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A single chromoprotein with triple chromophores acts as both a phytochrome and a phototropin.
- Source :
-
Proceedings of the National Academy of Sciences of the United States of America . 11/21/2006, Vol. 103 Issue 47, p17997-18001. 5p. 1 Diagram, 2 Graphs. - Publication Year :
- 2006
-
Abstract
- Plants sense their environmental light conditions by using three photoreceptors that absorb in the UV, blue/near UV, and red/far-red spectral ranges. These photoreceptors have specific chromophore components corresponding to their absorption spectra. Phytochrome, a red/far-red light receptor, has phytochromobilin as its chromophore, whereas the blue/near UV photoreceptors cryptochrome and phototropin have a pair of flavin derivatives. Plants use these various photoreceptors to assess the surrounding light environment. Phytochrome 3 (PHY3) is a red light receptor found in some ferns, which preferentially grow under weak light. PHY3 is composed of a phytochrome chromophore-binding domain in its N-terminal portion and an almost full-length phototropin in its C-terminal half. This unusual domain organization implies that two different light-sensing systems coexist in this single photoreceptor, although these light-sensing systems usually reside in independent photoreceptors. Here, we show that PHY3 acts as a dual-channel photoreceptor that possesses both the red light-sensing system of phytochrome and the blue light-sensing system of phototropin. Furthermore, red- and blue-light signals perceived by PHY3 are processed synergistically within this single chromoprotein. These unusual properties might confer an enhanced light sensitivity on PHY3, allowing ferns to grow under a low-light canopy. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00278424
- Volume :
- 103
- Issue :
- 47
- Database :
- Academic Search Index
- Journal :
- Proceedings of the National Academy of Sciences of the United States of America
- Publication Type :
- Academic Journal
- Accession number :
- 23406714
- Full Text :
- https://doi.org/10.1073/pnas.0603569103