Study of the photocycle and charge motions of the bacteriorhodopsin mutant D96N

C. Gergely, C. Ganea, G. Groma, G. Váró

Research output: Contribution to journalArticle

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Abstract

Absorption kinetic and electric measurements were performed on oriented purple membranes of D96N bacteriorhodopsin mutant embedded in polyacrylamide gel and the kinetic parameters of the photointermediates determined. The rate constants, obtained from fits to time-dependent concentrations, were used to calculate the relative electrogenicity of the intermediates. The signals were analyzed on the basis of different photocycle models. The preferred model is the sequential one with reversible reaction. To improve the quality of the fits the necessity of introducing a second L intermediate arose. We also attempted to interpret our data in the view of reversible reactions containing two parallel photocycles, but the pH dependencies of the rate constants and electrogenicities favored the model containing sequential reversible transitions. A fast equilibrium for the L2 mutually implies M1 transition and a strong pH dependence of the M2 electrogenicity was found, indicating that the M1 to M2 transition involves complex charge motions, as is expected in a conformational change of the protein.

Original languageEnglish
Pages (from-to)2478-2483
Number of pages6
JournalBiophysical Journal
Volume65
Issue number6
Publication statusPublished - 1993

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Bacteriorhodopsins
Purple Membrane
Proteins
polyacrylamide gels

ASJC Scopus subject areas

  • Biophysics

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Study of the photocycle and charge motions of the bacteriorhodopsin mutant D96N. / Gergely, C.; Ganea, C.; Groma, G.; Váró, G.

In: Biophysical Journal, Vol. 65, No. 6, 1993, p. 2478-2483.

Research output: Contribution to journalArticle

Gergely, C. ; Ganea, C. ; Groma, G. ; Váró, G. / Study of the photocycle and charge motions of the bacteriorhodopsin mutant D96N. In: Biophysical Journal. 1993 ; Vol. 65, No. 6. pp. 2478-2483.
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