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SPECTROSCOPIC STUDIES ON THE STRUCTURES OF RETINOCHROME and METARETINOCHROME *
Author(s) -
Kishigami Akio,
Sekiya Noriko,
Yoshihara Kazuo,
Hara Reiko,
Hara Tomiyuki,
Tokunaga Fumio
Publication year - 1991
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.1751-1097.1991.tb02121.x
Subject(s) - tryptophan , chemistry , circular dichroism , retinal , residue (chemistry) , irradiation , absorption (acoustics) , infrared , fourier transform infrared spectroscopy , photochemistry , crystallography , amino acid , materials science , organic chemistry , biochemistry , optics , physics , nuclear physics , composite material
– Spectroscopic measurements of retinochrome and the related photoproduct, metaretino‐chrome, were carried out to determine the conformation of the retinal and the protein. Absorption spectra with fourth derivatives indicate that the tryptophan residues are located in a hydrophobic core and that the environment around these residues does not change after light irradiation. Circular dichroism measurements indicate that retinochrome has a high helical content which is not altered by the conversion of retinochrome to metaretinochrome. Fourier transform infrared difference spectra demonstrate that retinochrome has the all ‐trans retinal and metaretinochrome has the 11‐CM retinal. Retinochrome has an absorption due to amino acid residue(s) which changes in metaretinochrome. This work demonstrates that conformational changes are not induced during the conversion but the electrical charge(s) of the protein are changed by irradiation.