Disease relevance of Thylakoids

• The P. hollandica psbA genes, which encode the photosystem II thylakoid protein D1, were cloned and sequenced and the sequences compared to those reported for cyanobacteria, a green alga, a liverwort, and several higher plants [1].
• There was a considerable difference in the slopes of O2 photoreduction (the Mehler reaction) in the cyanobacterium Synechocystis sp. strain PCC 6803 (0.497 +/- 0.004) and that of pea (Pisum sativum) thylakoids (0.526 +/- 0.001) [2].
• Lactobacillus helveticus is a homofermentative thermophilic lactic acid bacterium that is used in the manufacture of Swiss type and long-ripened Italian cheeses, such as Emmental, Grana, and Provolone cheeses [3].
• The predicted 29 amino acid transit peptide shows substantial homology to the Anabaena 7937 transit peptide, thought to direct the plastocyanin precursor to the thylakoid lumen [4].
• The periplasmic destination of MBH, Nap, and NosZ was restored by heterologous expression of Azotobacter chroococcum tatA mobilized into TF93. tatA encodes a bacterial Hcf106-like protein, a component of a novel protein transport system that has been characterized in thylakoids and shown to translocate folded proteins across the membrane [5].

High impact information on Thylakoids

• PGR5 encodes a novel thylakoid membrane protein that is involved in the transfer of electrons from ferredoxin to plastoquinone [6].
• Import and localization experiments with a reconstituted chloroplast system show that the ferredoxin transit peptide directs mature plastocyanin away from its correct location, the thylakoid lumen, to the stroma [7].
• Atc6 is a functional cytochrome c localized in the thylakoid lumen [8].
• When PSII is favoured (state 2), the redox conditions in the thylakoids change and result in activation of a protein kinase [9].
• A psbA gene encoding the target of photosystem II herbicide inhibition, the 32,000-dalton thylakoid membrane protein, has been cloned from a mutant of Anacystis nidulans R2, which is resistant to 3-(3,4-dichlorophenyl)-1,1-dimethylurea-(diuron) [10].

Chemical compound and disease context of Thylakoids

• Myxoxanthophyll is required for normal cell wall structure and thylakoid organization in the cyanobacterium Synechocystis sp. strain PCC 6803 [11].
• We have used recombinant CP29 protein, over-expressed in Escherichia coli and refolded in vitro with purified pigments, to obtain a protein indistinguishable from the native complex extracted from thylakoids, binding either violaxanthin or zeaxanthin together with lutein [12].
• Photosystem I and II core complexes were resolved in a single step from the thylakoid membrane of Synechocystis sp. PCC 6803 by using a mild solubilization procedure in dodecyl beta-D-maltoside and Deriphat/PAGE [13].
• Integration of a cyanobacterial protein involved in nitrate reduction (narB) into isolated Synechococcus but not into pea thylakoid membranes [14].
• Spinacine (4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid), the major reaction product of formaldehyde added to Grana Padano cheese, was administered to five groups of ten rats of each set at dietary concentrations that provided doses of O (control), 15, 30, 60 or 300 mg/kg body weight/day for 13 wk [15].

Biological context of Thylakoids

• The primary light-induced cleavage product of the D1 protein, a 23-kD fragment, was found to be degraded in isolated thylakoids in the dark during a process dependent on ATP hydrolysis and divalent metal ions, suggesting the involvement of FtsH [16].
• These results demonstrate that one of several pathways for protein routing to the thylakoids is homologous to the SRP pathway and point to a common evolutionary origin for the protein transport systems of the endoplasmic reticulum and the thylakoid membrane [17].
• The thylakoid membrane cytochrome b6-f complex (plastoquinol:oxidized-plastocyanin oxidoreductase, EC 1.10.99.1) catalyzes electron-transfer and proton-translocation reactions essential for oxygenic photosynthesis [18].
• These compounds have similar effects in chloroplast import assays: precursors of both the 33- and 23-kDa proteins are imported and processed to intermediate forms in the stroma, but transport into the thylakoid lumen is blocked when electron transport is inhibited or nigericin is present [19].
• An immunological approach using a polyclonal phosphothreonine antibody is introduced for the analysis of thylakoid protein phosphorylation in vivo [20].

Anatomical context of Thylakoids

• A purified fraction of unstacked thylakoid membranes (TMF1u) has been obtained from homogenates of Chlamydomonas reinhardtii (wild type 137+) by using repeated centrifugates in sucrose density gradients and low salt treatment [21].
• On the contrary, phosphatidylglycerol, the major polar lipid in the inner envelope membrane and the thylakoids, is probably not accessible to phospholipase C from the cytosol and therefore is probably localized mostly in the inner leaflet of the outer envelope membrane and in the other chloroplast membranes [22].
• Immunoblot analysis detected no thylakoid membrane proteins such as D1, light-harvesting complex, and OE23 in apg2 plastids, whereas soluble proteins such as rubisco large and small subunits were not decreased [23].
• Further evidence for a co-translational assembly of the D1 protein into photosystem II was obtained by analyzing ribosome nascent chain complexes liberated from the thylakoid membrane after a short pulse labeling [24].
• YidC is homologous to Alb3 and Oxa1 that function in the integration of proteins into the thylakoid membrane of chloroplasts and inner membrane of mitochondria, respectively [25].

Associations of Thylakoids with chemical compounds

• This conclusion was supported by immunological detection of free subunits after freshly isolated pea thylakoids were fractionated with low levels of Triton X-100 [26].
• When bicarbonate is added to mutant thylakoids or PSII particles, the O2 evolution rates exceed those of the wild type by up to 50% [27].
• The localization of the chlorophyll-protein complexes inside the thylakoid membrane of Acetabularia mediterranea was determined by fractionating the chloroplast membrane with EDTA and Triton X-100, by using pronase treatment, and by labeling the surface-exposed proteins with 125I [28].
• The thylakoid products of chloroplast translation were visualized by subjecting membranes purified from chloroplasts labeled with [35S]methionine to electrophoresis in high-resolution, SDS-containing acrylamide gradient slab gels and autoradiography [29].
• These thylakoid preparations were then fixed in glutaraldehyde followed by osmium tetroxide, embedded in Spurr, and sections were labeled with anti-PE 545 followed by protein A-large gold [30].

Gene context of Thylakoids

• Functional interaction of chloroplast SRP/FtsY with the ALB3 translocase in thylakoids: substrate not required [31].
• Immunoblot analysis of fractionated chloroplasts showed that the HCF136 protein is a lumenal protein, found only in stromal thylakoid lamellae [32].
• Our study points to a key role for the cytosol in protecting the chloroplast during light stress and provides evidence for cross-compartment protection of thylakoid and stromal/mitochondrial APXs by cytosolic APX1 [33].
• This finding suggests that VAR1 and VAR2 play a predominant role in the photosystem II repair cycle in thylakoid membranes [34].
• We propose that PAA1 and PAA2 function sequentially in copper transport over the envelope and thylakoid membrane, respectively [35].

Analytical, diagnostic and therapeutic context of Thylakoids

• The AtFKBP13 protein is synthesized as a precursor that is imported into chloroplasts and processed to the mature form located in the thylakoid lumen, as shown by chloroplast import assays and Western blot analysis [36].
• The purification procedure involved selective solubilization of the thylakoid membrane with dodecyl maltoside, followed by two anion-exchange chromatography steps and one size-exclusion chromatography step [37].
• The increased protease sensitivity of the gamma subunit of soluble CF1 after treatment with dithiothreitol or heat mimics the increased protease sensitivity of the gamma subunit of bound CF1 when thylakoids are treated with trypsin during illumination (Moroney, J. V., and McCarty, R. E. (1982) J. Biol. Chem. 257, 5915-5920) [38].
• When pea (Pisum sativum L., cv. Spring) chloroplasts are lysed in a buffer lacking Mg2+ and the thylakoids removed by centrifugation, the remaining mixture of light membranes and soluble proteins (LM/S) has high Mg(2+)-chelatase activity [39].
• Using parallel time-resolved and pulse-amplitude modulation fluorometry, we studied the influence of the intrathylakoid pH and the xanthophyll cycle carotenoids on the PSII chlorophyll (Chl) a fluorescence yield in thylakoids of Arabidopsis, spinach, and barley [40].

References