User:Ntague/sandbox

In addition to phytochromes, which are found in plants and cyanobacteria, LOV domains(Light-oxygen-voltage-sensing domain) from plants and yeast and cryptochrome domains from plants are other natural photosensory domains that have been used for optical control of biochemical pathways in cells. In addition, a synthetic photosensory domain has been engineered from the fluorescent protein Dronpa for optical control of biochemical pathways. In photosensory domains, light absorption is either coupled to a change in protein-protein interactions (in the case of phytochromes, some LOV domains, cryptochromes, and Dronpa mutants) or a conformational change that exposes a linked protein segment or alters the activity of a linked protein domain (in the case of phytochromes and some LOV domains). Light-regulated protein-protein interactions can then be used to recruit proteins to DNA, for example to induce gene transcription or DNA modifications, or to the plasma membrane, for example to activate resident signaling proteins. CRY2 also clusters when active, so has been fused with signaling domains and subsequently photoactivated to allow for clustering-based activation. The LOV2 domain of Avena sativa(common oat) has been used to expose short peptides or an active protein domain in a light-dependent manner , and has been used to inactivate proteins through a light controlled domain splitting strategy. Photodissociable Dronpa domains have been used to cage a protein active site in the dark, uncage it after cyan light illumination, and recage it after violet light illumination.