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1990 (1)
1Author    HimadriB. Pakrasi, KarinJ. Nyhus, HowardG. RanokRequires cookie*
 Title    Targeted Deletion Mutagenesis of the ß Subunit of Cytochrome b559 Protein Destabilizes the Reaction Center of Photosystem II  
 Abstract    Oligonucleotide-directed mutagenesis techniques were used to delete the psbF gene, encod­ ing the ß subunit o f the cytochrom e b559 protein o f the photosystem II com plex in the cyano­ bacterium, Synechocystis 6803. Cyt b559 is an integral com ponent o f PS II complex. However, its precise functional role in PS II remains to be determined. Previously, we created a mutant in which the psbF gene as well as three o f its neighbouring genes, psbE , psbL and p sb i were simultaneously deleted from the chrom osom e o f Synechocystis 6803 (Pakrasi, Williams and Arntzen, EMBO J. 7, 3 2 5 -3 3 2 , 1988). This mutant had no PS II activity. However, the role o f any one o f the four individual gene products could not be determined by studying this mutant. The newly generated mutant, T 256, had only one gene, p sbF , deleted from the genome. This mutant was also impaired in its PS II activities. In addition, it had barely detectable levels o f two other protein com ponents, D1 (herbicide binding protein) and D2, o f the reaction center o f PS II, in its thylakoid membranes. In contrast, two other proteins o f PS II, CP47 and CP43 were present in appreciable amounts. Fluorescence spectra (77 K) o f the mutant showed the absence o f a peak at 695 nm that was previously believed to originate from CP47. In addition, phycobilisomes, the light-harvesting antenna system o f PS II, were found to be assembled normally in this mutant. We conclude that the presence o f the ß subunit o f Cyt b559 in the thylakoid membranes is critically important for the assembly o f PS II reaction center. 
  Reference    Z. Naturforsch. 45c, 423 (1990); received November 21 1989 
  Published    1990 
  Keywords    Photosystem II, Cytochrom e b559, Site-Directed Mutagenesis, Protein Complex Stability, Synechocystis 6803 
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 TEI-XML for    default:Reihe_C/45/ZNC-1990-45c-0423.pdf 
 Identifier    ZNC-1990-45c-0423 
 Volume    45