scholarly journals Physiologically active chloroplasts contain pools of unassembled extrinsic proteins of the photosynthetic oxygen-evolving enzyme complex in the thylakoid lumen.

1991 ◽  
Vol 115 (2) ◽  
pp. 321-328 ◽  
Author(s):  
W F Ettinger ◽  
S M Theg
Keyword(s):  
Oxygen Evolving Complex ◽  
Ps Ii ◽  
Thylakoid Lumen ◽  
Core Proteins ◽  
Before And After ◽  
Detergent Treatment ◽  
Extrinsic Proteins ◽  
Oxygen Evolving ◽  
Triton X ◽  
Ps Ii Core

The oxygen-evolving complex (OEC) of photosystem II (PS II) consists of at least three extrinsic membrane-associated protein subunits, OE33, OE23, and OE17, with associated Mn2+, Ca2+, and Cl- ions. These subunits are bound to the lumen side of PS II core proteins embedded in the thylakoid membrane. Our experiments reveal that a significant fraction of each subunit is normally present in unassembled pools within the thylakoid lumen. This conclusion was supported by immunological detection of free subunits after freshly isolated pea thylakoids were fractionated with low levels of Triton X-100. Plastocyanin, a soluble lumen protein, was completely released from the lumen by 0.04% Triton X-100. This gentle detergent treatment also caused the release from the thylakoids of between 10 and 20%, 40 and 60%, and 15 and 50% of OE33, OE23, and OE17, respectively. Measurements of the rates of oxygen evolution from Triton-treated thylakoids, both in the presence and absence of Ca2+, and before and after incubation with hydroquinone, demonstrated that the OEC was not dissociated by the detergent treatment. Thylakoids isolated from spinach released similar amounts of extrinsic proteins after Triton treatment. These data demonstrate that physiologically active chloroplasts contain significant pools of unassembled extrinsic OEC polypeptide subunits free in the lumen of the thylakoids.

scholarly journals Characterization of the Free and Membrane-Associated Fractions of the Thylakoid Lumen Proteome in Arabidopsis thaliana

2021 ◽  
Vol 22 (15) ◽  
pp. 8126
Author(s):  
Peter J. Gollan ◽  
Andrea Trotta ◽  
Azfar A. Bajwa ◽  
Ilaria Mancini ◽  
Eva-Mari Aro
Keyword(s):  
Arabidopsis Thaliana ◽  
Photosynthetic Electron Transport ◽  
Oxygen Evolving Complex ◽  
Ps Ii ◽  
Post Translational Modifications ◽  
Thylakoid Lumen ◽  
Novel Proteins ◽  
The Difference ◽  
Oxygen Evolving

The thylakoid lumen houses proteins that are vital for photosynthetic electron transport, including water-splitting at photosystem (PS) II and shuttling of electrons from cytochrome b6f to PSI. Other lumen proteins maintain photosynthetic activity through biogenesis and turnover of PSII complexes. Although all lumen proteins are soluble, these known details have highlighted interactions of some lumen proteins with thylakoid membranes or thylakoid-intrinsic proteins. Meanwhile, the functional details of most lumen proteins, as well as their distribution between the soluble and membrane-associated lumen fractions, remain unknown. The current study isolated the soluble free lumen (FL) and membrane-associated lumen (MAL) fractions from Arabidopsis thaliana, and used gel- and mass spectrometry-based proteomics methods to analyze the contents of each proteome. These results identified 60 lumenal proteins, and clearly distinguished the difference between the FL and MAL proteomes. The most abundant proteins in the FL fraction were involved in PSII assembly and repair, while the MAL proteome was enriched in proteins that support the oxygen-evolving complex (OEC). Novel proteins, including a new PsbP domain-containing isoform, as well as several novel post-translational modifications and N-termini, are reported, and bi-dimensional separation of the lumen proteome identified several protein oligomers in the thylakoid lumen.

Photoinactivation of Photosynthetic Electron Transport under Anaerobic and Aerobic Conditions in Isolated Thylakoids of Spinach

1992 ◽  
Vol 47 (1-2) ◽  
pp. 63-68 ◽  
Author(s):  
Rekha Chaturvedi ◽  
M. Singh ◽  
P. V. Sane
Keyword(s):  
Electron Transport ◽  
Photosynthetic Electron Transport ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Ps Ii ◽  
Ps I ◽  
S2 State ◽  
The Stability ◽  
Oxygen Evolving ◽  
Spinach Thylakoids

Abstract The effect of exposure to strong white light on photosynthetic electron transport reactions of PS I and PS II were investigated in spinach thylakoids in the absence or presence of oxygen. Irrespective of the conditions used for photoinactivation, the damage to PS II was always much more than to PS I. Photoinactivation was severe under anaerobic conditions compared to that in air for the same duration. This shows that the presence of oxygen is required for prevention of photoinactivation of thylakoids. The susceptibility of water-splitting complex in photoinactivation is indicated by our data from experiments with chloride-deficient chloroplast membranes wherein it was observed that the whole chain electron transport from DPC to MV was much less photoinhibited than that from water. The data from the photoinactivation experiments with the Tris-treated thylakoids indicate another photodam age site at or near reaction centre of PS II. DCMU-protected PS II and oxygen-evolving complex from photoinactivation. DCMU protection can also be interpreted in terms of the stability of the PS II complex when it is in S2 state.

Stabilization of the oxygen-evolving complex of photosystem II bybicarbonate and glycinebetaine in thylakoid and subthylakoidpreparations

2003 ◽  
Vol 30 (7) ◽  
pp. 797 ◽  
Author(s):  
Vyacheslav V. Klimov ◽  
Suleyman I. Allakhverdiev ◽  
Yoshitaka Nishiyama ◽  
AndreiA. Khorobrykh ◽  
Norio Murata
Keyword(s):  
Photosystem Ii ◽  
Protective Effect ◽  
Thermal Inactivation ◽  
Oxygen Evolving Complex ◽  
Photosynthetic Oxygen Evolution ◽  
Protective Effects ◽  
Synechococcus Sp ◽  
Oxygen Evolving ◽  
Triton X ◽  
Water Oxidizing Complex

The protective effect of 1 M glycinebetaine on thermal inactivation of photosynthetic oxygen evolution in isolated photosystem II membrane fragments from spinach is observed in CO2-free medium in both the presence and absence of added 2 mM bicarbonate. Conversely, the protective effect of 2 mM bicarbonate against thermoinactivation is seen in the absence as well as in the presence of 1 M glycinebetaine. The stabilizing effect of bicarbonate is also observed in thylakoid membranes from Synechococcus sp. PCC 7002 treated with 0.1% Triton X-100, and in unbroken spinach thylakoids. It is shown for the first time that bicarbonate protects the water-oxidizing complex against inactivation induced by pre-incubation of photosystem II membrane fragments (25°C) and thylakoids (40°C) at low pH (5.0–5.5) in non-bicarbonate-depleted medium. We conclude that the protective effects of glycinebetaine and bicarbonate are of a different nature; glycinebetaine acts as a non-specific, compatible, zwitterionic osmolyte while bicarbonate is considered an essential constituent of the water-oxidizing complex of photosystem II, important for its functioning and stabilization.

Formation of the High-Spin S2 State Related to the Extrinsic Proteins in the Oxygen Evolving Complex of Photosystem II

2020 ◽  
Vol 11 (20) ◽  
pp. 8908-8913
Author(s):  
Shota Taguchi ◽  
Liangliang Shen ◽  
Guangye Han ◽  
Yasufumi Umena ◽  
Jian-Ren Shen ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
High Spin ◽  
Oxygen Evolving Complex ◽  
Extrinsic Proteins ◽  
S2 State ◽  
Oxygen Evolving

Surface structure of the photosystem II complex

1991 ◽  
Vol 49 ◽  
pp. 196-197
Author(s):  
Kenneth R. Miller ◽  
Jules S. Jacob
Keyword(s):  
Photosystem Ii ◽  
Photosynthetic Reaction Center ◽  
Oxygen Evolving Complex ◽  
Photosynthetic Membrane ◽  
Ps Ii ◽  
Quick Freezing ◽  
Inner Surface ◽  
Oxygen Evolving ◽  
Excellent Source ◽  
Photosynthetic Mutant

The Photosystem II (PS-II) complex is organized around a photosynthetic reaction center (RC) embedded in the photosynthetic membrane. PS-II traps the energy of sunlight and uses it drive highenergy electron transport across the photosynthetic membrane. PS-II is closely associated with a group of proteins known as the oxygen-evolving complex (OEC), which are bound to the inner surface of the photosynthetic membrane. This complex splits water to yield electrons that are passed to the RC, releasing molecular oxygen. We have used freeze-etch electron microscopy to study 2-dimensional crystals of the PS-II complex obtained from a photosynthetic mutant of barley (viridiszb63) kindly provided by Dr. David Simpson of the Carlsberg Institute of Copenhagen (Simpson & von Wettstein, 1980). The photosynthetic membranes of these mutant plants lack photosystem I, and consequently contain extensive crystalline membrane regions enriched in PS-II. These plants are an excellent source of PS-II sheetlike crystals, obtainable without the use of detergents or chemical modification: Figure 1, prepared by quick-freezing, deep-etching, and rotary shadowing, illustrates the appearance of these sheetlike crystals.

Surface Charge Density Changes in Isolated Photosystem II Membranes Induced by Depletion of the Extrinsic Polypeptides of the Oxygen Evolving System

1990 ◽  
Vol 45 (6) ◽  
pp. 627-632 ◽  
Author(s):  
Alexander G. Ivanov ◽  
Mira C. Busheva ◽  
Maya Y. Velitchkova
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Surface Charge Density ◽  
Oxygen Evolving Complex ◽  
Partial Recovery ◽  
Ps Ii ◽  
Extrinsic Polypeptides ◽  
Evolving System ◽  
Oxygen Evolving System ◽  
Oxygen Evolving

Abstract Treatment of PS II particles with either 1 M NaCl or alkaline Tris (1 M , pH 8.4) caused a considerable decrease in the average net negative surface charge density, concomitant with depletion of the extrinsic 17, 24 and 33 kDa proteins of the oxygen evolving complex from the membranes. The partial recovery of the values for surface charge in both NaCl- and Tris-treated membranes was registered after reconstitution experiments with the three proteins. These results are compared with the data for the charge densities of the thylakoid membranes, to examine the role of the three extrinsic proteins in the formation of heterogeneous arrangement of surface charge across the appressed (granal) thylakoids.

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