Photoconversion

Photoactivatable fluorescent proteins (PAFPs) exhibit fluorescence that can be modified by a light-induced chemical reaction. Many PAFPs have been engineered from existing fluorescent proteins or identified from large-scale screens in the wake of Kaede's discovery.

The classical PA-GFP converts from a non-radiant conformation to a GFP-like emitting fluorophore under UV excitation, while many of the other PAFPs undergo green-to-red photoconversions. Other colors are available. Some proteins take part in irreversible photoconversion reactions while other reactions can be reversed using light of a specific wavelength.