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photosystemII, etc ; chlorophyll; molecular dynamics; quantum mechanics; quinones; Show all 5 Subjects
Abstract:
... In photosystem II (PSII) and photosynthetic reaction centers from purple bacteria (PbRC), the electron released from the electronically excited chlorophyll is transferred to the terminal electron acceptor quinone, QB. QB accepts two electrons and two protons before leaving the protein. We investigated the molecular mechanism of quinone exchange in PSII, conducting molecular dynamics (MD) simulatio ...
photosystemII, etc ; carbon; carboxylation; chlorophyll; electron transfer; fluorescence; Show all 6 Subjects
Abstract:
... Solar‐induced chlorophyll fluorescence (SIF) has been used to infer photosynthetic capacity parameters (e.g., the maximum carboxylation rate Vcₘₐₓ, and the maximum electron transport rate Jₘₐₓ). However, the precise mechanism and practical utility of such approach under dynamic environments remain unclear. We used the balance between the light and carbon reactions to derive theoretical equations r ...
photosystemII, etc ; Thermosynechococcus elongatus; absorption; electron transfer; pH; stoichiometry; Show all 6 Subjects
Abstract:
... The stoichiometry and kinetics of the proton release were investigated during each transition of the S-state cycle in Photosystem II (PSII) from Thermosynechococcus elongatus containing either a Mn₄CaO₅ (PSII/Ca) or a Mn₄SrO₅ (PSII/Sr) cluster. The measurements were done at pH 6.0 and pH 7.0 knowing that, in PSII/Ca at pH 6.0 and pH 7.0 and in PSII/Sr at pH 6.0, the flash-induced S₂-state is in a ...
photosystemII, etc ; gene amplification; heme; ligands; operon; sequence analysis; Show all 6 Subjects
Abstract:
... Cytochrome (Cyt) b₅₅₉ is a key component of the photosystem II complex (PSII) that is essential for its proper functioning and assembly. Site‐directed mutants of the model cyanobacterium Synechocystis sp. PCC6803 with mutated heme axial ligands of Cyt b₅₅₉ have little PSII and are therefore unable to grow photoautotrophically. Here we describe two types of Synechocystis autotrophic transformants t ...
photosystemII, etc ; Synechocystis; catalysts; chloroplasts; genes; radiation resistance; research; Show all 7 Subjects
Abstract:
... Assembly of photosystem II (PSII), a water-splitting catalyst in chloroplasts and cyanobacteria, requires numerous auxiliary proteins which promote individual steps of this sequential process and transiently associate with one or more assembly intermediate complexes. In this study, we focussed on the role of a PSII-associated protein encoded by the ssl1498 gene in the cyanobacterium Synechocystis ...
photosystemII, etc ; Synechocystis; electrochemistry; electrodes; light intensity; photosynthetic electron transport; Show all 6 Subjects
Abstract:
... Light-activated photosystem II (PSII) carries out the critical step of splitting water in photosynthesis. However, PSII is susceptible to light-induced damage. Here, results are presented from a novel microbial electro-photosynthetic system (MEPS) that uses redox mediators in conjunction with an electrode to drive electron transport in live Synechocystis (ΔpsbB) cells lacking PSII. MEPS-generated, ...
photosystemII, etc ; crystallization; detergents; membrane proteins; neutrons; solar energy; temperature; Show all 7 Subjects
Abstract:
... Photosystems I (PSI) and II (PSII) are pigment–protein complexes capable of performing the light-induced charge separation necessary to convert solar energy into a biochemically storable form, an essential step in photosynthesis. Small-angle neutron scattering (SANS) is unique in providing structural information on PSI and PSII in solution under nearly physiological conditions without the need for ...
photosystemII, etc ; canopy; heavy metals; phosphorus; plant nutrition; rice; tillering; Show all 7 Subjects
Abstract:
... There is a lack of affordable and effective strategies to mitigate multiple heavy metal contamination in lowland rice production. We tested phosphorus (P) or silicon (Si) addition to a soil contaminated with both arsenic (As) and cadmium (Cd) for their mitigation potential in rice seedlings. Rice variety IR64 was grown in pots with either P (0, 2.5, 5, 10, 20 (recommended rate), 40 and 80 mg P kg⁻ ...
photosystemII, etc ; Synechocystis; energy; enzymes; fluorescence; half life; manganese; mutants; oxygen; research; Show all 10 Subjects
Abstract:
... Photosystem II (PSII), the enzyme responsible for oxidizing water into molecular oxygen, undergoes a complex lifecycle during which multiple assembly proteins transiently bind to and depart from PSII assembly intermediate complexes. Psb27 is one such protein. It associates with the CP43 chlorophyll-binding subunit of PSII to form a Psb27-PSII sub-complex that constitutes 7–10% of the total PSII po ...
photosystemII, etc ; Bacillariophyceae; Thalassiosira pseudonana; acclimation; chlorophyll; lutein; polypeptides; radiation resistance; thylakoids; Show all 9 Subjects
Abstract:
... In diatoms, light-harvesting processes take place in a specific group of proteins, called fucoxanthin chlorophyll a/c proteins (FCP). This group includes many members and represents the major characteristic of the diatom photosynthetic apparatus, with specific pigments bound (chlorophyll c, fucoxanthin, diadino- and diatoxanthin besides chlorophyll a). In thylakoids, FCP and photosystems (PS) form ...
photosystemII, etc ; Pisum sativum; energy transfer; glutamine; light harvesting complex; molecular dynamics; solvents; Show all 7 Subjects
Abstract:
... We investigate energy transfer pathways between strongly coupled chlorophylls (Chls) in the CP29 (LHCII B4.1) antenna complex of Pisum sativum, including the possibility of higher energy states. We test for the environmental effects caused by the protein, membrane and solvent using a hybrid QM/MM approach. Classical molecular dynamics simulations of the full CP29 complex embedded in a DOPC membran ...
photosystemII, etc ; X-radiation; biomass; deprotonation; dissociation; energy conversion; ligands; oxidation; protonation; solvents; Show all 10 Subjects
Abstract:
... Photosystem II (PSII) catalyzes light-driven water oxidization, releasing O₂ into the atmosphere and transferring the electrons for the synthesis of biomass. However, despite decades of structural and functional studies, the water oxidation mechanism of PSII has remained puzzling and a major challenge for modern chemical research. Here, we show that PSII catalyzes redox-triggered proton transfer b ...
photosystemII, etc ; Oryza sativa; carbon dioxide; cultivars; electron transfer; filling period; photochemistry; rice; Show all 8 Subjects
Abstract:
... Responses of crop photosystem activity to the short‐term elevation of carbon dioxide concentration ([CO₂]) have been studied extensively. However, long‐term effects of elevated [CO₂] (e[CO₂]) over multiple cropping generations have received little attention. Using open‐top chambers (OTCs), we set up ambient [CO₂] (CK) and two multigeneration e[CO₂] treatments during rice (Oryza sativa L.) growing ...
photosystemII, etc ; antheraxanthin; chloroplasts; littoral zone; lutein; macroalgae; radiation resistance; ultraviolet radiation; violaxanthin; zeaxanthin; Show all 10 Subjects
Abstract:
... The effects of enhanced ultraviolet-B (UV-B, 280–320 nm) radiation reaching the Earth’s surface has become an important issue in terrestrial and marine ecosystems. Living in the land–marine boundary, intertidal macroalgae have various adaptive strategies to resist drastic environmental changes. In this study, we investigated the effects of enhanced UV-B radiation on the photosynthetic performance ...
photosystemII, etc ; density functional theory; histidine; luminescence; mutants; pH; plastoquinones; protonation; redox potential; thylakoids; Show all 10 Subjects
Abstract:
... In photosystem II (PSII), the secondary plastoquinone electron acceptor QB functions as a substrate that converts into plastoquinol upon its double reduction by electrons abstracted from water. It has been suggested that a histidine residue, D1-H252, which is located at the stromal surface near QB, is involved in the pH-dependent regulation of electron flow and proton transfer to QB. However, defi ...
photosystemII, etc ; Thermosynechococcus elongatus; ion exchange chromatography; lipoproteins; mass spectrometry; membrane proteins; research; thylakoids; Show all 8 Subjects
Abstract:
... The assembly of large, multi-cofactor membrane protein complexes like photosystem II (PSII) requires a high level of coordination. The process is facilitated by a large network of auxiliary proteins that bind transiently to unassembled subunits, preassembled modules or intermediate states of PSII, which are comprised of a subset of subunits. However, analysis of these immature, partially assembled ...
photosystemII, etc ; chlorophyll; chloroplasts; cucumbers; electron transfer; genes; greenhouses; leaves; melatonin; photoinhibition; protein degradation; Show all 11 Subjects
Abstract:
... Decreases in chlorophyll and photosynthetic efficiency co-occur during aging and leaf senescence. Here, we report the positive functions of melatonin (MT) in delaying leaf senescence in cucumber plants. The results showed that natural leaf senescence induced the accumulation of endogenous MT and that spraying MT delayed leaf senescence in a concentration-dependent manner. Moreover, application of ...
photosystemII, etc ; biochemical compounds; chloroplasts; gene expression; oxidation; reactive oxygen species; research; signal transduction; Show all 8 Subjects
Abstract:
... Reactive oxygen species (ROS) are formed in photosystem II (PSII) under various types of abiotic and biotic stresses. It is considered that ROS play a role in chloroplast-to-nucleus retrograde signaling, which changes the nuclear gene expression. However, as ROS lifetime and diffusion are restricted due to the high reactivity towards biomolecules (lipids, pigments, and proteins) and the spatial sp ...
photosystemII, etc ; activation energy; electron paramagnetic resonance spectroscopy; enthalpy; entropy; lighting; oxygen; research; temperature; Show all 9 Subjects
Abstract:
... The temperature dependence of the formation of the g ~ 5 S₂ state electron paramagnetic resonance (EPR) signal in photosystem II (PSII) was investigated. The g ~ 5 signal was produced at an illumination above 200 K. The half inhibition temperature of the formation of the g ~ 5 EPR signal was approximately 215 K. The half inhibition temperature is close to that of the transition from the S₂ state-t ...
photosystemII, etc ; Microcystis; cross-linking reagents; fluorescence; limnology; oceanography; photosynthetic reaction centers; polymers; polysaccharides; Show all 9 Subjects
Abstract:
... Colony formation of cyanobacteria is crucial for the formation of surface blooms in lakes. However, the underlying mechanisms of colony formation involving in physiological and cell surface characteristics remain to not well be established. Six cyanobacterial Microcystis strains (including both unicellular and colonial ones) were employed to estimate the influences of their physiological traits an ...