The cooperativity phenomena in a pigment‐protein complex of light‐harvesting antenna revealed by picosecond absorbance difference spectroscopy

Danielius, R.; Mineyev, A.P.; Razjivin, A.P.

doi:10.1016/0014-5793(89)80716-1

Cited by 19 publications

(3 citation statements)

References 10 publications

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“…In the case of the B880 complex from Rhodospirillum rubrum, an increase of energy of the exciting pulse was followed by blue-shift of the picosecond absorbance difference spectrum (Borisov et al, 1982;Razjivin et al, 1982;Nuijs et al, 1985;Sundstrom et al, 1986;van Grondelle et al, 1988). The similar results were obtained for the B890 complex from Chromatium minutissimum (Danielius et al, 1989) and for the RC-less antenna preparations from R. rubrum (Danielius et al, 1986). The blue-shift of the fluorescence emission peak with the excitation energy increase was found at 4 K for R. rubrwn and Rhodobacter sphaeroides chromatophores (Vos et al, 1986) as well as for chromatophores from several Rhodopseudomonas acidophila mutants and for membrane fragments from Rhodopseudomonas viridis (Deinum et al, 1989).…”

Section: Introductionmentioning

confidence: 52%

Exciton dynamics in circular aggregates: application to antenna of photosynthetic purple bacteria

Novoderezhkin¹,

Razjivin²

1995

Biophysical Journal

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A theoretical model of exciton dynamics in circular molecular aggregates of light-harvesting bacteriochlorophyll of photosynthetic bacteria is proposed. The spectra and anisotropy of photoinduced absorption changes in the femto- and picosecond time domain are under its scope. The excited state of aggregate was treated due to the standard exciton theory, taking into account a pigment inhomogeneity. Dephasing processes via the exciton-phonon interactions were described by means of the Haken-Strobl equation. It was shown that only two exciton levels are dipole-allowed in the case of homogeneous circular aggregate. The pigment inhomogeneity results in the appearance of several weak transitions to higher exciton levels. It was proposed that the minor band (B896) in an absorption spectrum of the B875 complex as well as the similar minor band in spectra of B800-850 complex correspond to electron transition from the ground to the lowest exciton level, whereas the major band corresponds to transition to the higher exciton level. The proposed model shows the subpicosecond decay of anisotropy at the short-wavelength side of absorption band and a high degree of anisotropy at the long-wavelength side, even at high temperatures.

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Section: Introductionmentioning

confidence: 52%

Exciton dynamics in circular aggregates: application to antenna of photosynthetic purple bacteria

Novoderezhkin¹,

Razjivin²

1995

Biophysical Journal

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“…Several experimental facts obtained with the antenna of purple photosynthetic bacteria such as the shape of picosecond absorbance difference spectra Razjivin et al 1982;Nuijs et al 1985;Danielius et al 1989), the absorption anisotropy kinetics (Sundstrom et al 1986;Bergstrom et al 1988), the anomalously high value of absorption changes per absorbed quantum (Novoderezhkin and Razjivin, 1993b) are difficult to interpret using traditional models based on the assumption of localized exciton migration Razjivin et al 1982;Van Grondelle et al 1988;Hunter et al 1990;Sundstrom et al 1986;Pullerits and Freiberg 1991;Timpmann et al 1991;Visschers et al 1993;Van Mourik et al 1992;Pullerits et al 1994). …”

Section: Introductionmentioning

confidence: 99%

Exciton states of the antenna and energy trapping by the reaction center

Novoderezhkin

Razjivin

1994

Photosynth Res

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Forward and back energy transfer between antenna and RC in the photosynthetic apparatus of purple bacteria was studied taking into account the exciton states of the antenna. The exciton states were calculated for core antenna configuration in the form of a circular aggregate of N identical BChl molecules with the CN-symmetry. The influence of pigment inhomogeneity on the proposed exciton description of the antenna and its interaction with RC was investigated. The ratio between the rate constants of forward and back energy transfer between the exciton levels of the antenna and RC was obtained as a function of the temperature, the number of antenna BChls and the antenna exciton level position with respect to BChl special pair level of RC. A versatile analytical expression for this ratio which is independent of the BChl special pair level position and its dipole orientation was derived. The proposed model results in an irreversible excitation trapping by RC even at room temperature.

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“…For a fairly long time, the model of random walks of singlet excitations over a lattice of BChl monomers (or dimers) [ 22 ] remained the mainstream theoretical approach [ 23 , 24 , 25 ]. However, many steady-state absorption, time-resolved, and fluorescence spectroscopy data [ 26 ] and laser spectroscopy of ultra-high temporal resolution [ 27 , 28 ] contradicted this view of the nature of energy migration. The development of the energy transport theory based on the conception of delocalized exciton states in LHCs of purple bacteria [ 29 ] helped to predict the circular arrangement of pigments in LH2 and to explain many spectroscopy features of bacterial LHCs.…”

Section: Introductionmentioning

confidence: 99%

The Relationship between the Spatial Arrangement of Pigments and Exciton Transition Moments in Photosynthetic Light-Harvesting Complexes

Pishchalnikov

Chesalin

Razjivin

2021

IJMS

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Considering bacteriochlorophyll molecules embedded in the protein matrix of the light-harvesting complexes of purple bacteria (known as LH2 and LH1-RC) as examples of systems of interacting pigment molecules, we investigated the relationship between the spatial arrangement of the pigments and their exciton transition moments. Based on the recently reported crystal structures of LH2 and LH1-RC and the outcomes of previous theoretical studies, as well as adopting the Frenkel exciton Hamiltonian for two-level molecules, we performed visualizations of the LH2 and LH1 exciton transition moments. To make the electron transition moments in the exciton representation invariant with respect to the position of the system in space, a system of pigments must be translated to the center of mass before starting the calculations. As a result, the visualization of the transition moments for LH2 provided the following pattern: two strong transitions were outside of LH2 and the other two were perpendicular and at the center of LH2. The antenna of LH1-RC was characterized as having the same location of the strongest moments in the center of the complex, exactly as in the B850 ring, which actually coincides with the RC. Considering LH2 and LH1 as supermolecules, each of which has excitation energies and corresponding transition moments, we propose that the outer transitions of LH2 can be important for inter-complex energy exchange, while the inner transitions keep the energy in the complex; moreover, in the case of LH1, the inner transitions increased the rate of antenna-to-RC energy transfer.

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The cooperativity phenomena in a pigment‐protein complex of light‐harvesting antenna revealed by picosecond absorbance difference spectroscopy

Cited by 19 publications

References 10 publications

Exciton dynamics in circular aggregates: application to antenna of photosynthetic purple bacteria

Exciton dynamics in circular aggregates: application to antenna of photosynthetic purple bacteria

Exciton states of the antenna and energy trapping by the reaction center

The Relationship between the Spatial Arrangement of Pigments and Exciton Transition Moments in Photosynthetic Light-Harvesting Complexes

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