Light‐induced degradation of D2 protein in isolated photosystem II reaction center complex

Barbato, Roberto; Friso, Giulia; Laureto, Patrizia Polverino de; Frizzo, Annalisa; Rigoni, Fernanda; Giacometti, Giorgio M.

doi:10.1016/0014-5793(92)81360-x

Cited by 35 publications

(21 citation statements)

References 26 publications

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“…This is demonstrated by the changes induced by exposure of a PSII complex to UV-B radiation or excessive visible light in their MALDI spectra. As expected, a significant decrease in the relative abundance of the peaks due to D1 is observed after visible light stress and of those of both D1 and D2 proteins upon exposure to UV-B, in agreement with previous results (21)(22)(23)(24)(25)(26)(27)(28)(29). The observed significant increase in the number of peaks in the low molecular mass region (data not shown) also indicates the possibility of detecting fragments originating from radiation-induced degradation of PSII proteins.…”

Section: Discussionsupporting

confidence: 93%

Determination of Photosystem II Subunits by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

Szabó

Seraglia²,

Rigoni

et al. 2001

Journal of Biological Chemistry

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Photosystem II of higher plants and cyanobacteria is composed of more than 20 polypeptide subunits. The pronounced hydrophobicity of these proteins hinders their purification and subsequent analysis by mass spectrometry. This paper reports the results obtained by application of matrix-assisted laser desorption/ionization mass spectrometry directly to isolated complexes and thylakoid membranes prepared from cyanobacteria and spinach. Changes in protein contents following physiopathological stimuli are also described. Good correlations between expected and measured molecular masses allowed the identification of the main, as well as most of the minor, low molecular weight components of photosystem II. These results open up new perspectives for clarifying the functional role of the various polypeptide components of photosystems and other supramolecular integral membrane complexes.Photosystem II is a pigment-protein complex of the thylakoid membrane of higher plants, eukaryotic algae, and cyanobacteria. It catalyzes light-induced electron transfer from water to plastoquinone, with associated production of molecular oxygen. PSII 1 consists of a large complex with a number of polypeptide components, most of which are integral membrane proteins. A number of extrinsic proteins are also associated with it at the membrane surface. The entire set of electron transfer cofactors, including chlorophyll a, pheophytin a, plastoquinones, and non-heme iron, is associated with the D1/D2 heterodimer. These two proteins, together with the ␣ and ␤ subunits of cytochrome b 559 and the PsbI protein, constitute the so-called reaction center II (RCII), which is the smallest PSII subparticle still able to perform light-induced charge separation (1). Two large integral membrane proteins, CP43 and CP47, each coordinating a number (12-15) of chlorophyll a molecules, and several low molecular mass (Ͻ10 kDa) polypeptides are constituents of the PSII core complex, which is very similar in higher plants and prokaryotic cyanobacteria.During the last decade, considerable progress has been made in our understanding of the organization of polypeptides constituting the reaction center of PSII, but the topology and functional role of the small protein subunits are still largely unknown. Some of them are universal, whereas others are present only in cyanobacteria (PsbU and PsbV) or only in higher plants (e.g. PsbP, PsbQ, PsbS) (2).Investigation of the structural and functional roles of the various PSII subunits requires, as a preliminary step, a suitable method to detect them in the thylakoid membrane or purified subparticle preparations. The detection and study of stimuli-induced modifications of several PSII components have mainly been based on the use of polyclonal antibodies. However, these are often not available and, when available, are time-consuming to use.A different technique, capable of accurately detecting even small amounts of the various PSII subunits in an integrated system, could be of great help in studying the function of these protein...

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Section: Discussionsupporting

confidence: 93%

Determination of Photosystem II Subunits by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

Szabó

Seraglia²,

Rigoni

et al. 2001

Journal of Biological Chemistry

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“…Visualization of immunoreactions was performed using an alkdine-phosphatase-based chromogenic melhod. The following polyclonal antibodies were used: anti-D1C 1371, antiLD2 [38], anti-CP47, and anti-CP43 [I 81, anti-cytochrome 6-559 a-subunit 1391, whose properties have been reported previously. An antibody to thc rx-subunit of cytochromc h-559 from Synechocystis was raised in rabbit as follows: the appropriate green band from the Deriphat gel was electroeluted and polypeptides were resolved by preparative SDS/uredPAGE.…”

Section: Cellsmentioning

confidence: 99%

Pigment‐Protein Complexes from the Photosynthetic Membrane of the Cyanobacterium Synechocystis sp. PCC 6803

Barbato

Laureto²,

Rigoni

et al. 1995

European Journal of Biochemistry

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Photosystem I and I1 core complexes were resolved in a single step from the thylakoid menibrane of Synechot.y.rti.v sp. PCC 6803 by using a mild solubilization procedure in dodecyl /~-t)-maltoside arid Deriphat/PAGE. For each photosystem, two green bands were obtained containing oligomcric and monomeric forms of the core complexes of either photosystem. The oligoniers are likcly to be trimei-s i n the case of photosystem T and dinicrs for photosystem 11, The absorption spectra, polypeptide and pigment composition of green bands corresponding to cither photosystem I or photosyslem TI wci-e identical for monomeric and oligomeric forms. Thc cytochromc b-559 content of photosystem I1 was evalualed to bc one cytochrome h-S59/reaction centre both in the monomeric and diineric forms. Two new I5-kDa and 22-kDa carotenoid-binding proteins were isolated and their polypeptides purified to homogeneity.Keywords: photosystem I ; photosystem 11; pigment-protein complexes: cyanobacteria.In planls, green algae, and cyanobacteria light energy is converted into useful chemical energy by the action of two chlorophyll-containing membrane protein complexes which contain the rciiclioii centres of photosystems (PS) I and 11.PS 1 consists of a hctcrodimeric polypeptide complex, formed by the psuA and psuB gene products, to which P700 is bound together with 90-120 chlorophyll a molecules iind the primary and secondary electron acceptors, to form the chlorophyll protein complex known as CP 1 111. Isolation of PS I coniplexes from different organisms indicates the prcsence of several lower-molecular-mass polypeptides, besides CP I. These include the PsaD and PsaE proteins, which generate the docking site for ferredoxin 12, 31, PsaL, PsaF and P s d , the function of which is unclear [4, 51, and PsaC which contains the two iron-sulfur tcrminal acceptors FA and F,l.A minimal PS I1 unit thut is able to carry out charge separution has been isolated from several organisms including higher plants [h, 71, cyanobacteria [8, 91, and green algae [lo], and is composed of the D1 and D2 proteins, the CI-and /]-subunit of cytochromc b-559, and the product of the pshl gene. This complex contains all the redox-active cofactors involved in primary photochemistry, and it exists i n the thylakoid membrane closely associated with two chlorophyll-a-binding proteins named CP 47 and CP 43, to form a PS 11 particle often referred to as thc core complex. Other polypeptides are usually associated with this core complex, such as the 33-kDa extrinsic protein and the products of thc psbL, psbH, and psbK genes. However, none of these proteins sccms to bc strictly required for oxygen evolution. This particle is therefore the minimal structural entity able to perforrn oxygen evolution [ l 1 I and is found in all oxygenic organisms, irrespective of whether they are prokaryotic or euknryotic. Evidence gained from biophysical and biocliernical invcstigations indicated that both PS I and PS I1 may exist in the thylakoid rnembranc with different levels of oligomerization. Elec...

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“…1987;Towbin et al, 1979) and immunolabelled with D2-, C-terminal D1-, and Lhcb1-6-specific antibodies. The D2-specific antibody was a gift from Dr Barbato and was raised according to Barbato et al (1992). The C-terminal D1 (Dupont 304) antibody was a gift from Dr Nixon.…”

Section: Isolation Of Oxygen-evolving Psii Cores (Octglc Cores)mentioning

confidence: 99%

Isolation and Biochemical Characterization of Monomeric and Dimeric Photosystem II Complexes from Spinach and Their Relevance to the Organisation of Photosystem II In vivo

Hankamer

Nield

Zheleva

et al. 1997

European Journal of Biochemistry

196

188

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Membranes enriched in photosystem TI were isolated from spinach and further solubilised using n-octyl 8-D-glucopyranoside (OctGlc) and n-dodecyl P-D-maltoside (DodClc,). The OctGlc preparation had high rates of oxygen evolution and when subjected to size-exclusion HPLC and sucrose density gradient centrifugation, in the presence of DodGlc,, separated into dimeric (430 kDa), monomeric (236 kDa) photosystem I1 cores and a fraction containing photosystem I1 light-harvesting complex (Lhcb) proteins. The dimeric core fraction was more stable, contained higher levels of chlorophyll, 8-carotene and plastoquinone per photosystem I1 reaction centre and had a higher oxygen-evolving activity than the monomeric cores. Their subunit composition was similar (CP43, CP47, DI, D2, cytochrome b 559 and several lower-molecular-mass components) except that the level of 33-kDa extrinsic protein was lower in the monomeric fraction. Direct solubilisation of photosystem-11-enriched membranes with DodGlc,, followed by sucrose density gradient centrifugation, yielded a super complex (700 kDa) containing the dimeric form of the photosystem I1 core and Lhcb proteins: Lhcbl, Lhcb2, Lhcb4 (CP29), and LhcbS (CP26). Like the dimeric and monomeric photosystem I1 core complexes, the photosystem 11-LHCII complex had lost the 23-kDa and 17-kDa extrinsic proteins, but maintained the 33-kDa protein and the ability to evolve oxygen. It is suggested. with a proposed model, that the isolated photosystem 11-LHCII super complex represents an in vivn organisation that can sometimes form a lattice in granal membranes K K~V O K~S :dimer; photosynthesis; photosystem 11; spinach; structure.Photosystem I1 (PSII) is a pigment-protein complex embedded in the thylakoid membrane of higher plants, algae, and cyanobacteria. By utilizing sunlight, it catalyses the splitting of water into protons, electrons, and molecular oxygen. This is the most strongly oxidizing reaction known to occur in biology. The primary photochemical process driving this highly oxidizing reaction takes place in the reaction centre of PSII which, when isolated, consists of the D1 and D2 subunits, cytochrome b 559 (cyt b 559), and the psbl gene product (Nanba and Satoh, 1987;Barber et al., 1987). The reaction centre proteins are closely associated with two other chlorophyll-a-binding proteins (CP47 and CP43). as well as the oxygen-evolving complex (OEC) composed of a four-atom cluster of manganese and the 33-kDa PsbO extrinsic protein (Ikeuchi et al., 1985). Unlike cyanobacteria, higher plants and algae have two additional extrinsic proteins associated with the OEC which have apparent molecular masses of 23 kDa and 17 kDa (PsbP and PsbQ proteins, respectively) (Murata and Miyao, 1985). Higher plants and green algae also have chlorophyll-ah-binding antenna systems that transfer excitation energy to the PSII reaction centre rather than phycobilisomes, which function in the same way in red algae and cyanobacteria (Jansson, 1994). The chlorophyll-nlh-binding antenna consists of LHCII (Lhcbl, b2, a...

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Light‐induced degradation of D2 protein in isolated photosystem II reaction center complex

Cited by 35 publications

References 26 publications

Determination of Photosystem II Subunits by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

Determination of Photosystem II Subunits by Matrix-assisted Laser Desorption/Ionization Mass Spectrometry

Pigment‐Protein Complexes from the Photosynthetic Membrane of the Cyanobacterium Synechocystis sp. PCC 6803

Isolation and Biochemical Characterization of Monomeric and Dimeric Photosystem II Complexes from Spinach and Their Relevance to the Organisation of Photosystem II In vivo

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