Immobilization of bacteriorhodopsin and orientation of its transition moment in purple membrane

The molecular motion of bacteriorhodopsin mutant D96N in the purple membrane

“…Thus, the changed conformation of M-intermediate should slow the rotational motion of the monomer protein or lead the binding between M-intermediate and neighboring proteins. For wild-type bR, whether the protein undergoes the motion in the purple membrane is still an open question [4][5][6][7][8][9][10][11]. For D96N, however, we confirmed that non-excited molecules rotate within the membrane.…”

“…For detection of the motion, absorption anisotropy becomes a powerful tool. Using this method, however, an absence of the motion of retinal was reported [4][5][6][7][8]. The immobilization of the retinal was explained by the restriction with peptide chains around retinal and the rigid structure of the purple membrane.…”

Light scattering changes and protein distortion in the bacteriorhodopsin during the photocycle

“…Since the retinal chromophore is near perpendicular (-70 °) to the membrane normal [5,12,17], by exciting the sample using a ,-, polarized laser InP E; (7 2~ -1 30.…”

“…There has been a number of trials to find out whether the parts of the bacteriorhodopsin molecules move or not during the proton pumping photocycle. It has been proved that the retinal, the chromophore of the protein, does not move [1][2][3][4][5] and no motion of the protein side chains has been found [6]. On the other hand, evidence exists for movement: by increasing the solvent viscosity with glycerol, some steps of the photocycle slow down [7] and then the proton movement can be directly demonstrated by the PERS method [8].…”

Development of a Free-Electron Laser Center and Research in Medicine, Biology and Materials Science,

“…Increasing wattages were applied to the same nerve after a one minute interval. Korenstein and Hess, 1978). Also, investigations of the protein side chains show no evidence for motion during the photocycle (Cz~g6, et al, 1982).…”