Two-dimensional crystals of photosystem II: biochemical characterization, cryoelectron microscopy and localization of the D1 and cytochrome b559 polypeptides.

Photosystem II (PS II) is a photosynthetic reaction center found in higher plants which has the unique ability to evolve oxygen from water. Several groups have formed two-dimensional PS II crystals or have isolated PS II complexes and studied them by electron microscopy and image analysis. The majority of these specimens have not been well characterized biochemically and have yielded relatively low resolution two-dimensional projection maps with a variety of unit cell sizes. We report the characterization of the polypeptide and lipid content of tubular crystals of PS II. The crystals contain the reaction center core polypeptides D1, D2, cytochrome b559, as well as the chlorophyll-binding polypeptides (CP) CP47, CP43, CP29, CP26, CP24, and CP22. The lipid composition was similar to the lipids found in the stacked portion of thylakoids. We also report a 2.0-nm resolution projection map determined by electron microscopy and image analysis of frozen, hydrated PS II crystals. This projection map includes information on the portion of the complex buried in the lipid bilayer. The unit cell is a dimer with unit vectors of 17.0 and 11.4 nm separated by an angle of 106.6 degrees. In addition, Fab fragments against D1 and cytochrome b559 were used to localize those two polypeptides, and thus the reaction center, within the PS II complex. The results indicate that D1 and cytochrome b559 are found within one of the heaviest densities of the monomeric unit.

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Targeted Deletion Mutagenesis of the β Subunit of Cytochrome b559 Protein Destabilizes the Reaction Center of Photosystem II

Zeitschrift für Naturforschung C ◽

10.1515/znc-1990-0519 ◽

1990 ◽

Vol 45 (5) ◽

pp. 423-429 ◽

Cited By ~ 42

Author(s):

Himadri B. Pakrasi ◽

Karin J. Nyhus ◽

Howard Granok

Keyword(s):

Photosystem Ii ◽

Reaction Center ◽

Thylakoid Membranes ◽

Antenna System ◽

Β Subunit ◽

Cyt B ◽

Synechocystis 6803 ◽

Cytochrome B559 ◽

Ps Ii ◽

Individual Gene

Abstract Oligonucleotide-directed mutagenesis techniques were used to delete the psbF gene, encoding the β subunit of the cytochrom e b559 protein of the photosystem II complex in the cyano bacterium, Synechocystis 6803. Cyt b559 is an integral com ponent of PS II complex. However, its precise functional role in PS II remains to be determined. Previously, we created a mutant in which the psbF gene as well as three of its neighbouring genes, psbE , psbL and p sb i were simultaneously deleted from the chrom osom e of Synechocystis 6803 (Pakrasi, Williams and Arntzen, EMBO J. 7, 325 -332 , 1988). This mutant had no PS II activity. However, the role of any one of the four individual gene products could not be determined by studying this mutant. The newly generated mutant, T 256, had only one gene, p sbF , deleted from the genome. This mutant was also impaired in its PS II activities. In addition, it had barely detectable levels of two other protein com ponents, D1 (herbicide binding protein) and D2, of the reaction center of PS II, in its thylakoid membranes. In contrast, two other proteins of PS II, CP47 and CP43 were present in appreciable amounts. Fluorescence spectra (77 K) of the mutant showed the absence of a peak at 695 nm that was previously believed to originate from CP47. In addition, phycobilisomes, the light-harvesting antenna system of PS II, were found to be assembled normally in this mutant. We conclude that the presence of the β subunit of Cyt b559 in the thylakoid membranes is critically important for the assembly of PS II reaction center.

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Image Analysis by Electron Microscopy of Two-Dimensional Crystals Developed on a Mercury Surface of Chaperonin from Thermus thermophilus

The Journal of Biochemistry ◽

10.1093/oxfordjournals.jbchem.a123687 ◽

1991 ◽

Keyword(s):

Electron Microscopy ◽

Image Analysis ◽

Thermus Thermophilus ◽

Two Dimensional ◽

Mercury Surface

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PHOTOSYSTEM II REACTION CENTER COMPLEX PURIFIED FROM HIGHER PLANTS

The Oxygen Evolving System of Photosynthesis ◽

10.1016/b978-0-12-372360-4.50010-9 ◽

1983 ◽

pp. 27-38 ◽

Cited By ~ 13

Author(s):

Kimiyuki Satoh

Keyword(s):

Photosystem Ii ◽

Reaction Center ◽

Higher Plants ◽

Reaction Center Complex

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Analysis of the Photosystem II reaction center and its complex with CP47 using gelfiltration chromatography and electron microscopy

Photosynthesis: from Light to Biosphere ◽

10.1007/978-94-009-0173-5_115 ◽

1995 ◽

pp. 499-502

Author(s):

Camiel Eijckelhoff ◽

Henny van Roon ◽

Egbert J. Boekema ◽

Jan P. Dekker

Keyword(s):

Electron Microscopy ◽

Photosystem Ii ◽

Reaction Center

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Photoreduction of NADP+ in Photosystem II of Higher Plants: Requirement for Manganese

Zeitschrift für Naturforschung C ◽

10.1515/znc-1992-1-211 ◽

1992 ◽

Vol 47 (1-2) ◽

pp. 57-62 ◽

Cited By ~ 14

Author(s):

Suleyman I. Allakhverdiev ◽

Vyacheslav V. Klimov

Keyword(s):

Photosystem Ii ◽

Higher Plants ◽

Complete Removal ◽

Reaction Centers ◽

Higher Plant ◽

Ps Ii ◽

Alternate Pathway ◽

Manganese Extraction ◽

Quinone Acceptor ◽

Reduced State

Abstract The effects of reversible manganese extraction on NADP+ photoreduction were studied with higher plant subchloroplast preparations of photosystem II (PS II). Under anaerobic conditions, when the reaction centers (RCs) of PS II are “closed” (i.e. in the state [P680 Pheo] QA), and in the presence of ferredoxin-ferredoxin-NADP+ reductase, NADP+ reduction is observed at a rate of 0.8 -1.1 nmol/mg × chlorophyll × h. After complete removal of manganese from PS II, the rate of NADP+ reduction is reduced 40 - 50-fold. Upon the addition of Mn at a concentration of approx. 4 Mn atoms per reaction center, the NADP+ reduction is restored up to 85 -90% of the initial value. When half of this amount of Mn is combined with about 40 times of the equivalent concentration of other divalent ions (Ca2+, Sr2+, Mg2+ etc.) the reaction is also reactivated. Dinoseb (10-6 m) an inhibitor of electron transfer in PS II prevents NADP+ photoreduction. It is concluded that under conditions when the first quinone acceptor, QA, is in its reduced state (QA-) electrons are transferred from reduced pheophytin (Pheo·̅) to NADP+, indicating that PS II can reduce NADP+ without the participation of PS I. On the basis of these and literature data, an alternate pathway for electron phototransfer in PS II reaction centers of higher plants is suggested. Some problems concerning the Z-scheme are discussed.

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