Light increases resistance of thylakoid membranes to thermal inactivation.

In the region of slightly acidic pH (рН 5.7), the manganese cluster in oxygen-evolving complex of photosystem II (PSII) is more resistant to exogenous reductants. The effect of such pH on the heat inactivation efficiency of the electron transport chain (O evolution and 2,6-dichlorophenolindophenol reduction) in PSII membranes and thylakoid membranes was investigated.

Effect of the insecticide clothianidin on the photosynthetic electron transport chain in pea.

Clothianidin (CL) is a neonicotinoid insecticide widely used in crop protection against insect pests. However, its effects on photosynthesis remain largely unknown. Here, by investigating the influence of CL at the concentrations of 22 and 110 μg/L on the primary processes of photosynthesis, membrane fluidity and structural changes of pea chloroplasts, we located several primary binding sites of this pesticide.

Current analysis of cations substitution in the oxygen-evolving complex of photosystem II.

Water oxidation in photosystem II (PSII) is performed by the oxygen-evolving complex MnCaO which can be extracted from PSII and then reconstructed using exogenous cations Mn(II) and Ca. The binding efficiency of other cations to the Mn-binding sites in Mn-depleted PSII was investigated without any positive results. At the same time, a study of the Fe cations interaction with Mn-binding sites showed that it binds at a level comparable with the binding of Mn cations.

Effective binding of Tb and La cations on the donor side of Mn-depleted photosystem II.

The interaction of Tb and La cations with different photosystem II (PSII) membranes (intact PSII, Ca-depleted PSII (PSII[-Ca]) and Mn-depleted PSII (PSII[-Mn]) membranes) was studied. Although both lanthanide cations (Ln) interact only with Ca-binding site of oxygen-evolving complex (OEC) in PSII and PSII(-Ca) membranes, we found that in PSII(-Mn) membranes both Ln ions tightly bind to another site localized on the oxidizing side of PSII. Binding of Ln cations to this site is not protected by Ca and is accompanied by very effective inhibition of Mn oxidation at the high-affinity (HA) Mn-binding site ([Mn  + HO] couple was used as a donor of electrons).

Role of the PB-loop in ApcE and phycobilisome core function in cyanobacterium Synechocystis sp. PCC 6803.

The phycobilisome (PBS) is a giant highly-structured pigment-protein antenna of cyanobacteria and red algae. PBS is composed of the phycobiliproteins and several linker polypeptides. The large core-membrane linker protein (L or ApcE) influences many features and functions of PBS and consists of several domains including the chromophorylated PB-domain.