Abstract

The all-trans to 13-cis photoisomerization of the retinal chromophore in bacteriorhodopsin (bR) acts as a strong steric and electronic perturbation for the protein environment, thereby driving the proton pump mechanism. Photoexcitation and torsional movement are expected to be paralleled by various intra- and intermolecular relaxation processes. According to femtosecond (fs) time-resolved optical absorption spectroscopy the electronic ground state is reached after about 500 fs (J) [1-4], which then relaxes on a 3 ps time-scale to the K-state with the chromophore in 13-cis configuration.

© 2002 Optical Society of America