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LASER PHOTOLYSIS OF THE PURPLE MEMBRANE OF Halobacterium halobium IN THE PHOTOSTATIONARY STATE: THE PHOTOBRANCHING PROCESS FROM THE O 640 INTERMEDIATE
Author(s) -
Ohtani Hiroyuki,
Naramoto Satoru,
Yamamoto Noritaka
Publication year - 1994
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1994.tb05122.x
Subject(s) - bacteriorhodopsin , photostationary state , halobacterium , halobacteriaceae , quantum yield , photodissociation , intermediate state , photochemistry , irradiation , chemistry , reaction rate constant , crystallography , pigment , absorption (acoustics) , membrane , materials science , kinetics , photoisomerization , optics , halobacterium salinarum , physics , atomic physics , organic chemistry , isomerization , composite material , biochemistry , quantum mechanics , nuclear physics , fluorescence , catalysis
The photobranching process from the O 640 intermediate (O) in the photocycle of bacteriorhodopsin was studied. The O form accumulated with continuous wave visible light (390–800 nm) irradiation of the acidic (pH 3.9–6.0) purple membrane of Halobacterium halobium at 22°C. The photocycle of O via an L‐like (or N‐like) intermediate was driven by 630 nm pulsed light. The newly found intermediate has an absorption band in the 450–560 nm region. The “green‐light”‐absorbing pigment, tentatively called G 520 , was converted to O with a time constant of (1.2 ± 0.2) ms. No M‐like species was found in the cycle. The quantum yield of the cycle was estimated to be 0.30 ± 0.15.