Excitation trapping by different states of photosynthetic reaction centres

Vi, Godik; Ay, Borisov

doi:10.1016/0014-5793(77)80620-0

Cited by 48 publications

(18 citation statements)

References 15 publications

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“…This disagreement may come from the fact that these authors were employing reconstituted antenna + reaction centers complexes where the energy transfer from the antenna to the reaction centers was not totally restored as in native chromatophores. This is confirmed by the unexpectedly low degree of fluorescence quenching (10%) by the closed state of the reaction centers that they obtained, in disagreement with the results of Godik and Borisov (1977); Heathcote and Clayton (1977), and our data (Sebban et al, 1984).…”

Section: Time Resolved Fluorescence Experimentssupporting

confidence: 78%

ISOLATION and SPECTROSCOPIC CHARACTERIZATION OF THE B875 ANTENNA COMPLEX OF A MUTANT OF Rhodopseudomonas sphaeroides

Sebban

Robert

1985

Photochem & Photobiology

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Abstract— We describe a procedure of purification of the B875 antenna complex isolated from the 3P17 mutant strain of Rhodopseudomonas sphaeroides, enriched in B875. The integrity of this isolated complex, as well as a very low content of residual B800‐850 antenna, was suggested from low temperature absorption and resonance Raman spectra. Time resolved experiments were also carried out. The important result is the identity of the fluorescence lifetime of the B875 isolated complex (0.64 ± 0.03 ns) with that of the B875 antenna in vivo (0.63 ns), in the membrane of the C71 reaction center‐less mutant of Rhodopseudomonas sphaeroides, measured in our previous study. Our data suggest that the interactions between the bacteriochlorophylls of the complex, as well as the constraints imposed by their protein environment are not much changed from the in vivo state.

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Section: Time Resolved Fluorescence Experimentssupporting

confidence: 78%

ISOLATION and SPECTROSCOPIC CHARACTERIZATION OF THE B875 ANTENNA COMPLEX OF A MUTANT OF Rhodopseudomonas sphaeroides

Sebban

Robert

1985

Photochem & Photobiology

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“…3). A proportional relationship between these parameters was also observed in earlier contributions [15,16] The alternative type of quenching (quenching of the first type) is realized in systems, where a quencher molecule can quench an excited dye molecule only being in a close vicinity.…”

Section: Discussionsupporting

confidence: 71%

Quenching of chlorophyll fluorescence by quinones

et al. 1998

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Quinones caused quenching of Chl a fluorescence in native and model systems. Menadione quenched twofold the fluorescence of Chl a and BChl a in pea chloroplasts, chromatophores of purple bacteria, and liposomes at concentrations of 50‐80 μM. To obtain twofold quenching in Triton X‐100 micelles and in ethanol, the addition of 1.3 mM and 11 mM menadione was required, respectively. A proportional decrease in the lifetime and yield of Chl a fluorescence in chloroplasts, observed as the menadione concentration increased, is indicative of the efficient excitation energy transfer from bulk Chl to menadione. The decrease in the lifetime and yield of fluorescence was close to proportional in liposomes, but not in detergent micelles. The insensitivity of the menadione quenching effect to DCMU in chloroplasts, and similarity of its action in chloroplasts and liposomes indicate that menadione in chloroplasts interacts with antenna Chl, i. e., nonphotochemical quenching of fluorescence occurs.

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“…fAbbreviarions: BChl, bacteriochlorophyll. yield of the antenna. However, it was shown that the fluorescence yield of a mutant lacking the reaction centers, (Clayton et af., 1972) and of the antenna complex (Godik and Borisov, 1977) was substantially higher than the yield of chromatophores with closed reaction centers. The reaction center's "closed" state reached under saturating light then seemed to act as a quencher of bacteriochlorophyll antenna fluorescence.…”

Section: Introductionmentioning

confidence: 87%

SPECTRA OF FLUORESCENCE LIFETIME AND INTENSITY OF Rhodopseudomonas sphaeroides AT ROOM AND LOW TEMPERATURE. COMPARISON BETWEEN THE WILD TYPE, THE C 71 REACTION CENTER‐LESS MUTANT AND THE B800–850 PIGMENT‐PROTEIN COMPLEX

Sebban

Moya

1984

Photochem & Photobiology

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Spectra of the fluorescence lifetime and intensity of chromatophores from the wild type Rhodopseudomonas sphaeroides, from the C 71 reaction center-less mutant and of the B800-850 light harvesting pigment-protein complex have been studied by phase fluorimetry techniques at different light modulation frequencies at room and low temperature.As already known, closed reaction centers (saturating light) are still quenchers of antenna fluorescence although with a lower efficiency than when they are opened. The fluorescence yields and lifetimes of both the C 71 mutant strain and the B8W850complex are found to increase by about 30% between room and low temperature.The fluorescence lifetimes obtained for the C71 strain (0.65 ns at 20°C; 0.85 ns at 77 K) and for the 8850 complex (1 ns at 20°C; 1.3 ns at 77 K) indicate that the non-radiative deactivation pathways, in the antenna, remain important in the absence of the reaction centers even at low temperature. We suggest that these data arise from the presence of special antenna molecules which act as intrinsic quenchers of the B875 antenna fluorescence. Between room and low temperature, the fluorescence yield and lifetime of the wild type are found roughly constant. This result suggests that the energy trapping by the reaction centers is independent of the temperature. The mechanism governing the energy transfer from the antenna to the reaction centers may differ from the mechanism leading to the energy transfer within the antenna. We suggest that a partially irreversible trapping of the excitation energy, on its way to the reaction center, takes place in the vicinity of the reaction center.

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Excitation trapping by different states of photosynthetic reaction centres

Cited by 48 publications

References 15 publications

ISOLATION and SPECTROSCOPIC CHARACTERIZATION OF THE B875 ANTENNA COMPLEX OF A MUTANT OF Rhodopseudomonas sphaeroides

ISOLATION and SPECTROSCOPIC CHARACTERIZATION OF THE B875 ANTENNA COMPLEX OF A MUTANT OF Rhodopseudomonas sphaeroides

Quenching of chlorophyll fluorescence by quinones

SPECTRA OF FLUORESCENCE LIFETIME AND INTENSITY OF Rhodopseudomonas sphaeroides AT ROOM AND LOW TEMPERATURE. COMPARISON BETWEEN THE WILD TYPE, THE C 71 REACTION CENTER‐LESS MUTANT AND THE B800–850 PIGMENT‐PROTEIN COMPLEX

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