Optical and electrical characteristics of bacteriorhodopsin gelatin films and tin-oxide coated electrodes

The lifetime of the M-state of Bacteriorhodopsin (BR) is increased by genetic and chemical modifications and by solubilizing purple membranes with detergent. Chemically modified D96E as well as D96N films, possess close to 100% bleaching efficiency, which makes them attractive for use in image storage media. The mutant S35C has spectral and Kinetic properties identical to the WT, both in aqueous suspensions and in film and on antimony–tin-oxide electrodes. This suggests that substitution provides an attachment site that does not interfere with the function of BR. The magnitude of photocurrent transients generated by WT and mutant BR proteins both with natural chromophores and analogs were used to measure the efficiency of the ground-to-M-state transitions.