Light-induced linear dichroism in photoreversibly photochromic sensor pigments 2. Chromophore rotation in immobilized phytochrome
Publikation/Tidskrift/Serie: Photochemistry and Photobiology
Förlag: American Society for Photobiology
Large phytochrome ((P) from Avena sativa) immobilized via anti-phytochrome immunoglobulin bound to Sepharose beads was irradiated to saturation with unpolarized far-red (fr) light. The apparent absorbance level was recorded in a dual wavelength spectrophotometer with both measuring beams set to either 600 or 730 nm and polarized perpendicular to each other. The sample was then irradiated with red (r) polarized light. The apparent change in absorbance obtained after this irradiation indicated that purified phytochrome could show linear dichroism. From the absorbance values obtained it was computed that the direction of the long-wavelength transition moment changes by either 32.degree. or 148.degree., when phytochrome is transformed from P1r to Pfr. Considering the model of Hahn and Song (1981), the latter value appears more likely. In light of these results, the conclusions drawn from in vivo experiments on action dichroism in Dryopteris, Adiantum (Kadota et al.,1982) and Mougeoutia, which point to a 90.degree. rotation should be reconsidered.
- Biological Sciences
- ISSN: 0031-8655