title: Comparison of the contribution from different energy-linked reactions to the function of a membrane potential in photosynthetic bacteria.
abstract: The steady-state membrane potentials generated by light, PP(i), ATP or the reverse transhydrogenase reaction were studied in chromatophores from two different phototrophic bacteria, Rhodospirillum rubrum and Rhodopseudomonas viridis. The membrane potentials generated by the different energy-linked reactions were evaluated by a tetraphenylboron(TPB(-)) ion-selective electrode. The generated by light was estimated to be 110 mV and 50 mV in R. rubrum and Rps. viridis chromatophores, respectively. In the dark, PP (i), ATP and reversed transhydrogenase generated membrane potentials in R. rubrum and Rps. viridis chromatophores 50, 60 and 35 mV, and 14, 35 and 25 mV,respectively. The effect of magnesium ion on the membrane potential generated by different energy-linked reactions was also studied. The induced by different energy-generating reactions in R. rubrum and Rps. viridis chromatophores and the possible relationship to the chromatophore structures are discussed.
authors: Department of Biochemistry, Arrhenius Laboratories for Natural Science, University of Stockholra, Stockholm Sweden.
authors: B F
authors: BF
authors: Nore
authors: Y
authors: Y
authors: Sakai
authors: M
authors: M
authors: Baltscheffsky
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D002856:Chromatophores / Q000187:drug effects / Q000528:radiation effects; D043564:Inorganic Pyrophosphatase / Q000378:metabolism; D008027:Light; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D009250:NADP Transhydrogenases / Q000378:metabolism; D012241:Rhodopseudomonas / Q000187:drug effects / Q000378:metabolism / Q000502:physiology* / Q000528:radiation effects; D012247:Rhodospirillum rubrum / Q000187:drug effects / Q000378:metabolism / Q000502:physiology* / Q000528:radiation effects
chemical_list: D009250:NADP Transhydrogenases; D000251:Adenosine Triphosphatases; D043564:Inorganic Pyrophosphatase; D008274:Magnesium