Flavins Photochemistry and Photobiology
Chapter 9: Flavin-Based Photoreceptors in Plants
Published:15 Sep 2006
Special Collection: 1968-2006 ebook collection
The past decade has seen enormous progress in the identification and characterization of plant blue-light receptor molecules. Three blue-light receptor families are currently recognized: the cryptochromes, the phototropins, and members of the ZTL (for the German Zeitlupe for “slow motion”) or ADO (Adagio also for “slow motion”) family. In the ZTL/ADO family, only one member has been demonstrated to function as a photoreceptor to date. All three families relay on flavins as their chromophores, although the cryptochromes may additionally use either a deazaflavin or a pterin as an antenna chromophore. This article presents the events leading up to the discovery of each photoreceptor family, some of the known roles for the photoreceptors, and where possible reviews their biochemical and photochemical properties. The LOV domain, the photoreceptor module in the phototropins and the ZTK/ADO family, is given special attention as a result of the extensive recent biophysical investigations elucidating its property. The chapter concludes with a review of LOV-domain-containing proteins in bacteria and fungi, and cryptochrome homologs in prokaryotes. The coming years should see a great expansion of our knowledge of the plant photoreceptors and the signal transduction pathways that are active, but should also elucidate what the photoreceptor homologs and chromophore modules are doing in bacteria and fungi.