Reaction center structure

T Ichiye. A dawning light The beginnings of an understanding of the photosynthetic reaction center. Structure 4 1009-1012, 1996. 

Glazer, A. N., and Melis, A., 1987. Photochemical reaction centers Structure, organizadon and fnncdon. Annual Review of Plant Physiology 38 11-45. 

J. Breton and A. Vermeglio (eds.), The Photosynthetic Bacterial Reaction Center -Structure and Dynamics , Plenum Press, New York and London, 1988. 

Kirmaier, C. Holten, D. In The Photosynthetic Bacterial Reaction Center-Structure and Dynamics, Breton, J., Vermeglio, A., Eds. Plenum New York, 1988 p 219. 

Figure 6.6-18 Scheme of the photosynthetic reaction center structure. 

It should be mentioned that electron transfer to the quinone pool, both by PS II and by the reaction centers of purple bacteria, now proceeds via a two-electron gating mechanism after one electron has arrived at the temporarily bound quinone Qb, the semiquinone remains in its unprotonated, negatively charged form and tightly bound to the reaction center only after a second photoreaction does its full reduction, protonation and release as a quinol take place [19]. This procedure may also have played a role in the selection of the dimeric reaction center structure, but its importance most likely has to do with the reactivity of semiqui-nones with molecular oxygen and in that case it probably appeared much later. 

The fact that the pKa of the various oxidation states of quinones differ dramatically has been exploited in a recent design of artificial systems that mimic the light-driven transmembrane proton transport characteristic of natural photosynthesis [218]. Triad artificial reaction centers structurally related to 41 were vectorially inserted into the phospholipid bilayer of a liposome (vesicle) such that the majority of the quinone moieties are near the external surface of the membrane, and the majority of the carotenoids extend inward, toward the interior surface. The membrane... 

Overall view of the reaction center structure and view along the approximate symmetry axis. Protein chains are represented as curved lines (courtesy of Johann Deisenhofer). 

Summary Reaction-Center Structure and Photochemical Reactions. 62... 

We now summarize in Fig. 11 the reaction-center structure and the known electron-transport reactions in purple bacteria. A simplified representation of the reaction-center and the light-harvesting complexes contained in the bacterial membrane is shown in Fig. 11 (A), followed by a column model and a cofactor model in Fig. 11 (B). The cofactor model is used to illustrate the various electron-transport steps with the associated rate constants in Fig. 11 (C), where the cofactors in the starting state (oxidized or reduced) are shown in solid black. When a cofactor first becomes reduced or oxidized, it is shown as an open symbol. We will also use this cofactor model and reaction sequence as a framework for introducing the remaining chapters throughout the section on photosynthetic bacteria. 

Arnoux B and Reiss-Husson F (1996) Pigment-protein interactions in Rhodobacter sphaeroides Y photochemical reaction center comparison with other reaction center structures. EurBiophys J 24 233-242... 

Frank HA (1993) Carotenoids in photosynthetic bacterial reaction centers Structure, spectroscopy, and photochemistry. In The Photosynthetic Reaction Centerpp 221-237. Academic Press, New York... 

Frank HA (1992) Electron paramagnetic resonance studies of carotenoids. Meth Enzymol 213 305-312 Erank HA (1993) Carotenoids in photosynthetic bacterial reaction centers Structure, spectroscopy, and photochemistry. In Deisenhofer J andNorris JR(eds) The Photosynthetic Reaction Center, Vol II, pp 221-237. Academic Press, San Diego Prank HA and CogdeU RJ (1996) Carotenoids in Photosynthesis. Photochem Photobiol 63 257-264... 

Nabedryk al.. 1988. in The Photosynthetic Bacterial Reaction Center Structure Dynamics (Breton J. Vermeglio A., eds.) Vol. 149, pp. 237-250. NATO ASI Series. 

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