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Photosynthesis Research

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https://www.readbyqxmd.com/read/28213741/assembly-of-photoactive-orange-carotenoid-protein-from-its-domains-unravels-a-carotenoid-shuttle-mechanism
#1
Marcus Moldenhauer, Nikolai N Sluchanko, David Buhrke, Dmitry V Zlenko, Neslihan N Tavraz, Franz-Josef Schmitt, Peter Hildebrandt, Eugene G Maksimov, Thomas Friedrich
The photoswitchable orange carotenoid protein (OCP) is indispensable for cyanobacterial photoprotection by quenching phycobilisome fluorescence upon photoconversion from the orange OCP(O) to the red OCP(R) form. Cyanobacterial genomes frequently harbor, besides genes for orange carotenoid proteins (OCPs), several genes encoding homologs of OCP's N- or C-terminal domains (NTD, CTD). Unlike the well-studied NTD homologs, called Red Carotenoid Proteins (RCPs), the role of CTD homologs remains elusive. We show how OCP can be reassembled from its functional domains...
February 17, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28210833/energy-transfer-in-anabaena-variabilis-filaments-adapted-to-nitrogen-depleted-and-nitrogen-enriched-conditions-studied-by-time-resolved-fluorescence
#2
Aya Onishi, Shimpei Aikawa, Akihiko Kondo, Seiji Akimoto
Nitrogen is among the most important nutritious elements for photosynthetic organisms such as plants, algae, and cyanobacteria. Therefore, nitrogen depletion severely compromises the growth, development, and photosynthesis of these organisms. To preserve their integrity under nitrogen-depleted conditions, filamentous nitrogen-fixing cyanobacteria reduce atmospheric nitrogen to ammonia, and self-adapt by regulating their light-harvesting and excitation energy-transfer processes. To investigate the changes in the primary processes of photosynthesis, we measured the steady-state absorption and fluorescence spectra and time-resolved fluorescence spectra (TRFS) of whole filaments of the nitrogen-fixing cyanobacterium Anabaena variabilis at 77 K...
February 16, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28205063/excitation-energy-transfer-from-the-bacteriochlorophyll-soret-band-to-carotenoids-in-the-lh2-light-harvesting-complex-from-ectothiorhodospira-haloalkaliphila-is-negligible
#3
A P Razjivin, E P Lukashev, V O Kompanets, V S Kozlovsky, A A Ashikhmin, S V Chekalin, A A Moskalenko, V Z Paschenko
Pathways of intramolecular conversion and intermolecular electronic excitation energy transfer (EET) in the photosynthetic apparatus of purple bacteria remain subject to debate. Here we experimentally tested the possibility of EET from the bacteriochlorophyll (BChl) Soret band to the singlet S2 level of carotenoids using femtosecond pump-probe measurements and steady-state fluorescence excitation and absorption measurements in the near-ultraviolet and visible spectral ranges. The efficiency of EET from the Soret band of BChl to S2 of the carotenoids in light-harvesting complex LH2 from the purple bacterium Ectothiorhodospira haloalkaliphila appeared not to exceed a few percent...
February 16, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28205062/gallium-ferredoxin-as-a-tool-to-study-the-effects-of-ferredoxin-binding-to-photosystem-i-without-ferredoxin-reduction
#4
Clara Mignée, Risa Mutoh, Anja Krieger-Liszkay, Genji Kurisu, Pierre Sétif
Reduction of ferredoxin by photosystem I (PSI) involves the [4Fe-4S] clusters FA and FB harbored by PsaC, with FB being the direct electron transfer partner of ferredoxin (Fd). Binding of the redox-inactive gallium ferredoxin to PSI was investigated by flash-absorption spectroscopy, studying both the P700(+) decay and the reduction of the native iron Fd in the presence of FdGa. FdGa binding resulted in a faster recombination between P700(+) and (FA, FB)(-), a slower electron escape from (FA, FB)(-) to exogenous acceptors, and a decreased amount of intracomplex FdFe reduction, in accordance with competitive binding between FdFe and FdGa...
February 15, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28197891/simple-generalisation-of-a-mesophyll-resistance-model-for-various-intracellular-arrangements-of-chloroplasts-and-mitochondria-in-c3-leaves
#5
Xinyou Yin, Paul C Struik
The classical definition of mesophyll conductance (g m) represents an apparent parameter (g m,app) as it places (photo)respired CO2 at the same compartment where the carboxylation by Rubisco takes place. Recently, Tholen and co-workers developed a framework, in which g m better describes a physical diffusional parameter (g m,dif). They partitioned mesophyll resistance (r m,dif = 1/g m,dif) into two components, cell wall and plasmalemma resistance (r wp) and chloroplast resistance (r ch), and showed that g m,app is sensitive to the ratio of photorespiratory (F) and respiratory (R d) CO2 release to net CO2 uptake (A): g m,app = g m,dif/[1 + ω(F + R d)/A], where ω is the fraction of r ch in r m,dif...
February 14, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28188547/structurally-conserved-channels-in-cyanobacterial-and-plant-photosystem-ii
#6
Naoki Sakashita, Hiroshi C Watanabe, Takuya Ikeda, Hiroshi Ishikita
In the cyanobacterial photosystem II (PSII), the O4-water chain in the D1 and CP43 proteins, a chain of water molecules that are directly H-bonded to O4 of the Mn4Ca cluster, is linked with a channel that connects the protein bulk surface along with a membrane-extrinsic protein subunit, PsbU (O4-PsbU channel). The cyanobacterial PSII structure also shows that the O1 site of the Mn4Ca cluster has a chain of H-bonded water molecules, which is linked with the channel that proceeds toward the bulk surface via PsbU and PsbV (O1-PsbU/V channel)...
February 10, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28185041/variety-in-excitation-energy-transfer-processes-from-phycobilisomes-to-photosystems-i-and-ii
#7
Yoshifumi Ueno, Shimpei Aikawa, Kyosuke Niwa, Tomoko Abe, Akio Murakami, Akihiko Kondo, Seiji Akimoto
The light-harvesting antennas of oxygenic photosynthetic organisms capture light energy and transfer it to the reaction centers of their photosystems. The light-harvesting antennas of cyanobacteria and red algae, called phycobilisomes (PBSs), supply light energy to both photosystem I (PSI) and photosystem II (PSII). However, the excitation energy transfer processes from PBS to PSI and PSII are not understood in detail. In the present study, the energy transfer processes from PBS to PSs in various cyanobacteria and red algae were examined in vivo by selectively exciting their PSs or PBSs, and measuring the resulting picosecond to nanosecond time-resolved fluorescences...
February 9, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28181142/erratum-to-is-raf1-protein-from-synechocystis-sp-pcc-6803-really-needed-in-the-cyanobacterial-rubisco-assembly-process
#8
Piotr Kolesinski, Malgorzata Rydzy, Andrzej Szczepaniak
No abstract text is available yet for this article.
February 8, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28176042/acclimation-of-shade-tolerant-and-light-resistant-tradescantia-species-to-growth-light-chlorophyll-a-fluorescence-electron-transport-and-xanthophyll-content
#9
Vladimir I Mishanin, Boris V Trubitsin, Svetlana V Patsaeva, Vasily V Ptushenko, Alexei E Solovchenko, Alexander N Tikhonov
In this study, we have compared the photosynthetic characteristics of two contrasting species of Tradescantia plants, T. fluminensis (shade-tolerant species), and T. sillamontana (light-resistant species), grown under the low light (LL, 50-125 µmol photons m(-2) s(-1)) or high light (HL, 875-1000 µmol photons m(-2) s(-1)) conditions during their entire growth period. For monitoring the functional state of photosynthetic apparatus (PSA), we measured chlorophyll (Chl) a emission fluorescence spectra and kinetics of light-induced changes in the heights of fluorescence peaks at 685 and 740 nm (F 685 and F 740)...
February 8, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28176041/itzhak-ohad-1930-2016
#10
EDITORIAL
Noam Adir, Susana Geifman-Shochat, Dan G Ohad, Nir Ohad, Nir Keren
No abstract text is available yet for this article.
February 7, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28160125/evolution-of-the-z-scheme-of-photosynthesis-a-perspective
#11
REVIEW
Govindjee, Dmitriy Shevela, Lars Olof Björn
The concept of the Z-scheme of oxygenic photosynthesis is in all the textbooks. However, its evolution is not. We focus here mainly on some of the history of its biophysical aspects. We have arbitrarily divided here the 1941-2016 period into three sub-periods: (a) Origin of the concept of two light reactions: first hinted at, in 1941, by James Franck and Karl Herzfeld; described and explained, in 1945, by Eugene Rabinowitch; and a clear hypothesis, given in 1956 by Rabinowitch, of the then available cytochrome experiments: one light oxidizing it and another reducing it; (b) Experimental discovery of the two light reactions and two pigment systems and the Z-scheme of photosynthesis: Robert Emerson's discovery, in 1957, of enhancement in photosynthesis when two light beams (one in the far-red region, and the other of shorter wavelengths) are given together than when given separately; and the 1960 scheme of Robin Hill & Fay Bendall; and...
February 3, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28155215/david-w-krogmann-1931-2016
#12
Jerry J Brand, Cheryl A Kerfeld, William A Cramer, Govindjee
We provide here reflections on the life and career of David W. Krogmann (1931-2016), a great scientist, a mentor and an outstanding teacher, who had a remarkable impact on anyone who came in contact with him. Dave was a pillar of photosynthesis at Purdue University, and an international authority on electron transfer intermediates in oxygenic photosynthesis, particularly the soluble cytochromes. The photosynthetic system of his choice was cyanobacteria, and one of his major discoveries was the Orange Carotenoid Protein in these microrganisms...
February 2, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28150152/evolution-of-the-acceptor-side-of-photosystem-i-ferredoxin-flavodoxin-and-ferredoxin-nadp-oxidoreductase
#13
REVIEW
Juan José Pierella Karlusich, Néstor Carrillo
The development of oxygenic photosynthesis by primordial cyanobacteria ~2.7 billion years ago led to major changes in the components and organization of photosynthetic electron transport to cope with the challenges of an oxygen-enriched atmosphere. We review herein, following the seminal contributions as reported by Jaganathan et al. (Functional genomics and evolution of photosynthetic systems, vol 33, advances in photosynthesis and respiration, Springer, Dordrecht, 2012), how these changes affected carriers and enzymes at the acceptor side of photosystem I (PSI): the electron shuttle ferredoxin (Fd), its isofunctional counterpart flavodoxin (Fld), their redox partner ferredoxin-NADP(+) reductase (FNR), and the primary PSI acceptors F x and F A/F B...
February 1, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28110449/membrane-fluidity-controls-redox-regulated-cold-stress-responses-in-cyanobacteria
#14
Eugene G Maksimov, Kirill S Mironov, Marina S Trofimova, Natalya L Nechaeva, Daria A Todorenko, Konstantin E Klementiev, Georgy V Tsoraev, Eugene V Tyutyaev, Anna A Zorina, Pavel V Feduraev, Suleyman I Allakhverdiev, Vladimir Z Paschenko, Dmitry A Los
Membrane fluidity is the important regulator of cellular responses to changing ambient temperature. Bacteria perceive cold by the transmembrane histidine kinases that sense changes in thickness of the cytoplasmic membrane due to its rigidification. In the cyanobacterium Synechocystis, about a half of cold-responsive genes is controlled by the light-dependent transmembrane histidine kinase Hik33, which also partially controls the responses to osmotic, salt, and oxidative stress. This implies the existence of some universal, but yet unknown signal that triggers adaptive gene expression in response to various stressors...
January 21, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28108865/transition-from-exponential-to-linear-photoautotrophic-growth-changes-the-physiology-of-synechocystis-sp-pcc-6803
#15
R M Schuurmans, J C P Matthijs, K J Hellingwerf
Phototrophic microorganisms like cyanobacteria show growth curves in batch culture that differ from the corresponding growth curves of chemotrophic bacteria. Instead of the usual three phases, i.e., lag-, log-, and stationary phase, phototrophs display four distinct phases. The extra growth phase is a phase of linear, light-limited growth that follows the exponential phase and is often ignored as being different. Results of this study demonstrate marked growth phase-dependent alterations in the photophysiology of the cyanobacterium Synechocystis sp...
January 20, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28108864/is-raf1-protein-from-synechocystis-sp-pcc-6803-really-needed-in-the-cyanobacterial-rubisco-assembly-process
#16
Piotr Kolesinski, Malgorzata Rydzy, Andrzej Szczepaniak
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is responsible for carbon dioxide conversion during photosynthesis and, therefore, is the most important protein in biomass generation. Modifications of this biocatalyst toward improvements in its properties are hindered by the complicated and not yet fully understood assembly process required for the formation of active holoenzymes. An entire set of auxiliary factors, including chaperonin GroEL/GroES and assembly chaperones RbcX or Rubisco accumulation factor 1 (RAF1), is involved in the folding and subsequent assembly of Rubisco subunits...
January 20, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28093652/structural-basis-for-the-isotype-specific-interactions-of-ferredoxin-and-ferredoxin-nadp-oxidoreductase-an-evolutionary-switch-between-photosynthetic-and-heterotrophic-assimilation
#17
Fumio Shinohara, Genji Kurisu, Guy Hanke, Caroline Bowsher, Toshiharu Hase, Yoko Kimata-Ariga
In higher plants, ferredoxin (Fd) and ferredoxin-NADP(+) reductase (FNR) are each present as distinct isoproteins of photosynthetic type (leaf type) and non-photosynthetic type (root type). Root-type Fd and FNR are considered to facilitate the electron transfer from NADPH to Fd in the direction opposite to that occurring in the photosynthetic processes. We previously reported the crystal structure of the electron transfer complex between maize leaf FNR and Fd (leaf FNR:Fd complex), providing insights into the molecular interactions of the two proteins...
January 16, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28078551/the-proteolysis-adaptor-nbla-binds-to-the-n-terminus-of-%C3%AE-phycocyanin-implications-for-the-mechanism-of-phycobilisome-degradation
#18
Amelia Y Nguyen, William P Bricker, Hao Zhang, Daniel A Weisz, Michael L Gross, Himadri B Pakrasi
Phycobilisome (PBS) complexes are massive light-harvesting apparati in cyanobacteria that capture and funnel light energy to the photosystem. PBS complexes are dynamically degraded during nutrient deprivation, which causes severe chlorosis, and resynthesized during nutrient repletion. PBS degradation occurs rapidly after nutrient step down, and is specifically triggered by non-bleaching protein A (NblA), a small proteolysis adaptor that facilitates interactions between a Clp chaperone and phycobiliproteins...
January 11, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28062941/the-effects-of-ph-and-pco2-on-photosynthesis-and-respiration-in-the-diatom-thalassiosira-weissflogii
#19
Johanna A L Goldman, Michael L Bender, François M M Morel
The response of marine phytoplankton to the ongoing increase in atmospheric pCO2 reflects the consequences of both increased CO2 concentration and decreased pH in surface seawater. In the model diatom Thalassiosira weissflogii, we explored the effects of varying pCO2 and pH, independently and in concert, on photosynthesis and respiration by incubating samples in water enriched in H2(18)O. In long-term experiments (~6-h) at saturating light intensity, we observed no effects of pH or pCO2 on growth rate, photosynthesis or respiration...
January 6, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28039566/the-structure-of-fcpb-a-light-harvesting-complex-in-the-diatom-cyclotella-meneghiniana
#20
Anja Röding, Egbert Boekema, Claudia Büchel
Diatoms possess fucoxanthin chlorophyll proteins (FCP) as light-harvesting systems. These membrane intrinsic proteins bind fucoxanthin as major carotenoid and Chl c as accessory chlorophyll. The relatively high sequence homology to higher plant light-harvesting complex II gave rise to the assumption of a similar overall structure. From centric diatoms like Cyclotella meneghiniana, however, two major FCP complexes can be isolated. FCPa, composed of Fcp2 and Fcp6 subunits, was demonstrated to be trimeric, whereas FCPb, known to contain Fcp5 polypeptides, is of higher oligomeric state...
December 30, 2016: Photosynthesis Research
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