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Circular dichroism of phytochrome intermediates
Author(s) -
Eilfeld Petra H.,
Eilfeld Peter G.
Publication year - 1988
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1988.tb04959.x
Subject(s) - circular dichroism , phytochrome , chromophore , cotton effect , chemistry , vibrational circular dichroism , phytochrome a , etiolation , dichroic glass , absorption (acoustics) , crystallography , absorption spectroscopy , photochemistry , spectroscopy , spectral line , isomerization , materials science , enzyme , optics , biology , organic chemistry , biochemistry , physics , catalysis , red light , arabidopsis , composite material , quantum mechanics , mutant , botany , astronomy , gene , nanotechnology
Phototransformation P t to P fr was investigated with 124‐kDa phytochrome from etiolated oat seedlings ( Avena sativa L. cv. Pirol) using circular dichroism spectroscopy at ‐110°C to +30°C. Using absorption spectra of the intermediates formed at the respective temperatures, circular dichroism spectra (300–800 nm) of pure intermediates were calculated. The sign of the circular dichroic absorption bands changed upon formation of lumi‐R, the primary photoproduct of P r . This would be compatible with a Z→E isomerization taking place at this reaction step. The subsequent intermediates (meta‐R a and meta‐R c ) as well as P fr showed only small circular dichroism. Their absorption spectra were drastically shifted, but had similar spectral shapes. The results are discussed in terms of conformational changes of the phytochrome chromophore presumably taking place at the early steps of phototransformation P r to P fr .