D96N MUTANT BACTERIORHODOPSIN IMMOBILIZED IN SOL-GEL GLASS CHARACTERIZATION

The D96N mutant form of bacteriorhodopsin (BR) purple membrane fragmen ts isolated from the bacterium Halobacterium salinarium has been immob ilized by entrapment in sol-gel glass. The protein was characterized f or M state decay rate at different temperatures and pH values. Bleachi ng efficiency and absorbance maxima vs pH were also determined. The ki netic effects of triethanolamine and diethanolamine were also examined . Results indicated that the immobilized BR was affected in a manner s imilar to the mutant BR in aqueous suspension. Addition of guanidine, however, caused the immobilized BR to show kinetic parameters more clo sely related to the wild-type protein than the D96N mutant control. Sa mples of the aqueous suspension were characterized for particle size a nd particle size distribution. Dried samples of the immobilized BR wer e analyzed by field emission microscopy and BET to characterize both t he purple membrane fragments and the sol-gel pore characteristics.