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Photophosphorylation of epsilon ADP in a chloroplast synthetase system reconstituted with CF1 or with CF1 modified by covalently bound epsilon ADP has been studied. The reconstitution of EDTA-treated chloroplasts with CF1 restores the photophosphorylating activity to about 90%. When the CF1 modified by covalently bound epsilon ADP is used for reconstitution the photophosphorylating activity of EDTA-treated chloroplasts is restored to 37%. Based on the results of a photochemical study of the chloroplast ATP-synthetase system reconstituted with CF1 with covalently bound epsilon ADP it may be assumed that the substrate, adenine, participates in proton translocation to inorganic phosphate in the active center of the coupling enzyme during photophosphorylation.

Upon illumination of the system containing chlorophyll a+b adsorbed on a SiO2 sorbent, ADP and Pi in an aqueous solution, pH 7.6, the formation of ATP has been demonstrated, using 32P-phosphate. This process is inhibited in the absence of oxygen or in the presence of ascorbate. Under similar conditions without ADP pyrophosphate is formed; substitution of ADP for arginine results in a formation of arginine phosphate. Phosphorylation with a reduced yield has also been found upon illumination of chlorophyll adsorbate without other additives and an addition of ADP+Pi solution in the dark to the preilluminated adsorbate fast enough to prevent the decay of the light-induced product. A model according to which the chlorophyll-sensitized oxidation of orthophosphate ion the primary event in the reaction sequence, and the decomposition of orthophosphate radical anion into methaphosphate and hydroxyl species is the secondary step, has been proposed. A possible significance of the results obtained is discussed in terms of the concepts on the prebiotic evolution of energy metabolism.

The effect of redox and chelating reagents on the ATPase and ATP-synthetase activity in chloroplast membranes as well as the ATPase activity of isolated CF1-coupling factor from chloroplasts has been studied. The Mg2+-ATPase in thylakoid membranes and isolated Ca2+-ATPase is stimulated by dithionite. In the presence of reduced glutathione the effect of dithionite is similar to those of prolonged illumination or heating. Dichlorophenolindophenol partially inhibits this activity as well as citrate, tenoyltrifluoroacetone and the excess fo ATP. Photophosphorylation in chloroplast lamellae is inhibited with dithionite. It is suggested that the membrane bound ATPase from chloroplasts may be in two structural states which differ in their enzymic activity and in the coupling to electron transfer in membrane. The transitions between these states can be induced by redox reagents.

Effects of various temperatures on the rates of electron transport between two photosystems, the light-induced uptake of protons, kinetics of proton efflux from the chloroplasts in the dark and photophosphorylation were studied in isolated chloroplasts. There are correlations between the physical state of thylakoid membrane and the rates of electron- and proton transport processes. The temperature dependence of "structural" parameter (fluidity of lipids in membrane) as well as the rates of electron- and proton transport processes reveal the breaks under the same temperatures. Stimulation of photophosphorylation by temperature increasing correlates with the heat activation of chloroplasts latent ATPase due to thermoinduced structural changes in the heat activation of chloroplasts latent ATPase due to thermoinduced structural changes in the protein part of CF0-CF1 complex. The rate of photophosphorylation also correlates with the physical state of membrane lipids. Thermoinduced "melting" of the thylakoid membrane inhibits the ATP formation because of a decrease in photosystem 2 photochemical activity and stimulation of membrane conductivity for protons.

The effect of phosphorylation on glycolysis reactions was studied in respect with the rate of 1-14C-glucose metabolization and the composition of synthesized labelled products in isolated cells of assimilating millet leave tissues incapable to reassimilation of respiratory CO2. Data on oxygen metabolism in mesophyll protoplasts and in cells of parenchymal facing of vascular bundle sheaths in the absence and in the presence of electron acceptors (3,5-dichlorophenolindophenol and methylviologen) show that they retain adenylate pool and energy charge characteristic of photosynthetizing tissues. The glycolysis rate decreased in illuminated cells, which did not remove carbon products from chloroplasts. Analysis of compounds produced from 1-14C-glucose exogenous ADP effect on their ration and the change of adenylate energy charge in the presence of methylviologen demonstrates that the acting factor is a decrease of Pi and ADP concentrations in cytoplasm because of their use chloroplast phosphorylation. It is suggested, that a short-cut chain of glycolysis reactions may take place in intact cells assimilating CO2 in photosynthesis, and the capacity of this chain is determined by the type of carbon metabolism and photorespiration mechanism.

Structural changes of chloroplast fragments result in increased adsorption of adenine derivatives. The nativity of membranes is essential for AMP adsorption. Chloroplast fragments, containing CF1, adsorb adenine and adenosine by 30% and ADP by 50% more than the fragments, devoid of the enzyme. It is assumed that lipids may act as sorbents during nucleotides interaction with the chloroplast membrane.

An attempt is made to summarize the hypotheses of the mechanisms of the effect of adverse environmental factors on the structural and functional organization of the cell published in the literature. On the basis of the literature data and his own findings the author concludes that changes in cell structures are primary. The material foundation for these changes are biological membranes whose chemical composition and physical properties dictate stability of cell substructures. The complex of nonspecific changes in the cell leads to supercellular and superorgan adaptive reactions at whose level adaptation develops.

A kinetic study of ATP hydrolysis by soluble ATPase of chloroplasts (CF1) was made. At low concentrations of MgCl2 a linear increase of the reaction rate was observed during the increase in the ATP concentration up to 1 mM. At high concentrations of MgCl2 the dependence was of a more complicated nature. At MgCl2 concentrations lower than 0.1 mM the reaction approached second-order kinetics with respect to Mg2+; the increase in MgCl2 concentration resulted in a decrease of the reaction order. It is assumed that MgATP is the "true" substrate and MgADP the "true" inhibitor of the reaction. A reaction mechanism of ATP hydrolysis is postulated.

The nature of macroergic bonds and some problems of ATP formation and utilization are considered in terms of electron structure of phosphates. The main acting compound in the ATP synthesis and in the reactions of transfer and utilization of the energy of macroergic bonds as well, is ATP terminal phosphate or phosphoryl group which in the free state is a monomeric methaphosphate-ion. High reactive ability of monomeric methaphosphate-ion, its affinity of lown electrom pairs is conditioned by the presence of a vacant sp3-orbitals in phosphor atom of methaphosphate-ion. Therefore in the reactions with ATP participation the phosphoryl group plays the role of electrophilic agent. Formation of intermediate methaphosphate-ion preceding the synthesis of ATP from ADP during substrate phosphorylation results from the breakage of O--P bond, during which both electrons which form the bond stay in the oxygen atom. Another possible pathway of methaphosphate-ion formation is the ejaction of the electron from ortophosphate dianion with the help of suitable acceptor of the electrons, by light-stimulated pigment system of chloroplasts or chromatophores or singlet oxygen liberated during the decomposition of hydrogen peroxide with catalase. Due to the redistribution of electron density in the phosphate radical the latter turns into the monomeric methaphosphate-ion bound to ADP with the formation of ATP.

The function of H+-ATPase (CF1-CF0) complex from spinach chloroplasts was reconstituted on azolectin liposomes. Using these proteoliposomes, the 32P-ATP exchange reaction sensitive to dicyclohexylcarbodiimide and uncouplers was established. Combined incorporation of H+-ATPase and bacteriorhodopsin as a delta mu H+ inducer results in photophosphorylation. The optimal conditions for production of liposomes with a low permeability of membranes for ions were elaborated with a view towards improving the existing reconstitution methods.

A photo-electrochemical hypothesis of cyclic photophosphorylation in chromatophores suggests that electrons, thrown out by light from the reaction center, came back via the electron carrier chain within the hydrophobic part of the membrane taking up H+-ions through the entrance H+-channels. H+-ions and electrons are transferred to quinones or semiquinones which are transformed into semiquinones or hydroquinones accordingly. They release H+-ions into output channels, while the electrons are transferred to the next electron carrier. At non-cyclic photophosphorylation of the chloroplast the second photosystem takes electrons from water via primary donor and releases the H+-ions into the proton channels. After receiving an electron the oxidase takes up H+ through the H+-channels and gives the electron and H+ to O2. A direct method of the experimental check up of the electrochemical hypothesis is described.

The mutants Arabidopsis thaliana triplex and 58/15 with a high and low content of green pigments, respectively, and a higher rate of photosynthesis in comparison with the control form of Enkheim were studied. The significant differences in the structural organization of chloroplasts of both mutants were revealed. The two mutants are also characterized by a higher rate of ferricyanide reduction in the Hill reaction and ATP production via photophosphorylation. It was shown that mg2+, NH4Cl and (ADP + Pi) have different effects on the activity of these processes in different chloroplasts. On the whole the photosyntheic apparatus of mutants provides for a high efficiency of photosynthesis, while determines the survival of mutant 58/15 under pigment deficiency and increases the productivity of triplex mutant.

The energy-dependent processes coupled to electron transport were studied in isolated pea chloroplasts treated with low concentrations (1-5 mM) of glutaraldehyde (GA) in the dark and in the light sufficient to cause energization of the membrane. After GA treatment the chloroplasts exhibited a strong suppression of cyclic and non-cyclic phosphorylation, coupled (+ADP+Pi) electron transport and diminution of the light-activated Mg2+-ATPase activity. The rate of basal electron transport was unaffected. The GA-treated chloroplasts were found to retain the capacity to form the osmotic component of the transmembrane potential. These data and the results of the effect of florizine and ATP on electron transport suggest that the effect of GA on energy transduction processes associated with photophosphorylation may consist in its action on reversible H+-ATPase. In light-adapted samples treated with GA the data characterizing the formation of a high energy state (rate of photophosphorylation, steady-state level of photo-induced quenching of atebrin fluorescence and its dark recovery; photo-induced absorbance changes at 520 nm; rate of the slow phase of delayed fluorescence increment) appear to be changed to a greater extent as compared to the dark-adapted samples. The observed changes may arise from a greater conductivity of thylakoid membranes due to fixation of the H+-ATPase proton channel in the "open" state.

Galactolipase and protenase action on the low temperature fluorescence spectra of light chloroplast fragments obtained from grana or intergrana thylakoids and grana thylakoids system before and after isolation photosystem I particles have been studied. Identical hydrolytic enzymes action in the two type photosystem I particles have been studied. Identical hydrolytic enzymes action in the two type photosystem I particles were observed. Grana thylakoids system after removing photosystem I particles contained photosystem II in the most purified form. These measurements results confirmed our previous suggestion that the band at 735 nm in the low temperature fluorescence spectra of light and heavy fragments belongs to the different native chlorophyll a aggregates.

In aqueous solutions in air atmosphere chlorophylls a and b, pheophytin and beta-carotene adsorbed on aluminium oxide powder are capable of sensibilizing electron transfer from phosphate ions coupled with the formation of high energy bonds of adenosine phosphates. The highest activity of chlorophylls a and b and pheophytin is observed within the pH range of 7.5-7.8; that of beta-carotene--at pH 7.3-7.5.

The quantum yield of noncyclic photophosphorylation in chloroplasts excited by a series of 8 mus flashes of the saturating intensity displays a two-fold decrease when the flash-frequency is reduced from about 1.1 to about 0.8 s-1, whereas further decrease of flash frequency does not affect the average ATP yield per flash. Under excitation by two-flashes series the ATP yield is also about half-maximal. These observations are inconsistent with the concept postulating accumulation of energy contributions from several parallel or consecutive one-electron transfers as a prerequisite for ATP formation. The two-state model of a thylakoid membrane and of a coupling site is put forward according to which only one of these states ensures ATP formation in response to one electron transfer through one coupling site, whereas the other state is nonphosphorylating.

A comparative study of the intensity of O2 uptake, NADP+ reduction and ATP synthesis in pea chloroplasts grown upon different illumination conditions was carried out. The rates of O2 uptake in the absence of cofactors and in the presence of ferredoxin are almost identical for "dark" and "light" chloroplasts. In a medium containing oxidized NADP+ the rate of electron transport is considerably lower in the "dark" chloroplasts; the pseudocyclic transport coupled with simultaneous reduction of O2 in these chloroplasts is somewhat higher (on the average by 30%). The decrease of electron transfer to NADP+ caused by reduction of light intensity during plant growth (presumably due to the limiting step, i. e. ferredoxin--NADP+-reductase) is to some extent compensated for by a more effective utilization of O2 as an electron acceptor. This eventually results in an increase of the ATP/NADPH ratio.

The hexane treatment of the freeze-dried chloroplasts from bean leaves results in complete inhibition of electron transport from water to silicomolybdate, as a specific electron acceptor from photosystem 2 insensitive to 3-(3,4-dichlorophenyl)-1,1-dimethyl-urea. The photophosphorylation coupled to this electron flow is inhibited as well. The reconstruction with the concentrated hexane extract or with the coenzyme Q results in partial reactivation of the light-induced O2 evolution, silicomolybdate reduction and coupled phosphorylation. The electron transport model of the oxidizing side of photosystem 2 is put forward, according to which plastoquinone acts as an electron carrier between the manganese water-splitting complex and the photosystem 2 reaction center. The accumulation of positive charges during four subsequent photosystem 2 excitations occurs in the form of ion-pairs of plastosemiquinone radical anion with manganese (III) cation, separated from the photochemical center by a hydrophobic barrier. The two water molecules are oxidized by interaction with an electron acceptor of moderate redox potential near 0.8 beta without formation of toxic active species such as OH-radicals as intermediates.

Redox transients of P700 in bean chloroplasts induced by far-red continuous light and brief flashes (t1/2 = 7 musec) of white light were studied under various temperatures. It has been shown that light-induced electron transport between two photosystems occurs at temperatures from -5 degrees to 45 degrees. At temperature interval 5 divided by 30 degrees photosystem 2 donates electrons to P700+ in response to the flash with the maximum efficiency. The number of electrons donated from photosystem 2 does not depend on the temperature in the range 5 divided by 30 degrees. The rate of electron transport between photosystems increases when the temperature is increased from -5 degrees to 20 degrees and does not depend on the temperature above 20 degrees. Structural states of the lipid region of the thylakoid membrane were studied by the spin label method. It was shown that the flexibility and the rate of molecular motion of different spin-labeled fatty acids were increased after temperature variations from -10 degrees to 50 degrees. A correlation between the structural state of the lipid region of thylakoid membrane and the rate of electron transport was found.