Changes in the retinal transition dipole moment in bacteriorhodopsin of the purple membrane of Halobacterium Salinarium at the so-called PH(rev).
The chromophore transition dipole moment of light-adapted wild-type bacteriorhodopsin (WT-bR) in suspension is evaluated for pH range of 2.8-12. Significant variations in the transition dipole moment are observed at the so-called pH(rev). The results have reported a value of 11 and 8.5 Debye for chromophore transition dipole moment of the neutral purple and acid blue form of bacteriorhodopsin, respectively. There may be a correlation with the process of reversing the direction of the permanent electric dipole moment, due to the reversal of the surface charge asymmetry, of the purple membrane to its opposite side at that pH(rev).
Mostafa
Hamdy I A
HI
Department of Biophysics, Faculty of Science, Cairo University, Giza, Egypt. hamszil@yahoo.com
D001436:Bacteriorhodopsins / Q000502:physiology*; D019617:Halobacterium salinarum / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D008433:Mathematics; D010777:Photochemistry; D018717:Purple Membrane / Q000502:physiology*; D012172:Retinaldehyde / Q000737:chemistry; D013053:Spectrophotometry
D001436:Bacteriorhodopsins; D012172:Retinaldehyde