Lipids affect the charge stabilization in wild-type and mutant reaction centers of Rhodobacter sphaeroides R-26

László Nagy, Elfrida Fodor, Júlia Tandori, László Rinyu, Tibor Farkas

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13 Citations (Scopus)

Abstract

The effect of lipids on stabilization of electrons on the secondary quinone was studied in reaction centers (RC) of herbicide-sensitive and -resistant (L229Ile → Met) Rhodobacter sphaeroides R-26. The lipid concentration and the lipid/protein ratio of the intracytoplasmic membranes (ICM) were larger in the mutant RCs than in the wild-type. The free energy changes of Q(A)-Q(B) → Q(A)Q(B)- electron transfer were ΔG0 = -57 meV, -69 meV, -85 meV for the wild-type and ΔG0 = 0 meV, -15 meV, -46 meV for the mutant at pH = 8.0, in detergent, liposome and ICM, respectively. The differences in the stabilization energies of both strains decreased from the detergent via proteoliposome to chromatophore. We conclude that the energetics of the interquinone electron transfer depends on the environment of the reaction center. The steric and/or electrostatic interactions of the environment and Q(B) pocket can modulate the energetics of the charge stabilization over large distances. The interaction may have crucial importance on coupling the electron transport in the photosynthetic membrane to the anabolic/catabolic processes taking place in the cells.

Original languageEnglish
Pages (from-to)465-473
Number of pages9
JournalAustralian Journal of Plant Physiology
Volume26
Issue number5
DOIs
Publication statusPublished - Jan 1 1999

Keywords

  • Charge stabilization
  • Herbicide resistance
  • Liposomes
  • Membranes
  • Reaction center

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

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