β-Carotene within the isolated Photosystem II reaction centre: photooxidation and irreversible bleaching of this chromophore by oxidised P680

Telfer, Alison; Rivas, Javier De Las; Barber, James

doi:10.1016/s0005-2728(05)80125-2

Cited by 154 publications

(119 citation statements)

References 35 publications

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“…However, those in PS II were reported to be oxidized under photoinhibitory conditions (ref. [7] and this study). This seems to be a unique feature of PS II.…”

Section: Discussionsupporting

confidence: 66%

“…Photobleaching of carotenoids has been observed previously as one of the phenomenon diagnostic of photoinhibi- tic,n in chloroplasts [5] or PS II membranes [6] after removal of the Mn cluster, or in isolated reaction centers [7]. In this stlldy, illumination of a mutant lacking Yz in the Dl polypeptide was also shown to be accompanied by irreversible photobleaching of carotenoid(s) upon illumination.…”

Section: Photobleaching Of Carotenoidsmentioning

confidence: 67%

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Donor‐side photoinhibition in photosystem II from Chlamydomonas reinhardtii upon mutation of tyrosine‐Z in the D1 polypeptide to phenylalanine

et al. 1996

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When tyrosine-Z of the Dl-polypeptide of the photosystem II from Chlamydomonas reinhardtii was changed to phenylalanlne, the rapid donor to Pm+ was lost, and Pm+ accumulated on illumination. The rapid donation from tyroshte-Z was replaced by a slow electron transfer from an endogenous donor. Spectrophotometric measurements showed that carotenoids and chlorophylls were bleached by the Pa+ either directly or indirectly upon illumination. The carotenoid bleaching was inhibited in the presence of SOD or catalase, but the reaction did not require molecular oxygen as an electron acceptor. These observations led us to conclude that active oxygen radicals, possibly hydroxyl radicals, take part in the destruction of carotenoids in the Y161F mutant. Possible mechanisms for the destruction are discussed.

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“…However, those in PS II were reported to be oxidized under photoinhibitory conditions (ref. [7] and this study). This seems to be a unique feature of PS II.…”

Section: Discussionsupporting

confidence: 66%

Section: Photobleaching Of Carotenoidsmentioning

confidence: 67%

Donor‐side photoinhibition in photosystem II from Chlamydomonas reinhardtii upon mutation of tyrosine‐Z in the D1 polypeptide to phenylalanine

et al. 1996

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“…At 20°C, this 'red peak' is normally at 675.5-676 nm (Chapman et al, 1989). However, during illumination of the isolated reaction centres, this peak shifts to below 673 nm due to damage of the chlorophylls comprising the primary electron-donor P680 (Telfer et al, 1991). The 'red peak' of the preparation isolated from photoinhibited leaves is at 676 nm, indicating that the chromophores making up the special pair in the latge majority of centres are undamaged by photoinhibitory treatment of the leaves (Fig.…”

Section: Resultsmentioning

confidence: 97%

“…Donor-side inhibition is thought to result from the accumulation of P680+, which is a highly oxidising species (Thompson and Brudvig, 1988). This species can extract electrons from its surroundings and has been shown to cause irreversible bleaching of the accessory pigment molecules in the reaction-centre complex (Telfer et al, 1991(Telfer et al, , 1992. P680' can also remove electrons from its protein environment as evidenced by the oxidation of Tyrl61 residues on the D1 and D2 proteins (Debus et al, 1988;Vermaas et al, 1988).…”

mentioning

confidence: 99%

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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“…In both experimental systems the appearance of the C-terminal-containing fragment requires the presence of an electron acceptor so as to allow long-lived oxidised species to accumulate on the donor side of the reaction centre [9]. It is therefore proposed that in some way, possjbly by destruction of secondary pigments [26,27], these species trigger the proteolpic hjrdrolysis of a peptide bond in the polypeptide loop spanning transmembrane segments I and II at the lumenal side of the thylakoid membrane [l&28]. In so doing fragments of about 24 kDa and IO kDa are generated, where the former contains the C-terminus and the latter the Nterminus of the Dl -protein.…”

Section: Discussion If It Contains the C-terminus Of Thementioning

confidence: 99%

Two sites of primary degradation of the D1‐protein induced by acceptor or donor side photo‐inhibition in photosystem II core complexes

1992

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Depending on experimental conditions wc have found that photo-inhibitory treatment of photosystem II (PSIl)core complexes, isolated from wheat, can generate Iwo fragmenls of about 23-24 kDa that contain either the C-terminal or N-terminal regions of the Dl-prouin. A 24 kDa Gterminal fragment appears when the water splitting reaction is not functional and an electron acceptor is present. This'donor'.side inhibition also generates an N-terminal fragment of about IO kDa and is suggested to be due to the cleavage of a peptide bond in the region connecting transmembrane segments I and II of the DI-protein. In contrast, an N.terminal 23 kDa DImprotein fragment is detected when the water splitting reactions of the isolated complex are active, and occurs in the absence of an added electron acceptor. This 'acceptor'+ide photo-inhibition also generates a C-terminal fragment of about IO kDa.

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β-Carotene within the isolated Photosystem II reaction centre: photooxidation and irreversible bleaching of this chromophore by oxidised P680

Cited by 154 publications

References 35 publications

Donor‐side photoinhibition in photosystem II from Chlamydomonas reinhardtii upon mutation of tyrosine‐Z in the D1 polypeptide to phenylalanine

Donor‐side photoinhibition in photosystem II from Chlamydomonas reinhardtii upon mutation of tyrosine‐Z in the D1 polypeptide to phenylalanine

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

Two sites of primary degradation of the D1‐protein induced by acceptor or donor side photo‐inhibition in photosystem II core complexes

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