Rhodopsin's chromophore, 11-cis retinaldehyde, enables observation of macromolecular changes.
These changes occur on timescales from picoseconds to minutes.
Purpose of the Study:
To investigate rhodopsin's molecular processes triggered by light absorption.
To examine the formation of bleaching intermediates as a function of photon fluence.
Main Methods:
Utilized laser monochromatic light for photolysis with carefully measured photon flux.
Investigated rhodopsin's photochemical events and intermediate formation under controlled conditions.
Main Results:
Photon absorption initiates the formation of metastable bathorhodopsin within 6 picoseconds.
Artificial rhodopsin with 9-cis retinal yields a distinct bathorhodopsin, indicating active site distortions.
Bathorhodopsin undergoes thermal decay through lumirhodopsin and metarhodopsin I to metarhodopsin II, with a stable meta I-meta II equilibrium lasting seconds.
Conclusions:
Rhodopsin's photoactivation provides a model for energy utilization in biological cascades.
The study elucidates the picosecond to minute timescale molecular events in rhodopsin photobleaching.