On the molecular mechanism of light-induced D1 protein degradation in photosystem II core particles

Ah, Salter; Virgin, Ivar; Hagman, Åsa; Andersson, Bertil

doi:10.1021/bi00131a014

Cited by 100 publications

(76 citation statements)

References 37 publications

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“…2A). The 40-kDa band has been observed in a variety of PSII preparations as a result of photoinhibitory treatment (Aro et al, 1990;Shipton and Barber, 1991 ;De Las Rivas et al, 1992;Salter et al, 1992). It has been attributed to the generation of a linked protein dimer containing the whole D1 molecule and the a-subunit of cytochrome bSs9 (Barbat0 et al, 1992~).…”

Section: Resultsmentioning

confidence: 99%

“…The origin of the D1 protein breakdown fragments of molecular masses approximately 18-16 kDa is unclear, but these fragments have been observed in earlier studies using in vitro systems Barber, 1991, 1992;Salter et al, 1992;De Las Rivas et al, 1992;Friso et al, 1993). It is likely that two of these fragments are derived by a cleavage midway in the D1 protein and are therefore Nterminal and C-terminal in origin.…”

Section: Discussionmentioning

confidence: 97%

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

Shipton

Barber

1994

European Journal of Biochemistry

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Isolation of photosystem-I1 reaction centres from pea leaves after photoinhibitory treatment at low temperature (0-1 "C) has provided evidence for the mechanism of degradation of the D1 protein in vivo. These isolated reaction centres did not appear to be spectrally distinct from preparations obtained from control leaves that had not been photoinhibited. Breakdown fragments of both the D1 and D2 proteins were, however, found in preparations isolated from photoinhibited leaves, and showed similarities with those detected when isolated reaction centres were exposed to acceptorside photoinhibition. Analyses of the origin of D1 fragments indicated that the primary cleavage site of this protein was between transmembrane helices IV and V indicative of the acceptor-side mechanism for photoinhibition. The origins of other D1 protein fragments indicate that some donorside photoinhibition may also have occurred in vivo under the conditions employed. We have shown that the spectral and functional integrating of the isolated photosystem I1 reaction centre complex is resistant to proteolytic cleavage by trypsin. Use of a more non-specific protease (subtilisin), however, caused significant destabilisation of the special pair of chlorophylls constituting the primary electron donor, P680, with a consequential loss of functional activity. Thus, it is possible that specific cleavage of photosystem-I1 reaction-centre proteins may occur in vivo following photoinhibitory damage without a significant change in structural integrity, a conclusion supported by the finding that photodamaged and normal reaction centres were isolated together.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 97%

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

Shipton

Barber

1994

European Journal of Biochemistry

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“…High light leads to photo inhibition of PS II, if the resynthesis rate is no longer competent. The system as used here has been extensively studied in Chlamydomonas by Ohad et al [8,9] as well as in isolated thylakoid systems [18][19][20]. The trigger for the photodegradation of the D 1 protein is not known, but assumed to be damage to the protein [18].…”

Section: Discussionmentioning

confidence: 99%

Role of carotene in the rapid turnover and assembly of photosystem II in Chlamydomonas reinhardtii

1997

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Inhibitors of the phytoene desaturase in carotene biosynthesis were tested in the enhanced rapid turnover of the Dl protein of photosystem II in high light exposure of Chlamydomonas reinhardtii cells. After 1 h high light on heterotrophically grown cells in the presence of norflurazon or fluridone, photosynthesis activity in vivo and PS II activity in vitro is lost. The Dl protein has disappeared. PS I activity is not affected, nor is the D2 protein. It is concluded that (3-carotene is essential for the assembly of the Dl protein into functional photosystem II. It is suspected that bleaching of (3-carotene in the reaction center of PS II by high light destabilizes the structure and triggers the degradation of the Dl protein.

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“…(1987) and also has been observed under in vitro conditions in isolated thylakoids and purified PSII complexes and reaction centers (Ohad et al, 1985;Salter et al, 1992; de Las Rivas et al, 1993). The primary cleavage recently was shown to be dependent on hydrolysis of membrane-bound GTP, whereas the addition of ATP had no effect (Spetea et al, 1999).…”

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confidence: 83%

The Thylakoid FtsH Protease Plays a Role in the Light-Induced Turnover of the Photosystem II D1 Protein

et al. 2000

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The photosystem II reaction center D1 protein is known to turn over frequently. This protein is prone to irreversible damage caused by reactive oxygen species that are formed in the light; the damaged, nonfunctional D1 protein is degraded and replaced by a new copy. However, the proteases responsible for D1 protein degradation remain unknown. In this study, we investigate the possible role of the FtsH protease, an ATP-dependent zinc metalloprotease, during this process. The primary light-induced cleavage product of the D1 protein, a 23-kD fragment, was found to be degraded in isolated thylakoids in the dark during a process dependent on ATP hydrolysis and divalent metal ions, suggesting the involvement of FtsH. Purified FtsH degraded the 23-kD D1 fragment present in isolated photosystem II core complexes, as well as that in thylakoid membranes depleted of endogenous FtsH. In this study, we definitively identify the chloroplast protease acting on the D1 protein during its light-induced turnover. Unlike previously identified membrane-bound substrates for FtsH in bacteria and mitochondria, the 23-kD D1 fragment represents a novel class of FtsH substratefunctionally assembled proteins that have undergone irreversible photooxidative damage and cleavage. INTRODUCTIONProteins that are rendered nonfunctional due to interactions with reactive oxygen species or free radicals undergo proteolysis and are replaced by newly synthesized copies. This is particularly significant in the chloroplast thylakoid membrane. Here, enzymes operate in a highly oxidizing environment and therefore are susceptible to impairment of structure and function. Within the thylakoid membrane, photosystem II (PSII) is the component most sensitive to oxidative damage. This sensitivity is partially due to its function in water splitting, a reaction that requires an oxidizing potential of 1.1 V, but it is also due to the intrinsic formation by PSII of toxic oxygen species (Andersson and Barber, 1994). PSII is a large multisubunit protein complex integral to the thylakoid membrane (Andersson and Barber, 1994). Its reaction center contains the homologous D1 and D2 proteins, PsbI, PsbW (in which Psb stands for PSII, and I and W denote specific subunits), and cytochrome b 559 . The D1/D2 heterodimer binds all of the chlorophylls, quinones, and metal ligands necessary to perform primary PSII photochemistry and electron transport. The structure of the PSII reaction center recently has been determined at a resolution of 8 Å (Rhee et al., 1998), and the structure of the dimeric PSII core complex has been set at a resolution of ‫ف‬ 9 Å (Hankamer et al., 1999).Under conditions of high light intensity, electron transport within the complex is arrested, and consequently, the photosynthetic process is inactivated. This phenomenon is known as photoinhibition (Barber and Andersson, 1992;Prasil et al., 1992). The process is thought to occur via overreduction of the acceptor side of PSII, chlorophyll triplet formation, and production of toxic singlet oxygen (Vass et a...

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On the molecular mechanism of light-induced D1 protein degradation in photosystem II core particles

Cited by 100 publications

References 37 publications

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

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

Role of carotene in the rapid turnover and assembly of photosystem II in Chlamydomonas reinhardtii

The Thylakoid FtsH Protease Plays a Role in the Light-Induced Turnover of the Photosystem II D1 Protein

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