Chlorophyll-protein complexes

Kolubayev T, Geacintov N E, Paillotin G and Breton J 1985 Domain sizes in chloroplasts and chlorophyll-protein complexes probed by fluorescence yield quenching induced by singlet-triplet exciton annihilation Biochimica Biophys. Acta 808 66-76... 

A method of detecting herbicides is proposed the photosynthetic herbicides act by binding to Photosystem II (PS II), a multiunit chlorophyll-protein complex which plays a vital role in photosynthesis. The inhibition of PS II causes a reduced photoinduced production of hydrogen peroxide, which can be measured by a chemiluminescence reaction with luminol and the enzyme horseradish peroxidase (HRP). The sensing device proposed combines the production and detection of hydrogen peroxide in a single flow assay by combining all the individual steps in a compact, portable device that utilises micro-fluidic components. 

Detergent treatment of a suspension of thylakoids dissolves the membranes, releasing complexes containing both chlorophyll and protein. These chlorophyll-protein complexes represent integral components of the thylakoid membrane, and their organization reflects their roles as either light-harvesting com-... 

Mullineaux, C.W., Pascal, A.A., Horton, P. and Holzwarth, A.R. 1992. Excitation energy quenching in aggregates of the LHCII chlorophyll-protein complex A time-resolved fluorescence study. Biochim. Biophys. Acta 1141 23-28. 

Grenier, G., L. Protean, J.P. Marier, and G. Beaumont. 1987. Effects of a sublethal concentration of atrazine on the chlorophyll and lipid composition of chlorophyll-protein complexes of Lemna minor. Plant Physiol. Biochem. 25 409-413. 

Horton, R, Ruban, A. V., Rees, D., Rascal, A. A., Noctor, G., and Young, A. J. 1991. Control of the light-harvesting function of chloroplast membranes by aggregation of the LHCII chlorophyll protein complex. Eebs Lett. 292 1-4. 

Through the use of freeze-fracture and freezeetching techniques of electron microscopy, it is possible to see, embeddded in the thylakoid membranes, particles which may represent individual photosyn-thetic units (also called quantosomes).227 256-258 They are about 20 nm in diameter, and at least many of them presumably contain a reaction center surrounded by light-collecting chlorophyll-protein complexes. Others may represent the cytochrome b6f complex and... 

J.P. Thomber, J.C. Stewart, M.W.C. Hatton and J.L. Bailey, Studies on the nature of chloroplast lamellae, II, Chemical composition and further physical properties of two chlorophyll-protein complexes, Biochemistry 6 (1967) 2006-2014. 

Andersson, B. and Anderson J.M. 1980. Lateral heterogeneity in the distribution of chlorophyll-protein complexes of the thylakoid membranes of spinach chloroplasts. Biochim. Biophys. Acta 593.427-440. 

Bassi, R. and Simpson D.J. 1987c. Chlorophyll-protein complexes of barley photosystem I. Eur. J. Biochem. 163. 221-230. 

Ish-Shalom, D. and Ohad, I. 1983. Organization of chlorophyll-protein complexes of photosystem I in Chlamydomonas reinhardii. Biochim. Biophys. Acta 722,498-507. 

A relatively simple and quick procedure for the isolation of Photosystem I-enriched particles from the thermophilic cyanobacterium Phormidium laminosum, without the use of detergents for solubilization, is described. The procedure involves sonication of cells, centrifugation and DEAE-cellulose chromatography. The particles had an 02 uptake activity of up to 200 pmol 02. mg chlorophyll h 1 and appeared as vesicles of 200 100 nm diameter when observed under electron microscopy. The analysis of the chlorophyll-protein complexes by polyacrylamide gel electrophoresis showed that these particles are enriched in the complexes associated with Photosystem I and partially depleted in those associated with Photosystem II. The particles did not contain ferredoxin and were active in NADP-photoreduction only in the presence of added ferredox in. They were also able to photoreduce externally added electron mediators using ascorbate as electron donor, the reduced mediators can be coupled to hydrogenase for the production of H2 or for the activation of cyanobacterial phosphoribulokinase using a ferredoxin/thioredoxin system. 

Oquist, G., Fork, D.C., Schoch, S. and Malmberg, G. 1981. Solubilization and spectral characteristics of chlorophyll-protein complexes isolated from the thermophilic blue-green alga Synechococcus lividus. Biochim Biophys. Acta, 638.192-200. 

Reinman, S. and Thomber, J.P. 1979. The electrophoretic isolation and partial characterization of three chlorophyll-protein complexes from blue-green algae. Biochim. Biophys. Acta, 547,188-197. 

Stewart, A.C. 1980. The chlorophyll-protein complexes of a thermophilic blue-green alga. FEBS Lett., 114, 67-72. 

Thomber, J.P. 1969. Comparison of a chlorophyll a-protein complex isolated from a blue-green alga with chlorophyll-protein complexes obtained from green bacteria and higher plants. Biochim. Biophys. Acta, 172. 230-241. 

The values of A,max for Chi a in vivo result from interactions between a chlorophyll molecule and the surrounding molecules, such as the proteins and the lipids in the chloroplast lamellar membranes (Fig. 1-10) as well as adjacent water molecules. Indeed, all Chi a molecules are associated with proteins in chlorophyll-protein complexes. Hydrophobic interactions among... 

Carotenoids involved in photosynthesis are bound to and help stabilize chlorophyll-protein complexes, of which various types occur in the lamellar membranes of chloroplasts (Fig. 1-10). Carotenoids also are found in organelles known as chromoplasts, which are about the size of chloroplasts and are often derived from them. For instance, lycopene (red) is in tomato fruit chromoplasts, and a- and pi-carotenes (orange) occur in carrot root chromoplasts. A great diversity of carotenoids occurs in the chromoplasts of flower petals, which is important for attracting pollinators, and fruits, which aids in seed dispersal by attracting other animals. 

The chlorophyll-protein complexes are oriented in the lamellar membranes in such a way that the electron transfer steps at the reaction centers lead to an outward movement of electrons. For instance, the electron donated by Photosystem II moves from the lumen side to the stromal side of a thylakoid (see Figs. 1-10 and 5-19). The electron that is donated back to the trap chi (Pgg0) comes from H20, leading to the evolution of 02 by Photosystem II (Eq. 5.8). The 02 and the H+ from this reaction are released inside the thylakoid (Fig. 5-19). Because 02 is a small neutral molecule, it readily diffuses out across the lamellar membranes into the chloroplast stroma. However, the proton (H+) carries a charge and hence has a low partition coefficient (Chapter 1, Section 1.4A) for the membrane, so it does not readily move out of the thylakoid lumen. 

LeongTA and Anderson JM. (1984). Adaptation of the thy lakoid membranes of pea chlorop lasts to light intensities. I. Study on the distribution of chlorophyll-protein complexes. Photosynth. Research5, 105-115. 

Simeonova, E., van Hasselt, P.R., Dobrucki, J. and Mostowska, A. (2005) Light-dependent reversal of dark-chilling induced changes in chloroplast structure and arrangement of chlorophyll-protein complexes in bean thylakoid membranes. Biochim. Biophys. Acta, 1710, 13-23. 

LHC lb / LHC 1-730 (M) 22 Lhca1(N) LIgM-harvesting chlorophyll-protein complex LHC II bihde ... 

As shown in both Fig. 21 (A) and (B), there are five major protein complexes in the thylakoid-mem-brane network (1) the photosystem-11 core with bound inner antennae (collectively designated as PS II ), (2) the photosystem-I core with bound anteimae LHC I (collectively designated as PS I ), (3) the cytochrome (jg/complex, (4) theCFo CF, ATP-synthase and, finally (5) a separate, peripheral lightharvesting, chlorophyll-protein complex called LHC 11 that supplements the inner antennae bound to the photosystem-II reaction center. ... 

DETronrud, MF Schmid and BW Mathews (1986) Structure and x-ray amino acid sequence of a bacteriochlo-rophyll a protein from Prosthecochloris aestuarii refined at 1.9 resolution. J Mol Biol 188 443-454 T Katoh, M MImuro and S Takalchl (1989) Light-harvesting particles Isolated from a brown alga, DIctyota dichotoma. A supramolecular assembly of fucoxanthin-chlorophyll-protein complexes. Biochim Biophys Acta 976 233-240... 

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