Primary Proteins:
  1. R3-2+PCB
  2. smURFP
  3. TDsmURFP
  4. TeAPCα

Bleach Measurements

Protein (state) t1/2 (s) Power Light Mode In Cell Fusion ˚C
TDsmURFP 190.0 Arc-lamp Widefield
A caution on interpretation of photostability measurements
Add photostability measurements


We chose TeAPCα (15 kD) [as a precursor for smURFP] because it lacked 29 amino acids common to other APCαs. Expression of TeAPCα with heme oxygenase-1 (HO-1) and phycocyanobilin–ferredoxin oxidoreductase (PcyA) for PCB production showed no fluorescence.

In our approach, we first evolved TeAPCα mutants to autocatalytically attach PCB (without a lyase) and fluoresce. Second, since PCB is not present in mammals, we evolved derivatives that bind BV, a molecule ubiquitous in eukaryotes and produced at the rate of 300–500 mg per d in humans.