Molecular Organization of photosystem II Reaction Center Complex

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We have succeeded in isolating a pigment-protein consisting of D-1 (psbA product), D-2 (psbD product) and cytochrone b-559 (psbE and psbF products). The complex is active in the reversible photoaccumulation of reduced pheophytin a which is ascribable to the intermediary electron acceptor of photosystem II. The isolated complex contains approx. 4-5 chlorophyll a, 2 pheophytin a, 1 beta-carotene and 1-2 cytochrome b-559 beme per unit polypeptides. Time-resolved spectroscopy of the complex in the ps and ns time range indicaed that the efficient formation of the primary radical pair of photosystem II, P-680^+ and Pheo^-, which had a life time of about 30 ns. From these results it is clearly concluded that the complex consisting of D-1, D-2 and cytochrome b-559 contains the site of charge separation in photosystem II of oxygenic photosynthesis.We have also succeeded in demonstrating that the photosystem II core complex retaining a polypeptide of 33 KDa of hydrophic nature is the minimum for the manifestation of the oxygen-evolution of photosynthesis.