Biochemical and spectroscopic characterization of the blue-green photoreceptor in Halobacterium halobium

Journal Article · Thu Jan 01 00:00:00 EST 1987 · Proc. Natl. Acad. Sci. U.S.A.; (United States)

DOI:https://doi.org/10.1073/pnas.84.2.402· OSTI ID:6847166

Scherrer, P; McGinnis, K; Bogomolni, R A

Spectroscopic evidence indicates the presence of a second sensory receptor sR-II in Halobacterium halobium, which causes a repellent response to blue-green light. Reactions with hydroxylamine and NaCNBH/sub 3/ and reconstitution of the bleached pigment with retinal show that it is very similar to the other retinylidene pigments bacteriorhodopsin, halorhodopsin, and especially the earlier-discovered phototaxis receptor, sensory rhodopsin, renamed sR-I587. The second sensory receptor, sR-II480, has an absorbance maximum at 480 nm and undergoes a cyclic photoreaction with a half-time of approximately 200 msec. Its predominant photocycle intermediate absorbs maximally near 360 nm. The receptor can be detected spectroscopically in the presence of sR-I587 and quantitated through its transient response to 450-nm excitation. It is selectively bleached by low hydroxylamine concentrations that are insufficient to bleach sR-I587 significantly. Its photochemical and phototactic activities can be restored by addition of retinal. The mobility of the receptor, on NaDodSO4/polyacrylamide gels, was similar or identical to that of sR-I587 and slightly faster than bacteriorhodopsin, yielding an apparent molecular mass of 23-24 kDa.

• Research Organization: Cardiovascular Research Institute, San Francisco, CA
• OSTI ID: 6847166
• Journal Information: Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHOTOSYNTHETIC BACTERIA
PHOTOSYNTHETIC REACTION CENTERS
BIOCHEMICAL REACTION KINETICS
PHOTOSYNTHESIS
RHODOPSIN
SPECTROPHOTOMETRY
CHEMICAL REACTIONS
KINETICS
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PIGMENTS
PROTEINS
REACTION KINETICS
SYNTHESIS
550200* - Biochemistry
550500 - Metabolism