Analysis of photoinduced reverse changes in bacterial reaction centers
Abstract
Background: The membrane protein-pigment complexes of photosynthetic isolated reaction centers (RC) Rhodobacter Sphaeroides are macromolecular systems for studying the physical mechanisms of electron and proton transport in biological structures, the role of molecular dynamics. The experimental kinetics of cyclic electron transfer in molecular complexes has a multiexponential character with negative values of decrements. For their description, a system of balance equations is used.
Objective of the work is to determine the features of the kinetics of cyclic electron transfer in the RC using two models of electron transfer and the connection of such features with space-time motions in the RC.
Materials and methods: Measurement of the absorption kinetics was performed at 865 nm using a two-channel diode spectrometer. The experimental kinetics of RC absorption (the main reaction of the system) was represented by the fitting method in the form of a sum of three exponential functions. In the first model with time-variable rate constants of the balance equations, the wavelet transform method of the logarithmic derivative of the electron transfer kinetics was used. In the second model, the equation of state and three differential equations with constant coefficients were used as the algebraic sum of the rate constants. To determine the values of the rate constants in the balance equation, an optimization problem was solved. The solution of the system of balance equations by the matrix method made it possible to determine the features of the kinetics of the population of substates of the RC.
Results of calculations showed that the features of the wavelet spectrum of the logarithmic derivative of the electron transfer kinetics in the first model coincided with the features of the population kinetics of substates of the RC of the second RC model. These features were in the bands 1 s, 3 s, 60 s from the moment of switching on (off) the light and depend on the photoexcitation parameters.
Conclusions: The features of the kinetics of the populations of substates in the RC both at the stage of illumination and at the relaxation stage are determined by changes in the structure of the RC in the form of effects of hidden parameters of the structural self-regulation of the RC (feedback through the RC structure).
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References
Feher, G., Allen, J.P., Okamura, M.Y., Rees, D.C. (1989). Structure and function of bacterial photosynthetic reaction centres. Nature, 339, 111-116.
Deisenhofer, J., Epp, O., Miki, R., Huber, R., Michel, H. (1985). Structure of the protein subunits in the photosynthetic reaction centre of Rhodopseudomonasviridis at 3Å resolution. Nature, 318, 618–624.
Andreasson, U., Andreasson, L.E. (2003). Characterization of a semi-stable, charge-separated state in reaction centers from Rhodobacter sphaeroides. Photosynth Res., 75(3), 223-233.
Qiang, Xu, and Gunner M.R. (2001) Trapping Conformational Intermediate States in the Reaction Center Protein from Photosynthetic Bacteria. Biochemistry, 40(10), 3232–324.
Rubin, A.B. (2017). Compendium of Biophysics. Wiley. 666 p.
Deshmukh, S.S., Williams, J.C., Allen, J.P., Kalman, L. (2011). Light-induced conformational changes in photosynthetic reaction centers: dielectric relaxation in the vicinity of the dimer. Biochemistry. 50(3), 340–834.
Kharkyanen, V.N., Barabash, Y.M., Berezetskaya, N.M., Lukashev, E.P., Knox, P.P., Christophorov, L.N. (2011). Peculiarities of light-induced slow protein dynamic in the photosynthetic reaction center. Chemical Physics Letters, 512, 113–117.
Golbeck, J., Art van der Est. (2014). The Biophysics of Photosynthesis. Springer.
D'jakonov, V.P. (2000). Vejvlety. Ot teorii k praktike. Moscow: SOLON-Press. (in Russian)
Stark, H.-G. (2005). Wavelets and Signal Processing. Springer.
Maks, Zh. (1983). Metody i tehnika obrabotki signalov pri fizicheskih izmerenijah. Moscow: Mir. (in Russian)
Zakharova, N.I., Churbanova, I.Yu. (2000). Methods of isolation of reaction center preparations from photosynthetic purple bacteria. Biochemistry, 65, 181-193.
Serdenko, T.V., Barabash, Y.M., Knox, P.P., Seifullina, N.Kh. (2016). The kinetic model for slow photoinduced electron transport in the reaction centers of purple bacteria. Nanoscale Research Letters, 11, 286. URL: https://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1502-x.
Barabash, Y.M., Lyamets, A.K. (2016). A method of decomposition of the basic reaction of biological macromolecules into exponential components. Nanoscale Research Letters, 11, 544. URL: https://nanoscalereslett.springeropen.com/articles/10.1186/s11671-016-1758-1.
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