title: Time-resolved fluorometry of purple membrane of Halobacterium halobium. O640 and an O-like red-shifted intermediate Q.
abstract: The photocycle of the light-adapted purple membrane was studied with a time-resolved fluorometry apparatus: fluorescence of the sample suspension (greater than 660 nm) was pumped with a 633-nm cw laser and the temporal change induced by a 532-nm pulsed laser was measured with a photon-counting-type transient recorder. The formation and the decay of the O640 intermediate were clearly observed in the pH region between 4.0 and 11.4. A photochemical cycle of N560 was apparently driven in alkaline suspension (pH greater than 9.3). An O-like fluorescent intermediate Q appears and decays with time constants of less than 0.1 ms and 1.7 +/- 0.2 ms, respectively.
authors.affiliation: Department of Biomolecular Engineering, Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ohtani
authors.forename: H
authors.initials: H
authors.lastname: Itoh
authors.forename: T
authors.initials: T
authors.lastname: Shinmura
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry*; D002462:Cell Membrane / Q000737:chemistry*; D005470:Fluorometry / Q000379:methods*; D019617:Halobacterium salinarum / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009584:Nitrogen / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D010777:Photochemistry; D013696:Temperature
chemical_list: D001436:Bacteriorhodopsins; D009584:Nitrogen; D010100:Oxygen