The nature of oscillations in the kinetics of electron transfer in the reaction center of purple bacteria

Abstract

87 The reaction centers (RCs) of purple bacteria are natural nanostructures able to transform electron excitation energy into the energy of separated charges with a high efficiency (~100%). The RC main unit is formed of two protein subunits, L and M, with four bacteriochlorophyll (BCl) molecules, two bacteriopheophytin ( H A and H B ) molecules, and two quinone ( Q A and Q B ) molecules attached to them. An iron atom is localized between the quinones. In turn, two of the four BCl molecules form a special pair, the primary electron donor P. Spatial organization of the Rhodobacter sphaeroides RC has been determined with a resolution of 2.65 A [1]. Study of the interaction between the excited states and the charge transfer states of RC cofactors provided for discovering oscillations in the kinetics of stimulated luminescence in the R. sphaeroides RC at the excitation at Q y absorption band of the special pair [2, 3]. Shuvalov et al. studied the oscillations in the absorption band of the reduced intermediate acceptor [4, 5]. These oscillations were explained by a wave packet formed on the potential energy surface for the interaction between the special pair and BCl in the active photosynthesis chain during electron transfer. The oscillation data were described by the Redfield super