CBST researchers are continuing to improve their understanding of the photochemistry of plant phytochromes, and are thus able to develop smaller, single-domain phytofluors. Such small fluorescent proteins are critical for allowing nondisruptive labeling of living cells.

Roger Tsien, a world expert and pioneer in the field of fluorescent proteins, acknowledged that these phytofluors are the only photoswitchable molecules to work in the far-arc regime, and will play an essential role in ultra-high resolution imaging of tissue in the future.

Phytochrome-based fluorescent probes (phytofluors) developed  previously all rely on manipulation of the 3-domain PAS-GAF-PHY photosensory core (above)

Mutagenesis of the lone GAF domain of tlr0924 allows smaller probes with the same fluorescence quantum yield (above)