Two stable electron-conformational states of photoactivated reaction center and their observation in primary donor recovery kinetics

Goushcha, Alexander O.; Berezetska, Natalja M.; Kapoustina, M. T.; Kharkyanen, V. N.

doi:10.1007/bf00954459

Cited by 2 publications

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References 16 publications

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“…Nevertheless, a more detailed approach to describe the real functioning system is necessary for understanding the dynamics of an ensemble of RCs. The complex nonlinear dependencies and hysteresis effects observed for the RC absorbance changes ,, and the dependence of the primary donor re-reduction kinetics − on various conditions of optical excitation were taken as evidence for dynamic self-regulation. In this work, we present a self-consistent stochastic description of the ensemble of macromolecules undergoing ET, and we demonstrate the importance of nonlinear dynamic effects in the experimentally observed dependencies .…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Dynamic Processes in an Ensemble of Photosynthetic Reaction Centers. Theory and Experiment

et al. 1997

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The results of a theoretical study of the dynamic self-organization phenomenon in the photosynthetic reaction center (RC) from purple bacteria are presented accounting for the stochastic effects an RC ensembles. The adiabatic approximation is applied to determine the specific role of slow structural (protein/cofactors) modes in the correlated behavior of the electronic and structural variables. It is shown that, at certain values of light intensity, the system undergoes bifurcation. The bistability region for the generalized structural variable occurs where the system has two stable states, one characteristic for the dark-adapted sample (i.e., the sample under very low illumination intensity) and the other for the light-adapted sample. The description is based on the solution of the “forward” Kolmogorov equations using the Markov approach. A distribution function describing the probability of finding the electron localized on a particular cofactor with a certain value of the generalized structural variable is used. Modeling shows a good agreement with the results of experimental investigations of transient optical absorbance changes of the isolated RCs from the purple bacterium Rhodobacter sphaeroides. The results indicate that the free energy difference between QA - and QB - changes substantially in different conformational states of the protein/cofactors induced by light over a wide range of the illuminating light intensity.

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Section: Introductionmentioning

confidence: 99%

Nonlinear Dynamic Processes in an Ensemble of Photosynthetic Reaction Centers. Theory and Experiment

et al. 1997

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Theoretical modelling and experimental investigation of nonlinear dynamic precedes in ensemble of photosynlhetic reaction centers

et al. 1998

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Ереванский государственный медицинский университет 375033, Ереван, ул. Ватутина, 2/2 Институт физики ПАН Украины 252650, Киев, пр. Науки, 46 Результаты теоретического изучения явления динамической самоорганизации в специфических макромолекулярных структурах, фотосинтетических реакционных центрах (РЦ), представлены с учетом стохастических еффектов, возникающих в ансамбле РЦ. Модель для общего описания кинетики переходов фотомобилизованного электрона и конформационных изменений структуры базируется на решении прямых уравнений Колмогорова с использованием марковского приближе ния. Зависимость общей функции распределения от конформационной координаты рассматрива ется для случая, когда система находится в термодинамическом равновесии, и для полностью неравновесного состояния. Расчеты показывают возможность бистабильного поведения системы в некотором интервале скоростей фотомобилизованного электрона. Модель хорошо согласуется с результатами экспериментальных исследований коэффициента оптического поглощения РЦ пурпурных бактерий Rhodopsceudomonas sphaeroides.

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Two stable electron-conformational states of photoactivated reaction center and their observation in primary donor recovery kinetics

Cited by 2 publications

References 16 publications

Nonlinear Dynamic Processes in an Ensemble of Photosynthetic Reaction Centers. Theory and Experiment

Nonlinear Dynamic Processes in an Ensemble of Photosynthetic Reaction Centers. Theory and Experiment

Theoretical modelling and experimental investigation of nonlinear dynamic precedes in ensemble of photosynlhetic reaction centers

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