Figure 7.

Reaction Sequence of aCRY and Comparison of the Absorption Spectrum of the Neutral Radical with in Vivo Responses to Light of Different Spectral Qualities and with Absorption Spectra of FAD Radical States of Other CRYs.

(A) The three redox states associated with aCRY in vitro (i.e., oxidized, neutral radical, and fully reduced FAD) are depicted. At the specified wavelengths of light, a conversion of oxidized to neutral radical or of neutral radical to the fully reduced state of FAD takes place.

(B) The absorption spectrum of the flavin neutral radical of aCRY is shown for comparison according to Figure 5B.

(C) Relative increase in the accumulation of GLN1 mRNA after exposure to different light qualities (i.e., blue, yellow, red, and far-red light) for 120 min. Responses in both the wild type (colored bars) and the acry mutant (gray bars) are shown. The width of the bars corresponds to the FWHM of the respective LED emission spectrum.

(D) For comparison, C. reinhardtii CPH1 was selected as a representative plant CRY. It shows the blue shift of the local absorption maxima of the neutral radical to 540 and 580 nm, which is characteristic for a plant CRY. dCRY, an animal type I CRY from Drosophila, forms the anion radical with an absorption maximum at 367 nm and weak absorption at >510 nm. Arabidopsis CRY3 is a member of DASH CRYs and contains an antenna chromophore with pronounced absorption at 384 nm. All spectra contain some additional contributions from the oxidized state at <500 nm.