scholarly journals Proteomic Insights into Phycobilisome Degradation, A Selective and Tightly Controlled Process in The Fast-Growing Cyanobacterium Synechococcus elongatus UTEX 2973

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 374 ◽  
Author(s):  
Aparna Nagarajan ◽  
Mowei Zhou ◽  
Amelia Y. Nguyen ◽  
Michelle Liberton ◽  
Komal Kedia ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Photosystem Ii ◽  
Doubling Time ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Synechococcus Elongatus ◽  
Nutrient Depletion ◽  
Reversible Process ◽  
Fast Growing ◽  
Pigment Protein Complexes

Phycobilisomes (PBSs) are large (3–5 megadalton) pigment-protein complexes in cyanobacteria that associate with thylakoid membranes and harvest light primarily for photosystem II. PBSs consist of highly ordered assemblies of pigmented phycobiliproteins (PBPs) and linker proteins that can account for up to half of the soluble protein in cells. Cyanobacteria adjust to changing environmental conditions by modulating PBS size and number. In response to nutrient depletion such as nitrogen (N) deprivation, PBSs are degraded in an extensive, tightly controlled, and reversible process. In Synechococcus elongatus UTEX 2973, a fast-growing cyanobacterium with a doubling time of two hours, the process of PBS degradation is very rapid, with 80% of PBSs per cell degraded in six hours under optimal light and CO2 conditions. Proteomic analysis during PBS degradation and re-synthesis revealed multiple proteoforms of PBPs with partially degraded phycocyanobilin (PCB) pigments. NblA, a small proteolysis adaptor essential for PBS degradation, was characterized and validated with targeted mass spectrometry. NblA levels rose from essentially 0 to 25,000 copies per cell within 30 min of N depletion, and correlated with the rate of decrease in phycocyanin (PC). Implications of this correlation on the overall mechanism of PBS degradation during N deprivation are discussed.

Thylakoid membrane development in pigment-deficient wheat chloroplasts

1991 ◽  
Vol 49 ◽  
pp. 214-215
Author(s):  
Thomas Freeman ◽  
Murray Duysen ◽  
Ken Eskins ◽  
James Guikema
Keyword(s):  
Photosystem Ii ◽  
Protein Complexes ◽  
Continuous Light ◽  
Thylakoid Membranes ◽  
Higher Plant ◽  
Wheat Seedlings ◽  
Etiolated Seedlings ◽  
Pigment Protein Complexes ◽  
Thylakoid Stacking ◽  
Membrane Development

The thylakoid membranes of higher plant chloroplasts contain at least two major pigment protein complexes, photosystem I (PSI), and photosystem II (PSII). The mature apoprotein of these complexes (involved in the initial reactions of photosynthesis) bind specific chlorophylls (Chl) and specific carotenoids in an unknown manner. It has been suggested, however, that the synthesis of pigments is normally coordinated with that of apoproteins. We have examined the effect of gabaculine (3-amino-2, 3-dihydrobenzoic acid) on granal thylakoid stacking as well as pigment and apoprotein accumulations for PSI and PSII in wheat.Gabaculine (0.5mM) was applied with nutrient solution to 6.5 day-old wheat seedlings maintained in a growth chamber at 23C. One seedling lot grown under continuous light (400 μmol photons s-1 m-2) possessed green primary leaves at time of treatment whereas another seedling lot, dark grown, possessed only etiolated primary leaves. Twelve hours after treatment, the etiolated seedlings were transferred into continuous light. The primary and secondary leaves were subsequently harvested from 14 day-old seedlings of both lots.

scholarly journals Mass spectrometry-based cross-linking study shows that the Psb28 protein binds to cytochrome b559 in Photosystem II

2017 ◽  
Vol 114 (9) ◽  
pp. 2224-2229 ◽  
Author(s):  
Daniel A. Weisz ◽  
Haijun Liu ◽  
Hao Zhang ◽  
Sundarapandian Thangapandian ◽  
Emad Tajkhorshid ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Photosystem Ii ◽  
Protein Interactions ◽  
Protein Complexes ◽  
Protein Docking ◽  
Cross Linking ◽  
Protein Protein Interactions ◽  
Cytochrome B559 ◽  
Reaction Center Complex ◽  
Assembly Intermediate

Photosystem II (PSII), a large pigment protein complex, undergoes rapid turnover under natural conditions. During assembly of PSII, oxidative damage to vulnerable assembly intermediate complexes must be prevented. Psb28, the only cytoplasmic extrinsic protein in PSII, protects the RC47 assembly intermediate of PSII and assists its efficient conversion into functional PSII. Its role is particularly important under stress conditions when PSII damage occurs frequently. Psb28 is not found, however, in any PSII crystal structure, and its structural location has remained unknown. In this study, we used chemical cross-linking combined with mass spectrometry to capture the transient interaction of Psb28 with PSII. We detected three cross-links between Psb28 and the α- and β-subunits of cytochrome b559, an essential component of the PSII reaction-center complex. These distance restraints enable us to position Psb28 on the cytosolic surface of PSII directly above cytochrome b559, in close proximity to the QB site. Protein–protein docking results also support Psb28 binding in this region. Determination of the Psb28 binding site and other biochemical evidence allow us to propose a mechanism by which Psb28 exerts its protective effect on the RC47 intermediate. This study also shows that isotope-encoded cross-linking with the “mass tags” selection criteria allows confident identification of more cross-linked peptides in PSII than has been previously reported. This approach thus holds promise to identify other transient protein–protein interactions in membrane protein complexes.

scholarly journals Structural and functional analyses of photosystem II in the marine diatom Phaeodactylum tricornutum

2019 ◽  
Vol 116 (35) ◽  
pp. 17316-17322 ◽  
Author(s):  
Orly Levitan ◽  
Muyuan Chen ◽  
Xuyuan Kuang ◽  
Kuan Yu Cheong ◽  
Jennifer Jiang ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Spatial Organization ◽  
Higher Plants ◽  
Electron Tomography ◽  
Protein Complexes ◽  
Spatial Differentiation ◽  
Thylakoid Membranes ◽  
Marine Diatom ◽  
Red Algal ◽  
Antenna Proteins

A descendant of the red algal lineage, diatoms are unicellular eukaryotic algae characterized by thylakoid membranes that lack the spatial differentiation of stroma and grana stacks found in green algae and higher plants. While the photophysiology of diatoms has been studied extensively, very little is known about the spatial organization of the multimeric photosynthetic protein complexes within their thylakoid membranes. Here, using cryo-electron tomography, proteomics, and biophysical analyses, we elucidate the macromolecular composition, architecture, and spatial distribution of photosystem II complexes in diatom thylakoid membranes. Structural analyses reveal 2 distinct photosystem II populations: loose clusters of complexes associated with antenna proteins and compact 2D crystalline arrays of dimeric cores. Biophysical measurements reveal only 1 photosystem II functional absorption cross section, suggesting that only the former population is photosynthetically active. The tomographic data indicate that the arrays of photosystem II cores are physically separated from those associated with antenna proteins. We hypothesize that the islands of photosystem cores are repair stations, where photodamaged proteins can be replaced. Our results strongly imply convergent evolution between the red and the green photosynthetic lineages toward spatial segregation of dynamic, functional microdomains of photosystem II supercomplexes.

Strong light-induced reorganization of pigment–protein complexes of thylakoid membranes in rye (spectroscopic study)

2012 ◽  
Vol 169 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Ewa Janik ◽  
Waldemar Maksymiec ◽  
Wojciech Grudziński ◽  
Wiesław I. Gruszecki
Keyword(s):  
Spectroscopic Study ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Strong Light ◽  
Pigment Protein Complexes

scholarly journals Differential Mobility of Pigment-Protein Complexes in Granal and Agranal Thylakoid Membranes of C3 and C4 Plants

2012 ◽  
Vol 161 (1) ◽  
pp. 497-507 ◽  
Author(s):  
Helmut Kirchhoff ◽  
Richard M. Sharpe ◽  
Miroslava Herbstova ◽  
Robert Yarbrough ◽  
Gerald E. Edwards
Keyword(s):  
Protein Complexes ◽  
Thylakoid Membranes ◽  
C4 Plants ◽  
C3 And C4 Plants ◽  
Differential Mobility ◽  
Pigment Protein Complexes

scholarly journals A Novel Chloroplast Super-Complex Consisting of the ATP Synthase and Photosystem I Reaction Center

2019 ◽  
Author(s):  
Satarupa Bhaduri ◽  
Sandeep K Singh ◽  
Whitaker Cohn ◽  
S. Saif Hasan ◽  
Julian P. Whitelegge ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Membrane Protein ◽  
Reaction Center ◽  
Atp Synthase ◽  
Photosystem I ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Native Page ◽  
Membrane Protein Complexes ◽  
Reaction Center Complexes

AbstractSeveral ‘super-complexes’ of individual hetero-oligomeric membrane protein complexes, whose function is to facilitate intra-membrane electron and proton transfer and harvesting of light energy, have been previously characterized in the mitochondrial cristae and chloroplast thylakoid membranes. The latter membrane is reported here to also be the location of an intra-membrane super-complex which is dominated by the ATP-synthase and photosystem I (PSI) reaction-center complexes, defined by mass spectrometry, clear-native PAGE and Western Blot analyses. This is the first documented presence of ATP synthase in a super-complex with the PSI reaction-center located in the non-appressed stromal domain of the thylakoid membrane.

Chlorophyll Photobleaching in Pigment-Protein Complexes

1986 ◽  
Vol 41 (3) ◽  
pp. 284-290 ◽  
Author(s):  
Robert Carpentier ◽  
Roger M. Leblanc ◽  
Guy Bellemare
Keyword(s):  
Energy Transfer ◽  
Hordeum Vulgare ◽  
Chlamydomonas Reinhardtii ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Wild Type ◽  
Protection Mechanism ◽  
Long Wavelength ◽  
Pigment Protein Complexes ◽  
Type Mutant

Pigment photobleaching was performed in thylakoid membranes of Hordeum vulgare (wild type, mutant Chlorina f2, Norfluranzon treated seedlings) and in pigment-protein complexes (CP-I and LHCP) isolated from H. vulgare and Chlamydomonas reinhardtii. Multiphasic kinetics were obtained in all of the above cases. Energy transfer towards pigments absorbing at longer wavelength is postulated as a general protection mechanism against photobleaching. This mechanism explains a substantial bleaching of carotenoids and a faster bleaching of chlorophyll aggregates, absorbing at long wavelength. These conclusions were valid for isolated complexes as well as for thylakoid membranes, although membranes were less sensitive to light.

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