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1983 (1)
1Author    G. O., G. S. Chäfer, H. S. Tro, Tm AnRequires cookie*
 Title    Synthesis of 2'-/3'-0-Acylated Adenine Nucleotide Analogs and Their Interactions in Photophosphorylation  
 Abstract    By mono esterification o f 3'(2')-hydroxyl residues o f adenine nucleotides with various carb-oxylic acids a series o f nucleotide analogs is available including fluorescent and photoaffinity labels. Their chemical synthesis is described. The equilibrium between 2' and 3' esters is determined by N M R spectroscopy, stability o f the esters and their tendency o f acyl migration is discussed. The interaction o f the A D P derivatives with the chloroplast ATP synthesizing system is in­ vestigated. Actually, the analogs are typical energy transfer inhibitors, strongly inhibiting photo­ phosphorylation and concom itant coupled electron transport (ci50 values ranging from 0.3 to 85 |iM). On the basis o f inhibitory activities o f analogs bearing varying 3'-(2')-substituents, struc-ture-activity relationships are discussed. The inhibitory properties o f the em ployed A D P analogs are based on their specific interaction with the catalytic AD P binding site o f CF] and their extrem ely slow phosphorylation on the enzyme (rate 0.25% or less com pared to A D P phosphorylation). Inhibition is com petitive to AD P but non-com petitive with regard to P; . It is specific for the A D P derivatives, whereas the corresponding ATP analogs are only weak inhibitors in phosphorylation and the AMP derivatives are com pletely inactive. In light-triggered ATP hydrolysis, however, the ATP analogs exhibit an even stronger com petitive inhibition than the A D P derivatives. The results suggest that a conformational change o f ATPase takes place when the chloroplasts are transferred from energized to de-energized conditions which greatly affects the properties o f the active site with respect to nucleotide binding. In tro d u c tio n 
  Reference    Z. Naturforsch. 38c, 49 (1983); received October 7 1982 
  Published    1983 
  Keywords    N ucleotide Analogs, Photophosphorylation, Energy Transfer Inhibition 
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 TEI-XML for    default:Reihe_C/38/ZNC-1983-38c-0049.pdf 
 Identifier    ZNC-1983-38c-0049 
 Volume    38