reaches an equilibrium state with a major absorbance peak at 338 nm, indicating that the chromophore is neutral, but missing at least one double bond relative to a mature GFP-type chromophore. With exposure to UV light, AausFP4 fully converts to an anionic GFP-like state with 477-nm peak absorbance. This transformation is reversible by exposure to bright blue light or by storage in the dark, as in Dreiklang. Another interesting development is recently reported by Sugiura and Nagai . The authors engineered a novel bright fluorescent protein Sumire with the shortest wavelength (414 nm) of any fluorescent protein reported to date. Motivated by Dreiklang properties, the authors assigned the violet fluorescence to a hydrated GFP-like chromophore analogous to that in the OFF-state in Dreiklang.