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TIME RESOLUTION OF A BACK PHOTOREACTION IN BACTERIORHODOPSIN
Author(s) -
Kalisky Ofra,
Lachish Uri,
Ottolenghi Michael
Publication year - 1978
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.1751-1097.1978.tb07705.x
Subject(s) - bacteriorhodopsin , chemistry , photochemistry , polyene , resolution (logic) , excitation , analytical chemistry (journal) , physics , biochemistry , organic chemistry , quantum mechanics , artificial intelligence , membrane , computer science , chromatography
— The back photoreaction from the M(412nm) intermediate in the photocycle of light‐adapted bacteriorhodopsin, BR LA (570 nm), is studied using pulsed laser excitation. The decay of a primarily produced species, M P , regenerates BR LA (570nm) in a process characterized by a half life of 200 ns at 25°C. The absorption maximum of M P is blue shifted (Λ max ≃ 395 nm) relative to that of M(412nm). The primary photochemical step, M(412nm) → M P , is attributed to a conformational change in the polyene residue. The energy and entropy of activation of the subsequent M P → BR LA (570 nm) relaxation are reported and discussed.