Kinetics of photo-active bacteriorhodopsin analog 3,4-didehydroretinal.

Kinetics of the photo-induced processes of the transient states of the 3,4-didehydroretinal (3,4-dhr) modified bacteriorhodopsin (bR) was studied by a flash photolysis method in a water suspension at room temperature. The excitation initiated a photocycle with several transient intermediates similar to the trans photocycle of native bR. The main observation of the study was that although major part (80%) of the population of the M state relaxed via the O intermediate as in natural bR, 20% relaxed directly to the bR ground state in 200 ms.