|Protein (state)||t1/2 (s)||Power||Light||Mode||In Cell||Fusion||˚C|
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.