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Time‐resolved fluorometry of purple membrane of Halobacterium halobium O 640 and an O‐like red‐shifted intermediate Q
Author(s) -
Ohtani Hiroyuki,
Itoh Hiroyasu,
Shinmura Toshiki
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80643-u
Subject(s) - fluorescence spectroscopy , chemistry , halobacteriaceae , spectroscopy , crystallography , halobacterium , membrane , fluorescence , bacteriorhodopsin , physics , biochemistry , optics , halobacterium salinarum , quantum mechanics
The photocycle of the light‐adapted purple membrane was studied with a time‐resolved fluorometry apparatus: fluorescence of the sample suspension (>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 O 640 intermediate were clearly observed in the pH region between 4.0 and 11.4. A photochemical cycle of N 560 was apparently driven in alkaline suspension (pH > 9.3). An O‐like fluorescent intermediate Q appears and decays with time constants of <0.1 ms and 1.7 ± 0.2 ms, respectively.