Excited-state dynamics of bacteriorhodopsin.

T. Kouyama*, K. Kinosita, A. Ikegami

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    36 Citations (Scopus)


    Near infrared emission of bacteriorhodopsin at neutral pH and at room temperature was characterized by a large Stokes shift. This characteristic was lost in an acidic pH (approximately pH 2) where a remarkable enchancement (more than 10 times) in the fluorescence quantum yield accompanied the red shift in the main absorption band. It is suggested from fluorescence polarization measurements that the emission occurs from the first allowed excited state of the retinylidene chromophore, irrespective of pH. We suggest that the large Stokes shift observed at neutral pH is a result of a charge displacement (e.g., proton translocation) that occurs immediately after excitation, and is prevented by protonation (in the ground state) of an amino-acid residue in the protein.

    Original languageEnglish
    Pages (from-to)43-54
    Number of pages12
    JournalBiophysical Journal
    Issue number1
    Publication statusPublished - 1985 Jan

    ASJC Scopus subject areas

    • Biophysics


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