Gong, W. Kok, B. Cooperation of charges in photosynthetic O2 evolution—I. A linear four-step mechanism. Cox, N. Electronic structure of the oxygen-evolving complex in photosystem II prior to O—O bond formation. Science , — Barber, J. Photosystem II: the water splitting enzyme of photosynthesis and the origin of oxygen in our atmosphere.
Renger, G. Photosynthetic water oxidation to molecular oxygen: apparatus and mechanism. Acta , — Siegbahn, P. Structures and energetics for O2 formation in photosystem II.
Haumann, M. Photosynthetic water oxidation: a simplex-scheme of its partial reactions. Acta , 86—91 McEvoy, J. Water-splitting chemistry of photosystem II. Yamanaka, S. Jeoung, J. Carbon dioxide activation at the Ni,Fe-cluster of anaerobic carbon monoxide dehydrogenase. Ferreira, K. Architecture of the photosynthetic oxygen-evolving center. Umena, Y. Crystal structure of oxygen-evolving photosystem II at a resolution of 1.
Nature , 55—60 Zhang, C. A synthetic Mn4Ca-cluster mimicking the oxygen-evolving center of photosynthesis. Dobbek, H. Crystal structure of a carbon monoxide dehydrogenase reveals a [Ni-4Fe-5S] cluster. Pecoraro, V. A proposal for water oxidation in photosystem II.
Pure Appl. Limburg, J. O2 evolution and permanganate formation from high-valent manganese complexes. Hoganson, C. A metalloradical mechanism for the generation of oxygen from water in photosynthesis. Dau, H. Eight steps preceding O—O bond formation in oxygenic photosynthesis—a basic reaction cycle of the photosystem II manganese complex.
Tommos, C. Oxygen production in nature: a light-driven metalloradical enzyme process. Askerka, M. Biochemistry 55 , — Gao, Y. Tong, L. Structural modifications of mononuclear ruthenium complexes: a combined experimental and theoretical study on the kinetics of ruthenium-catalyzed water oxidation. Staehle, R. Duan, L. A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem II.
A structure-consistent mechanism for dioxygen formation in photosystem II. Chlorophyll triplet quenching and photoprotection in the higher plant monomeric antenna protein Lhcb5. B , — Barra, M. Specific loss of the extrinsic 18 Kda protein from Photosystem II upon heating to 47 degrees C causes inactivation of oxygen evolution likely due to Ca release from the Mn-complex.
Borisova-Mubarakshina, M. Long-term acclimatory response to excess excitation energy: evidence for a role of hydrogen peroxide in the regulation of photosystem II antenna size.
Bradley, R. The involvement of photosystem-ii-generated H2o2 in photoinhibition. FEBS Lett. Cardona, T. Charge separation in Photosystem II: a comparative and evolutionary overview.
Acta , 26— Chen, L. Protecting effect of phosphorylation on oxidative damage of D1 protein by down-regulating the production of superoxide anion in photosystem II membranes under high light.
Cleland, R. Voltammetric detection of superoxide production by photosystem II. Coleman, W. The effect of chloride on the thermal inactivation of oxygen evolution. Cupellini, L. Photoprotection and triplet energy transfer in higher plants: the role of electronic and nuclear fluctuations. Zeaxanthin protects plant photosynthesis by modulating chlorophyll triplet yield in specific light-harvesting antenna subunits.
Lutein is needed for efficient chlorophyll triplet quenching in the major LHCII antenna complex of higher plants and effective photoprotection in vivo under strong light. BMC Plant Biol. Dau, H. Recent developments in research on water oxidation by photosystem II. DeLano, W. Dexter, D. A theory of sensitized luminescence in solids. Dietz, K. Redox- and reactive oxygen species-dependent signaling into and out of the photosynthesizing chloroplast. Plant Physiol. Domonkos, I.
Carotenoids, versatile components of oxygenic photosynthesis. Lipid Res. Edelman, M. D1-protein dynamics in photosystem II: the lingering enigma. Enami, I. Is the primary cause of thermal inactivation of oxygen evolution in spinach PS-ii membranes release of the extrinsic 33 kda protein or of MN.
Acta , 52— Erickson, E. Light stress and photoprotection in Chlamydomonas reinhardtii. Plant J. Fine, P. The oxygen-evolving complex requires chloride to prevent hydrogen-peroxide formation. Biochemistry 31, — Fischer, B. Production, detection, and signaling of singlet oxygen in photosynthetic organisms. Redox Signal. Singlet oxygen resistant 1 links reactive electrophile signaling to singlet oxygen acclimation in Chlamydomonas reinhardtii. Foyer, C. Redox regulation in photosynthetic organisms: signaling, acclimation, and practical implications.
Frankel, L. Identification of oxidized amino acid residues in the vicinity of the Mn4CaO5 cluster of Photosystem II: implications for the identification of oxygen channels within the photosystem. Biochemistry 51, — Oxidized amino acid residues in the vicinity of Q A and Pheo D1 of the photosystem II reaction center: putative generation sites of reducing-side reactive oxygen species.
Gollan, P. Photosynthetic light reactions: integral to chloroplast retrograde signalling. Havaux, M. Carotenoid oxidation products as stress signals in plants. The violaxanthin cycle protects plants from photooxidative damage by more than one mechanism.
Autoluminescence imaging: a non-invasive tool for mapping oxidative stress. Trends Plant Sci. Jarvi, S. Photosystem II repair in plant chloroplasts - regulation, assisting proteins and shared components with photosystem II biogenesis. Karpinski, S. Light acclimation, retrograde signalling, cell death and immune defences in plants.
Plant Cell Environ. Khorobrykh, S. Experimental evidence suggesting that H2O2 is produced within the thylakoid membrane in a reaction between plastoquinol and singlet oxygen. Komenda, J. Giardi and E.
Google Scholar. Assembling and maintaining the photosystem II complex in chloroplasts and cyanobacteria. Krieger-Liszkay, A. Singlet oxygen production in photosynthesis. Laloi, C. Key players of singlet oxygen-induced cell death in plants. Plant Sci. Cross-talk between singlet oxygen- and hydrogen peroxide-dependent signaling of stress responses in Arabidopsis thaliana.
Lambreva, M. Protein Pept. Lee, K. Liu, Z. Crystal structure of spinach major light-harvesting complex at 2. PSII is a complex protein structure found in plants and algae. It has a counterpart called photosystem I, an equally complex light-powered producer of oxygen and biomaterials.
Some questions and answers below will help elucidate the researchers' findings about a small metal catalyst and an amino acid inside PSII that work hand-in-glove to produce O2. O2 is released from water as a byproduct. Their work was funded by the National Science Foundation.
PS II is a biochemical complex made mostly of large amino acid corkscrew cylinders and some smaller such cylinders strung together with amino acid strands. The reaction cycle that extracts the O2 from H2O occurs at a tiny spot, which the study focused on. For scale, if PSII were a fairly tall, very wide building, the spot might be the size of a large door in about the lower center of the building, and the metal cluster would be located there.
Intertwined in the proteins would be sprawling molecules that include beta-carotene and chlorophyll, a great natural photoelectric semiconductor. The metal catalyst acts like a capacitor, building up charge that it uses to expedite four chemical reactions that release the O2 by removing four electrons, one-by-one, from two water molecules.
An additional highly reactive compound acts as a "switch" to drive the electron movement in each step of the reaction cycle. There are recent reports in the literature that, as a response to 1 O 2 production, genes are specifically up-regulated which are involved in the molecular defence response of the plant against photo-oxidative stress Leisinger et al.
Leisinger et al. Op den Camp et al. By contrast, other reactive oxygen species like superoxide did not rapidly up-regulate the expression of these genes. In the flu mutant, 1 O 2 is produced peripherally at the membrane surface and can, therefore, react with compounds of the stroma. Under natural conditions, 1 O 2 will be produced within the reaction centre of PSII and will react with different target molecules than in this mutant.
Fischer, however, using inhibitors of the photosynthetic electron transport, studied 1 O 2 formation in PSII and only found a significant up-regulation of the glutathione peroxidase homologous gene from Chlamydomonas B Fischer, personal communication.
The question arises how an extremely short-lived molecule like 1 O 2 can give rise to a signal that can be transmitted to the nucleus to regulate gene expression. Some other reactive oxygen species like superoxide or peroxide have been shown to act directly as second messengers in the regulation of expression of the oxidative stress response genes such as gutathione peroxidases, glutathione- S -transferases, and ascorbate peroxidase for reviews see Mullineaux et al.
Because of the short lifetime of 1 O 2 , it can be excluded that it oxidizes a component of a signal transduction chain directly. Instead reaction products originating either from the D1 protein degradation or products of chlorophyll degradation can be envisaged as signal molecules. It has been shown that chlorophyll precursors like Mg-protoporphyrin IX can act as a signalling molecule in a signalling pathway between the chloroplasts and the nucleus Strand et al.
By analogy, one can also speculate that a chlorophyll degradation product such as pheophytin, chlorophyllide, or pheophorbide for chl degradation, see Matile et al. Such a molecule could be transported out of the chloroplast to the cytosol by an ABC protein where it mediates a signal to the nucleus to regulate the expression of genes.
It was also shown that an ABC transporter in the tonoplast membrane can transport chlorophyll catabolites to the vacuole Lu et al. Alternatively, lipid peroxides may function as signalling molecules because unsaturated fatty acids are the preferred targets of 1 O 2. However, no increase in 1 O 2 -mediated non-enzymatic lipid peroxidation could be found in the flu mutant, which accumulates protochlorophyllide and shows a higher yield of 1 O 2 formation than wild-type plants Op den Camp et al.
Linolenic acid was rapidely oxidized upon illumination of the flu mutant, but the oxidation patterns observed were indicative for enzymatic oxidation and not for non-enzymatic oxidation by 1 O 2. In general, fatty acid-derived signals may be involved in signalling pathways connected with cell death and the expression of stress-related genes Weber, Adamska I.
ELIPs—light induced stress proteins. Physiologia Plantarum , — Biochimica et Biophysica Acta , — Photoinhibition of photosystem II. Protoporphyrin IX content correlates with activity of photobleaching herbicides. Plant Physiology 90 , — Photoinhibition of hydroxylamine-extracted photosystem II membranes: identification of the sites of photodamage.
Biochemistry 30 , — Brettel K. Electron transfer and arrangement of the redox factors in photosystem I. Oxygen uptake photosensitized by disorganized chlorophyll in model systems and thylakoids of greening barley. Photochemistry and Photobiology 7 , — Debus RJ. The manganese and calcium ions of photosynthetic oxygen evolution. Demmig-Adams B. Carotenoids and photoprotection in plants: a role for the xanthophyll zeaxanthin.
Biochimica et Biophysica Acta , 1 — Characterization of triplet-states in isolated photosystem II reaction centres—oxygen quenching as a mechanism for photodamage. Edge R, Truscott TG. Carotenoid radicals and the interaction of carotenoids with active oxygen species. Advances in photosynthesis: the photochemistry of carotenoids , Vol. Dordrecht: Kluwer, — Architecture of the photosynthetic oxygen-evolving center. Science , — Singlet oxygen production in herbicide-treated photosystem II.
FEBS Letters , — The effect of an applied electric field on the charge recombination kinetics in reaction centers reconstituted in planar bilayers. Biophysical Journal 48 , — Current perspectives of singlet oxygen detection in biological environments. Journal of Photochemistry and Photobiology 14 , — Photosystem II and photosynthetic oxidation of water: an overview. Quinones as prosthetic groups in membrane electron transfer proteins. Systematic replacement of the primary ubiquinone of photochemical reaction centers with other quinones.
In: Trumpower BL, ed. Functions of quinones in energy conserving systems. New York: Academic Press, — Halliwell B, Gutteridge JM. Free radicals in biology and medicine , 3rd edn. Oxford: Oxford University Press. Singlet oxygen production in thylakoid membranes during photoinhibition as detected by EPR spectroscopy.
Photosynthesis Research 39 , — Photoinhibition of photosynthesis in vivo results in singlet oxygen production: detection via nitroxide-induced fluorescence quenching in broad bean leaves.
Biochemistry 37 , — Singlet oxygen imaging in Arabidopsis thaliana leaves under photoinhibition by excess photosynthetically active radiation. Physiologia Plantarum , 10 — Engagement of specific sites in the plastoquinone niche regulates degradation of the D1 protein in photosystem II. Journal of Biological Chemistry , — Light-dependent degradation of the D1 protein in photosystem II is acceleerated after inhibition of the water-splitting reaction.
Biochemistry 29 , — A change in the mid-point potential of the quinone Q A in photosystem II associated with photoactivation of oxygen evolution. Kamiya N, Shen JR. Crystal structure of oxygen-evolving photosystem II from Thermosynechococcus vulcanus at 3. Evidence for the delocalization of the triplet state 3 P in the D 1 D 2 cytb -complex of photosystem II. Berichte der Bunsen Gesellschaft , — Oscillations of reaction centre II-D1 protein degradation in vivo induced by repetitive flashes.
Mechanism of photosystem II inactivation and D1 protein degradation at low light intensities: the role of electron back flow. Inhibition of photosystem II activity by saturating single turnover flashes in calcium-depleted and active photosystem II. Photosynthesis Research 63 , — Biochemistry 33 , — Kramer H, Mathis P. Quantum yield and rate of formation of the carotenoid triplet state in photosynthetic structures.
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