Time-resolved long-lived infrared emission from bacteriorhodopsin during its photocycle

TitleTime-resolved long-lived infrared emission from bacteriorhodopsin during its photocycle
Publication TypeJournal Article
Year of Publication2002
AuthorsWang, J, EL-Sayed, MA
JournalBiophysical Journal
Volume83
Pagination1589-1594
Date PublishedSep
ISBN Number0006-3495
Accession NumberWOS:000177774500033
Abstract

The infrared emission observed below 2000 cm(-1) upon exciting retinal in bacteriorhodopsin (bR) is found to have a rise time in the submicrosecond time regime and to relax with two exponential components on the submillisecond to millisecond time scale. These time scales, together with the assignment of this emission to hot vibrations from the all-trans retinal (in bR) and the 13-cis retinal (in the K intermediate), support the recent assignment of the J-intermediate as an electronically excited species (Atkinson et al., J. Phys. Chem. A. 104:4130-4139, 2000) rather than a vibrationally hot K intermediate. A discussion of these time scales of the observed infrared emission is given in terms of the competition between radiative and nonradiative relaxation processes of the vibrational states involved.