Blue light effect on proton pumping by bacteriorhodopsin

Proton pumping in closed vesicular systems containing bacteriorhodopsin that is initiated by an orange flash, is diminished by a subsequent blue flash. This blue light effect is due to light absorbed by the photocycle intermediate M412 (M), which was formed by the orange flash. A kinetic analysis of...

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Bibliographic Details
Published in:Biophysical journal 1983-08, Vol.43 (2), p.251-254
Main Authors: Ohno, K., Govindjee, R., Ebrey, T.G.
Format: Article
Language:English
Subjects:
bacteriorhodopsin
Bacteriorhodopsins - metabolism
Biological and medical sciences
Biological Transport, Active
Carotenoids - metabolism
Cell structures and functions
Chloroplast, photosynthetic membrane and photosynthesis
Fundamental and applied biological sciences. Psychology
Halobacterium - metabolism
Halobacterium halobium
Hydrogen-Ion Concentration
Light
Molecular and cellular biology
Phospholipids - metabolism
photocycles
Protons
purple membranes
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Summary:Proton pumping in closed vesicular systems containing bacteriorhodopsin that is initiated by an orange flash, is diminished by a subsequent blue flash. This blue light effect is due to light absorbed by the photocycle intermediate M412 (M), which was formed by the orange flash. A kinetic analysis of the blue-light-induced reduction of proton pumping shows that of the two components of M, only the slowly decaying component is involved in the reduction of proton movement. This may be the first correlation between a proton movement and a specific photochemical intermediate of bacteriorhodopsin. Furthermore, we report that blue light, acting on the slowly decaying intermediate, probably causes a movement of the protons in a direction opposite to that normally seen for light absorbed by bacteriorhodopsin.
ISSN:0006-3495
1542-0086
DOI:10.1016/S0006-3495(83)84347-1