Electric-field effects in 13-demethyl-11,14-epoxyretinal-bacteriorhodopsin films

Paul Kolodner; Evgeniy P. Lukashev; Yuan Chin Ching; I. Rousso; M. Sheves

doi:10.1111/j.1751-1097.1999.tb01955.x

Electric-field effects in 13-demethyl-11,14-epoxyretinal-bacteriorhodopsin films

Paul Kolodner, Evgeniy P. Lukashev, Yuan Chin Ching, I. Rousso, M. Sheves

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Abstract

We report the results of experiments on the application of electric fields across thin, dry films of a bacteriorhodopsin (BR) analog pigment in which the retinal chromophore has been replaced with 13-demethyl-11,14-epoxyretinal. As previously observed in other BR variants with low Schiff-base pK values, this pigment exhibits protonation and deprotonation of the Schiff base under an applied electric field, depending on the initial Schiffbase protonation state or effective pH. At low effective pH, a fast (<200 μs) deprotonation reaction dominates. At high pH, an apparently different mechanism leads to Schiff-base protonation on the time scale of seconds. Comparison of our results with a simple model suggests that the external field causes a shift in the pK of the Schiff base by 1-2 pH units.

Original language	English
Pages (from-to)	103-110
Number of pages	8
Journal	Photochemistry and Photobiology
Volume	70
Issue number	1
DOIs	https://doi.org/10.1111/j.1751-1097.1999.tb01955.x
State	Published - 1 Jan 1999
Externally published	Yes

ASJC Scopus subject areas

Radiation
Biochemistry
Physical and Theoretical Chemistry

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10.1111/j.1751-1097.1999.tb01955.x

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abstract = "We report the results of experiments on the application of electric fields across thin, dry films of a bacteriorhodopsin (BR) analog pigment in which the retinal chromophore has been replaced with 13-demethyl-11,14-epoxyretinal. As previously observed in other BR variants with low Schiff-base pK values, this pigment exhibits protonation and deprotonation of the Schiff base under an applied electric field, depending on the initial Schiffbase protonation state or effective pH. At low effective pH, a fast (<200 μs) deprotonation reaction dominates. At high pH, an apparently different mechanism leads to Schiff-base protonation on the time scale of seconds. Comparison of our results with a simple model suggests that the external field causes a shift in the pK of the Schiff base by 1-2 pH units.",

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AU - Rousso, I.

AU - Sheves, M.

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AB - We report the results of experiments on the application of electric fields across thin, dry films of a bacteriorhodopsin (BR) analog pigment in which the retinal chromophore has been replaced with 13-demethyl-11,14-epoxyretinal. As previously observed in other BR variants with low Schiff-base pK values, this pigment exhibits protonation and deprotonation of the Schiff base under an applied electric field, depending on the initial Schiffbase protonation state or effective pH. At low effective pH, a fast (<200 μs) deprotonation reaction dominates. At high pH, an apparently different mechanism leads to Schiff-base protonation on the time scale of seconds. Comparison of our results with a simple model suggests that the external field causes a shift in the pK of the Schiff base by 1-2 pH units.

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Electric-field effects in 13-demethyl-11,14-epoxyretinal-bacteriorhodopsin films

Abstract

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