Optimized Streptavidin for Fluorescent Labeling of Biotinylated Targets.

In order to develop a streptavidin-biotin system with optimal performance in fluorescent labeling, in this issue of Cell Chemical Biology, Jacobsen et al. (2017) focused on changing the surface density of amino groups present on streptavidin via lysine mutagenesis. The streptavidin mutant containing only one free amino group was found superior to other streptavidin variants and was named Flavidin for fluorophore-friendly streptavidin.