another ifp protein

We wrote about Katushka in 2007. Now, a Katushka variant named Katushka-9-5 was identified to have less citotoxicity in bacteria, HeLa cells and X. laevis embryos. This variant was further optimized by semisaturated site-directed mutagenesis to obtain two fluorescent protein variants with further red-shifted emission (eqFP650 and eqFP670).

The picture depicts some characteristics of current far-red fluorescent proteins. This far-red rodeo aims to find the optimal protein for deep-tissue imaging (see the zebrafish on the left). In the right image there are just bacterial streaks (although they utterly seem feasting fishes). EqFP650 and eqFP670 are property of Evrogen.

Source:  Nature Methods 7, 827 (2010). doi:10.1038/nmeth.1501