Photocurrent response of bacteriorhodopsin adsorbed on bimolecular lipid membranes

P. Seta, P. Ormos, B. D'Epenoux, C. Gavach

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The photo response of bacteriorhodopsin adsorbed on a bimolecular lipid membrane has been investigated using short-circuit current measurements. The results revealed a biphasic current vs. time curve for the photocurrent at pH values of approx. 7. This phenomenon could be modified by altering either the value of the external applied electrical field or the proton concentration differences. The observed effects of the external applied voltage, pH gradient and lipophilic proton carriers enabled us to conclude that the bacteriorhodopsin can be adsorbed in two different states, which give rise to a pumping effect and a flux of protons in opposite directions. A theoretical analysis of the photocycle in relation to the electrical field which acts on the proton uptake and release is proposed. The main effect of this field is to diminish the pumping rate due to the proton motive force resulting from the creation of space-charge in the vicinity of purple membrane fragments.

Original languageEnglish
Pages (from-to)37-52
Number of pages16
JournalBBA - Bioenergetics
Volume591
Issue number1
DOIs
Publication statusPublished - Jun 10 1980

Keywords

  • (Bimolecular lipid membrane)
  • Bacteriorhodopsin binding
  • Lipid bilayer
  • Photocurrent response

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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