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Updated: Jul 5, 2026

FRET Microscopy for Real-time Monitoring of Signaling Events in Live Cells Using Unimolecular Biosensors
Published on: August 20, 2012
Improved photostable FRET-competent biarsenical-tetracysteine probes based on fluorinated fluoresceins
Carla C Spagnuolo1, Rudolf J Vermeij, Elizabeth A Jares-Erijman
1Departamento de Química Organica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, CIHIDECAR, CONICET, Ciudad Universitaria-Pabellón II, 1428, Buenos Aires, Argentina.
Abstract:
We have developed fluoro-substituted versions of the biarsenical-tetracysteine label FlAsH, exhibiting significant improvements in important properties over the original fluorescein derivative. In complexes with tetracysteine targets, F2FlAsH exhibits 50 times improved photostability, lower pH sensitivity, higher absorbance and quantum yield than FlAsH, and F4FlAsH adds a new color to the palette of biarsenical dyes. The two probes also provide a new FRET pair with a larger Ro value (54 A) than any previously obtained with biarsenical dyes.

