Title: Further characterization of the two Photosystem II reaction center complex preparations from the thermophilic cyanobacterium Synechococcus sp.
Abstract: Photochemical and chemical properties of two Photosystem II reaction center complexes isolated from the thermophilic cyanobacterium Synechococcus sp. were examined. (1) The intact reaction center complexes contain each one of photoreducible pheophytin, secondary electron acceptor (QA) and cytochrome b-559 per 32–46 chlorophyll a molecules. (2) The reaction center complexes which lack the chlorophyll-binding 40 kDa polypeptide (CP2-b) showed photoaccumulation of reduced pheophytin and photoreduction of QA, indicating that the complexes can carry out not only the primary-charge separation, but also the stabilization of the separated charges. The contents of pheophytin, QA and cytochrome b-559 were, however, considerably reduced in CP2-b. (3) The two complexes contained very small amounts of manganese. (4) CP2-b was partially deprived of the small polypeptides: the ratios of the peak areas (corrected for molecular weight) of the 47/40/31 plus 28/9 kDa polypeptide bands resolved in sodium dodecyl sulfate gels after electrophoresis under denaturating conditions were approx. 1:1:2:2 in the intact complexes and 1:0:0.4:1 in CP2-b. The results were discussed in terms of the functional molecular organization of the Photosystem II reaction center complexes.
Publication Year: 1985
Publication Date: 1985-04-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 55
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