Extraction and Reconstitution of Photosystem II

Okayama, Shigeki; Butler, Warren L.

doi:10.1104/pp.49.5.769

Cited by 76 publications

(27 citation statements)

References 18 publications

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“…The fluorescence quenching imposed by DBMIB at low temperature is not relieved by irradiation. (The quenching by DBMIB is similar to that observed previously [8]with hexane extracted chloroplasts that had been reconstituted with plastoquinone A).…”

Section: Resultssupporting

confidence: 86%

The effects of dibromothymoquinone on fluorescence and electron transport of spinach chloroplasts

Lozier

Butler

1972

FEBS Letters

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Section: Resultssupporting

confidence: 86%

The effects of dibromothymoquinone on fluorescence and electron transport of spinach chloroplasts

Lozier

Butler

1972

FEBS Letters

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“…8) or a monomer (9) of chlorophyll (Chl), and the primary acceptor, Q, a special form of plastoquinone (PQ) (8)(9)(10)(11)(12)(13)(14). From measurements of nanosecond recombination luminescence from PS II, the lifetime of the state [P68OPheo] has been found to be z3 ns at 295 K [3].…”

mentioning

confidence: 99%

Interaction between the intermediary electron acceptor (pheophytin) and a possible plastoquinone-iron complex in photosystem II reaction centers

Klimov

Dolan²,

Shaw³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

116

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Photoreduction of the intermediary electron acceptor, pheophytin (Pheo), in photosystem II reaction centers of spinach chloroplasts or subchloroplast particles (TSF-II and TSF-IIa) at 220 K and redox potential Eh = -450 mV produces an EPR doublet centered at g = 2.00 with a splitting of 52 G at 7 K in addition to a narrow signal attributed to Pheo (g = 2.0033, AH -13 G). The doublet is eliminated after extraction of lyophilized TSF-II with hexane containing 0. Phototrapping of Pheo-in PS II at 295 K is accompanied by the appearance of an EPR signal with g k 2.0035 and AH 13 G (1 G = 10-4 tesla) (6, 7), similar to that of the monomeric The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §17734 solely to indicate this fact. 7227anion radical of Pheo in vitro (18). After phototrapping of Pheo at 220 K, however, an EPR "doublet" centered at g = 2.00 with a splitting of m52 G is also observed (7). In analogy with a similar observation in bacterial reaction centers (19)(20)(21)(22), it was suggested that the doublet is probably the result of interaction of Pheo' with Q, which includes Fe or some other transition metal (7). Here we report data supporting the idea that a PQ-Fe complex acts as the stable "primary" electron acceptor in PS II reaction centers and that an exchange interaction of its singly reduced form with Pheo-accounts for the split EPR signal. MATERIALS AND METHODSSpinach chloroplasts and subchloroplast particles (Tritonfractionated subchloroplast fragments, TSF-II and TSF-IIa), highly enriched in PS II reaction center components and free of P700, were isolated as described (23- Iron was extracted by incubating PS II preparations (Chl at 50 mg/ml) in 10 mM Tris-HCI (pH 8.0) containing 0.3-1 M LiCl04 with or without 2.5 mM o-phenanthroline, for 2 hr at 20C, followed by centrifugation (200,000 X g for 40 min) and dialysis (12 hr at 2°C) of the pellet against 10 mM Tris-HCl (pH 8.0)/50 mM NaCI/10 AM EDTA (David Knaff, personal communication; also ref. 27). In the reconstitution experiments the extracted material was additionally dialyzed for 12 hr at 20C under anaerobic conditions against 10 mM acetate buffer (pH 5.5) containing 0.2 M LiCl04 and 1 MM EDTA, with or without 0.2 mM Fe(NH4)2(SO4)2, MnSO4, or MgSO4.Nonheme iron content was determined by the bathophenanthroline method (28). Changes in absorbance and fluorescence yield, induced by actinic light (intensity t0.05 Jcm2-s-l) from a 1000-W incandescent lamp filtered by 5 cm of CuSO4 solution, were measured in a phosphoroscopic pho-

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“…Instead of Vitamin K, Bishop (1959) found Q254 and showed that it restored activity. Later, Okayama and Butler (1972) showed, using hexane extraction, partial restoration by PQ and partial restoration by carotene. We found 50% restoration of ferricyanide and NADPH reduction with reduced PQ and less restoration with oxidized PQ (Wood and Crane 1965;Wood et al 1966).…”

Section: The Re-discovery Of the Plastoquinonementioning

confidence: 99%

Discovery of plastoquinones: a personal perspective

Crane

2010

Photosynth Res

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The discovery and the rediscovery of plastoquinone (PQ) are described together with the definition of its structure as a 2,3-dimethyl 5 solanosyl benzoquinone. The discovery, by M. Kofler, was a result of a search for Vitamin K. Its rediscovery was made by me, when I was at The Enzyme Institute of the University of Wisconsin, analyzing animals and plants for the newly discovered coenzyme Q. In green plants, I found another lipophilic quinone in addition to coenzyme Q. Some misleading evidence suggested as if the new quinone had coenzyme Q activity in mitochondria, but improved methods gave negative results. When I found that the quinone was concentrated in chloroplasts, I considered a role for it in photosynthesis analogous to the role of coenzyme Q in mitochondria. After moving to the Chemistry Department, University of Texas at Austin, I used a plain light bulb and some spinach chloroplasts to show that PQ could be involved in photosynthetic redox reactions. This effect was supported by Norman Bishop's restoration of chloroplast electron transport after solvent extraction, with PQ and photoreduction studies by E. R. Redfern and J. Friend in R. A. Morton's laboratory in Liverpool, UK. We also found an additional analog of PQ in addition to a second analog found in Wisconsin. We called the new analogs PQB and PQC. Although we found some restoration effects with PQC, the discovery by W. T. Griffiths in Morton's laboratory, that PQB and PQC consisted of six forms of PQ each, made it more likely that the new analogs were breakdown products. Morton's group established the structure of the PQCs as a series of PQs, with a hydroxyl group on the prenyl side chain, and the PQB series as having fatty acids esterified to the hydroxyl groups of PQC. Possible functions of the analogs are also discussed in this article.

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Extraction and Reconstitution of Photosystem II

Cited by 76 publications

References 18 publications

The effects of dibromothymoquinone on fluorescence and electron transport of spinach chloroplasts

The effects of dibromothymoquinone on fluorescence and electron transport of spinach chloroplasts

Interaction between the intermediary electron acceptor (pheophytin) and a possible plastoquinone-iron complex in photosystem II reaction centers

Discovery of plastoquinones: a personal perspective

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