Photoinhibition of Photosystem II and photodamage of the oxygen evolving manganese cluster

Tyystjärvi, Esa

doi:10.1016/j.ccr.2007.08.021

Cited by 285 publications

(199 citation statements)

References 248 publications

(525 reference statements)

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“…This might explain its essential function under stress conditions, but it is not clear why manganese should be retained in the PSII D(inact) complex before the exchange of the D1 protein. One explanation might be that this intermediate PSII D(inact) complex represents a reversible inactive complex, which was postulated recently in the "two-step photoinhibition model" (43)(44)(45). This model suggests an inactivation (possibly reversible) of the water-oxidizing complex caused by absorption of UV or blue light, which in turn blocks the electron supply from water to the strong oxidant P680 ϩ .…”

Section: Characterization Of Psii Complexes From ⌬Psb27 Cells Revealsmentioning

confidence: 99%

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

Grasse

Mamedov

Becker

et al. 2011

Journal of Biological Chemistry

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The multisubunit membrane protein complex Photosystem II (PSII) catalyzes one of the key reactions in photosynthesis: the light-driven oxidation of water. Here, we focus on the role of the Psb27 assembly factor, which is involved in biogenesis and repair after light-induced damage of the complex. We show that Psb27 is essential for the survival of cyanobacterial cells grown under stress conditions. The combination of cold stress (30°C) and high light stress (1000 mol of photons ؋ m ؊2 ؋ s ؊1 ) led to complete inhibition of growth in a ⌬psb27 mutant strain of the thermophilic cyanobacterium Thermosynechococcus elongatus, whereas wild-type cells continued to grow. Moreover, Psb27-containing PSII complexes became the predominant PSII species in preparations from wild-type cells grown under cold stress. Two different PSII-Psb27 complexes were isolated and characterized in this study. The first complex represents the known monomeric PSII-Psb27 species, which is involved in the assembly of PSII. Additionally, a novel dimeric PSII-Psb27 complex could be allocated in the repair cycle, i.e. in processes after inactivation of PSII, by 15 N pulse-label experiments followed by mass spectrometry analysis. Comparison with the corresponding PSII species from ⌬psb27 mutant cells showed that Psb27 prevented the release of manganese from the previously inactivated complex. These results indicate a more complex role of the Psb27 protein within the life cycle of PSII, especially under stress conditions. Photosystem II (PSII)2 is the first component of the photosynthetic electron transfer chain located in the thylakoid membranes of cyanobacteria and plant chloroplasts. It catalyzes the light-driven oxidation of water to molecular oxygen (1, 2). The first organisms capable of this reaction were Gram-negative cyanobacteria that evolved 3.5 billion years ago (3).Active cyanobacterial PSII consists of 20 permanent subunits, which were identified in the x-ray structure of PSII complexes isolated from Thermosynechococcus elongatus BP-1 (henceforth T. elongatus) (4). The central D1 and D2 subunits ligate multiple cofactors that facilitate the water-splitting reaction and mediate the electron transfer to plastoquinone B (Q B ). The central antenna proteins CP43 and CP47 capture the light energy, which in turn excites the Chl D1 molecule of P680. This causes a charge separation at the primary donor with the electron subsequently transferred to pheophytin (5). After Chl D1 ϩ is reduced by P D1 , the electron is transferred from pheophytin to Q A and Q B , respectively. In turn, P D1 ϩ is rereduced by electrons from the CaMn 4 cluster and the water-splitting reaction.During the early steps of biogenesis that probably takes place in the cytoplasmic membrane (6) a PSII precomplex is formed consisting of the central heterodimer D1 and D2, cytochrome b 559 , and PsbI (7-9). This precomplex is the smallest known unit capable of charge separation. Before a functional manganese cluster can be assembled, the D1 protein that is expressed as a precursor...

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Section: Characterization Of Psii Complexes From ⌬Psb27 Cells Revealsmentioning

confidence: 99%

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

Grasse

Mamedov

Becker

et al. 2011

Journal of Biological Chemistry

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“…A similar argumentation holds for increased sensitivity to photoinhibition under extreme hypoxia. Algal cells traveling from upper to deeper water layers might first be confronted with high light intensities inducing photoinhibition, and next be transported to dark, hypoxic water layers in which they can not recover from photoinhibitory effects (Sundby and Schiött, 1992;Tyystjaervi, 2008). Finally, a molecular oxygen sensor is probably present in all cells, and regulatory genes related to low oxygen concentrations, downregulating protein synthesis and supressing cell growth during hypoxia to save energy for essential metabolic processes, might also be present in phytoplankton (Wu, 2002).…”

Section: Figmentioning

confidence: 99%

“…However, the environmental conditions in this hypereutrophied system, may have negatively affected algal growth. There is abundant evidence that extremely low oxygen concentrations negatively affect photosynthesis (Krause et al, 1985;Sundby and Schiött, 1992;Gong et al, 1993;Peckol and Rivers, 1995;Tyystjaervi, 2008) as well as metabolism (Kessler, 1974). Molecular sensors and regulatory genes related to low oxygen concentrations are present in most organisms (Wu, 2002).…”

Section: Water Quality In the Fw Schelde From The 1960s To Presentmentioning

confidence: 99%

A macro-tidal freshwater ecosystem recovering from hypereutrophication: the Schelde case study

et al. 2009

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Abstract. We report a 40 year record of eutrophication and hypoxia on an estuarine ecosystem and its recovery from hypereutrophication. After decades of high inorganic nutrient concentrations and recurring anoxia and hypoxia, we observe a paradoxical increase in chlorophyll-a concentrations with decreasing nutrient inputs. We hypothesise that algal growth was inhibited due to hypereutrophication, either by elevated ammonium concentrations, severe hypoxia or the production of harmful substances in such a reduced environment. We study the dynamics of a simple but realistic mathematical model, incorporating the assumption of algal growth inhibition. It shows a high algal biomass, net oxygen production equilibrium with low ammonia inputs, and a low algal biomass, net oxygen consumption equilibrium with high ammonia inputs. At intermediate ammonia inputs it displays two alternative stable states. Although not intentional, the numerical output of this model corresponds to observations, giving extra support for assumption of algal growth inhibition. Due to potential algal growth inhibition, the recovery of hypereutrophied systems towards a classical eutrophied state, will need reduction of waste loads below certain thresholds and will be accompanied by large fluctuations in oxygen concentrations. We conclude that also flow-through systems, heavily influenced by external forcings which partly mask internal system dynamics, can display multiple stable states.

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“…In these conditions, the PQ pool may become highly reduced, and the lightinduced loss of PSII activity occurs (for review, see Adir et al, 2003). 1 O 2 is a very reactive oxygen species that can attack proteins, pigments, nucleic acids, and lipids, and is thought to be the most harmful ROS responsible for light-induced loss of PSII activity (Vass et al, 1992), degradation of the D1 protein (one of the PSII reaction center proteins), and pigment bleaching (for review, see Prasil et al, 1992;Aro et al, 1993;Nixon et al, 2005;Vass and Aro, 2007;Tyystjärvi, 2008).…”

Section: Resistance Of the Flv4-2/oe Mutant To Photodamage Correlatesmentioning

confidence: 99%

Flavodiiron Protein Flv2/Flv4-Related Photoprotective Mechanism Dissipates Excitation Pressure of PSII in Cooperation with Phycobilisomes in Cyanobacteria

et al. 2013

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(A.R., I.V.) Oxygenic photosynthesis evolved with cyanobacteria, the ancestors of plant chloroplasts. The highly oxidizing chemistry of water splitting required concomitant evolution of efficient photoprotection mechanisms to safeguard the photosynthetic machinery. The role of flavodiiron proteins (FDPs), originally called A-type flavoproteins or Flvs, in this context has only recently been appreciated. Cyanobacterial FDPs constitute a specific protein group that evolved to protect oxygenic photosynthesis. There are four FDPs in Synechocystis sp. PCC 6803 (Flv1 to Flv4). Two of them, Flv2 and Flv4, are encoded by an operon together with a Sll0218 protein.Their expression, tightly regulated by CO 2 levels, is also influenced by changes in light intensity. Here we describe the overexpression of the flv4-2 operon in Synechocystis sp. PCC 6803 and demonstrate that it results in improved photochemistry of PSII. The flv4-2/OE mutant is more resistant to photoinhibition of PSII and exhibits a more oxidized state of the plastoquinone pool and reduced production of singlet oxygen compared with control strains. Results of biophysical measurements indicate that the flv4-2 operon functions in an alternative electron transfer pathway from PSII, and thus alleviates PSII excitation pressure by channeling up to 30% of PSII-originated electrons. Furthermore, intact phycobilisomes are required for stable expression of the flv4-2 operon genes and for the Flv2/Flv4 heterodimer-mediated electron transfer mechanism. The latter operates in photoprotection in a complementary way with the orange carotenoid protein-related nonphotochemical quenching. Expression of the flv4-2 operon and exchange of the D1 forms in PSII centers upon light stress, on the contrary, are mutually exclusive photoprotection strategies among cyanobacteria.Photosynthetic light reactions are evolutionarily highly conserved among oxygenic photosynthetic organisms from cyanobacteria to higher plants. Because of dangerous chemistry of the water splitting reactions, oxygenic photosynthesis produces reactive oxygen species (ROS) and other radicals that potentially could destroy the photosynthetic machinery. To avoid permanent damage, all oxygenic photosynthetic organisms are equipped with an array of various photoprotective and regulatory mechanisms. Accumulating evidence on these regulatory mechanisms has revealed vast evolutionary differences between organisms performing oxygenic photosynthesis.Photosynthetic organisms have a capacity to adjust to different light intensities and to changes in the availability of electron sinks, which depends largely on metabolic cues. When light or metabolic conditions change, photosystems can dissipate excess energy as heat in nonphotochemical energy dissipation processes in the light-harvesting antenna systems (for review, see Horton et al., 1996;Müller et al., 2001). Cyanobacteria have phycobilisomes (PBs) as light-harvesting antenna, which also participate in state transitions (for review, see van Thor et al., 1998;Mullineaux ...

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Photoinhibition of Photosystem II and photodamage of the oxygen evolving manganese cluster

Cited by 285 publications

References 248 publications

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

Role of Novel Dimeric Photosystem II (PSII)-Psb27 Protein Complex in PSII Repair

A macro-tidal freshwater ecosystem recovering from hypereutrophication: the Schelde case study

Flavodiiron Protein Flv2/Flv4-Related Photoprotective Mechanism Dissipates Excitation Pressure of PSII in Cooperation with Phycobilisomes in Cyanobacteria

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