PT  - JOURNAL ARTICLE
AU  - Thi Yen Hang Bui
AU  - Elke De Zitter
AU  - Benjamien Moeyaert
AU  - Ludovic Pecqueur
AU  - Bindu Y Srinivasu
AU  - Anastassios Economou
AU  - Marc Fontecave
AU  - Luc Van Meervelt
AU  - Peter Dedecker
AU  - Brandán Pedre
TI  - Oxygen-induced chromophore degradation in the photoswitchable red fluorescent protein rsCherry
AID  - 10.1101/2023.01.13.523900
DP  - 2023 Jan 01
TA  - bioRxiv
PG  - 2023.01.13.523900
4099  - http://biorxiv.org/content/early/2023/01/13/2023.01.13.523900.short
4100  - http://biorxiv.org/content/early/2023/01/13/2023.01.13.523900.full
AB  - 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.Competing Interest StatementThe authors have declared no competing interest.