Figure 2. Working model for the recombination in FRET biosensors.
(A) The recombination of FRET biosensors with h25-e75YPet generates CFP, which includes the critical amino acid substitution of Y66W from GFP. (B) The recombination of FRET biosensors with e75-h25YPet generates GFP or YFP, which includes the critical amino acid substitution of T203Y from GFP.