Oxygen-induced chromophore degradation in the photoswitchable red fluorescent protein rsCherry.
Bui, T.Y.H., De Zitter, E., Moeyaert, B., Pecqueur, L., Srinivasu, B.Y., Economou, A., Fontecave, M., Van Meervelt, L., Dedecker, P., Pedre, B.(2023) Int J Biol Macromol 239: 124179-124179
- PubMed: 36972828 
- DOI: https://doi.org/10.1016/j.ijbiomac.2023.124179
- Primary Citation of Related Structures:  
8B65, 8B7G - PubMed Abstract: 
Reversibly switchable monomeric Cherry (rsCherry) is a photoswitchable variant of the red fluorescent protein mCherry. We report that this protein gradually and irreversibly loses its red fluorescence in the dark over a period of months at 4 °C and a few days at 37 °C. We also find that its ancestor, mCherry, undergoes a similar fluorescence loss but at a slower rate. X-ray crystallography and mass spectrometry reveal that this is caused by the cleavage of the p-hydroxyphenyl ring from the chromophore and the formation of two novel types of cyclic structures at the remaining chromophore moiety. Overall, our work sheds light on a new process occurring within fluorescent proteins, further adding to the chemical diversity and versatility of these molecules.
Organizational Affiliation: 
Biochemistry, Molecular and Structural Biology Unit, Department of Chemistry, KU Leuven, Belgium.