<i>In vivo</i> and <i>in vitro</i> photoinhibition reactions generate similar degradation fragments of D1 and D2 photosystem‐II reaction‐centre proteins

Shipton, Catherine A.; Barber, James

doi:10.1111/j.1432-1033.1994.tb18682.x

Cited by 46 publications

(28 citation statements)

References 66 publications

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“…Exposing the algal cells to the elevated salt concentration resulted in a decline in the D1 protein. This finding is in line with the well-documented role of the D1 protein in down-regulating the activity of PSII (Smith et al, 1990;Harrison et al, 1992;Shipton & Barber, 1994;Komenda & Masojidek, 1995;Zeng & Vonshak, 1998;Sudhir et al, 2005). The decrease in the level of the protein in response to high salt was much higher in wild-type cells.…”

Section: Discussionsupporting

confidence: 77%

DCMU-resistance mutation confers resistance to high salt stress in the red microalgaPorphyridiumsp. (Rhodophyta)

Manandhar-Shrestha

Arad

Vonshak

2009

European Journal of Phycology

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The response of photosynthesis to salinity stress in wild-type and DCMU-resistant (strain DC-2) Porphyridium sp. was investigated. Both wild-type and DC-2 were able to acclimate and establish a new steady state of growth when exposed to salt stress, but growth rate of the DC-2 mutant strain was 1.25-fold higher than growth rate of wild-type cells. Following establishment of a new steady state under the salt stress conditions, the maximal irradiance-saturated photosynthetic capacity (P max ), light saturation (I k ) and the photosynthetic efficiency () were 1.5-, 1.8-and 1.1-fold, respectively, higher in the DC-2 mutant cells than wild-type. Furthermore, salt-stressed DC-2 mutant cells exhibited 1.6-fold higher maximal efficiency of PS II (Fv/Fm) after 200 min exposure and 3-fold higher level of D1 protein after 24 h exposure to salt than wild-type cells. Exposing the salt-stressed cells to high photon flux density (3000 mmol m -2 s -1 ) for 1 h resulted in a higher resistance of mutant cells than wild-type to light stress, as reflected in 1.3-fold decline in the Fv/Fm. This finding corresponds well with the levels of the D1 protein measured in the cells. These observations indicate that the D1 protein of the PS II apparatus in the DC-2 mutant was more resistant to stress. However, under non-stressed (light and salt) conditions, no differences were observed between wild-type and the DC-2 mutant cells for all the parameters studied. The DC-2 mutant responded better than wild-type to environmental stresses, namely salinity and light due to the modification induced in PS II.

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Section: Discussionsupporting

confidence: 77%

DCMU-resistance mutation confers resistance to high salt stress in the red microalgaPorphyridiumsp. (Rhodophyta)

Manandhar-Shrestha

Arad

Vonshak

2009

European Journal of Phycology

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“…In donor-side photoinhibition, cleavage in the luminal AB or CD loops has been reported. Cleavage at the luminal AB loops produces 10-kD N-terminal and 24-kD C-terminal fragments (Barbato et al, 1991;De Las Rivas et al, 1992), whereas cleavage at the CD loops results in the generation of 16-kD N-terminal and 18-kD C-terminal fragments (De Las Rivas et al, 1992;Shipton and Barber, 1994;Kettunen et al, 1996;Wiklund et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

“…In acceptor-side photoinhibition, the primary cleavage of the D1 protein appears to occur in the stromal loop connecting the transmembrane helices D and E, based on the detection of 23-kD N-terminal and 10-kD C-terminal fragments in samples examined by various authors (Greenberg et al, 1987;Canovas and Barber, 1993;Shipton and Barber, 1994;Kanervo et al, 1998). In donor-side photoinhibition, cleavage in the luminal AB or CD loops has been reported.…”

Section: Introductionmentioning

confidence: 99%

Formation of DEG5 and DEG8 Complexes and Their Involvement in the Degradation of Photodamaged Photosystem II Reaction Center D1 Protein in Arabidopsis

et al. 2007

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The widely distributed DEGP proteases play important roles in the degradation of damaged and misfolded proteins. Arabidopsis thaliana contains 16 DEGP-like proteases, four of which are located in the chloroplast. Here, we show that DEG5 and DEG8 form a hexamer in the thylakoid lumen and that recombinant DEG8 is proteolytically active toward both a model substrate (b-casein) and photodamaged D1 protein of photosystem II (PSII), producing 16-kD N-terminal and 18-kD C-terminal fragments. Inactivation of DEG5 and DEG8 resulted in increased sensitivity to photoinhibition. Turnover of newly synthesized D1 protein in the deg5 deg8 double mutant was impaired, and the degradation of D1 in the presence of the chloroplast protein synthesis inhibitor lincomycin under high-light treatment was slowed in the mutants. Thus, DEG5 and DEG8 are important for efficient turnover of the D1 protein and for protection against photoinhibition in vivo. The deg5 deg8 double mutant showed increased photosensitivity and reduced rates of D1 degradation compared with single mutants of deg5 and deg8. A 16-kD N-terminal degradation fragment of the D1 protein was detected in wild-type plants but not in the deg5 deg8 mutant following in vivo photoinhibition. Therefore, our results suggest that DEG5 and DEG8 have a synergistic function in the primary cleavage of the CD loop of the PSII reaction center protein D1.

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“…Cleavage on the stromal side, between transmembrane helices IV ancl V, should result in loss of DCMU-binding sites (Greenberg et al, 1987;De La Rivas et al, 1993) and, if this was the only site of proteolysis, one would expect equivalence in the antibody-detectable D1 protein and DCMU-binding site concentrations. Some studies of low-temperature photoinhibition of peas in vitro seem to indicate this form of acceptorside proteolysis (Shipton and Barber, 1994), but other studies of spinach under these conditions (Chow et al, 1989) show that DCMU-binding site concent rations can remain well above functional PSII center concentrations. However, if cleavage occurs on the luminal side, between transmembrane helices I and I1 (Shipton and Bzrber, 19911, the resulting 23-kD fragment might continue to bind DCMU.…”

Section: Discussionmentioning

confidence: 99%

Photosystem II Regulation and Dynamics of the Chloroplast D1 Protein in Arabidopsis Leaves during Photosynthesis and Photoinhibition

Russell¹,

Critchley²,

Robinson³

et al. 1995

Plant Physiol.

135

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Arabidopsis fbaliana leaves were examined in short-term (1 h) and long-term (1 O h) irradiance experiments involving growth, saturating and excess light. Changes in photosynthetic and chlorophyll fluorescence parameters and in populations of functional photosystem II (PSII) centers were independently measured. Xanthophyll pigments, 3-(3,4-dichlorophenyI)-l,l-dimethylurea (DCMU)-binding sites, the amounts of D1 protein, and the rates of D1 protein synthesis were determined. These comprehensive studies revealed that under growth or light-saturating conditions, photosynthetic parameters remained largely unaltered. Photoprotection occurred at light saturation indicated by a dark-reversible increase in nonphotochemical quenching accompanied by a 5-fold increase in antheraxanthin and zeaxanthin. No consistent change i n the concentrations of functional PSll centers, DCMU-binding sites, or D1 protein pool size occurred. D1 protein synthesis was rapid. In excess irradiance, quantum yield of O, evolution and the efficiency of PSll were reduced, associated with a 15-to 20-fold increase in antheraxanthin and zeaxanthin and a sustained increase i n nonphotochemical quenching. A decrease in functional PSll center concentration occurred, followed by a decline in the concentration of D1 protein; the latter, however, was not matched by a decrease in DCMU-binding sites. I n the most extreme treatments, DCMUbinding site concentration remained 2 times greater than the concentration of D1 protein recognized by antibodies. D 1 protein synthesis rates remained unaltered at excess irradiances.During the last decade studies of photosynthesis and photoinhibition in higher plants have been driven by many advances in our understanding and by the availability of new techniques for in vivo and in vitro investigations. Following the biochemical studies of Kyle et al. (1984) with photoheterotrophic Chlamydomonas, attention has focused on a central role for the synthesis and degradation of the D1 protein of the heterodimer of the PSII reaction center

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In vivo and in vitro photoinhibition reactions generate similar degradation fragments of D1 and D2 photosystem‐II reaction‐centre proteins

Cited by 46 publications

References 66 publications

DCMU-resistance mutation confers resistance to high salt stress in the red microalgaPorphyridiumsp. (Rhodophyta)

DCMU-resistance mutation confers resistance to high salt stress in the red microalgaPorphyridiumsp. (Rhodophyta)

Formation of DEG5 and DEG8 Complexes and Their Involvement in the Degradation of Photodamaged Photosystem II Reaction Center D1 Protein in Arabidopsis

Photosystem II Regulation and Dynamics of the Chloroplast D1 Protein in Arabidopsis Leaves during Photosynthesis and Photoinhibition

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