A possible relationship between the effect of factors on photoactivation of photosystem II depleted of functional Mn and cytochrome b.

The photoassembly of the MnCaO cluster in Mn-depleted photosystem II preparations (photoactivation) was studied under the influence of oxidants, reductants and pH. New data on the effect of these factors on the photoactivation yield are presented. The presence of the oxidant, ferricyanide, negatively affected the photoactivation yield over the entire concentration range studied (0-1 mM).

Correction: Khorobrykh, A. Hydrogen Peroxide and Superoxide Anion Radical Photoproduction in PSII Preparations at Various Modifications of the Water-Oxidizing Complex. 2019, , 329.

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Functional characterization of the corticular photosynthetic apparatus in grapevine.

A comparative analysis of functional characteristics of the grapevine leaf photosynthetic apparatus (LPA) and corticular photosynthetic apparatus (CPA) in chlorenchyma tissues of first-year lignified vine was performed. Obtained results demonstrate significant differences between the functional properties of the CPA and the LPA. CPA contains an increased proportion (about 2/3) of Q-non-reducing centers of photosystem II (PSII) that is confirmed by elevated O-J phase in fluorescence kinetics, high PSIIβ content, and slower Q reoxidation.

Hydrogen Peroxide and Superoxide Anion Radical Photoproduction in PSII Preparations at Various Modifications of the Water-Oxidizing Complex.

The photoproduction of superoxide anion radical (O) and hydrogen peroxide (HO) in photosystem II (PSII) preparations depending on the damage to the water-oxidizing complex (WOC) was investigated. The light-induced formation of O and HO in the PSII preparations rose with the increased destruction of the WOC. The photoproduction of superoxide both in the PSII preparations holding intact WOC and the samples with damage to the WOC was approximately two times higher than HO.

Two pathways of photoproduction of organic hydroperoxides on the donor side of photosystem 2 in subchloroplast membrane fragments.

Earlier the catalase-insensitive formation of organic hydroperoxides (via the interaction of organic radicals produced due to redox activity of P (or TyrZ) with molecular oxygen) has been found in Mn-depleted PS2 preparations (apo-WOC-PS2) by Khorobrykh et al. (Biochemistry 50:10658-10665, 2011). The present work describes a second pathway of the photoproduction of organic peroxides on the donor side of PS2.