Vectorial Charge Transfer Reactions on the Donor Side of Manganese-Depleted and Reconstituted Photosystem 2 Core Complexes

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I. O. Petrova, V. N. Kurashov, A. A. Zaspa, A. Yu. Semenov, and M. D. Mamedov^*

Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119234 Moscow, Russia; fax: (495) 939-3181; E-mail: mahirmamedov@yandex.ru; mamedov@genebee.msu.ru

^* To whom correspondence should be addressed.

Received December 18, 2012

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The light-induced functioning of photosystem 2 (PS 2) is directly linked to the translocation of both electrons and protons across the membrane, which results in the formation of transmembrane electric potential difference (ΔΨ). Generation of ΔΨ due to S-state transitions of the water oxidation complex was demonstrated for the first time in Mn-depleted and reconstituted PS 2 core complexes incorporated into liposomes. The kinetics and relative amplitudes of the electrogenic reactions in dark-adapted samples during S₁→S₂, S₂→S₃, and S₄→S₀ transitions in response to the first, second and third laser flashes were comparable to those obtained in the intact PS 2 core particles. These results expand current understanding of the nature and mechanisms of electrogenic (vectorial) reactions due to a charge transfer on the donor side of PS 2.

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KEY WORDS: photosystem 2, apo-WOC-PS 2, photoactivation, S-state transitions, proteoliposomes, direct electrometric technique

DOI: 10.1134/S0006297913040081

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