Tools for sub-cellular physiology
The binding of a fluorogen to a fluorogen activating peptide can be used to activate fluorescence of multichromophore structures. Exploiting efficient intramolecular energy transfer from an environmentally sensitive donor, we are developing a family of ratiometric indicators that are targeted to a genetically encoded peptide and ‘activated by targeting’ to a fluorescent state. Different designs of these probes result in either dual-band excitation or dual-band emission, which can be used to build quantitative indicators. Sensors for a range of analytes are possible, but immediate targets include mitochondrial potential, peroxisomal stress, reactive oxygen species, and biological cations.