RED-SHIFTED PHOTOCHROMIC BEHAVIOR OF A BACTERIORHODOPSIN FILM MADE FROM THE L93T GENETIC VARIANT

We present experimental results demonstrating the red-shifted photochr omic behavior of a gelatin film made from L93T, a genetic variant of b acteriorhodopsin. The red shift of the absorbance spectrum on illumina tion with visible light is due to a short M-state lifetime and a longe r-lived O state whose absorption peaks at 610 nm. Pump-probe measureme nts show the O state to have a lifetime of approximately 2.2 s in the gelatin film, with a single exponential decay behavior. We also presen t holographic kinetic results for both red (633-nm) and blue (442-nm) readout wavelengths. (C) 1996 Optical Society of America