nm) allowed us to separate contributions from different low-lying excited states of peridinin. The results demonstrate a special light-harvesting strategy in the PCP complex that uses the ICT state of peridinin to enhance energy transfer efficiency. C arotenoids are among the most abundant pigments in nature, having a wide variety of functions in living organisms. In photosynthetic organisms, besides their important regulatory role in the flow of the absorbed energy, carotenoids serve predominantly as light-harvesting pigments, efficiently covering the spectral region 450-550 nm (1). They transfer absorbed light energy to chlorophyll (Chl) or bacteriochlorophyll (BChl) molecules that funnel energy toward the reaction center where a charge separation occurs (1). The ability of the carotenoids to act both as photoprotection agents and light-harvesting pigments is a consequence of their unique photophysical properties (2). A typical carotenoid belongs to an idealized C 2h point symmetry group. In the manifold of singlet states of a carotenoid, the one-photon optical transitionϪ in C 2h group notation) is symmetry forbidden, resulting in the absence of an S 0 3S 1 absorption and in very weak fluorescence from the S 1 state (2). The well-known absorption of carotenoids in the blue-green region of the visible spectrum is caused by a strongly allowed transition from the S 0 (1A g Ϫ ) state to the S 2 (1B u ϩ ) state. Usually, fluorescence from the S 1 and S 2 states of carotenoids has a good spectral overlap with the Q y and Q x bands of Chls͞BChls, which favors energy transfer. On the other hand, the forbidden nature of the S 1 state results in a very weak transition dipole and puts substantial limits on efficient Förster mechanism of energy transfer (3). Furthermore, although the S 2 state has a strong transition dipole moment, there is a rapid internal conversion to the S 1 state in 50-300 fs (4), so that energy transfer from the S 2 state has to be extremely fast to compete with the S 2 to S 1 relaxation. Despite these apparent limitations, carotenoids are indeed efficient energy donors in various light-harvesting complexes of bacteria, algae, and higher plants, where efficiency of carotenoid to Chl͞ BChl energy transfer approaches 100% (1, 5, 6). Such high efficiencies are achieved by tight packing at van der Waals radius of pigments in light-harvesting complexes, ...

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The chromophore topography and binding environment of peridinin·chlorophyll a·protein complexes from marine dinoflagellate algae

Cited by 91 publications

References 6 publications

Tuning Energy Transfer in the Peridinin–chlorophyll Complex by Reconstitution with Different Chlorophylls

Tuning Energy Transfer in the Peridinin–chlorophyll Complex by Reconstitution with Different Chlorophylls

Photosynthetic characteristics and organization of chlorophyll in marine dinoflagellates

Carotenoid to chlorophyll energy transfer in the peridinin–chlorophyll- a –protein complex involves an intramolecular charge transfer state

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