ELECTROOPTICAL MEASUREMENTS ON PURPLE MEMBRANE CONTAINING BACTERIORHODOPSIN MUTANTS

Electrooptical measurements on purple membrane containing the wild-typ e and 10 different bacteriorhodopsin mutants have shown that the direc tion of the permanent electric dipole moment of all these membranes re verses at different pH values in the range 3.2-6.4. The induced dipole moment and the retinal angle exhibit an increased value at these pHs. The results demonstrate that the bacteriorhodopsin protein makes an i mportant contribution to the electrooptical properties of the purple m embrane.