Ultrafast spectroscopy of the visual pigment rhodopsin

M. Yan, D. Manor, G. Weng, H. Chao, L. Rothberg, T. M. Jedju, R. R. Alfano, R. H. Callender

Research output: Contribution to journalArticle

46 Scopus citations

Abstract

We report on time-resolved absorption studies of the bovine visual pigment rhodopsin with subpicosecond resolution at room temperature. Our data show that bathorhodopsin, rhodopsin's early photoproduct, is photochemically formed in 3.0 ± 0.7 ps. The data suggest that bathorhodopsin formation is kinetically preceded by two species along the rhodopsin-to-bathorhodopsin reaction coordinate. The first is identified with the vertically excited Franck-Condon state. This decays with an ≃200-fs lifetime to an intermediate, which then decays to bathorhodopsin in 3.0 ps. We assign this intermediate to be an excited state transient near 90° along the 11-12 torsional coordinate of rhodopsin's chromophore. Exchange of rhodopsin's exchangeable protons for deuterons does not affect the observed dynamics. These observations are both qualitatively and quantitatively consistent with molecular dynamics calculations, which model the rhodopsin to bathorhodopsin phototransition as a cis-trans isomerization along the 11-12 torsional coordinate of rhodopsin's chromophore.

Original languageEnglish (US)
Pages (from-to)9809-9812
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume88
Issue number21
DOIs
StatePublished - Jan 1 1991
Externally publishedYes

Keywords

  • absorption
  • bathorhodopsin
  • primary processes
  • subpicosecond

ASJC Scopus subject areas

  • General

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