The possible functions of a light-induced electron transfer to oxygen in the photosynthetic electron transport chain of higher plant chloroplasts are considered. The thermodynamic preconditions, as well as the experimental data about the participations of ferredoxin, the components of photosystems I and II, and plastoquinone in oxygen reduction are examined. It is concluded that, even in the pr...

In photosynthesis, the flavoenzyme ferredoxin:NADP(+) oxidoreductase (FNR) catalyses the final electron transfer from ferredoxin to NADP(+), which is considered as the main pathway of high-energy electron partitioning in chloroplasts (DOI: 10.1111/j.1365-313X.2009.03999.x[1], DOI: 10.1038/srep10085[2]). Different detergents and pH treatments of photosynthetic membranes isolated from the Arabido...

Photosystem II is a specialized protein complex that uses light energy to oxidize water, resulting in the release of molecular oxygen into the atmosphere, and to reduce plastoquinone, which is released into the hydrophobic core of the photosynthetic membrane. All oxygenic photosynthetic organisms, which include plants, algae and some bacteria, depend on photosystem II to extract electrons from ...

In photosynthetic reaction centers, the excitation with light leads to the formation of a charge separated state across the photosynthetic membrane. For the reaction center of purple non-sulphur bacteria, it was previously generally assumed that this primary charge separation could only start with the excitation of the so-called special pair of bacteriochlorophyll molecules located in the heart...

Obtaining well ordered crystals of membrane proteins is the single most serious stumbling block in the pursuit of their high-resolution structures. The applicability of lipidic cubic phase-mediated crystallization is demonstrated on a diverse set of bacterial membrane proteins: two photosynthetic reaction centres, a light-harvesting complex and two retinal proteins, halorhodopsin and bacteriorh...

Fluorescence lifetime measurements with nanometer spatial resolution are made possible by incorporating time-correlated single photon counting with a near-field fluorescence microscope. Using this apparatus, single pieces of intact photosynthetic membrane from the Chlamydomonas reinhardtii strain doubly deficient in photosystem I (PS I) and photosystem I1 (PS 11) are examined. Comparison of sim...

Carotenoids are photoprotective pigments present in many photosynthetic and nonphotosynthetic organisms. The desaturation of phytoene into phytofluene is an early step in the biosynthetic pathway that in the photosynthetic bacterium Rhodobacter capsulatus is mediated by the product of the crtI gene. Here we report the sequence of this gene and the identification of CrtI as a membrane protein of...

Photosynthesis, Respiration, Blue-Green Algae, Arrhenius Plots, Phase Transition Temperatures Photosynthetic and respiratory electron-transport reactions by the blue-green alga, Anabaena variabilis, exhibit a strict temperature dependence in vivo as well as in the cell-free system. The ratio of respiratory oxygen uptake in the dark and oxygen evolution in the light is high after growth at low t...