Base de dados : MEDLINE
Pesquisa : D12.776.765.199.750.750 [Categoria DeCS]
Referências encontradas : 6018 [refinar]
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  1 / 6018 MEDLINE  
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PMID:29236502
Autor:Allodi MA; Otto JP; Sohail SH; Saer RG; Wood RE; Rolczynski BS; Massey SC; Ting PC; Blankenship RE; Engel GS
Endereço:Department of Chemistry, The Institute for Biophysical Dynamics, The James Franck Institute, The University of Chicago , Chicago, Illinois 60637, United States.
Título:Redox Conditions Affect Ultrafast Exciton Transport in Photosynthetic Pigment-Protein Complexes.
Fonte:J Phys Chem Lett; 9(1):89-95, 2018 Jan 04.
ISSN:1948-7185
País de publicação:United States
Idioma:eng
Resumo:Pigment-protein complexes in photosynthetic antennae can suffer oxidative damage from reactive oxygen species generated during solar light harvesting. How the redox environment of a pigment-protein complex affects energy transport on the ultrafast light-harvesting time scale remains poorly understood. Using two-dimensional electronic spectroscopy, we observe differences in femtosecond energy-transfer processes in the Fenna-Matthews-Olson (FMO) antenna complex under different redox conditions. We attribute these differences in the ultrafast dynamics to changes to the system-bath coupling around specific chromophores, and we identify a highly conserved tyrosine/tryptophan chain near the chromophores showing the largest changes. We discuss how the mechanism of tyrosine/tryptophan chain oxidation may contribute to these differences in ultrafast dynamics that can moderate energy transfer to downstream complexes where reactive oxygen species are formed. These results highlight the importance of redox conditions on the ultrafast transport of energy in photosynthesis. Tailoring the redox environment may enable energy transport engineering in synthetic light-harvesting systems.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Light-Harvesting Protein Complexes); 0 (Photosynthetic Reaction Center Complex Proteins)


  2 / 6018 MEDLINE  
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PMID:28941458
Autor:Yakovlev AG; Shuvalov VA
Endereço:Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia. yakov@genebee.msu.su.
Título:Femtosecond Relaxation Processes in Rhodobacter sphaeroides Reaction Centers.
Fonte:Biochemistry (Mosc); 82(8):906-915, 2017 Aug.
ISSN:1608-3040
País de publicação:United States
Idioma:eng
Resumo:Energy relaxation was studied with difference femtosecond spectroscopy in reaction centers of the YM210L mutant of the purple photosynthetic bacterium Rhodobacter sphaeroides at low temperature (90 K). A dynamical long-wavelength shift of stimulated emission of the excited state of the bacteriochlorophyll dimer P was found, which starts simultaneously with P* formation and is accompanied by a change in the spectral shape of this emission. The characteristic value of this shift was about 30 nm, and the characteristic time about 200 fs. Difference kinetics ΔA measured at fixed wavelengths demonstrate the femtosecond shift of the P* stimulated emission appearing as a dependence of these kinetics on wavelength. We found that the reported long-wavelength shift can be explained in terms of electron-vibrational relaxation of the P* excited state with time constants of vibrational and electronic relaxation of 100 and 50 fs, respectively. Alternative mechanisms of the dynamical shift of the P* stimulated emission spectrum are also discussed in terms of energy redistribution between vibrational modes or coherent excitation of the modes.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Bacterial Proteins); 0 (Bacteriochlorophylls); 0 (Photosynthetic Reaction Center Complex Proteins)


  3 / 6018 MEDLINE  
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PMID:28688734
Autor:Altamura E; Fiorentino R; Milano F; Trotta M; Palazzo G; Stano P; Mavelli F
Endereço:Chemistry Department, University "Aldo Moro", Via Orabona 4, I-70126 Bari, Italy.
Título:First moves towards photoautotrophic synthetic cells: In vitro study of photosynthetic reaction centre and cytochrome bc1 complex interactions.
Fonte:Biophys Chem; 229:46-56, 2017 Oct.
ISSN:1873-4200
País de publicação:Netherlands
Idioma:eng
Resumo:Following a bottom-up synthetic biology approach it is shown that vesicle-based cell-like systems (shortly "synthetic cells") can be designed and assembled to perform specific function (for biotechnological applications) and for studies in the origin-of-life field. We recently focused on the construction of synthetic cells capable to converting light into chemical energy. Here we first present our approach, which has been realized so far by the reconstitution of photosynthetic reaction centre in the membrane of giant lipid vesicles. Next, the details of our ongoing research program are presented. It involves the use of the reaction centre, the coenzyme Q-cytochrome c oxidoreductase, and the ATP synthase for creating an autonomous synthetic cell. We show experimental results on the chemistry of the first two proteins showing that they can efficiently sustain light-driven chemical oscillations. Moreover, the cyclic pattern has been reproduced in silico by a minimal kinetic model.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Liposomes); 0 (Photosynthetic Reaction Center Complex Proteins); EC 1.10.2.2 (Electron Transport Complex III)


  4 / 6018 MEDLINE  
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PMID:28601078
Autor:Khatypov RA; Khristin AM; Fufina TY; Shuvalov VA
Endereço:Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia. rgreen1@rambler.ru.
Título:An Alternative Pathway of Light-Induced Transmembrane Electron Transfer in Photosynthetic Reaction Centers of Rhodobacter sphaeroides.
Fonte:Biochemistry (Mosc); 82(6):692-697, 2017 Jun.
ISSN:1608-3040
País de publicação:United States
Idioma:eng
Resumo:In the absorption spectrum of Rhodobacter sphaeroides reaction centers, a minor absorption band was found with a maximum at 1053 nm. The amplitude of this band is ~10,000 times less and its half-width is comparable to that of the long-wavelength absorption band of the primary electron donor P . When the primary electron donor is excited by femtosecond light pulses at 870 nm, the absorption band at 1053 nm is increased manifold during the earliest stages of charge separation. The growth of this absorption band in difference absorption spectra precedes the appearance of stimulated emission at 935 nm and the appearance of the absorption band of anion-radical B at 1020 nm, reported earlier by several researchers. When reaction centers are illuminated with 1064 nm light, the absorption spectrum undergoes changes indicating reduction of the primary electron acceptor Q , with the primary electron donor P remaining neutral. These photoinduced absorption changes reflect the formation of the long-lived radical state PB H Q .
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Bacterial Proteins); 0 (Photosynthetic Reaction Center Complex Proteins)


  5 / 6018 MEDLINE  
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PMID:28542634
Autor:Ohno H; Takeda K; Niwa S; Tsujinaka T; Hanazono Y; Hirano Y; Miki K
Endereço:Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, Japan.
Título:Crystallographic characterization of the high-potential iron-sulfur protein in the oxidized state at 0.8 Å resolution.
Fonte:PLoS One; 12(5):e0178183, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:High-potential iron-sulfur protein (HiPIP) is a soluble electron carrier protein of photosynthetic bacteria with an Fe4S4 cluster. Although structural changes accompanying the electron transfer are important for understanding of the functional mechanism, the changes have not been clarified in sufficient detail. We previously reported the high-resolution crystal structures of HiPIP from a thermophilic purple bacterium Thermochromatium tepidum in the reduced state. In order to perform a detailed comparison between the structures in different redox states, the oxidized structure should also be revealed at high resolution. Therefore, in the present study we performed a crystallographic analysis of oxidized HiPIP and a structural comparison with the reduced form at a high resolution of 0.8 Å. The comparison highlighted small but significant contraction in the iron-sulfur cluster. The changes in Fe-S bond lengths were similar to that predicted by theoretical calculation, although some discrepancies were also found. Almost distances between the sulfur atoms of the iron-sulfur cluster and the protein environment are elongated upon the oxidation. Positional changes of hydrogen atoms in the protein environment, such as on the amide-hydrogen of Cys75 in the proximity of the iron-sulfur cluster, were also observed in the accurate analyses. None of the water molecules exhibited significant changes in position or anisotropy of atomic displacement parameter between the two states, while the orientations of some water molecules were different.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Bacterial Proteins); 0 (Iron-Sulfur Proteins); 0 (Photosynthetic Reaction Center Complex Proteins); 0 (high potential iron-sulfur protein)


  6 / 6018 MEDLINE  
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PMID:28510131
Autor:Knox PP; Timofeev KN; Gorokhov VV; Seifullina NK; Rubin AB
Endereço:Faculty of Biology, Moscow State University, Moscow, 119234, Russia.
Título:Generation of radical form of dipyridamole at illumination of photosynthetic reaction centers of Rb. sphaeroides.
Fonte:Dokl Biochem Biophys; 473(1):118-121, 2017 Mar.
ISSN:1608-3091
País de publicação:Russia (Federation)
Idioma:eng
Resumo:The study of the effect of vasodilator, antiplatelet agent, and inhibitor P-glycoprotein dipyridamole (DIP) on the functioning of the transmembrane protein of the reaction center (RC) of Rb. sphaeroides showed that the activation of RC by constant light generates the DIP radical cation, which significantly affects the kinetics of recombination of charges divided between photoactive bacteriochlorophyll and quinone acceptors. Thus, the antioxidant properties of DIP may affect the functional activity of membrane proteins, and this apparently should be taken into account in the studies of the mechanisms of therapeutic action of this drug.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Free Radicals); 0 (Photosynthetic Reaction Center Complex Proteins); 64ALC7F90C (Dipyridamole)


  7 / 6018 MEDLINE  
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PMID:28364799
Autor:Jin Y; Chen S; Fan X; Song H; Li X; Xu J; Qian H
Endereço:College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, PR China.
Título:Diuron treatment reveals the different roles of two cyclic electron transfer pathways in photosystem II in Arabidopsis thaliana.
Fonte:Pestic Biochem Physiol; 137:15-20, 2017 Apr.
ISSN:1095-9939
País de publicação:United States
Idioma:eng
Resumo:Three ecotypes of Arabidopsis thaliana, ecotype Columbia (Wild type, Wt) and two mutants (pgr5 and ndf4), were used to evaluate the effects of diuron on photosynthetic activity of A. thaliana. It was found that diuron adversely affected the fresh weight and chlorophyll content of the plants. Chlorophyll fluorescence studies determined that the pgr5 mutant was more sensitive to diuron than Wt and the ndf4 mutant. Gene expression analysis revealed different roles for the two cyclic electron transfer (CET) pathways, NAD(P)H dehydrogenase (NDH) and proton gradient regulation (PGR5) pathways, in the plant after diuron treatment. For example, a gene in the NDH pathway, lhca5, was activated in the low dose (LD) group in the pgr5 mutant, but was down-regulated in the moderate dose (MD) group, along with two other NDH-related genes (ppl2 and ndhH). In the PGR5 pathway, the pgr5 gene was functional under conditions of increased stress (MD group), and was up-regulated to a greater extent in the ndf4 mutant than that in the Wt and pgr5 mutant. Our results suggest that the PGR5 pathway in plants is more important than the NDH pathway during resistance to environmental stress. Deficiencies in the PGR5 pathway could not be counteracted by the NDH pathway, but deficiencies in the NDH pathway could be overcome by stimulating PGR5.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Arabidopsis Proteins); 0 (Herbicides); 0 (PGR5 protein, Arabidopsis); 0 (Photosynthetic Reaction Center Complex Proteins); 9I3SDS92WY (Diuron)


  8 / 6018 MEDLINE  
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PMID:28358305
Autor:Takshi A; Yaghoubi H; Wang J; Jun D; Beatty JT
Endereço:Department of Electrical Engineering, University of South Florida (USF), Tampa, FL 33620, USA. atakshi@usf.edu.
Título:Electrochemical Field-Effect Transistor Utilization to Study the Coupling Success Rate of Photosynthetic Protein Complexes to Cytochrome c.
Fonte:Biosensors (Basel); 7(2), 2017 Mar 30.
ISSN:2079-6374
País de publicação:Switzerland
Idioma:eng
Resumo:Due to the high internal quantum efficiency, reaction center (RC) proteins from photosynthetic organisms have been studied in various bio-photoelectrochemical devices for solar energy harvesting. In vivo, RC and cytochrome (cyt ; a component of the biological electron transport chain) can form a cocomplex via interprotein docking. This mechanism can be used in vitro for efficient electron transfer from an electrode to the RC in a bio-photoelectrochemical device. Hence, the success rate in coupling RCs to cyt is of great importance for practical applications in the future. In this work, we use an electrochemical transistor to study the binding of the RC to cytochrome. The shift in the transistor threshold voltage was measured in the dark and under illumination to estimate the density of cytochrome and coupled RCs on the gate of the transistor. The results show that ~33% of the cyt s on the transistor gate were able to effectively couple with RCs. Due to the high sensitivity of the transistor, the approach can be used to make photosensors for detecting low light intensities.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Photosynthetic Reaction Center Complex Proteins); 9007-43-6 (Cytochromes c)


  9 / 6018 MEDLINE  
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PMID:28273503
Autor:Khudyakova AY; Kreslavski VD; Shirshikova GN; Zharmukhamedov SK; Kosobryukhov AA; Allakhverdiev SI
Endereço:Institute of Basic Biological Problems, Russian Academy of Sciences, Institutskaya Street 2, Pushchino, Moscow Region 142290, Russia; Institute for Biological Instrumentation, Russian Academy of Sciences, Institutskaya Street 7, Pushchino, Moscow Region 142290, Russia; Controlled Photobiosynthesis L
Título:Resistance of Arabidopsis thaliana L. photosynthetic apparatus to UV-B is reduced by deficit of phytochromes B and A.
Fonte:J Photochem Photobiol B; 169:41-46, 2017 Apr.
ISSN:1873-2682
País de publicação:Switzerland
Idioma:eng
Resumo:The photosynthetic responses of 25-day-old Arabidopsis phyA phyB double mutant (DM) compared with the wild type (WT) to UV-B radiation (1Wm , 30min) were investigated. UV-B irradiation led to reduction of photosystem 2 (PS-2) activity and the photosynthetic rate. In plants grown under both white and red light (λ - 660nm) the reduction was greater in DM plants compared to the WT. Without UV-B irradiation a decrease in PS-2 activity was observed in DM grown under RL only. It is assumed that the lower content of UV-absorbing pigments and carotenoids observed in DM may be one of the reasons of reduced PS-2 resistance to UV-B. Higher decrease in activities under UV in DM plants grown under RL compared to DM plants grown under white light is likely due to the lack of activity of cryptochromes in plants grown under red light. Rates of post-stress recovery of photosynthetic activity of DM compared with WT plants under white and red light of low intensity were studied. Almost complete recovery of the activity was found which was not observed under dark conditions and in the presence of a protein synthesis inhibitor, chloramphenicol. It is assumed that phytochrome system participates in stress-protective mechanisms of the photosynthetic apparatus to UV-radiation.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Cryptochromes); 0 (Photosynthetic Reaction Center Complex Proteins); 0 (Photosystem II Protein Complex); 0 (Phytochrome A); 136250-22-1 (Phytochrome B)


  10 / 6018 MEDLINE  
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PMID:28219973
Autor:Goddard-Borger ED; Williams SJ
Endereço:ACRF Chemical Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.
Título:Sulfoquinovose in the biosphere: occurrence, metabolism and functions.
Fonte:Biochem J; 474(5):827-849, 2017 Feb 20.
ISSN:1470-8728
País de publicação:England
Idioma:eng
Resumo:The sulfonated carbohydrate sulfoquinovose (SQ) is produced in quantities estimated at some 10 billion tonnes annually and is thus a major participant in the global sulfur biocycle. SQ is produced by most photosynthetic organisms and incorporated into the sulfolipid sulfoquinovosyl diacylglycerol (SQDG), as well as within some archaea for incorporation into glycoprotein N-glycans. SQDG is found mainly within the thylakoid membranes of the chloroplast, where it appears to be important for membrane structure and function and for optimal activity of photosynthetic protein complexes. SQDG metabolism within the sulfur cycle involves complex biosynthetic and catabolic processes. SQDG biosynthesis is largely conserved within plants, algae and bacteria. On the other hand, two major sulfoglycolytic pathways have been discovered for SQDG degradation, the sulfo-Embden-Meyerhof-Parnas (sulfo-EMP) and sulfo-Entner-Doudoroff (sulfo-ED) pathways, which mirror the major steps in the glycolytic EMP and ED pathways. Sulfoglycolysis produces C3-sulfonates, which undergo biomineralization to inorganic sulfur species, completing the sulfur cycle. This review discusses the discovery and structural elucidation of SQDG and archaeal N-glycans, the occurrence, distribution, and speciation of SQDG, and metabolic pathways leading to the biosynthesis of SQDG and its catabolism through sulfoglycolytic and biomineralization pathways to inorganic sulfur.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Cytochromes); 0 (Glycolipids); 0 (Lipids); 0 (Methylglucosides); 0 (Photosynthetic Reaction Center Complex Proteins); 0 (sulfolipids); 0 (sulfoquinovosyl diglyceride); 3458-06-8 (sulfoquinovose); 70FD1KFU70 (Sulfur); EC 2.4.1.- (Glucosyltransferases); EC 2.4.1.121 (UDP-sulfoquinovose synthase, Chlamydomonas reinhardtii)



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