Resonance raman studies of the primary photochemical event in visual pigments

B. Aton, A. G. Doukas, D. Narva, Robert Callender, U. Dinur, B. Honig

Research output: Contribution to journalArticle

99 Citations (Scopus)

Abstract

Resonance Raman multicomponent spectra of bovine rhodopsin, isorhodopsin, and bathorhodopsin have been obtained at low temperature. Application of the double beam 'pump-probe' technique allows us to extract a complete bathorhodopsin spectrum from the mixture in both protonated and deuterated media. Our results show that the Schiff base of bathorhodopsin is fully protonated and that the extent of protonation is unaffected by its photochemical formation from either rhodopsin or isorhodopsin. The Raman spectrum of bathorhodopsin is significantly different than that of either parent pigment, thus supporting the notion that a geometric change in the chromophore is an important component of the primary photochemical event in vision. A normal mode analysis is carried out with particular attention devoted to the factors that determine the frequency of the C=N stretching vibration. We find that the increased frequency of this mode in protonated relative to unprotonated Schiff bases is due to coupling between C=N stretching and C=N-H bending motions, and the shift observed upon deuteration of the Schiff base can also be understood in these terms. Various models for the primary event are discussed in light of our experimental and theoretical results.

Original languageEnglish (US)
Pages (from-to)79-94
Number of pages16
JournalBiophysical Journal
Volume29
Issue number1
DOIs
StatePublished - 1980
Externally publishedYes

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Retinal Pigments
Schiff Bases
Rhodopsin
Vibration
Temperature
bathorhodopsin
isorhodopsin

ASJC Scopus subject areas

  • Biophysics

Cite this

Resonance raman studies of the primary photochemical event in visual pigments. / Aton, B.; Doukas, A. G.; Narva, D.; Callender, Robert; Dinur, U.; Honig, B.

In: Biophysical Journal, Vol. 29, No. 1, 1980, p. 79-94.

Research output: Contribution to journalArticle

Aton, B. ; Doukas, A. G. ; Narva, D. ; Callender, Robert ; Dinur, U. ; Honig, B. / Resonance raman studies of the primary photochemical event in visual pigments. In: Biophysical Journal. 1980 ; Vol. 29, No. 1. pp. 79-94.
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