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FLASH‐INDUCED FAST CHANGE IN SURFACE POTENTIAL AND FLUIDITY OF PURPLE MEMBRANE STUDIED BY SPIN LABEL METHOD
Author(s) -
Tokutomi Satoru,
Iwasa Tatsuo,
Yoshizawa Tǒru,
Ohnishi Shunichi
Publication year - 1981
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.1751-1097.1981.tb05447.x
Subject(s) - bacteriorhodopsin , chemistry , membrane fluidity , flash (photography) , membrane , biophysics , membrane potential , photochemistry , chemical physics , biochemistry , optics , biology , physics
— Flash‐induced changes in surface potential and fluidity of purple membrane were studied by a spin label method. Changes in surface potential and fluidity were monitored by observing the distribution of charged and uncharged spin labels between the purple membrane and the aqueous phase. On flash illumination, a transient hyperpolarization of the surface potential and a transient fluidization of the membrane hydrophobic region are induced. The former may probably reflect the proton movement near the purple membrane surface, while the latter may result from photo‐induced conformational changes of bacteriorhodopsin. The two events are different in time course. The relationships between the two events, and the formation and decay of the intermediates of bacteriorhodopsin in the photoreaction cycle are discussed.