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Low‐temperature spectrophotometry of phoborhodopsin
Author(s) -
Shichida Yoshinori,
Imamoto Yasushi,
Yoshizawa Tôru,
Takahashi Tetsuo,
Tomioka Hiroaki,
Kamo Naoki,
Kobatake Yonosuke
Publication year - 1988
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(88)80050-4
Subject(s) - spectrophotometry , irradiation , chemistry , rhodopsin , pigment , photochemistry , absorption (acoustics) , analytical chemistry (journal) , chromatography , materials science , biochemistry , organic chemistry , retinal , physics , nuclear physics , composite material
Photoreactions of the fourth rhodopsin‐like pigment, phoborhodopsin (pR480), of Halobacterium halobium were studied by low‐temperature spectrophotometry. Upon irradiation of pR480 at ‐ 80 as well as ‐ 170°C with 436 nm light, a new intermediate having a difference absorption maximum at about 520 nm was produced. We designate this intermediate 'P520'. Prolonged irradiation caused the formation of a photosteady‐state mixture composed of P520 and pR480, indicating that P520 was photoreversible to pR480 at ‐ 80°C. P520 was thermally converted back to pR480 through P350 and P530, both of which were detected previously [(1986) Biochem. Biophys. Res. Commun. 139, 389–395]. Based on these results, a new photochemical reaction cycle of pR is presented.