Photosynthetic reaction center photosystem

Michel, H., Deisenhofer, J. Relevance of the photosynthetic reaction center from purple bacteria to the structure of photosystem II. BicKhemistry 27 1-7, 1988. 

PHOTOSYNTHETIC REACTION CENTER PHOTOSYNTHETIC WATER OXIDATION PHOTOSYSTEM I pH profile for inactivation,... 

The observation of a photosynthetic reaction center in green sulfur bacteria dates back to 1963.39 Green sulfur bacteria RCs are of the type I or the Fe-S-type (photosystem I). Here the electron acceptor is not the quinine instead, chlorophyll molecules (BChl 663, 81 -OII-Chi a, or Chi a) serve as primary electron acceptors, and three Fe4S4 centers (ferredoxins) serve as secondary acceptors. A quinone molecule may or may not serve as an intermediate carrier between the primary electron acceptor (Chi) and the secondary acceptor (Fe-S centers).40 The process sequence leading to the energy conversion in RCI is shown in Figure 21. 

The capture of solar energy occurs in photosystems. Each photosystem consists of an antenna complex and a photosynthetic reaction center. The... 

Michel, H. and Deisenhofer J. 1986. X-ray diffraction studies on a crystalline bacterial photosynthetic reaction center a progress report and conclusions on the structure of photosystem II reaction centers. In Encyclopedia of Plant Physiol., new series) (Eds. L.A.Staehelin and Amtzen) (Springer, Berlin). Vol. 19, 371-381. 

Hou, J.-M., Boichenko, V.A., Diner, B.A., Mauzerall, D. (2001) Thermodynamics of electron transfer in oxygenic photosynthetic reaction centers Volume change, enthalpy, and entropy of electron transfer reactions in manganese-depleted photosystem II core complexes, Biochemistry 40(24), 7117-7125. 

Rigby, S.E.J., Evans, M.C.W., and Heathcote, P. (2000) Electron nuclear double resonance (ENDOR) spectroscopy of radicals in photosystem I and related type 1 photosynthetic reaction centers, Biochim. Biophys. Acta 1507 247-259. 

In green plants and certain algae, the photosynthetic machinery is elaborated over those found in purple bacteria and is now able to reach the high potentials needed to oxidize water to dioxygen. This oxygenic photosystem is comprised of two photosynthetic reaction centers (sensitizer assemblies), photosystem I (PS I) and... 

Antenna photosynthetic pigment complex that absorbs energy and transfers it to a reaction center Photosystem I reaction center from oxygen-evolving photosynthetic organisms that oxidizes plastocyanin and reduces NADP+... 

Bacterial photosynthetic reaction centers (PRC) have been among the most actively studied ET proteins since DeVault and Chance first measured C. vinosum tunneling rates in the early 1960s. In many cases, measurements of ET kinetics preceded determination of the three-dimensional structure of the membrane-bound protein assembly. It was not until the X-ray crystal-stracture determinations of the Rhodopseudomonas (Rps.) viridus and Rhodobacter (Rb.) sphaeroides PRCs that distances could be assigned to specific rate constants. The recent crystal structures of photosystems l and from cyanobacteria promise to clarify critical aspects of the ET mechanisms in oxygenic PRC. ... 

Figure 1. The major transmembrane photosynthetic reaction centers (RC) (top) and respiratory complexes (bottom) are composed of light (zigzag) activated chains (dark gray) of redox centers (open polygons) that create a transmembrane electric field and move protons (double arrows) to create a transmembrane proton gradient, fulfilling the requirements of Mitchell s chemiosmotic hypothesis. Diffusing substrates include ubiquinone (hexagon) and other sources of oxidants and reductants. PSI and PSII, photosystems I and II, respectively.

J Xiong, S Subramaniam and Govindjee (1996) Modeling of the D1/D2 proteins and cofactors ofthe photosystem II reaction center. Implications for herbicide and bicarbonate binding. Protein Sci 5 2054-2073 FI Michel and J Deisenhofer (1988) Relevance ofthe photosynthetic reaction centers from purple bacteria to the structure of photosystem II. Biochemistry 27 1-7... 

Light reactions taking place in photosynthetic reaction center depend on a supply of light energy harvested by a number of antenna chlorophyll-protein complexes. The arrangement of these complexes in photosystem II is similar to that in the photosynthetic purple bacteria discussed earlier in Chapter 3. Basically, there is a core antenna complex closely associated with the reaction center, plus some slightly more distant, peripheral antenna complexes. 

In DR Ort and CF Yocum (eds) Oxygenic Photosynthesis. The Light Reactions, pp 213-247. Kluwer R2. M Seibert (1993) Biochemical, biophysical, and structural characterization of the isolated photosystem II reaction center complex. In J Deisenhofer and JR Norris (eds) The photosynthetic Reaction Center, vol 1 319-356 R3. WW Parson and B Ke (1982) Primary photochemical reactions. In Govindjee (ed) Photosynthesis Energy Conversion by Plants and Bacteria, Vol 1, pp 331-385. Acad Press R4. VV Klimov and AA Krasnovsky (1981) Pheophytin as the primary electron acceptor in photosystem 2 reaction centres. Photosynthetica 15 592-609... 

JE Mullet, JJ Burke and CJ Arntzen (1980) Chlorophyll proteins of photosystem I. Plant Physiol 65 814-822 E Lam, W Ortiz, S Mayfield and R Malkin (1984) Isolation and characterization of a light-harvesting chlorophyll a/b protein complex associated with photosystem I. Plant Physiol 74 650-655 E Lam, W Ortiz and R Malkin (1984) Chlorophyll alb proteins of photosystem I. FEBS Lett 168 10-14 H Michel (1982) 3-dimensional crystals of a membrane protein complex. The photosynthetic reaction center from Rhodopseudomonas viridis. J Mol Biol 158 567-572... 

Fig. 2. (A) K-band ESP-EPR spectra of the CPI complex (top) and Rb sphaeroides R26 reaction-center complex (bottom) in the charge-separated states [P700 -A,4 and [P870 Q4, respectively (B) X-band ESP-EPR spectra of spinach PS-I particles extracted with a hexane-MeOH mixture (a), reconstituted with protonated (b) and deuterated (c) vitamin Ki (C) ESP-EPR spectra of spinach PS-I particle in glycine buffer at pH 10.8 and untreated (a), reduced with 50 mM dithionite and 0,5 mM methyl viologen and dark-incubated (b), and the reduced sample dialyzed overnight against glycine buffer and reconcentrated (c). Figure source (A) Petersen, Stehlik, Gast and Thurnauer (1987) Comparison of the electron spin polarized spectrum found in plant photosystem I and in iron-depleted bacterial reaction centers with time-resolved K-band EPR evidence that the photosystem I acceptor is a quinone. Photosynthesis Res 14 22 (B) and (C) Snyder and Thurnauer (1993) Electron spin polarization in photosynthetic reaction centers. In J Deisenhofer and JR Norris (eds) The Photosynthetic Reaction Center, Vol 11 313,315.

Fig. 15. Plot ofthe extent of absorbance change due to P7007P430" recombination measured at 695 nm vs. the redox potential of 14 quinones and 7 non-quinone carbonyl compounds, the fluorenones (individual compounds are identified below the plot). The solid curve is the theoretical, one-electron Nernst curve centered near the redox potential of FeS-X in vivo. Data adapted from Itoh and Iwaki (1992) Exchange ofthe acceptor phylloquinone by artificial quinones and fluorenones in green plant photosystem I photosynthetic reaction center. In N Malaga, T Okada and H Masuhara (eds) Dynamics and Mechanism of Photoinduced Transfer and Related Phenomena. p.533. Elsevier,...

S Itoh and M Iwaki (1991) Full replacement of the function of the secondary electron acceptor phylloquinone (=vitamin KO by non-quinone carbonyl compounds in green plant photosystem I photosynthetic reaction centers. Biochemistry 30 5340-5346... 

The three-dimensional structures of the photosynthetic reaction centers from two purple bacteria have been determined, permitting scientists to trace the detailed paths of electrons during and after the absorption of light. Similar proteins and pigments compose photosystem II of plants as well, and the conclusions drawn from studies on this simple photosystem have proven applicable to plant systems. 

Although cyanobacteria also use two photosystems, most photosynthetic bacteria have only a single photosynthetic reaction center... 

Michel, H. Deisenhofer, J. "Relevance of the Photosynthetic Reaction Center from Purple Bacteria to the Structure of Photosystem E, Biochemistry 1988,27,... 

Michel H and Deisenhofer J (1988) Relevance of the photosynthetic reaction center from purple bacteria to the structure of Photosystem II. Biochemistry 27 1-7 Michel H, Weyer KA, Gruenberg K, Dunger I, Oesterhelt D and Lottspeich F (1986a) The Tight and medium subunits of the photosynthetic reaction centre from Rhodopseudomonas viridis Isolation of the genes, nucleotide and amino acid sequence. EMBOJ5 1149-1158... 

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