Participation of inorganic phosphates as electron donors in the primary reactions of photosynthesis in Rhodobacter sphaeroides
Goncharova, N.V.; Ivanovskiĭ, R.N.; Filatova, L.V.
Biofizika 47(3): 490-499
2002
ISSN/ISBN: 0006-3029 PMID: 12068606 Document Number: 542532
The formation of ATP during photophosphorylation in chromatophores from purple nonsulfur bacterium Rhodobacter sphaeroides in the presence of phenazine methosulfate and without exogenous electron carriers under constant illumination and by the action of single light flashes was studied. It was shown that the photoinduced transport of electrons to the exogenous electron acceptor depends on phosphate. It was assumed that phosphate ions are electron donors in the reaction center P870; by the action of light, P870 converts the phosphate ion HPO4(2-) into anion radical HPO4-.. In the difference EPR spectra "light minus darkness" at 77 K, an asymmetrical doublet signal with a weak low-field line was observed. The signal had a g-tensor of about 2.014 and a hyperfine coupling constant of about 2.5 mT and belongs probably to the phosphate anion radical.