Excerpts

We created monomeric optimized variants of ECFP and EYFP, which fold faster and more efficiently at 37°C and have superior solubility and brightness. Bacteria expressing SCFP3A were 9-fold brighter than those expressing ECFP and 1.2-fold brighter than bacteria expressing Cerulean. In HeLa cells, the improvements were less pronounced; nonetheless, cells expressing SCFP3A and SYFP2 were both 1.5-fold brighter than cells expressing ECFP and EYFP(Q69K), respectively.

Changing leucine68 back to valine decreased the relative bleaching time of SYFP2 by 30%. Thus, mutation V68L contributes to the photostability of YFP.